Technical aspects of modern coronary artery bypass surgery

Technical Aspects of Modern Coronary Artery Bypass Surgery Technical Aspects of Modern Coronary Artery Bypass Surgery Technical Aspects of Modern Coronary Artery Bypass Surgery Technical Aspects of Modern Coronary Artery Bypass Surgery Technical Aspects of Modern Coronary Artery Bypass Surgery Technical Aspects of Modern Coronary Artery Bypass Surgery Technical Aspects of Modern Coronary Artery Bypass Surgery Technical Aspects of Modern Coronary Artery Bypass Surgery Technical Aspects of Modern Coronary Artery Bypass Surgery Technical Aspects of Modern Coronary Artery Bypass Surgery Technical Aspects of Modern Coronary Artery Bypass Surgery Technical Aspects of Modern Coronary Artery Bypass Surgery Technical Aspects of Modern Coronary Artery Bypass Surgery Technical Aspects of Modern Coronary Artery Bypass Surgery Technical Aspects of Modern Coronary Artery Bypass Surgery Technical Aspects of Modern Coronary Artery Bypass Surgery Technical Aspects of Modern Coronary Artery Bypass Surgery

C H A P T E R

1

Closing the gap between best

evidence and common practice in surgical coronary revascularization: The rationale for superspecialization

John D Puskas 1 and David P Taggart 2 , 31

Department of Cardiovascular Surgery, Mount Sinai Morningside, New York, NY, United

3

Consultant Cardiac Surgeon, Oxford University Hospitals, Oxford, United Kingdom

Everybody is against specialization except the patient Francis D Moore (Surgeon Scientist)

1913 2001

In an effort to improve outcomes for patients with valvular heart disease, there has been aconcerted push over the past decade toward the creation of “Heart Valve Centers” or “HeartValve Reference Centers.” In 2017 the European Society of Cardiology and EuropeanAssociation for Cardiothoracic Surgery even jointly published a document outlining the stan-

organizations preeminent in the fields of Cardiac Surgery, Interventional Cardiology,

Proposal to Optimize Care for Patients with Valvular Heart Disease These same organizations

“provid-ing optimal care to patients with valvular heart disease is an increas“provid-ingly complex process,

and long-term follow-up.” They also note, “there are an increasing number of treatmentoptions available to patients with valvular heart disease; yet not all patients are aware of orhave access to the full spectrum of interventions.” The authors go on to propose an improvedsystem of care for patients at valvular heart disease centers, whose primary goal is to optimizeoutcomes for all patients They argue that the “case for centers with the ability to offer morecomprehensive care is logical.” The authors state their intent is “to set performance and

1

Technical Aspects of Modern Coronary Artery Bypass Surgery

© 2021 Elsevier Inc All rights reserved.

quality goals for a valve center to meet benchmarks to be considered either comprehensive orprimary in a manner that would be more objective than simple self-designation.”

There are few who would argue with such sentiments, motivation, and logic Of course,that then begs the question: why do the same statements not also apply equally well topatients with ischemic heart disease? Yet the stark reality is that no similar joint multina-tional or multidisciplinary proposal has ever been undertaken or even suggested forpatients with ischemic heart disease This is truly remarkable and counterintuitive, espe-cially considering that vastly more patients in the developed world undergo procedures totreat coronary artery disease than valvular heart disease

recom-mend to “perform [CABG] procedures in a hospital structure and by a team specialized incardiac surgery, using written protocols” (Class I, LOE B), they stop well short of recom-mending any special training, team, or focus on surgical coronary revascularization

clear that the majority of all adult cardiac surgical procedures performed in North America isisolated coronary artery bypass grafting (CABG) (55%), while CABG plus mitral valve (MV)

or aortic valve (AV) procedures comprise an additional 8% of all procedures; thus while lated MV or AV procedures cumulatively account for 16% of all procedures, CABG makes up63% of all procedures recorded in the contemporary STS database

iso-Not only does CABG make up the large majority of all procedures performed by adultcardiac surgeons but also it continues to be performed by much the same techniques thatwere developed 40 years ago Full sternotomy with aortic cannulation and clamping for car-dioplegic arrest and bypass with a single internal thoracic artery graft to the left anterior des-cending coronary artery plus reversed saphenous vein grafts (SVGs) to all non-left anteriordescending (LAD) coronary targets, remaining the most commonly performed procedure incardiothoracic surgery While this is an excellent and well-proven option for many patients,

it does not mean that it is the best option for all patients It ignores the fact that aortic ulation is the single most important contributor to perioperative stroke and that SVGs have.50% rate of failure at 10 years

manip-For more than three decades it has been repeatedly demonstrated that arterial graftshave much superior angiographic patency rates when compared to vein grafts over thelong term Numerous authors have reported superior survival, major adverse cardiovascu-lar events-free survival, and intervention-free survival with multiple arterial conduits com-pared to a single internal thoracic artery (ITA)-LAD graft plus SVGs, since the seminal

This has been shown to be true even in diabetic patients, in whom the provision ofbilateral internal thoracic arteries (BITA) grafting rather than single internal thoracic artery(SITA) grafting confers a greater survival benefit than SITA grafting in nondiabetic

An insightful analysis of intraoperative conversion from planned BITA to SITA grafting inthe arterial revascularization trial (ART) suggests that even self-selected surgeons have highlyvariable expertise in deploying BITA conduits, despite having performed a large number of

2 1 Closing the gap between best evidence and common practice

CABG procedures in their careers In this report the overall rate of unintentional conversionfrom BITA to SITA was 14% and ranged from 0% to 100% among individual surgeons and

more than one arterial conduit enjoyed significantly better 10 years survival and a significantlylower incidence of death/myocardial infarction/stroke than those who received a single arte-rial conduit[9]

Gaudino and colleagues reported a metaanalysis of pooled patient-level data from sixprevious prospective randomized trials comparing outcomes after CABG with LITA-LADplus SVGs (single arterial conduit) versus LITA-LAD plus at least one radial artery graft(multiple arterial conduits) This dataset confirmed that death/myocardial infarction/repeat revascularization was less frequent when a radial artery graft was included (typi-cally grafted to the second most important coronary target), driven by a significant reduc-

has yielded similar findings with the continued divergence of these curves in favor of

and improved clinical outcomes with radial artery grafting, less than 7% of isolated CABG

The combination of BITA grafting and radial artery grafting allows total arterial cularization (TAR), which has been shown to confer a long-term benefit in terms of symp-

multivessel CABG procedures worldwide

The evidence that minimizing aortic manipulation can significantly reduce the incidence

of stroke has been well documented over decades of practice Most recently, Zhao and leagues reported a network metaanalysis of 13 studies, including 37,720 patients, comparingoutcomes with four alternative CABG techniques, namely, traditional on-pump CABG, off-pump CABG (OPCAB) with a partial aortic clamp for proximal anastomoses, OPCAB with

col-a clcol-ampless fcol-acilitcol-ating device for proximcol-al col-ancol-astomoses, col-and OPCAB with col-a no-col-aortic-touch(an-aortic) technique in which all graft inflow was from in situ BITA conduits Theyreported that an-aortic OPCAB was associated with a hazard ratio of 0.22 for stroke, 0.50 formortality, 0.73 for myocardial infarction, compared to traditional CABG Indeed, the relativerisk of virtually every adverse event correlated with the extent of aortic manipulation in the

So, why does the gap between best evidence and clinical practice in CABG not only sist but also that may even be widening? Why is this tolerated by cardiac surgeons andcardiologists? The answers to these questions are necessarily subjective and cannot be con-firmed There are, however, a number of plausible reasons

per-3

1 Closing the gap between best evidence and common practice

Technical Aspects of Modern Coronary Artery Bypass Surgery

First, literally all of the quality metrics for which surgeons and hospitals are heldaccountable are based on 30-day outcomes; it is obvious that the conventional SITA-plus-SVGs CABG approach can yield very good 30-day results in many/most patients whilethe benefit of the more technically challenging multiple arterial conduits will not becomeapparent until much later follow-up.

Second, most training programs continue to teach the conventional SITA-plus-SVGsCABG operation to virtually all trainees in a manner that has not changed meaningfullyfor more than three decades Hands-on training in even relatively simple techniques such

as skeletonized harvest of BITA conduits is uncommon, yet facility with skeletonizedBITA harvest is, arguably, the most important stepping-stone to virtually all advanced sur-gical coronary revascularization Radial artery conduits can be harvested very safely,quickly, and reliably by endoscopic techniques, but these skills are possessed by few surgi-cal assistants and even fewer surgeons Training in skeletonized BITA harvest and endo-scopic harvest of radial arteries remains a challenge that has not been emphasized by ourprofessional bodies and, possibly as a consequence, being imperfectly met by industry

FIGURE 1.1 A network metaanalysis demonstrating progressively improved clinical results with coronary bypass techniques that entail progressively less aortic manipulation [13] (A) Stroke, (B) mortality, (C) myocardial infarction, (D) renal failure, (E) bleeding, and (F) atrial fibrillation.

4 1 Closing the gap between best evidence and common practice

Similarly, the adoption of OPCAB has stalled and even receded, despite the numerouspotential benefits of the procedure, in part because comprehensive training in the technicalnuances that make the OPCAB approach reliable and reproducible has never been madewidely available or supported Industry support for improvement in instruments to facili-tate OPCAB has also stalled Poorly trained and equipped surgeons have sometimes per-

The STS database reveals that there are approximately 1150 cardiac surgery programs

in the United States, employing 2676 cardiac surgeons and performing 160,000 CABGoperations per year This amounts, on average, to 139 CABG cases per center per year andapproximately one CABG case per surgeon per week It is well known that there exists avolume quality relationship for complex procedures of many types and across manyindustries, especially those dependent on skilled teamwork Indeed, in other surgical fieldssuch as orthopedics and neurosurgery superspecialization in a limited repertoire of proce-dures is the norm Similarly, our own field has endorsed the need for specialists in AVand MV disease, major aortic disease, and the surgical management of heart failure; trai-nees expect to enter these superspecialties after completing an additional year(s) of struc-tured training Acknowledging the obvious fact that the margin for tolerable error insuture placement for a valvular or aortic procedure is on the order of 1 5 mm and for acoronary anastomosis is on the order of 0.1 0.5 mm brings the greater technical difficulty

of coronary surgery into sharp focus Oddly, however, it is the less technically demanding,less common procedures in our specialty that have received the greater focus on superspe-cialization, while surgical coronary revascularization is widely considered a “commodity”suitable for every cardiac surgeon to perform with no additional training Indeed it is oftendismissed as “just another CABG.”

It is, therefore, also possible that a major impediment to consistent excellence in CABG

is that there are simply too many surgeons each performing too few CABG procedures It

is intuitive and plausible that concentrating the experience of a larger number of CABGcases in the hands of fewer cardiac surgeons and surgical teams would promote theadvancement of the field This could be the natural consequence of designating surgicalcoronary revascularization a superspecialty within cardiothoracic surgery However, itmay not be necessary to redistribute CABG cases in order to promote innovation andimprove quality in CABG surgery Simply adding the provision of multiple arterial graftsand avoidance of aortic manipulation to our quality metrics and providing additionalremittance for intraoperative graft assessment would certainly change surgeon behaviorand improve surgical coronary revascularization Of course, formal endorsement by ourprofessional bodies of a clinical training pathway to superspecialization in CABG, analo-gous to the additional training typically expected of surgeons intending to specialize inaortic surgery or transplantation/management of heart failure, would be the most effectiveway to systematically improve the quality of training in surgical coronary revasculariza-tion and thus the quality of CABG surgery provided to patients While not every cardiacsurgeon who performs CABG would need to complete such an additional year(s) of train-ing, every major department should have at least one surgeon who has a committed focus

on the surgical management of coronary artery disease This must include a commitment

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1 Closing the gap between best evidence and common practice

Technical Aspects of Modern Coronary Artery Bypass Surgery

to a comprehensive Heart Team approach, with shared decision-making, adherence toguidelines and appropriateness criteria, public reporting of outcomes, participation in

Focused educational efforts dedicated to the state of the art in surgical coronary larization are sorely needed and should be strongly supported by all professional bodies incardiothoracic surgery and especially cardiology The International Coronary Congress(www.internationalcoronarycongress.com) is the only international symposium dedicatedannually to identifying the best practices in CABG and promulgating them worldwide.Regrettably, textbooks in the field of cardiac surgery have typically included a single chapterfor CABG, while devoting a similar amount of space to each of numerous niche procedures.The first major comprehensive textbook on state-of-the-art surgical coronary revasculariza-tion will be published this year by Oxford University Press, and the present textbook of sur-gical techniques in CABG published by Elsevier is another important step forward

revascu-References

[1] Chambers JB, Prendergast B, Lung B, Rosenhek R, Zamorano JL, Pierard LA, et al Standards defining a

“Heart Valve Centre”: ESC working group on valvular heart disease and European Association of Cardiothoracic Surgery Viewpoint Eur J Cardio-Thoracic Surg 2017;52:418 24.

[2] Nishimura RA, O’Gara PT, Bavaria JE, Brindis RG, Carroll JD, Kavinsky CJ, et al AATS/ACC/ASE/SCAI/ STS expert consensus systems of care document: a proposal to optimize care for patients with valvular heart disease: a joint report of the American Association for Thoracic Surgery, American College of Cardiology, American Society of Echocardiography, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons Catheter Cardiovasc Interv 2018;2019 Available from: https://doi.org/ 10.1002/ccd.28196

[3] Eur Heart J 2014;35:2541 619 https://doi.org/10.1093/eurheartj/ehu278

[4] D’Agostino RS, Jacobs JP, Badhwar V, Fernandez FG, Paone G, Wormuth DW, et al The society of thoracic surgeons adult cardiac surgery database: 2019 update on outcomes and quality Ann Thorac Surg 2019;107:24 32.

[5] Lytle BW, Blackstone EH, Loop FD, Houghtaling PL, Arnold JH, Akhrass R, et al Two internal thoracic artery grafts are better than one J Thorac Cardiovasc Surg 1999;117(5).

[6] Puskas, et al Bilateral internal thoracic artery grafting is associated with significantly improved long-term outcomes even among diabetic patients Ann Thorac Surg 2012;94:710 16.

[7] Gaudino M, Chikwe J, Falk V, Lawton JS, Puskas JD, Taggart DP Transatlanticeditorial: the use of multiple arterial grafts for coronary revascularization inEurope and North America Eur J Cardiothorac Surg 2020;57 (6):1032 1037 Available from: https://doi.org/10.1093/ejcts/ezaa077

[8] Benedetto U, Altman DG, Flather M, Gerry S, Gray A, Lees B, et al Incidence and clinical implications of intraoperative bilateral internal thoracic artery graft conversion: insights from the arterial revascularization trial J Thorac Cardiovasc Surg 2018;155.

[9] Taggart DP, Benedetto U, Gerry S, et al Bilateral versus single internal-thoracic-artery grafts at 10 years.

N Engl J Med 2019;380:437 46.

[10] Gaudino M, Benedetto U, Fremes S, Biondi-Zoccai G, Stat M, Sedrakyan A, et al Radial artery of saphenous vein grafts in coronary artery bypass surgery NEJM 2018;1 9 Available from: https://doi.org/10.1056/ NEJMoal716026

[11] Gaudino M, Benedetto U, Fremes S, et al Association of Radial Artery Graft vs Saphenous Vein Graft With Long-term Cardiovascular Outcomes Among Patients Undergoing Coronary Artery Bypass Grafting: A Systematic Review and Meta-analysis JAMA 2020;324(2):179 187.

[12] Tatoulis J, Wynne R, Skillington PD, Buxton BF Total arterial revascularization: achievable and cally effective—a multicenter analysis Ann Thorac Surg 2015;100:1268 75.

prognosti-6 1 Closing the gap between best evidence and common practice

[13] Zhao DF, Edelman J, Seco M, Bannon PG, Wilson MK, Byrom MJ, et al Coronary artery bypass grafting with and without manipulation of the ascending aorta A network meta-analysis J Am Coll Cardiol 2017;69(8) [14] Taggart DP, Thuijs DJFM, Di Giammarco G, Puskas JD, Wendt D, Trachiotis GD, et al Intraoperative transit- time flow measurement and high-frequency ultrasound assessment in coronary artery bypass grafting.

J Thorac Cardiovasc Surg 2020;159:1283 92.

[15] Shroyer AL, Grover FL, Hattler B, Collins JF, McDonald GO, Kozora E, et al On-pump versus off-pump onary artery bypass surgery N Engl J Med 2009;361:1827 37.

cor-[16] Puskas JD, Williams WH, Mahoney EM, Huber PR, Block PC, Duke PG, et al Off-pump vs conventional onary artery bypass grafting: early and 1-year graft patency, cost and quality-of-life outcomes JAMA 2004;291:1841 9.

cor-[17] Puskas JD, Williams WH, O’Donnell R, Patterson RE, Sigman SR, Smith AS, et al Off-pump and on-pump coronary artery bypass grafting are associated with similar graft patency, myocardial ischemia and freedom from reintervention: long-term follow-up of a randomized trial Ann Thorac Surg 2011;91:1836 43.

[18] Diegeler A, Borgermann J, Kappert U, Hilker M, Doenst T, Boning A, et al Five-year outcome after off-pump

or on-pump coronary artery bypass grafting in elderly patients Circulation 2019;139:1865 71.

[19] Lamy A, Devereaux PJ, Prabhakaran D, Taggart DP, Hu S, Straka Z, et al Five-year outcomes after off-pump

or on-pump coronary artery bypass grafting N Engl J Med 2016;375:2359 68.

[20] Mack M, Taggart D Coronary revascularization should be a subspecialty focus in cardiac surgery J Thorac Cardiovasc Surg 2019;157:945 7.

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1 Closing the gap between best evidence and common practice

Technical Aspects of Modern Coronary Artery Bypass Surgery

C H A P T E R

2

Surgical strategy in multiple

arterial grafting Mario Gaudino

Department of Cardiothoracic Surgery, Weill Cornell Medicine, New York, NY, United States

Failing to plan is planning to fail Benjamin Franklin.

The importance of the strategy and good clinical sense

While the cutting-and-sewing part of coronary surgery is important, the real key to asuccessful outcome is the surgical strategy

It is important to keep in mind that:

1 Percutaneous coronary interventions have very high periprocedural safety, and theresults become inferior to surgery only in the midterm and only if the operative risk forsurgery is very low

2 The traditional coronary artery bypass grafting (CABG) operation [internal thoracicartery (ITA) and veins] is extremely safe and highly reproducible The available data donot clearly prove a survival advantage with the use of multiple arterial grafts (MAG)and suggest that the difference in favor of the MAG strategy, if existent, is moderateand becomes evident only in the mid- to long-term follow-up

Due to these considerations, it is my belief that MAG should be used only if the

In fact, I do not believe that the available evidence justifies any increase in operative tality and risk of major complications with adding one or more arterial grafts to the ITA.The risk/benefit ratio of the use of MAG is dependent not only on patients’ characteris-tics but also, and critically, on the experience of the operating surgeon and of the operatingteam[1,2]

mor-It is key that the surgeon knows all the available technical solutions, but also that he orshe has a realistic idea of his/her own skills and the experience of the team to be able toindividualize the operation to the patient, the surgeon, and the setting

In general, my advice is to err on the side of safety and privilege clinical outcomesover the surgeon’s ego and technique An alive patient with ITA and veins is a verygood result, but a catastrophe after a complex all-arterial bypass operation is not.

grafts are easier than Y or T grafts, and sequentials have better hemodynamics but requiremore attention and time All this is even more evident when operating on the beatingheart Those simple concepts have been the foundation of my grafting strategy in the lasttwo decades

Indications for the use of arterial grafts

As explained earlier, while the use of MAG should be considered in every patient, therisk/benefit ratio must be carefully evaluated in light of the available evidence and of theoperating surgeon’s experience

It is important to remind that while we have data to suggest improvement in clinicaloutcomes with the addition of a second arterial graft, there is very little evidence to sup-port a further benefit for three or more arterial grafts or total arterial revascularization, astreatment allocation bias is the likely explanation for the difference seen in the observa-tional series[4]

I am typically reluctant to use MAG for combined cases and in emergency orunstable situations except in very young patients with excellent cardiac function If theteam is experienced, harvesting of the radial artery does not take longer than harvesting of

a saphenous vein and can be considered, although the possible prolonged need for pressor may raise concerns of graft spasm I never use the right ITA in unstable cases

vaso-A classical debate among coronary surgeons is the stenosis cutoff acceptable for arterialgrafts The evidence on the detrimental effect of chronic coronary competitive flow on

tol-erant than the ITA, and the left anterior descending (LAD) territory is much more ing than the others (especially the right coronary artery territory)

forgiv-The impact of preoperative fractional flow reserve (FFR) on arterial bypass graft motic function (IMPAG) trial has shown that an FFR cutoff of 0.78 is associated with 97%

However, most of the patients referred for surgery do not have FFR data, especially forthe circumflex and right coronary distribution

The degree of stenosis is of very limited utility because the same percentage of stenosismay have very different consequences in terms of residual flow based on the diameter ofthe vessel

If FFR data are not available, I base my decisions on the ratio between the diameter

of the conduit and the diameter of the residual lumen of the target vessel and generallyaccept a ratio of 1.2 or above Another important consideration is the graft configura-tion, as aorta-anastomosed grafts are less affected by competitive flow than in situ and

Y grafts

10 2 Surgical strategy in multiple arterial grafting

Technical Aspects of Modern Coronary Artery Bypass Surgery

A classic face-off: right internal thoracic artery or radial artery?

As the left ITA is the cornerstone of CABG, the instinctive second arterial graft formany surgeons is the right ITA

While the right ITA is a superb conduit (and my first choice for young patients), somepoints need to be made:

1 The level and amount of the evidence supporting improved patency rate, and clinicaloutcomes compared to the saphenous vein are by far higher for the radial artery thanfor the right ITA (the latter is in fact a class I indication in myocardial revascularization

2 The radial artery is much easier to manipulate and to sew Surgeon’s experience andconfidence with arterial grafts are much more important for the outcome of the right

3 Because of its superior length and diameter, the radial artery allows much more

freedom in terms of graft configuration and number of anastomoses

The two considerations to be made when selecting which second arterial graft to use are thesurgeon’s experience and the complexity of the grafting strategy For surgeons with limitedexperience and for complex graft configurations (multiple sequentials, distal targets, etc.), the

considerable experience in MAG, the right ITA is a good alternative

There are clinical or anatomic situations that clearly indicate the use of one of the twoconduits: the right ITA is better in case of moderate stenosis of the target vessel and theradial artery is better in patients at high risk of sternal wound complications

Aorta-based or internal thoracic artery based grafts?

The ITA is a third-order artery and has a dp/dt lower than the coronary arteries,while aorta-based grafts have hemodynamics more similar to the coronary arteries

Angiographic randomized trials comparing the saphenous vein

versus the radial or right internal thoracic artery

evi-dence: the radial artery versus the saphenous vein and right internal thoracic artery versus saphenous vein.

11

Aorta-based or internal thoracic artery based grafts?

This is the physiologic rationale of the higher vulnerability to competitive flow of

Those considerations must guide the choice of the site for the proximal anastomosis

A widely diffused urban legend in coronary surgery is that the anastomosis of the ITA

to the aorta is technically challenging and leads to suboptimal patency rate

I have used the ITA-to-aorta anastomosis regularly over the course of the last two ades (a free right ITA to the LAD is my default operation in patients with a left upperextremity A/V fistula), and in my view, it can be very safely and efficiently performed

The Radial Artery Patency and Clinical Outcomes trial has shown excellent patency rate

of the free ITA at 10 years The observational studies reporting poor results of the free ITAare biased from the use of the ITA on the aorta in case of damage to the conduit duringharvesting or insufficient length

Sequentials? On- or off-pump?

There is no doubt that sequential grafts have superior hemodynamics, and it is likely(although unproven) that the higher flow may translate to increased patency rate On theother hand, sequentials require more time and attention and are not for beginners

The surgeon at the beginning of his/her learning curve with sequentials should startwith the saphenous vein and the radial artery ITA sequentials are more difficult—and thelateral wall is more challenging

For experienced surgeons, sequentials are an excellent strategy and, once the technical tor is neutralized, are probably associated with improved clinical and angiographic outcomes

fac-Graing Complexity

Surgeon’s Experience

RITA

RITA RA

–

+

+ –

FIGURE 2.2 Scheme for the choice of the ond arterial graft.

sec-12 2 Surgical strategy in multiple arterial grafting

Technical Aspects of Modern Coronary Artery Bypass Surgery

The debate regarding on- versus off-pump coronary surgery has occupied the cardiac

outside the aim of this technical book, no randomized trial has shown convincing clinicalbenefits in the average patient using the off-pump technique While it is conceivable thatthere may be subsets of patients at high risk who may benefit from the avoidance of thecardiopulmonary bypass—this has not been proven yet

On the other hand, the technical complexity of the anastomosis is enhanced on the ing heart, and the importance of the surgeons’ experience is further increased off-pump.Again, good clinical judgment and a realistic sense of the surgeon’s own limitations arekey factors in the decision to perform the operation on- or off-pump

beat-3.6 mm

Ascending aorta

[1] Schwann TA, Habib RH, Wallace A, Shahian DM, O’Brien S, Jacobs JP, et al Operative outcomes of multiple-arterial versus single-arterial coronary bypass grafting Ann Thorac Surg 2018;105(4):1109 19 [2] Gaudino M, Bakaeen F, Benedetto U, Rahouma M, Di Franco A, Tam DY, et al Use rate and outcome in bilateral internal thoracic artery grafting: insights from a systematic review and meta-analysis J Am Heart Assoc 2018;7(11)[Internet] Available from: https://www.ahajournals.org/doi/10.1161/JAHA.118.009361 [3] Schwann TA, Habib RH, Wallace A, Shahian D, Gaudino M, Kurlansky P, et al Bilateral internal thoracic artery versus radial artery multi-arterial bypass grafting: a report from the STS database Eur J Cardio- Thorac Surg 2019;56(5):926 34.

[4] Gaudino M, Di Franco A, Rahouma M, Tam DY, Iannaccone M, Deb S, et al Unmeasured confounders in observational studies comparing bilateral versus single internal thoracic artery for coronary artery bypass grafting: a meta-analysis J Am Heart Assoc 2018;7(1).

[5] Spadaccio C, Glineur D, Barbato E, Di Franco A, Oldroyd KG, Biondi-Zoccai G, et al Fractional flow based coronary artery bypass surgery: current evidence and future directions JACC Cardiovasc Interv 2020;13.

reserve-[6] Glineur D, Grau JB, Etienne P-Y, Benedetto U, Fortier JH, Papadatos S, et al Impact of preoperative fractional flow reserve on arterial bypass graft anastomotic function: the IMPAG trial Eur Heart J 2019;40(29):2421 8 [7] Glineur D, Rahouma M, Grau JB, Etienne P-Y, Fortier JH, Papadatos S, et al FFR cutoff by arterial graft con- figuration and location: IMPAG trial insights JACC Cardiovasc Interv 2020;13(1):143 4.

[8] Neumann F-J, Sousa-Uva M, Ahlsson A, Alfonso F, Banning AP, Benedetto U, et al ESC/EACTS guidelines

on myocardial revascularization Eur Heart J 2019;40(2):87 165.

[9] Gaudino M, Alessandrini F, Pragliola C, Cellini C, Glieca F, Luciani N, et al Effect of target artery location and severity of stenosis on mid-term patency of aorta-anastomosed vs internal thoracic artery-anastomosed radial artery grafts Eur J Cardio-Thorac Surg 2004;25(3):424 8.

[10] Gaudino M, Angelini GD, Antoniades C, Bakaeen F, Benedetto U, Calafiore AM, et al Off-pump coronary artery bypass grafting: 30 years of debate J Am Heart Assoc 2018;7(16):e009934.

14 2 Surgical strategy in multiple arterial grafting

Technical Aspects of Modern Coronary Artery Bypass Surgery

is easily harvested either endoscopically or via a traditional open approach Importantly, RAharvesting can be done concurrently with harvesting of the other conduits including internalthoracic arteries or saphenous veins and thus its use does not extend the duration of surgery.

It can reach, with few exceptions, all coronary targets It is easily anastomosed to the aortausing standard instruments In contradistinction to the use of bilateral thoracic arteries as cor-onary grafts to facilitate multiarterial coronary reconstruction, its use is not associated withany increased risk of sternal wound complications Given its size, there is minimal size dis-crepancy between the RA and coronary targets, an element thought important in graft dura-bility The RA is easy to handle and requires no additional technical training for the cardiacsurgeon who has mastered grafting the coronary circulation using internal thoracic arterygrafts Surgeons, with interest and expertise in the use of RA, utilize this graft routinely inapproximately 60% 75% of all coronary artery bypass grafting patients with excellent results

collat-eral circulation of the hand via the ulnar artery, appropriate arterial line management, andthe need for an additional team member skilled in harvesting of the RA To insure the

and endoscopic harvesting expertise and experience is needed Given the cosmetic

Assessing ulnar collateral circulation

It is essential to assure adequate ulnar collateral circulation of the hand in any patientwho is thought to be a candidate for RA coronary artery grafting This can be

accomplished in a variety of ways although there is no one agreed upon standard Thesimplest and most frequently used technique, is the traditional Allen’s Test assessing foradequate hand reperfusion via the ulnar artery by visual inspection of the hand followingopening of the wrist after releasing of digital compression of the ulnar artery while main-taining continued compression of the RA This maneuver functionally eliminates RA per-fusion of the hand and allows for the assessment of hand perfusion based strictly on ulnarflow which will be the only blood supply to the hand following RA harvesting.Reappearance of perfusion of the palm within 5 seconds of releasing ulnar artery compres-sion indicates the presence of adequate collateral perfusion Reappearance of palmar per-fusion within 5 10 seconds is considered borderline collateral perfusion, while the lack ofreappearance of perfusion longer than 10 seconds after ulnar release is considered to beindicative of inadequate collateral perfusion False negative results may be obtained withinadequate RA compression False positives may be seen if the test is performed in a coolenvironment resulting in vasoconstriction of both the radial and ulnar arteries This assess-ment can easily be done at the patient’s bedside and does not require any additionalequipment It is reliable and inexpensive and it is a good initial screening test that maybe

is used by our group, relies on an oxymetric assessment of adequacy of ulnar collateralflow This is performed by using a portable pulse oximeter to determine adequate ulnarcollateral flow by reappearance of baseline oxygen saturation levels and plethysmographictracing following the release of digital pressure on the ulnar artery while the RA remainscompressed When the wave form and saturation numbers return almost instantaneously

to baseline after the release of the RA, harvesting of the conduit is safe We believe thatthis modality adds objectivity to the standard Allen’s Test In our practice, this preopera-tive assessment is further confirmed intraoperatively by monitoring the pulse oximetryreadings from the index finger once the patient has been heparinized; all the RA brancheshave been transected and the RA is clamped with an atraumatic clamp prior to its prox-imal and distal transection Using this approach, we have not experienced anyinstances of hand ischemia following harvesting of the RA Other modalities availablefor the assessment of adequate ulnar collateral flow that have been used in clinical

measurement Ultrasonography may provide additional useful information on the size

of the RA, possible calcifications, and anatomic variations although we have not foundthese to be clinically essential To date, there are no head-to-head comparative outcomestudies between these various techniques assessing ulnar collateral circulation, butregardless of which technique is utilized, the incidence of ischemic hand complicationfollowing harvesting of the RA is exceedingly rare

Anatomy of the forearmUnderstanding the anatomy of the forearm is essential for safe and efficient RA harvest-

16 3 Harvesting the radial artery

Technical Aspects of Modern Coronary Artery Bypass Surgery

branch is the recurrent RA This vessel should not be mistaken for the much larger ulnarartery and can be transected with impunity maximizing the length of the available con-duit The RA courses in the forearm between the brachioradialis and flexor carpi radialismuscles and lies beneath the fascia connecting these muscles Proximally, the RA coursesdeep to the bicipital aponeurosis with its origin from the brachial artery just distal to theinsertion of the biceps tendon onto the radius The collateral circulation between the RAand the ulnar artery is facilitated by the deep and superficial palmar arterial arches The

RA is not in proximity to any motor nerves and thus motor deficits have not been reported

consid-ered during RA harvesting, and these provide sensation to the forearm, the thumb, andthe dorsum of the hand The lateral antebrachial cutaneous nerve, a branch of the muscu-locutaneous branch of the lateral cord of the brachial plexus, lies in proximity, but notimmediately adjacent, to the RA in its proximal third It provides sensory innervation ofthe radial aspect of the forearm The superficial radial nerve which provides sensation tothe thenar eminence and the dorsum of the radial aspect of the hand including the indexand middle fingers, courses beneath the brachioradialis muscle, and is close to the RA inthe distal third of the forearm Given their anatomical proximity to the RA, these nervesare at most risk for injury in the harvesting process Sensory deficits following RA harvest-

successfully to mitigate this complaint if it becomes a source of concern for the patient

pre-served especially in its proximal extent at the elbow where the ulnar and radial arteriesare in relatively close proximity

A number of anatomic variations from the normal anatomy have been described

such anatomic variability must be kept in mind during the RA harvesting process

Radial artery harvesting technique Patient positioning

The patient is positioned in the supine position with the upper extremity from which the

RA is to be harvested extended at the patient’s side on an arm board Usually the nant arm is chosen to harvest the RA, but the final decision is based on the adequacy of ulnarcollateral flow as well as whether the patient had previous instrumentation of the RA duringcardiac catheterization RA recently used for cardiac catheterization should be avoided if pos-sible under most circumstances Care should be taken not to hyper extend the extremity past

nondomi-90 degrees with respect to the operative table to prevent brachial plexus traction injury Thearm is prepped and draped circumferentially Adequate padding to minimize neurologic

FIGURE 3.2 Sensory innervation of the arm and forearm Source: From Henry Gray, Anatomy of the Human Body, 20e, 1918, https://commons.wikimedia.org/wiki/File:Gray812and814.svg

18 3 Harvesting the radial artery

Technical Aspects of Modern Coronary Artery Bypass Surgery

complications in the form of nerve palsy is essential A sterile pulse oximetry probe is applied

to the index finger for continuous monitoring of the plethysmography and oxygen saturationlevels during the harvesting process and in preparation for an intraoperative Allen’s Test asthe final determinant of the adequacy of ulnar collateral circulation just prior to ligation andtransection of the RA A sterile towel is wrapped around the hand and a Steri-Drape is used

to secure the arm on the arm board with the wrist extended over a rolled towel at the wrist

Open harvesting technique

The RA is harvested through an incision extending approximately from 1 cm distal to the

pulse at the elbow and the RA pulse at the wrist are helpful in locating the proximal anddistal aspects of the harvest incision Hemostasis is achieved with low power (20 W) electro-cautery The dissection is carried through the subcutaneous tissues with subsequent opening

of the fascia between the brachioradialis and flexor carpi radialis muscles This exposes the

RA quite clearly as it courses in the areolar connective tissue below the fascia A Weitlanerretractor gently retracting the two muscles is helpful in exposing the RA The recurrentsuperficial RA is identified and maybe divided between fine clips or 4-0 silk ties to maxi-mize graft length Hemostasis is essential in the harvesting process and prevents misidentifi-cation of vessels and nerves The patient receives 5000 units of heparin intravenously prior

to harvesting any of the RA branches Proximally, the ulnar artery must be unambiguouslyidentified and preserved prior to RA transection Distally, the superficial palmar arch should

be preserved to optimize collateral flow to the hand via the ulnar artery Preservation of RAendothelial integrity is an important aspect of the harvesting process and impacts long-termdurability of the graft Thus minimal manipulation, and preferably relying on the “no touchtechnique” of the RA during its harvesting should be the guiding principle and requires anexperienced harvester Typically, the RA is harvested in a pedicled fashion with its veneacomitantes and a variable amount of surrounding connective tissue included in the har-vested pedicle We prefer to transect the RA branches between fine clips using scissors.Alternatively, similar to the harvesting technique of internal thoracic arteries, the RA side ofits tributaries can be clipped and the distal aspects controlled with electrocautery with excel-

on the RA and the signal from the pulse oximeter on the ipsilateral hand is checked for any

changes are noted, the RA is ligated proximally and distally with a heavy nonabsorbable tieand transected Its proximal end is cannulated with a fine olive tipped cannula and gentlyflushed with an appropriate vasodilator solution Gentle distension of the RA with the vaso-dilator solution allows for application of any additional clips to the RA branches to insuremeticulous hemostasis when the RA is placed into the coronary circulation The RA maybemarked with an indelible marker to minimize twisting of the graft when placed into the cor-onary system Following this preparation, the RA is stored in an appropriate warmed bath

Regardless of the specific technique, the integrity of the RA must be respected andmanipulation of the RA should only be accomplished via its pedicle At times, gentle

19

Radial artery harvesting technique

TABLE 3.1 Radial artery preservation/storage solutions in clinical use.

Option 1 Option 2 Option 3 Option 4

300 mL Ringer’s lactate, Verapamil

5 mg, Nitroglycerine 2.5 mg, Heparin

500 U, sodium bicarbonate 0.2 mEq

FIGURE 3.3 Open RA harvest technique (A) Exposure of RA via incision from wrist to just proximal to the elbow crease (B) Final assessment of adequacy of ulnar collateral circulation by occlusion of RA with all branches being transected prior to proximal RA ligation and harvesting RA, Radial artery.

20 3 Harvesting the radial artery

Technical Aspects of Modern Coronary Artery Bypass Surgery

traction using a fine elastic vessel loop maybe helpful in facilitating the dissection The use

of an harmonic scalpel has also been described in the open approach and greatly

the very largest branches This shortens the time required to harvest the graft Compared

to electrocautery, the harmonic scalpel generates less heat, thus eliminating potentiallydamaging thermal spread to the RA Less vasospasm has also been reported with the use

Covering the RA pedicle with a vasodilator mediating storage solution soaked gauzeduring its harvesting to prevent desiccation and prevent vasospasm maybe helpful.Importantly, the distal RA is smaller and more prone to spasm; thus, if possible, the moreproximal portion of the RA should be used for the majority of the coronary conduit.Following meticulous hemostasis in the forearm, the incision maybe closed prior to pro-ceeding with coronary grafting with approximation of only the subcutaneous tissue andskin The fascia is not closed in an effort to prevent the development of compartment syn-drome Alternatively, if hemostasis demands, the incision can be packed with lap padsand only closed following administration of protamine Drains are almost never required

A dry sterile dressing is applied to the incision and the forearm is wrapped with an elasticbandage to enhance hemostasis

The vast majority of groups use a pedicled RA graft, especially when harvesting via theopen technique The pedicle is, however, significantly less robust in the endoscopicapproach Paralleling the experience with skeletonization of the internal thoracic arteries,

harvesting the RA without its associated connective tissue pedicle or venea comitantes

sequential anastomosis, allow a closer inspection of the graft to exclude harvest traumaand also possibly avoid kinking or twisting of the RA, it is unclear what, if any practicaladvantages this approach may have There are no studies comparing the outcomes of skel-etonized versus pedicled RA grafts Using a harmonic scalpel to harvest the RA in a skele-tonized approach has been reported to be associated with more endothelial damage then

Following harvesting, the RA should be stored in an appropriate preservation solutionprior to implantation into the coronary circulation—most authors agree on the importance

of using a normothermic bath The ideal storage solution should minimize thrombusformation, preserve endothelial integrity, maximize the size of the RA, and prevent thedevelopment of vasospasm given the robust muscular elements found in the RA media.Various preservation solution formulations have been used to store the RA prior to

storage solutions constitutes the optimal preparation and no comparative outcomes ies have been published An additional, albeit rare, technique for maximal graft dilatation

circumstances, diminutive (with a diameter of less than 2 mm) RA should be avoided ascoronary grafts Intraarterial injection of vasodilators may increase the size of the vessel,but must be balanced against possible endothelial injury associated with high-pressureinjection and mechanical injury

21

Radial artery harvesting technique

Endoscopic harvesting technique

Given the recent growth in, and surgeon as well as patient acceptance of, endoscopicsaphenous vein harvesting, minimally invasive RA harvesting techniques have been devel-oped These techniques entail a fully endoscopic approach akin to saphenous vein harvestingrelying on carbon dioxide insufflation to facilitate creation of a working tunnel for the visuali-zation of the RA Earlier techniques of minimally invasive RA harvesting relied on a limitedincision proximally and distally with the creation of a mechanically (retractor) supported sub-cutaneous tunnel without the use of an endoscope or carbon dioxide insufflation The RA washarvested under direct vision A number of commercially available endoscopic harvesting

Vessel Harvesting System, Terumo VirtuoSaph Plus Endoscopic Vessel Harvesting System,and Saphena Medical Venapax Endoscopic Vessel Harvesting System)

The donor arm is prepped and positioned as in an open approach The arm is marked gitudinally at the intended incision site proximal to the wrist crease and similarly at the distalextent of the harvest tunnel, two fingers width distal from the elbow crease A 1.5 2.5 cm lon-gitudinal incision is made proximal to the wrist crease to allow for exposure and inspection of

overlying fascia has been incised to allow scope entry The RA is controlled circumferentiallyusing sharp dissection or electrocautery A 7 mm endoscope adapted with a clear plastic coni-cal tip is inserted into the subcutaneous tissues superficial to the RA A blunt tipped trocar con-taining a balloon that is inflated to create an adequate seal at the skin incision site to allowinsufflation of carbon dioxide to permit appropriate visualization and dissection of the RA is

10 12 mmHg with a flow rate of approximately 3 5 L/min is required to develop and tain a working tunnel The balloon may or may not be inflated depending on the visualizationwithin the tunnel and should be left to the discretion of the harvester, depending on theamount of space needed for the trochar Careful consideration is used as to not put too muchpressure on the RA The tunnel overlying the RA is constructed bluntly by advancing theendoscope proximately toward the elbow as the connective tissue is carefully dissected off of

tis-sue are made laterally, three to four on either side of the RA The veins adjacent to either side

of the RA are kept intact and dissected along with the RA pedicle Following completion of theentire tunnel from wrist to elbow, the endoscope is withdrawn, its conical tip is removed, andthe seal on the blunt tip trochar is changed to the wider seal The endoscope is then insertedinto a dissection cannula and reintroduced into the blunt tip trochar and into the previously

FIGURE 3.4 Exploratory incision for determination of RA location and quality in endoscopic RA harvesting.

RA, Radial artery.

22 3 Harvesting the radial artery

Technical Aspects of Modern Coronary Artery Bypass Surgery

defined tunnel The anterior fascia between the brachioradialis and the flexor carpi radialis is

working space The endoscopic dissection is carried forward toward the elbow centeredaround the veins surrounding the RA so as to minimize direct traction of and contact with the

RA Once the anterior dissection has been accomplished, a plane posterior to the RA is

counter incision is made at the proximal extent of the tunnel to facilitate a maneuver known as

a “stab and grab” whereby the RA is visualized at its intended proximal transection site where

it is controlled by a silk tie introduced via the counter incision under endoscopic visualization.Prior to ligation and transection of the RA, the pedicle is clamped with a bulldog clamp at theincision at the wrist and the pulse oximetry on the ipsilateral index finger is observed for anychanges in oxygen saturation or the associated plethysmographic wave form Once adequatecollateral flow is confirmed, the proximal and distal aspects of the RA are ligated The

FIGURE 3.6 Endoscopic control of RA arterial and venous side branches RA, Radial artery.

FIGURE 3.5 Construction of tunnel used in endoscopic RA harvesting, fasciotomy, endoscopic appearance of

RA RA, Radial artery.

23

Radial artery harvesting technique

proximal end of the RA is transected distal to the ligature and the RA is delivered into the

as in the open approach prior to implantation into the coronary circulation

Although the use of a tourniquet placed on the ipsilateral arm has been described andused extensively in the past as an additional element aimed at facilitating hemostasis, wehave not found this to be helpful or necessary When used, the tourniquet is applied ster-ilely to the arm proximal to the elbow Once the RA is visualized via the wrist incision,the tourniquet is inflated to about 75 mmHg higher than the blood pressure to optimizehemostasis and endoscopic visualization The tourniquet should not be applied for longerthan 60 minutes to minimize ischemic injury to the hand

Endoscopic versus open techniquesEndoscopic RA harvesting improves patient satisfaction and has been shown to be well

metaanalysis reported a decreased wound healing complication rate with endoscopic

the lateral antebrachial nerve and the superficial radial nerve, vary substantially based on the

with the endoscopic technique and 27% in the open approach in contradistinction, Bleiziffer

There are contradicting data on the effect of the endoscopic approach on the lium [18,20,21] While no differences between open and endoscopic harvesting in RA

underpowered for clinical outcomes

The decision to proceed with an open versus an endoscopic RA harvesting depends on theskill set, experience, and comfort level of the harvester and the operative team Althoughthe cosmetic considerations are important, the overarching goal of using the RA is to enhancelong-term patient survival which ultimately depends on the integrity of the RA endotheliumand thus the ultimate decision regarding the harvesting process must be made with this inmind Thus logic dictates that groups with relatively little experience with RA would bestserve their patients by beginning their RA journey with an open harvesting technique, and

as the learning curve is overcome, the endoscopic approach should become the default

FIGURE 3.7 Delivery of RA into the proximal incision following distal ligation and transection RA, Radial artery.

24 3 Harvesting the radial artery

Technical Aspects of Modern Coronary Artery Bypass Surgery

technique The importance of collective team experience and expertise with RA in optimizingpatient outcomes cannot be overstated in light of data finding an association between subopti-

References

[1] Carpentier A, Guermonprez JL, Deloche A, Frechette C, DuBost C The aorta-to-coronary radial artery bypass graft Ann Thorac Surg 1973;16:111 21 Available from: https://doi.org/10.1016/S0003-4975(10)65825-0 [2] Gaudino M, Benedetto U, Fremes S, Biondi-Zoccai G, Sedrakyan A, Puskas JD, et al Radial-artery or saphenous-vein grafts in coronary-artery bypass surgery N Engl J Med 2018;378:2069 77 Available from: https://doi.org/10.1056/NEJMoa1716026

[3] Schwann TA, Tranbaugh RF, Dimitrova KR, Engoren MC, Kabour A, Hoffman DM, et al Time-varying vival benefit of radial artery versus vein grafting: a multiinstitutional analysis Ann Thorac Surg 2014;97:1328 34 Available from: https://doi.org/10.1016/j.athoracsur.2013.09.096

sur-[4] Tatoulis J, Buxton BF, Fuller JA, Meswani M, Theodore S, Powar N, et al Long-term patency of 1108 radial arterial-coronary angiograms over 10 years Ann Thorac Surg 2009;88:23 30 Available from: https://doi org/10.1016/j.athoracsur.2009.03.086

[5] Dimitrova KR, Hoffman DM, Geller CM, DeCastro H, Dienstag B, Tranbaugh RF Endoscopic radial artery harvest produces equivalent and excellent midterm patency compared with open harvest Innovations 2010;5:265 9 Available from: https://doi.org/10.1097/imi.0b013e3181ee93f0

[6] Bleiziffer S, Hettich I, Eisenhauer B, Ruzicka D, Voss B, Bauernschmitt R, et al Neurologic sequelae of the donor arm after endoscopic versus conventional radial artery harvesting J Thorac Cardiovasc Surg 2008;136:681 7 Available from: https://doi.org/10.1016/j.jtcvs.2008.02.067

[7] Abu-Omar Y, Mussa S, Anastasiadis K, Steel S, Hands L, Taggart DP Duplex ultrasonography predicts safety of radial artery harvest in the presence of an abnormal Allen test Ann Thorac Surg 2004;77:116 19 Available from: https://doi.org/10.1016/S0003-4975(03)01515-7

[8] Tatoulis J, Royse AG, Buxton BF, Fuller JA, Skillington PD, Goldblatt JC, et al The radial artery in coronary surgery: a 5-year experience—clinical and angiographic results Ann Thorac Surg 2002;73:143 8 Available from: https://doi.org/10.1016/S0003-4975(01)03290-8

[9] Alameddine AK, Alimov VK, Engelman RM, Rousou JA, Iii JEF, Deaton DW, et al Anatomic variations of the radial artery: significance when harvesting for coronary artery bypass grafting J Thorac Cardiovasc Surg 2004;127 (6):1825 7.

[10] Marzban M, Arya R, Hossein M Sharp dissection versus electrocautery for radial artery harvesting Tex Heart Inst J 2006;33:5.

[11] Rukosujew A, Reichelt R, Fabricius AM, Drees G, Tjan TDT, Rothenburger M, et al Skeletonization versus pedicle preparation of the radial artery with and without the ultrasonic scalpel Ann Thorac Surg 2004;77:120 5 Available from: https://doi.org/10.1016/S0003-4975(03)01488-7

[12] Maruo A, Hamner CE, Rodrigues AJ, Higami T, Greenleaf JF, Schaff HV Nitric oxide and prostacyclin in ultrasonic vasodilatation of the canine internal mammary artery Ann Thorac Surg 2004;77:126 32 Available from: https://doi.org/10.1016/S0003-4975(03)01293-1

[13] Taggart DP, Mathur MN, Ahmad I Skeletonization of the radial artery: advantages over the pedicled nique Ann Thorac Surg 2001;72:298 9 Available from: https://doi.org/10.1016/S0003-4975(00)02699-0 [14] Gaudino M, Fremes S, Schwann TA, Tatoulis J, Wingo M, Tranbaugh RF Technical aspects of the use of the radial artery in coronary artery bypass surgery Ann Thorac Surg 2019;108:613 22 Available from: https:// doi.org/10.1016/j.athoracsur.2018.10.066

tech-[15] Sousa-Uva M, Gaudino M, Schwann T, Acar C, Nappi F, Benedeto U, et al Radial artery as a conduit for onary artery bypass grafting: a state-of-the-art primer Eur J Cardiothorac Surg 2018;54:971 6 Available from: https://doi.org/10.1093/ejcts/ezy335

cor-[16] Blitz A, Osterday RM, Brodman RF Harvesting the radial artery Ann Cardiothorac Surg 2013;2:10.

[17] Connolly MW, Torrillo LD, Stauder MJ, Patel NU, McCabe JC, Loulmet DF, et al Endoscopic radial artery harvesting: results of first 300 patients Ann Thorac Surg 2002;74:502 6 Available from: https://doi.org/ 10.1016/S0003-4975(02)03717-7

25

References

[18] Shapira OM, Eskenazi BR, Anter E, Joseph L, Christensen TG, Hunter CT, et al Endoscopic versus conventional radial artery harvest for coronary artery bypass grafting: Functional and histologic assessment of the conduit.

J Thorac Cardiovasc Surg 2006;131:388 94 Available from: https://doi.org/10.1016/j.jtcvs.2005.07.036

[19] Rahouma M, Kamel M, Benedetto U, Ohmes LB, Di Franco A, Lau C, et al Endoscopic versus open radial artery harvesting: a meta-analysis of randomized controlled and propensity matched studies J Card Surg 2017;32:334 41.

[20] Nowicki M, Misterski M, Malinska A, Perek B, Ostalska-Nowicka D, Jemielity M, et al Endothelial integrity

of radial artery grafts harvested by minimally invasive surgery—immunohistochemical studies of CD31 and endothelial nitric oxide synthase expressions: a randomized controlled trial Eur J Cardiothorac Surg 2011;39:471 7 Available from: https://doi.org/10.1016/j.ejcts.2010.08.005

[21] Gaudino MF, Lorusso R, Ohmes LB, Narula N, McIntire P, Gargiulo A, et al Open radial artery harvesting better preserves endothelial function compared to the endoscopic approach Interact Cardiovasc Thorac Surg 2019;29:561 7 Available from: https://doi.org/10.1093/icvts/ivz129

[22] Schwann TA, Habib RH, Wallace A, Shahian DM, O’Brien S, Jacobs JP, et al Operative outcomes of multiple-arterial versus single-arterial coronary bypass grafting Ann Thorac Surg 2018;105:1109 19 Available from: https://doi.org/10.1016/j.athoracsur.2017.10.058

26 3 Harvesting the radial artery

Technical Aspects of Modern Coronary Artery Bypass Surgery

C H A P T E R

4

Harvesting the skeletonized internal

mammary artery Viral Patel, Omar Hussian and Faisal Bakaeen

Department of Thoracic and Cardiovascular Surgery, Heart, Vascular and Thoracic Institute,

Cleveland Clinic Foundation, Cleveland, OH, United States

IntroductionSince the landmark paper from Loop et al in 1986, the use of the left internal mammaryartery (LIMA) for revascularization of the left anterior ascending (LAD) artery is the stan-

criti-cal to the outcome of coronary artery bypass grafting

Described is the approach to harvesting a skeletonized LIMA; the decision betweenskeletonized and pedicled mammary harvest is beyond the scope of this technical chapter,but a surgeon should never hesitate to use either technique depending on their level ofcomfort or expertise Skeletonized is associated with reduced incidence of sternal woundcomplications and medastinitis and is the preferred approach for patients undergoing

Approach

A median sternotomy is performed with careful attention to maintaining a midline sion of the sternum In the event of paramedian sternotomy, care is taken to preventundue tension on the sternum during retraction and thereby preventing sternal fracture

divi-On closure, the sternum is reinforced to promote healing either as described initially by

VIDEO 4.1 Technique of the right internal thoracic artery to aorta anastomosis The video can be found on online at http://doi.org/10.1016/B978-0-12-820348-4.00004-2

The IMA retractor facilitates exposure of the internal mammary vessels and is placedwith cephalad arm at the left manubrium or angle of Louis and the caudal arm ideally

Fibrous attachments or muscular restrictions are released along the cephalad and caudalaspects of the sternum to facilitate exposure for LIMA harvest

ExposureUsing electrocautery set to coagulate at 40 50 W, fatty adhesions between the mediasti-num and sternum are released with care to cauterize any encased vessels and not violatethe endothoracic fascia In proceeding laterally the left pleura is kept intact when possible,

The internal thoracic vessels are exposed by lowering electrocautery to 20 or 30 W and ing the endothoracic fascia The internal mammary vein serves as a useful landmark; the LIMAlies laterally The fascia is opened where visibility is optimal along the artery; the proximal third

enter-of the artery typically has looser fatty surrounding tissues and is a good starting point The cia can be opened near the medial mammary vein to expose the LIMA laterally and leave thevein attached to the chest wall The correct approach allows the endothoracic fascia to be dis-sected off the chest wall and will lead to clear visualization of the internal mammary artery and

Once the correct plane and exposure are confirmed, fine forceps and gentle upward motion

of the electrocautery tip are used for blunt dissection to extend exposure of the mammary artery(Fig 4.4) The endothoracic fascia is opened with electrocautery away from the mammary vein

so as to leave the vein attached to the chest wall The thin strip of fascia, attached to the artery,can be used as a “handle” for mobilization The pulsating and shiny white mammary artery isvisualized laterally as the fascia is separated from the vein Beyond the LIMA is usually a lateralbranch of the mammary vein that is left in situ

retractor for hemisternum elevation LIMA, Left internal mammary artery.

Technical Aspects of Modern Coronary Artery Bypass Surgery

28 4 Harvesting the skeletonized internal mammary artery

This exposure is extended so as to visualize the artery along the entirety of its course

on the chest wall

FIGURE 4.3 Exposing the LIMA: (a) internal mammary artery, (b) fascial handle, and (c) parietal pleura LIMA, Left internal mammary artery.

its course: (a) endothoracic fascia, (b) internal mammary artery, and (c) parie- tal pleura LIMA, Left internal mam- mary artery.

endothoracic fascia, (b) internal mammary artery, (c) nal mammary vein, and (d) parietal pleura.

inter-29

Exposure

Harvesting the left internal mammary arteryOnce the LIMA is well exposed, it must be harvested by freeing it of its attachments tothe chest wall Harvest proceeds with minimal direct manipulation of the mammary arteryand with the electrocautery set to coagulation at 15 20 W on desiccating Direct manipula-tion leads to bruising, hematoma formation, or arterial dissection or thrombosis Further,undue tension on the artery is avoided so as to prevent avulsion of branches and possiblesubsequent injury to the LIMA.

Typically, there is one significant intercostal branch per rib space, as well as multiple

internal mammary artery [4] Source: From Berdajs D., Turina M.I (2011) Coronary Bypass Grafts In: Operative Anatomy of the Heart Springer, Berlin, Heidelberg https://doi.org/ 10.1007/978-3-540-69229-4_3

30 4 Harvesting the skeletonized internal mammary artery

Technical Aspects of Modern Coronary Artery Bypass Surgery

Gentle traction with an open forceps on the endothoracic fascia or artery itself provides

Arterial branches are bluntly and thoroughly exposed prior to clipping or cauterizing.The vein can be pressed into the chest wall as a plane is developed between the mammary

FIGURE 4.6 Exposure of branches: (a) internal mammary artery, (b) internal mammary artery branch, (c) internal mammary vein, and (d) parietal pleura.

FIGURE 4.7 Clip application: (a) internal mammary artery, (b) internal mammary artery branch with clip, (c) internal mammary vein, and (d) parietal pleura.

31

Harvesting the left internal mammary artery

Proximal harvestHarvest can proceed either proximally or distally.

The proximal portion of the artery will separate from the mammary vein The mary vein (retracted here with forceps) will course through the fat pad at the superioraspect of the mediastinum toward the subclavian vein Care is taken when dissectingthrough this fat pad to avoid injury to the vein If this fat pad and vein are compromisingexposure, the vein is doubly ligated or clipped and transected Rotating the table awayfrom the surgeon can enhance exposure and visualization of the most proximal portion ofthe artery The fascia is opened along the artery as it takes a slightly lateral course from

are doubly clipped and (B) divided with sharp tenotomy scissors: (a) internal mammary artery, (b) internal mammary artery branch with clip, (c) internal mammary vein, and (d) pari- etal pleura.

32 4 Harvesting the skeletonized internal mammary artery

Technical Aspects of Modern Coronary Artery Bypass Surgery

the vein Following the artery slightly lateral avoids injury to the subclavian vein(Fig 4.11).

The artery is exposed to the level of the subclavian vein, and as the first intercostalbranch of the artery is quite large, it is identified and clipped Importantly, the phrenicnerve courses near the mammary vessels in this area; thermal injury to the nerve isavoided

Distal harvestDistally the artery enters the transversus thoracis muscle and tends to course laterally

singly clipped then cauterized: (a) nal mammary artery, (b) internal mam- mary artery branch with clip, and (c) internal mammary vein.

and fibrous tissue are directly ized: (a) internal mammary artery and (b) internal mammary vein.

cauter-33

Distal harvest

Careful dissection of the transversus thoracis muscle will reveal the veins and artery intheir intramuscular course The branches are identified and clipped in the same manner asabove (Fig 4.13).

FIGURE 4.11 (A) Proximal harvest and (B) proximal harvest: (a) internal mammary artery, (b) internal mary vein (retracted), and (c) sternohyoid muscle Source: (A) From Berdajs D., Turina M.I (2011) Coronary Bypass Grafts In: Operative Anatomy of the Heart Springer, Berlin, Heidelberg https://doi.org/10.1007/978-3-540-69229-4_3

mam-34 4 Harvesting the skeletonized internal mammary artery

Technical Aspects of Modern Coronary Artery Bypass Surgery

The artery is harvested until a distinct bifurcation is appreciated at the level of thexiphoid where the caliber of the vessel narrows significantly Occasionally, the mammarybifurcates into two large caliber branches These can be separately exposed and used as aY-graft, although the prevalently muscular histology of the distal part of the artery may

FIGURE 4.12 Distal harvest: (a) internal mammary artery, (B) endothoracic fascia, and (c) transversus thoracis muscle.

FIGURE 4.13 Bifurcation: (a) internal mammary artery with bifurcation, (b) internal mammary vein, and (c) transversus thoracis muscle.

35

Distal harvest

Mobilizing the internal thoracic artery

As branches are secured and separated, the artery begins to mobilize off of the chestwall (Fig 4.15)

As the artery mobilizes away from the chest wall, it can be manipulated with closed oropen forceps to provide traction The artery is freed of both lateral and medial branches ofthe mammary vein as well as any fascial attachments Small perforating branches areclipped that may avulse if not anticipated and identified

Y-Graft: (a) internal mammary artery with bifurcation anastamosed to two

OM branches LIMA, Left internal mammary artery; OM, obtuse marginal.

internal mammary artery with cation, (b) internal mammary vein, and (c) transversus thoracis muscle.

bifur-36 4 Harvesting the skeletonized internal mammary artery

Technical Aspects of Modern Coronary Artery Bypass Surgery

The artery is dissected free of the lateral internal thoracic vein and remaining fascial

Left pleuraThe left pleura is routinely opened to facilitate LIMA course into the pericardium.There is evidence to suggest keeping the pleura intact may benefit postoperative pulmo-

placed (Fig 4.17)

FIGURE 4.16 Freely mobilized LIMA LIMA, Left internal mammary artery.

FIGURE 4.17 Left pleura is opened.

37

Left pleura

Freeing the internal mammary arteryAfter heparin is administered and consideration is given to target vessels and necessarylength of conduit, the artery is doubly clipped and separated from the chest wall.Adequate blood flow is confirmed Bulldog is placed while the operation proceeds.

Dilatation of the internal mammary artery

We use topical papaverine If there is concern about spasm, we use low-dose nous milrinone or nitroglycerin

intrave-In the case of small conduits, we occlude the conduit distally immediately after nization and checking flow, and let it beat against the clip while wrapped in a gauzesoaked with papaverine The artery almost always dilates to adequacy by the time you areready to do your distal

hepari-In the case of small conduits, we try to go more proximal on the target vessel and usethe larger segment of the internal thoracic artery

Rarely, have we injected papaverine directly into the conduit and then occluded it Thismay potentially risk chemical intimal injury but works well

Complications, pearls, and pitfallsDuring harvest of the LIMA, thermal injury, shear forces, or uncontrolled bleeding cancause injury to the arterial conduit Evidence of arterial injury manifest initially with colorchange—typically, a bruised or injured artery appears purple and edematous, whereas

a clean uninjured artery will appear shiny white with nearly similar caliber throughout itscourse

The artery itself is gently palpated for a quality pulse If the vessel is not pulsatile, picion is high for thrombosis or dissection If unclear, the echo or flow probe may be used

sus-to assess the conduit

In the event of hematoma, an assessment is made of its effect on the conduit If thehematoma is small and is not compromising vessel flow and/or pulsatility, it can be leftalone An expanding, tense hematoma that is compromising pulsatility must be evacuated

In this case the surrounding adventitia is opened, and pressure is held with a sponge Ifthe hematoma is a result of bleeding from a small branch, this can be identified andclipped or stitched If pulsatility does not improve, the artery should be assessed fordissection

In the event of a focal dissection, the area of focal dissection can be transected and theartery can be anastomosed end to end and used for grafting

Finally, in the event of an irreparable injury, the artery can be harvested as a free graftfor proximal anastomosis to the ascending aorta or taken as a composite graft fromanother conduit

38 4 Harvesting the skeletonized internal mammary artery

Technical Aspects of Modern Coronary Artery Bypass Surgery

[5] Guizilini S, Gomes W, Faresin S, et al Influence of pleurotomy on pulmonary function after off-pump nary artery bypass grafting Ann Thorac Surg 2007;84(3):p817 22.

coro-39

References

C H A P T E R

5

Retractors for harvesting the internal

thoracic artery Thin Xuan Vo and David Glineur

Division of Cardiac Surgery, University of Ottawa Heart Institute, Ottawa, ON, Canada

IntroductionThe internal thoracic artery (ITA), namely, the left ITA (LITA), is arguably the most vitalconduit for the conduct of coronary artery bypass grafting (CABG) due to its superior long-term patency and mortality benefit Harvesting of the ITA must be done in an efficient andatraumatic fashion to preserve full functionality and longevity of the conduit This is espe-cially true where the LITA will be used in composite grafting configurations and will serve

as the main conduit for other conduits to branch form Skeletonization of the ITA requireseven more meticulous technique as there is less fascia to manipulate on the ITA

ITA harvest requires excellent surgical exposure while aiming to distort a patient omy as minimal as possible Aggressive manipulation of a patient anatomy with excessivesternal retraction can lead to consequences such as postoperative pain, respiratory insuffi-ciency, rib fractures, sternal fractures, costochondral dislocation, and neuropathy (e.g., bra-

these complications Prior to the advent of retractors created for ITA harvest, an assistant

there are now a variety of sternal and ITA retractors that provide adequate exposure ofthe ITA for safe and expedient harvest

This chapter will cover the most common retractors for the harvest of the ITA throughmedian sternotomy Minimally invasive options are covered more in depth in other chap-ters Advantages and disadvantages of each retractor will be discussed and are summa-

there is limited evidence for using one retractor over another Retractor use should beadapted to each clinical situation taking into account patient factors and clinical context.Furthermore, the use of each retractor is often institution and surgeon specific

41

Technical Aspects of Modern Coronary Artery Bypass Surgery

© 2021 Elsevier Inc All rights reserved.

Bugge retractor

modifi-cation of a standard median sternotomy retractor to allow for angulated and asymmetricalretraction of the ITA Each side of the retractor has a mounted tilted blade that allows forone side of the sternum to be lifted while the other side of the sternum is simultaneously

TABLE 5.1 Summary of the advantages and disadvantages of common internal thoracic artery retractorsystems

Retractor Advantages Disadvantages

Bugge retractor • Simple and easy to use

• No assembly required

• Entire apparatus in sterile field

• Bulky

• Increased risk of sternal and rib fracture

• Increased risk of costochondral dislocation

Couetil retractor and

other “rake” retractors

• Compact

• Simple and easy to use

• No assembly required

• Entire apparatus in sterile field

• Only one vector of retraction

• Increased risk of sternal and rib fracture

Pittman retractor • Excellent exposure

• Decreased interference from lungs

• Decreased risk of sternal fracture, rib fracture, and costochondral dislocation

• Requires assembly and anchoring outside of the sterile field

• Increased risk of brachial plexus irritation/injury

Rultract retractor • Excellent exposure, especially in

patients with large body habitus

• Decreased risk of sternal fracture, rib fracture, and costochondral dislocation

• Many options for adjustment

FIGURE 5.1 The Bugge retractor

in position Note that the retractor blade is placed just distal to the manubrium sternal junction and spans the midsternum.

42 5 Retractors for harvesting the internal thoracic artery