This study describes some new anatomical findings of the right accessory lobe and a new experimental porcine lung transplant model and our experience with surgical training for the first clinical lung transplant of Vietnam. Subjects and methods: 20 pigs were used for anatomical study. Heart - lung blocks were removed. Methylene blue was selectively injected to different branches of pulmonary artery. Then, all heart - lung blocks were carefully dissected. 30 pigs were used to invent a new surgical model. The caudal lobes of the right lungs were harvested from 15 deceased donors, then transplanted into the opposite position as left caudal lobes (having been rotated 180° along the vertical axis) of 15 recipients following left pneumonectomy. Graft function was determined for 3 hours after reperfusion. Results: Only 13/20 cases, the right accessory lobe veins enter the root of the right caudal lobe veins as described by other authors, 3/20 enter the right inferior pulmonary veins, 2/20 enter the position between the right and the left inferior pulmonary veins, 2/20 enter the left inferior pulmonary veins. Porcine living donor using right lung is impossible, using left lung is possible, but different strategies must be used to preserve the blood supply to the donor’s right accessory lobe. With deceased donor, both the right and left caudal lobes could be used, the right accessory lobes should be excluded. In new surgical model study, all 15 recipients survived, all grafts showed excellent acute and long-term function. Conclusion: A new porcine lobar lung transplant from deceased donor has been invented. This model could be used easily for all anatomical variants.
Journal of military pharmaco-medicine n02-2019 A STUDY OF PORCINE LUNG ANATOMICAL CHARACTERISTICS AND A NOVEL EXPERIMENTAL LUNG TRANSPLANT MODEL Nguyen Trung Chuc1; Do Xuan Hai1; Ngo Thi Dong1 Thieu Ban Trang1; Trinh Cao Minh1; Do Quyet1 SUMMARY Objectives: This study describes some new anatomical findings of the right accessory lobe and a new experimental porcine lung transplant model and our experience with surgical training for the first clinical lung transplant of Vietnam Subjects and methods: 20 pigs were used for anatomical study Heart - lung blocks were removed Methylene blue was selectively injected to different branches of pulmonary artery Then, all heart - lung blocks were carefully dissected 30 pigs were used to invent a new surgical model The caudal lobes of the right lungs were harvested from 15 deceased donors, then transplanted into the opposite position as left caudal lobes (having been rotated 180° along the vertical axis) of 15 recipients following left pneumonectomy Graft function was determined for hours after reperfusion Results: Only 13/20 cases, the right accessory lobe veins enter the root of the right caudal lobe veins as described by other authors, 3/20 enter the right inferior pulmonary veins, 2/20 enter the position between the right and the left inferior pulmonary veins, 2/20 enter the left inferior pulmonary veins Porcine living donor using right lung is impossible, using left lung is possible, but different strategies must be used to preserve the blood supply to the donor’s right accessory lobe With deceased donor, both the right and left caudal lobes could be used, the right accessory lobes should be excluded In new surgical model study, all 15 recipients survived, all grafts showed excellent acute and long-term function Conclusion: A new porcine lobar lung transplant from deceased donor has been invented This model could be used easily for all anatomical variants * Keywords: Experimental lung transplant; Anatomy characteristics INTRODUCTION Living donor lobar lung transplantation (LDLLT) is performed as a life-saving procedure for critically ill patients who are unlikely to survive the long wait for cadaveric lungs It has been proved life saving for various lung diseases and appears to provide similar or better survival than cadaveric lung transplantation On 21 Feb, 2017, Vietnam Military Medical University has successfully performed performed the first living donor lobar lung transplant in Vietnam The recipient who received a right lower lobe from his father and a left lower lobe from his uncle was a years old boy with end stage idiopathic bronchiectasis diagnosed since birth The donors were his biological father, aged 28 years and his uncle, aged 30 years Vietnam Military Medical University Corresponding author: Nguyen Trung Chuc (nguyentrungek@gmail.com) Date received: 20/12/2018 Date accepted: 16/01/2019 147 Journal of military pharmaco-medicine n02-2019 This was the result of lung transplantation program started since 2016 in which an experimental study was included The lung transplant in developing countries such as Vietnam, it is still rare Obstacles include a lack of experienced surgeons because we can‟t afford to send doctors for studying abroad This study describes some anatomical characteristics of the right accessory lobe and a novel porcine experimental lung transplant model and the implication with surgical training for lung transplantation MATERIAL AND METRHODS The study was done with the approval of the Animal Experiment and Research Committee of the institution The animals were treated according to the Animal Regulations of the Vietnam Military Medical University published in 1989 Anatomical study - Methodology: Experimental, crosssectioned descriptive study - Animal preparation: 20 pigs were used for anatomical study - Heart - lung block harvest: All pigs were anesthetized with ketamine (10 mg/kg), positioned in supine on operation table, heparinized (100 UI/kg), external jugular veins and femoral arteries were exposed and cannulated Normal saline solution was infused through external jugular vein catheter and blood was withdrawn from femoral artery catheter at the same time until animal death Median stenotomy was done Heart - lung blocks were removed with laryngotracheal junction cranially and 148 aorta piercing the diagphram caudally Methylene blue was selectively injected to different branches of pulmonary artery Then, all heart - lung blocks were carefully dissected by skillfull surgeon using surgical loups New transplant model - Methodology: Experimental study - Animal preparation: 30 domestic pigs with the weight from 40 - 50 kg which were divided into 15 donors and 15 recipients were used The weight discrepancy of a donor-recipient pair is not more than 10 kg The animals received no solid food for 18h before the procedure, with water available ad libitum Donor operation The premedication was done with intramuscular ketamine (10 mg/kg) and atropine sulfate (0.25 mg/kg) During surgery, we placed a peripheral catheter, and previous 100% oxygenation was established as monitored with electrocardiogram (ECG) and pulseoximetry Anesthesia was induced with propofol (4 mg/kg), fentanyl (3 μg/kg) and atracurium besilate (0.6 mg/kg) through a dorsal vein of the ear Surgical tracheotomy was performed with an endotracheal tube measuring - mm in internal diameter Respiratory assistance included a Dräger SA ventilator Ventilation was controlled by volume (tidal volume mL/kg, 12 - 15 breaths/min, ratio between inspiration and expiration of 1:2) and it was adjusted during surgery in order to maintain in arterial blood between 35 and 40 mmHg of carbonic anhydride; Journal of military pharmaco-medicine n02-2019 meanwhile, the inspired fraction of oxygen (FiO2) was maintained at during the whole procedure The anesthesia was maintained with propofol at continuous perfusion (8 - 10 mg/kg/h), with fentanyl and atracurium in bolus, as needed The airway pressure (AWP), blood pressure, pulmonary arterial pressure (PAP), central venous pressure, arterial blood gases, PA blood gases, and cardiac output were measured The mediastinum was accessed by a median sternotomy, and the heart and lungs were exposed by extended pleural and pericardial incision The superior and inferior vena cava, the ascending aorta and the trunk of the pulmonary artery (PA) were dissected After administration of heparine (3 mg/kg), a 18F cannula was inserted into the main PA through a pursestring suture Previous to the administration of the flush solution, 250 g of prostaglandin-E1 (alprostadil) was injected in the PA Then the superior vena cava was occluded, the aorta crossclamped, and the inferior vena cava and the left atrial appendage were incised for decompression of the PA flush The lungs were perfused with 50 - 60 mL/kg of cold (4°C) low-potassium-dextrin-glucose solution, at a pressure of 40 cm H2O Topic cooling of the lungs was performed by instillation of cold saline solution into the pleural spaces After the flush, harvesting of the heart - lung in block was completed by clamping the trachea at middle-inspiration vein, artery and bronchus were dissected free from surrounding tissue (figure 1) During the dissection of accessory lobe, care should be taken to avoid possible injuries to the neighbouring structures causing air leak afterwards The accessory lobe vessels were ligated and divided with 4.0 silk suture The bronchus was cut transversely for to mm and sutured with 4.0 polypropylene suture in interrupted fashion After finishing the exclusion of the right accessory lobe, we dissected the pedicle of the right caudal lobe that was going to be reimplanted: the right pulmonary artery (after ligature and sectioning of the cranial and middle lobar branches), the right caudal pulmonary vein (liberated from the pleural adherences until the segmental branches and cut at the root where the right caudal lobe vein enters the left atrium) and the right main bronchus (after cutting and suturing the cranial and middle lobar bronchus) This was followed by the bench surgery, and the right accessory lobe should be excluded in advance The accessory lobar (Red arrow: The artery; blue arrow: The vein; white arrow: The vein; White arrow: The bronchus) Figure 1: Exposing pedicle of right accessory lobe 149 Journal of military pharmaco-medicine n02-2019 A B Figure 2: Experimental design (A: The right caudal lobe had been transplanted into the left pleural cavity as left caudal lobe after having been rotated 180° along the vertical axis; B: The outline illustrating the implantation of the graft in the left pleural cavity) Recipient operation The recipient pig was sedated in the same manner as the donor pig The pig was placed in the right lateral position, and a fifth intercostal thoracotomy was performed The left pulmonary vein, left main pulmonary artery, and left main bronchus were seperated, and the left lung was extracted Heparin (200 U/kg) was administered intravenously The right caudal lobe had been transplanted into the left pleural cavity as left caudal lobe after having been rotated 180° along the vertical axis (figure 2A) The pulmonary 150 structures were anastomosed in the following order: Bronchus, pulmonary artery and pulmonary vein Because the graft was rotated 180° along the vertical axis, everal stratergies was done to prevent the broncho-vascular structures from tension and kinking (figure 2B) The garft‟s artery will be posterio-superior to the graft‟s bronchus, meanwhile the left main pulmonary artery is anterior to the bronchus, so care should be taken during the left pneumonectomy in order to gain the enough lenght of the left main pulmonary artery stump (the left main Journal of military pharmaco-medicine n02-2019 pulmonaty artery should be divided distal to the branch of left apical segment), in relation to the bronchial structure, the right lower lobe bronchus (the graft) should be anastomosed to the left upper lobe bronchus (recipient) instead of the left lower lobe bronchus This would adjust morphological similarity between the right lower lung lobe with the left pleural cavity As regards pulmonary veins, the right lower lobe vein (the graft) should be connected to the left atrial appendage instead of the upper pulmonary vein to avoid excessive strain Retrograde reperfusion was carried out first, unclamping the left auricle, followed by anterograde reperfusion, unclamping the pulmonar artery Then, the ventilation of the implanted lobe was performed The pig was returned to the supine position The arterial blood gases, PA blood gases, cardiac output, AWP, PAP, central venous pressure, and left atrial pressure were measured at 10, 30, 60, 120, and 180 minutes after reperfusion The right main pulmonary artery was intermittently clamped using a tourniquet for minutes before each measurement The following measured parameters were assigned to evaluate graft function: Partial pressure of oxygen in arterial blood gases for oxygenation or gas exchange; PAP for problems in vessel anastomosis and influence of the small pulmonary vascular beds; and AWP for decreased lung compliance due to congestion of the graft, problems with the bronchial anastomosis, or secretions To investigate the graft intestinal widening, lung biopsies were taken after hours follow-up Lung tissue samples were inflation-fixed in 10% buffered formalin and stained with hematoxylin and eosin * Statistical analysis: The data are expressed as means and standard deviation The statistical study was carried out using the SPSS 20.0 statistical package The ANOVA test was used to detect differences in the evolution of the variables among the different moments of the experimental procedure The differences were considered statistically significant with a p value of < 0.05 RESULTS Anatomical findings Only 13/20 cases, the right accessory lobe veins enter the root of the right caudal lobe veins as described by other authors (fig 3A), 3/20 enter the right inferior pulmonary veins (fig 3B), 2/20 enter the position between the right and the left inferior pulmonary veins (fig 3C), 2/20 enter the left inferior pulmonary veins (fig 3D) The new experimental transplant model lung As for the new lung transplant model, all 15 recipient were survived during follow-up period The transplanted lungs appeared excellent function To assess lung funcytion, following indicators were selected: Partial arterial oxygen pressure (PaO 2), pulmonary artery pressure (PAP) and airway pressure (AWP) 151 Journal of military pharmaco-medicine n02-2019 Table 1: PaO2, PAP, AWP values after reperfusion (Values are expressed as mean ± SD PaO2: Arterial oxygen partial pressure PAP: Pressure of pulmonary artery; AWP (airway pressure): Pressure of airway) Figure 3: The anatomical findings of effluence of right accessory lobe vein (circle) (A: Entering the root of the right caudal lobe veins; B: Entering the right inferior pulmonary veins; C: Entering the position between the right and the left inferior pulmonary veins; D: Entering the left inferior pulmonary veins) The differences of values of the PaO2, PAP and AWP indicators at the collecting data time after reperfusion and baseline values were not statistically significant with p = 0.2; 0.4 and 0.7, respectively The macro-image and histological results of 15 samples showed no signs of interstitial edema (figure 4) 152 Journal of military pharmaco-medicine n02-2019 Figure 4: The macro-image and histological results of transplanted lungs after hours of perfusion No evidence of interstitial edema can be found DISCUSSION In the anatomical study, the phenotype of right accessory lobe vein entering the root of the right caudal lobe veins was found in 13/20 cases (65%) This result is slightly different from the result of S Nikakuki A new finding in our study is the case of right accessory lobe vein pouring into the left inferior pulmonary vein (2/20) Due to the anatomical characteristics of vascular and bronchial structure, it is not possible to use right lung for living donor lung transplant only left lung can be used Specifically, due to the right apical segmental bronchus raising directly from the trachea and the existence of the right accessory lobe, so it is not likely to harvest the right lung from living donor as well as to implant the lung graft into the right chest cavity In addition, given detecting the new anatomical phenotype of the right accessory lobe vein, it is necessary to take strategy to preserve the blood supply of the right accessory lobe in case of this vein entering the left inferior lobe vein while harvesting the left lower lobe in living donor lung transplant model or performing left pneumonectomy in preparation for lung implantation In deceased donor lung transplant, only the left lung is usually used as a graft due to the anatomical characteristics mentioned above According to our model created in this study, it is possible to use both right lung and left lung In the case of using the right lung, the right accessory lobe must be cut first To assess lung function after reperfusion, measured parameters were assigned: partial pressure of oxygen in arterial (PaO2) blood gases for oxygenation or gas exchange; PAP for problems in vessel anastomosis and influence of the small pulmonary vascular beds; and AWP for decreased lung compliance due to congestion of the graft, problems with the bronchial anastomosis, or secretions and finally histopathological results for microscopic edema In the study of the new lung transplant model, 153 Journal of military pharmaco-medicine n02-2019 all 15 recipients survived The graft function performed well after transplantation and there were not statistically significant differences in PaO 2, PAP and AWP between the points of measuring and the baseline (p > 05) With the new deceased donor lung transplant model, the use of animal in researching and training surgical techniques has been maximized In the old deceased donor lung transplant model, only left lung from the donor can be used as the graft for one recipient Meanwhile, both left and right lungs from the donor can be used for separate recipients with our model which can potentially facilitate experimental lung transplantation and surgical training In 2015, date reported a successful lung transplantation case in which the right lower lobe was transplanted into the left chest cavity in order to improve size matching between the donor and the recipient Our research has deeply analyzed the differences in the bronchovascular system between pigs and people to invent a new technically feasible lung transplant model on pigs The bronchovascular structure of the right lower lobe must be carefully evaluated so that when rotated 180° along the body axis and implanted into the left chest cavity, vessels and bronchus of the graft are not kinked This analysis and evaluation contributes significantly to the perfection of surgical techniques as the surgeon guides the anatomical space in both normal and abnormal positions 154 Porcine living donor using right lung is impossible, using left lung is possible, but different strategies must be used to preserve the blood supply to the donor‟s right accessory lobe With deceased donor, both the right and left caudal lobes could be used, the right accessory lobes should be excluded In new surgical model study, all 15 recipients survived, all grafts showed excellent acute and longterm function CONCLUSION Lung transplant could be performed successfully in a developing country An creative experiment program, advanced training methods could be substituted for abroad training A new porcine lobar lung transplant from deceased donor has been invented This model could be used easily for all anatomical variants REFERENCES Oto T, Okada Y, Bando T, Minami M, Shiraishi T, Nagayasu T et al Registry of the Japanese Society of Lung and Heart-Lung Transplantation: The official Japanese lung transplantation report 2012 Gen Thorac Cardiovasc Surg 2013, 61, pp.208-211 Yeung JC, Cypel M, Waddell TK, van Raemdonck D, Keshavjee S Update on donor assessment, resuscitation, and acceptance criteria, including novel techniques non-heartbeating donor lung retrieval and ex vivo donor lung perfusion Thorac Surg Clin 2009, 19, pp.261-274 Journal of military pharmaco-medicine n02-2019 Aigner C, Winkler G, Jaksch P, Ankersmit J, Marta G, Taghavi S et al Sizereduced lung transplantation: An advanced operative strategy to alleviate donor organ shortage Transplant Proc 2004, 36, pp.28012815 Otani S, Oto T, Kakishita T, Miyoshi K, Hori S, Yamane M et al Early effects of the ex vivo evaluation system on graft function after swine lung transplantation Eur J Cardiothorac Surg 2011, 40, pp.956-961 Aigner C, Jaksch P, Taghavi S, Wisser W, Marta G, Winkler G et al Donor total lung capacity predicts recipient total lung capacity after size-reduced lung transplantation J Heart Lung Transplant 2005, 24, pp.2098-2102 Date H, Matsumura A, Manchester J.K, Obo H, Lima O, Cooper J.M et al Evaluation of lung metabolism during successful twentyfour-hour canine lung preservation J Thorac Cardiovasc Surg 1993, 105, pp.480-491 Oto T, Rabinov M, Negri J, Marasco S, Rowland M, Pick A et al Techniques of reconstruction for inadequate donor left atrial cuff in lung transplantation Ann Thorac Surg 2006, 81, pp.1199-1204 Backhus L.M, Sievers E.M, Schenkel F.A, Barr M.L, Cohen R.G, Smith M.A et al Pleural space problems after living lobar transplantation J Heart Lung Transplant 2005, 24, pp.2086-2090 155 ... characteristics of the right accessory lobe and a novel porcine experimental lung transplant model and the implication with surgical training for lung transplantation MATERIAL AND METRHODS The study was done... Registry of the Japanese Society of Lung and Heart -Lung Transplantation: The official Japanese lung transplantation report 2012 Gen Thorac Cardiovasc Surg 2013, 61, pp.208-211 Yeung JC, Cypel M, Waddell... lobar lung transplant from deceased donor has been invented This model could be used easily for all anatomical variants REFERENCES Oto T, Okada Y, Bando T, Minami M, Shiraishi T, Nagayasu T et al