Handbook of Advanced Interventional Cardiology - part 4 potx

184 Practical Handbook of Advanced Interventional Cardiology shear stress at the exit of the newly stented area following the straightening of the vessel. 7 Different options in the treatment of long lesio n are listed in Tabl e 9 - 4. TECHNICAL TIP Long or short balloons: Long balloons can dilate long lesions with one balloon placement rather than doing re- peated infl ations with a short balloon, thus avoiding plaque shifting and giving a better, smooth initial result. Dilating a Table 9-2 Evaluation of complexity prior to interventions 6 Factors affecting the ability to access the lesion Left main disease Proximal tortuosity Origin, size, and course of artery potentially infl uences guide selection, backup Compliant vessel proximal to the target lesion (no calcifi cation) Non-critical lesions proximal to the target lesion Presence of branches affecting wire passage Factors affecting the ability to cross the lesion with a wire or a balloon Degree of stenosis and length of lesion Lesion morphology: eccentricity, thrombus, presence of calcium, complexity Lesion characteristics that affect the outcome Characteristics associated with increased incidence of dis- section Characteristics associated with increased incidence of thrombotic occlusion Lesion characteristics that affect the reconstruction of a “perfect” lumen Bifurcated lesions Ostial lesion Angulated lesions Small vessel Lesion or arterial characteristics associated with decreased ability to deliver a stent (in the case of emergency manage- ment of complication: dissection, perforation, acute closure, slow fl ow, etc.) Diffuse disease Severe calcifi cation (stiff, non-accommodating channel) Marked tortuosity or angulation Complex Lesions 185 long lesion with a short balloon can disrupt the plaque in multiple places and allow blood to enter the channel behind the plaque causing dissection. For long lesions located on bends, there is less occurrence of dissection with the use of a long balloon placed entirely around the bend. 8 The rate of restenosis, however, continues to be quite high in PCI of any long lesion. 7 Rotational atherectomy was considered desirable for debulking long and superfi cially calcifi ed lesion but it should be used with caution because of the large amount of atheromatous debris removed and released. It may cause Table 9-3 New risk assessment schema Risk factors Strongest correlates Non-chronic total occlusion Degenerated saphenous vein graft (SVG) Moderately strong correlates Length >10 mm Lumen irregularity Large fi lling defect Calcium + angle >45° Eccentric Severe calcifi cation SVG age >10 years Results Highest risk either of the strongest correlates High risk ≥3 moderate correlates without strong- est correlates Moderate risk 1–2 moderate correlates without strongest correlates Low risk no risk factors Table 9-4 Strategies of long lesion interventions 1. Pretreatment with antiplatelet agents 2. Ample use of intracoronary (IC) nitroglycerine to prevent distal vessel spasm 3. Avoid excessive particle embolization during rotablation 4. Avoid vessel-fl ow mismatch 5. Debulking prior to stenting 6. Drug-eluting stent 7. Brachytherapy (VBT) 186 Practical Handbook of Advanced Interventional Cardiology excessive distal microembolization with subsequent no-re- fl ow and ischemic events. 9 The data from the New Approaches to Coronary Inter- vention (NACI) registry showed that each 1-mm increase in lesion length was associated with an increased relative risk of 1.014 (95% CI, 1.004–1.025) for target lesion revascular- ization (TLR) at 1 year. 10 W i t h d r u g - e l u t i n g s t e n t ( D E S ) , s p o t stenting is the technique of the past. EVIDENCE-BASED MEDICINE APPLICATIONS Drug Eluting Stent: The SIRolImUS-Eluting Stent in De Novo Native Coronar y L e sions ( S IR IUS ) trial : In this trial, for the control group, the rate of restenosis was 29.7% for 8-mm bare stents and 52.4% for bare stents measuring 40 mm. By contrast, the rate of restenosis of the sirolimus- eluting stents of <8 mm length was only 1.7%. It was 6.5% in lesions treated with 40-mm stents. In general, for every 10 mm of bare metal stent implanted, the rate of restenosis increased by 13%. In the sirolimus group, this increase was 1.6% for every additional 10-mm stent used from a baseline of 1.7% (Tabl e 9 - 5 ). 11 CALCIFIED LESIONS A calcifi ed lesion is defi ned as any angiographically ap- parent calcium in the target vessel. Its level of calcifi cation is classifi ed as mild if cardiac motion is required to see the calcium, moderate when it is obvious without cardiac motion, and severe. Heavy calcifi cation is a predictor of dissection that occurs at a hinge point where calcifi ed and pliable vessel segments are subject to barotrauma. The reason is that the p re ss u r e i s co n ce n tr at ed on t he mo st re s is t an t a re a ( t he c a l c i- fi ed segment) and the tissue next to the calcifi ed area. The mechanism of acute lumen gain after PTCA in calcifi ed lesion is dissection while it is plaque compression and vessel expan- sion in fi brotic lesion. Higher pressure infl ation also increases Table 9-5 Restenosis versus stent length In-segment restenosis Stent length Control (%) Sirolimus (%) 10 mm 31.3 7.3 20 mm 37.5 8.5 30 mm 44.0 10.1 40 mm 51.5 11.8 Complex Lesions 187 the risk of balloon rupture (14%), 7 perforation, or balloon material entrapment. 12 The selection of devices in calcifi ed lesion depends on vessel size, tortuosity, presence of thrombus, bifurcation, lesion length, eccentricity, ostial location, vein graft and di- abetes. Ideally, a patient with heavily calcifi ed lesion should have IVUS to locate the calcium and its extent. If it is deep then there are no problems with PTCA. If it is superfi cial, the patient should have rotational atherectomy. However, be- cause of excessive distal embolism, rotational atherectomy is not as commo n ly used as before. TECHNICAL TIPS **Device selection: First, predilate a lesion with POBA. If the lesion can be dilated then stenting would be feasible. Most lesions with mild calcifi cations respond to this; sim- ply try. If a lesion cannot be fully dilated at 18 ATM then stent placement is contraindicated since incomplete stent expansion increases the risk of subacute thrombosis and restenosis. Then rotablation or cutting balloon angioplasty can be tried. However, if the lesion is distal and the proximal segment is severely calcifi ed and tortuous (>60° angula- tion), then it is diffi cult to advance a cutting balloon to the lesion site. In these heavily calcifi ed lesions, primary rotab- lation is suggested. 13 **Advancing a stent in a tortuous artery: Even after ro- tablation and balloon dilation, stenting of severely calcifi ed lesions is still diffi cult because hard and eccentric plaque in a proximal tortuous segment may still prevent the advance- ment of stent. In these circumstances, it is important not to force the stent into the lesion since this maneuver may result in stent deformation and inability to remove the stent later, if needed. In order to advance the stent, the guide backup should be optimal, the “buddy wire” technique may be used to straighten the proximal segment, to shift the stent over the edge of the plaque. Complete predilation of the lesion or further debulking of the lesion with rotablation may be needed. 13 **Expanding a stent with CB after failure of high pres- sure infl ation: Even after being advanced to the lesion area, not every stent can be fully deployed due to unex- pected severe calcifi cation of the lesion. In a case report by Colombo et al., while a stent was being deployed in the proximal LAD, the distal part of a stent could not be opened even at 30 ATM. So the balloon was exchanged with a cutting balloon (CB) that was advanced into the distal seg- ment and infl ated at 12 ATM. The CB was withdrawn and 188 Practical Handbook of Advanced Interventional Cardiology exchanged for a non-compliant balloon that fully expanded the stent at 28 ATM. 14 CAVEAT: Avoid stent embolization while exchanging a balloon in a tortuous and calcifi ed segment: While exchanging a balloon on a half deployed stent, the stent is easier to be dislodged backward, especially if the stent has a funnel shape (the proximal end is larger than the distal un- deployed end). Make an extra effort to keep the stent immo- bile while removing the old balloon and advancing the new balloon inch by inch. These situations happen in the follow- ing situations: (1) angulated segment; (2) sharply tapered vessel with distal segment much smaller than proximal segment; and (3) insertion site between saphenous vein graft or internal mammary artery graft to the native vessel. In summary, in PCI for calcifi ed lesions, the results are usually suboptimal because only 24% of cases achieved 90% cross-sectional area of the reference lumen. 15 Even with higher pressure infl ation (>18 ATM), some stents are still un- derdilated. Without prior calcium removal, it may not be pos- sible to fully expand a stent, because of severe calcifi cation or large plaque burden. In order to advance the stent through calcifi ed and rigid lumen, extensive manipulation would de- nude the endothelial layer and cause more intimal hyperplasia and restenosis. Cutting balloon angioplasty or plain balloon angioplasty with one or two buddy wires can help to break the plaque and allow full stent deployment. Rotational atherec- tomy is the method of choice for debulking the calcifi ed lesion with adjunctive angioplasty or stenting, however, the resteno- sis rate after bare stent and rota-stent was still high. There are no new data with DES or brachytherapy on calcifi ed lesions. ANGULATED LESIONS An angulated lesion is defi ned as a lesion on a bend of 45° or more. With simple POBA, the success rate was 70% with 13% ischemic complications. 16 The risk of acute closure was 2% if the bend was less than 45°, and 8% if the bend was between 45° and 90°; it was 13% if the bend was more than 90°. 7 BEST METHOD Advance a wire through angulated segments: 1. First maneuver – select a balanced wire: At fi rst a fl op- py wire seems to navigate easily the tortuous segments. It does not cause pseudo-lesions or wire bias. However, after a few excessive turns, it is impossible to advance Complex Lesions 189 a too fl oppy wire further. It behaves like a wet noodle. In contrast, it may be diffi cult to make a fi rst extensive twist and turn with a very fi rm wire. Furthermore, a stiff wire may cause “bias” while passing through heavily calcifi ed and angulated segment and shift interventional devices against the wall of the artery, making their passage dif- fi cult. In most cases a moderately fi rm wire is appropri- ate. 17 2. Add a second wire: On many occasions, a fl oppy wire is able to be advanced though tortuous segments; however, it is not strong enough to tract a device. Then a second, soft or stiffer wire may need to be advanced parallel to the fi rst one by wrapping around the fi rst one (the “buddy wire”). 3. Add a second device: Sometimes, a wire may be ad- vanced at best to the proximal end of a distal segment of an artery. Then, advance a balloon as far as possible, then the wire, to the distal end. TECHNICAL TIPS **Advance a second, stiffer wire along the fi rst wire through angulated segments: On many occasions, a fl oppy wire is not strong enough to tract a device. Then a second soft or stiffer wire may need to be advanced paral- lel to the fi rst one. In this case, advance the second wire as usual, then, at the bend, twist it more, for example by wrap- ping it around the fi rst wire three or four times. By that, the second wire will be advanced to the same branch or distal segment of the fi rst wire as intended. If the second wire is not planned to be positioned at the same branch or distal end, just wrap the fi rst wire around the second one once or twice so the fi rst wire can turn around the bend and be direc te d separately to its own branch. **Advance a stiff wire with the help of a balloon: Ideally, in many PCIs, it is best to have a wire advanced deeply to the distal end of any instrumented artery. However, in many real-life situations, a wire could easily cross the lesion at the mid-segment (e.g. of the RCA or LCX) and at best, might only be advanced just to the proximal end of the distal seg- ment (e.g. before the PDA or after a large OM). Advance a balloon near the tip of the wire then advance the wire. If the balloon can be advanced across the lesion, then infl ate the balloon at low pressure, thus avoiding dissection. While the balloon is infl ated, advance the wire to the distal end. The shaft of the balloon catheter will straighten the proximal segment and a wire indwelled inside an infl ated balloon can be advanced without much diffi culty to the distal end, providing a better support for later device tracking (Figure 9-1 A–C). 190 Practical Handbook of Advanced Interventional Cardiology BEST METHOD Avoiding perforation while advancing a balloon around a bend: should we add a new wire or change the balloon? Sometimes, if the wire is too soft and the currently available high-pressure balloons may have a very stiff tip that is not fl exible enough to make a turn around the bend, its tip keeps pointing straight to the lateral wall. The reason is the tip of the balloon catheter is stiffer than the shaft of the wire. So the Figure 9-1: (A) There is diffi culty in advancing the wire. (B) The wire can be advanced only to the mid-segment of the LAD. While the balloon is infl ated, the wire can be advanced further. (Continued) A B Complex Lesions 191 balloon-wire complex would have to follow the direction of its stiffer component (the tip of the balloon), pointing toward the wall, rather than curving around the bend. A further push may puncture the wall. In this case, either insert a second stiffer wire (buddy wire) to make the curve more rounded and so less bias for the balloon, or choose a lower profi le and more fl exible balloon. 17 In any circumstance, a second, stiffer wire is preferred because, as in this case, if a balloon cannot be advanced, how can a stent be advanced through the angu- lated segment? The stent may succeed to be advanced on the second, stiffer wire rather the fi rst, softer wire. BEST METHOD Guess the chance for success of device advancement before and after wiring: With the advent of DES, there are more patients eligible for stenting even their anatomy is not favorable. Many elderly patients have very tortuous and calcifi ed arteries. 1. First maneuver – look at the angiogram – no calcium: Before wiring, the fi rst factor predictive of success for advancing any interventional device (wire, balloon, stent or thrombectomy, etc.) across a tortuous segment is the lack of calcifi cation (e.g. in young patients). These arter- ies can let any stiff device slide through without problem. Figure 9-1: (C) The wire is advanced to the distal LAD, thus securing an excellent wire position and support for further movement of bulkier devices. C 192 Practical Handbook of Advanced Interventional Cardiology 2. Second maneuver – look at the angiogram – large arteries: The second factor is the size of the artery. If the artery is quite large, the wire can bypass the angles and connect all these segments on a straight line or a round curve that facilitates a lot the advancement of devices (Figure 9-2 A–C). 3. Third maneuver – look at the angiogram – the angle after wiring: After wiring, if the wire is able to stretch on a straight-line form or round curve, then the chance for the devices to move forward is much higher. 4. Fourth maneuver: The usual requirements: Finally, one cannot overemphasize the optimal backup of a guide, the trackability by a stiffer wire and the fl exibility of the interventional device. All of these will help to ad- vance the device to the area needed (Table 9-6). **How long a balloon should be when wrapping around a bend: The re i s le s s oc curr en ce o f d is se c ti on w it h t he u se of a long balloon placed entirely around the bend because the longer the balloon, the greater the force required to Figure 9-2: Advancing a wire through tortuous arteries. (A) The tortuous LCX with 90° angle from the LM. There was a severe lesion at the ostium of the large OM. There was a bro- ken tip of a wire in the distal segment of the OM. This was the result of the jailed wire technique when a wire was jailed at the OM when a stent was deployed at the mid-LCX across the OM. (Continued) A Complex Lesions 193 Figure 9-2 B,C: (B) After wiring, it was clear that the wire by- passed all the angles and formed a straight line from the tip of the guide to the OM. There was no sharp angle between the left main and LCX. This straight line facilitated the advance- ment of a balloon or stent. (C) The ostium of the OM after stenting was wide open. B C [...]... 0 or I) with either known duration of more than 3 months or *Basic; * *Advanced; ***Rare, exotic, or investigational From: Nguyen T, Hu D, Saito S, Grines C, Palacios I (eds), Practical Handbook of Advanced Interventional Cardiology, 2nd edn © 2003 Futura, an imprint of Blackwell Publishing 203 2 04 Practical Handbook of Advanced Interventional Cardiology presence of bridging collaterals.1 A chronically... Table 9-9 The SIRIUS trial : vessel size sub-analysis In-stent restenosis TLR (up to 270 days ) Vessel size Sirolimus Control Sirolimus Small (2.3 mm) Medium (2.8 mm) Large (3.25 mm) 15% 7.5 % 2 .4% 23.1% 13 .4% 14. 5% 8.8% 3.0% 1.8% 200 Practical Handbook of Advanced Interventional Cardiology Table 9-1 0 Differences between the RAVEL and SIRIUS trials SIRIUS Study lesion length Allowed number of stents...1 94 Practical Handbook of Advanced Interventional Cardiology Table 9-6 Factors that guarantee success of device advancement in angulated segments 1 2 3 4 Lack of calcification (accommodating vessel) Large size of vessel so the wire can bypass the angles Possibility of wiring on a straight-line form or round curve Excellent guide support, wire trackability... balloon catheter can be advanced near the tip to increase the stiffness of the wire Sometimes, the balloon and the wire can be advanced as a unit to increase the chance of crossing a hard surface.10 Then, after removal of the wire, injection of contrast could be performed after blood has been aspirated through the 2 14 Practical Handbook of Advanced Interventional Cardiology Figure 1 0-5 : Parallel wire method... twisting a 0.0 14" wire and a balloon-on-a-wire to trap fibrin strands and subsequently withdrawing both wires into a deeply seated guide catheter This maneuver yielded a large amount of thrombus, and subsequent angiography showed an excellent result with 196 Practical Handbook of Advanced Interventional Cardiology B Figure 9-3 : (B) Diffuse, large thrombi in the proximal RCA no evidence of residual thrombus.21... still higher, relatively speaking, in the smaller lumen of a vessel with diameter . line facilitated the advance- ment of a balloon or stent. (C) The ostium of the OM after stenting was wide open. B C 1 94 Practical Handbook of Advanced Interventional Cardiology straighten it. 18 . during rotablation 4. Avoid vessel-fl ow mismatch 5. Debulking prior to stenting 6. Drug-eluting stent 7. Brachytherapy (VBT) 186 Practical Handbook of Advanced Interventional Cardiology excessive. 1 84 Practical Handbook of Advanced Interventional Cardiology shear stress at the exit of the newly stented area following the straightening of the vessel. 7 Different