Intermittent Ex Vivo Lung Perfusion in a Porcine Model for Prolonged Lung Preservation.

BACKGROUND: Ex vivo lung perfusion expands the lung transplant donor pool and extends preservation time beyond cold static preservation. We hypothesized that repeated regular ex vivo lung perfusion would better maintain lung grafts. METHODS: Ten pig lungs were randomized into 2 groups. The control underwent 16 h of cold ischemic time and 2 h of cellular ex vivo lung perfusion. The intermittent ex vivo lung perfusion group underwent cold ischemic time for 4 h, ex vivo lung perfusion (first) for 2 h, cold ischemic time for 10 h, and 2 h of ex vivo lung perfusion (second). Lungs were assessed, and transplant suitability was determined after 2 h of ex vivo lung perfusion. RESULTS: The second ex vivo lung perfusion was significantly associated with better oxygenation, limited extravascular water, higher adenosine triphosphate, reduced intraalveolar edema, and well-preserved mitochondria compared with the control, despite proinflammatory cytokine elevation. No significant difference was observed in the first and second perfusion regarding oxygenation and adenosine triphosphate, whereas the second was associated with lower dynamic compliance and higher extravascular lung water than the first. Transplant suitability was 100% for the first and 60% for the second ex vivo lung perfusion, and 0% for the control. CONCLUSIONS: The second ex vivo lung perfusion had a slight deterioration in graft function compared to the first. Intermittent ex vivo lung perfusion created a better condition for lung grafts than cold static preservation, despite cytokine elevation. These results suggested that intermittent ex vivo lung perfusion may help prolong lung preservation.

Arterial Hyperoxemia During Cardiopulmonary Bypass Was Not Associated With Worse Postoperative Pulmonary Function: A Retrospective Cohort Study.

BACKGROUND: Arterial hyperoxemia may cause end-organ damage secondary to the increased formation of free oxygen radicals. The clinical evidence on postoperative lung toxicity from arterial hyperoxemia during cardiopulmonary bypass (CPB) is scarce, and the effect of arterial partial pressure of oxygen (Pa o2 ) during cardiac surgery on lung injury has been underinvestigated. Thus, we aimed to examine the relationship between Pa o2 during CPB and postoperative lung injury. Secondarily, we examined the relationship between Pa o2 and global (lactate), and regional tissue malperfusion (acute kidney injury). We further explored the association with regional tissue malperfusion by examining markers of cardiac (troponin) and liver injury (bilirubin). METHODS: This was a retrospective cohort study including patients who underwent elective cardiac surgeries (coronary artery bypass, valve, aortic, or combined) requiring CPB between April 2015 and December 2021 at a large quaternary medical center. The primary outcome was postoperative lung function defined as the ratio of Pa o2 to fractional inspired oxygen concentration (F io2 ); P/F ratio 6 hours following surgery or before extubation. The association between CPB in-line sample monitor Pa o2 and primary, secondary, and exploratory outcomes was evaluated using linear or logistic regression models adjusting for available baseline confounders. RESULTS: A total of 9141 patients met inclusion and exclusion criteria, and 8429 (92.2%) patients had complete baseline variables available and were included in the analysis. The mean age of the sample was 64 (SD = 13), and 68% were men (n = 6208). The time-weighted average (TWA) of in-line sample monitor Pa o2 during CPB was weakly positively associated with the postoperative P/F ratio. With a 100-unit increase in Pa o2 , the estimated increase in postoperative P/F ratio was 4.61 (95% CI, 0.71-8.50; P = .02). Our secondary analysis showed no significant association between Pa o2 with peak lactate 6 hours post CPB (geometric mean ratio [GMR], 1.01; 98.3% CI, 0.98-1.03; P = .55), average lactate 6 hours post CPB (GMR, 1.00; 98.3% CI, 0.97-1.03; P = .93), or acute kidney injury by Kidney Disease Improving Global Outcomes (KDIGO) criteria (odds ratio, 0.91; 98.3% CI, 0.75-1.10; P = .23). CONCLUSIONS: Our investigation found no clinically significant association between Pa o2 during CPB and postoperative lung function. Similarly, there was no association between Pa o2 during CPB and lactate levels, postoperative renal function, or other exploratory outcomes.

What determines outcomes in multivalve reoperations? Effect of patient and surgical complexity.

OBJECTIVE: Patient characteristics, risks, and outcomes associated with reoperative multivalve cardiac surgery are poorly characterized. Effect of patient variables and surgical components of each reoperation were evaluated with regard to operative mortality. METHODS: From January 2008 to January 2022, 2324 patients with previous cardiac surgery underwent 2352 reoperations involving repair or replacement of multiple cardiac valves at Cleveland Clinic. Mean age was 66 ± 14 years. Number of surgical components representing surgical complexity (valve procedures, aortic surgery, coronary artery bypass grafting, and atrial fibrillation procedures) ranged from 2 to 6. Random forest for imbalanced data was used to identify risk factors for operative mortality. RESULTS: Surgery was elective in 1327 (56%), urgent in 1006 (43%), and emergency in 19 (0.8%). First-time reoperations were performed in 1796 (76%) and 556 (24%) had 2 or more previous operations. Isolated multivalve operations comprised 54% (1265) of cases; 1087 incorporated additional surgical components. Two valves were operated on in 80% (1889) of cases, 3 in 20% (461), and 4 in 0.09% (2). Operative mortality was 4.2% (98 out of 2352), with 1.7% (12 out of 704) for elective, isolated multivalve reoperations. For each added surgical component, operative mortality incrementally increased, from 2.4% for 2 components (24 out of 1009) to 17% for ≥5 (5 out of 30). Predictors of operative mortality included coronary artery bypass grafting, surgical urgency, cardiac, renal dysfunction, peripheral artery disease, New York Heart Association functional class, and anemia. CONCLUSIONS: Elective, isolated reoperative multivalve surgery can be performed with low mortality. Surgical complexity coupled with key physiologic factors can be used to inform surgical risk and decision making.

Radiation Exposure in Extracorporeal Life Support.

Extracorporeal membrane oxygenation (ECMO) exposes patients to multiple radiologic studies. We hypothesized ECMO patients endure radiation exposure in excess of the International Commission of Radiological Protection (ICRP) recommendations of cumulative effective dose (CED, >20 mSv and 5-year cumulative limit of CED >100 mSv). We conducted a retrospective observational study in an academic medical center between January 2016 and December 2018 involving adult admissions (N = 306) on ECMO. Ionizing radiation was calculated from reference values to determine CED. Approximately 9.4% (N = 29) patients accrued CED >50 mSv and 4.5% (N = 14) accrued CED >100 mSv during ECMO. Over the entire hospitalization, 28% (N = 85) accrued >50 mSv and 14.7% (N = 45) accrued CED >100 mSv. Median CED during ECMO was 2.3 mSv (IQR, -0.82 to 8.1 mSv), and the entire hospitalization was 17.4 mSv (IQR, -4.5 to 56.6 mSv). Thirteen percent of the median CED accrued during hospitalization could be attributed to ECMO. Longer hospitalization was associated with a higher CED (50 days [IQR, -25 to 76 days] in CED >50 vs. 19 days [IQR, -10 to 32 days] in CED <50). Computer tomography (CT) scans and interventional radiology (IR) procedures contributed to 43.8% and 44.86%, respectively, of CED accrued on ECMO and 52.2% and 37.1% of CED accumulated during the whole hospitalization. Guidelines aimed at mitigating radiation exposure are urgently needed.

Increasing surgeon experience and cumulative institutional experience drive decreasing hospital mortality after reoperative cardiac surgery.

OBJECTIVE: The study objective was to identify the effects of surgeon experience and age, in the context of cumulative institutional experience, on risk-adjusted hospital mortality after cardiac reoperations. METHODS: From 1951 to 2020, 36 surgeons performed 160,338 cardiac operations, including 32,871 reoperations. Hospital death was modeled using a novel tree-bagged, generalized varying-coefficient method with 6 variables reflecting cumulative surgeon and institutional experience up to each cardiac operation: (1) number of total and (2) reoperative cardiac operations performed by a surgeon, (3) cumulative institutional number of total and (4) reoperative cardiac operations, (5) year of surgery, and (6) surgeon age at each operation. These were adjusted for 46 patient characteristics and surgical components. RESULTS: There were 1470 hospital deaths after cardiac reoperations (4.5%). At the institutional level, hospital death decreased exponentially and became less variable, leveling at 1.2% after approximately 14,000 cardiac reoperations. For all surgeons as a group, hospital death decreased rapidly over the first 750 reoperations and then gradually decreased with increasing experience to less than 1% after approximately 4000 reoperations. Surgeon age up to 75 years was associated with ever-decreasing hospital death. CONCLUSIONS: Surgeon age and experience have been implicated in adverse surgical outcomes, particularly after complex cardiac operations, with young surgeons being novices and older surgeons having declining ability. However, at Cleveland Clinic, outcomes of cardiac reoperations improved with increasing primary surgeon experience, without any suggestion to mid-70s of an age cutoff. Patients were protected by the cumulative background of institutional experience that created a culture of safety and teamwork that mitigated adverse events after cardiac surgery.

Lung Transplant After a Heart Transplant: A Case Report.

A heart-lung transplant is considered in patients with end-stage heart and lung disease. However, there is no report of a patient receiving a staged heart transplant followed by a lung transplant. Our case report describes a successful left single lung transplant for idiopathic pulmonary fibrosis 6 years after a heart transplant. This case illustrates that this approach can avoid significantly increased wait time until transplant, and it shows that early interstitial lung disease may not be a contraindication for the heart transplant.

Left ventricular assist device mode: Co-pulse left ventricular unloading in a working mode of ex vivo heart perfusion.

BACKGROUND: For normothermic ex vivo heart perfusion (EVHP), a resting mode and working mode have been proposed. We newly developed a left ventricular assist device (LVAD) mode that supports heart contraction by co-pulse synchronized LVAD. METHODS: Following resting mode during time 0 to 1 hour, pig hearts (n = 18) were perfused in either resting, working, or LVAD mode during time 1 to 5 hour, and then myocardial function was evaluated in working mode at 6 hour. The preservation ratio was defined as the myocardial mechanical function at 330 minute divided by the function at 75 minute. In LVAD mode, LVAD unloaded the pressure and the volume in the left ventricle in the systolic phase. RESULTS: The LVAD group was significantly associated with higher preservation ratios in cardiac output (resting, 33 ± 3; working, 35 ± 5; LVAD, 76% ± 5%; p < 0.001), stroke work, dP/dt maximum, and dP/dt minimum compared with the other groups. Glucose consumption was significantly reduced in the resting group. The LVAD group was significantly associated with higher myocardial oxygen consumption (resting, 2.2 ± 0.3; working; 4.6 ± 0.5; LVAD, 6.1 ± 0.5 mL O2/min/100 g, p < 0.001) and higher adenosine triphosphate (ATP) levels (resting, 1.1 ± 0.1; working, 0.7 ± 0.1; LVAD, 1.6 ± 0.2 µmol/g, p = 0.001) compared with the others. CONCLUSION: These data suggest that myocardial mechanical function was better preserved in LVAD mode than in resting and working modes. Although our data suggested similar glycolysis activity in the LVAD and working groups, the higher final ATP in the LVAD group might be explained by reduced external work in LVAD.

Effect of donor smoking and substance use on post-lung transplant outcomes.

OBJECTIVE: The study objective was to determine effects of donor smoking and substance use on primary graft dysfunction, allograft function, and survival after lung transplant. METHODS: From January 2007 to February 2020, 1366 lung transplants from 1291 donors were performed in 1352 recipients at Cleveland Clinic. Donor smoking and substance use history were extracted from the Uniform Donor Risk Assessment Interview and medical records. End points were post-transplant primary graft dysfunction, longitudinal forced expiratory volume in 1 second (% of predicted), and survival. RESULTS: Among lung transplant recipients, 670 (49%) received an organ from a donor smoker, 163 (25%) received an organ from a donor with a 20 pack-year or more history (median pack-years 8), and 702 received an organ from a donor with substance use (51%). There was no association of donor smoking, pack-years, or substance use with primary graft dysfunction (P > .2). Post-transplant forced expiratory volume in 1 second was 74% at 1 year in donor nonsmoker recipients and 70% in donor smoker recipients (P = .0002), confined to double-lung transplant, where forced expiratory volume in 1 second was 77% in donor nonsmoker recipients and 73% in donor smoker recipients. Donor substance use was not associated with allograft function. Donor smoking was associated with 54% non-risk-adjusted 5-year survival versus 59% (P = .09) and greater pack-years with slightly worse risk-adjusted long-term survival (P = .01). Donor substance use was not associated with any outcome (P ≥ 8). CONCLUSIONS: Among well-selected organs, lungs from smokers were associated with non-clinically important worse allograft outcomes without an inflection point for donor smoking pack-years. Substance use was not associated with worse allograft function. Given the paucity of organs, donor smoking or substance use alone should not preclude assessment for lung donation or transplant.

The American Association for Thoracic Surgery (AATS) 2022 Expert Consensus Document: The use of mechanical circulatory support in lung transplantation.

OBJECTIVE: The use of mechanical circulatory support (MCS) in lung transplantation has been steadily increasing over the prior decade, with evolving strategies for incorporating support in the preoperative, intraoperative, and postoperative settings. There is significant practice variability in the use of these techniques, however, and relatively limited data to help establish institutional protocols. The objective of the AATS Clinical Practice Standards Committee (CPSC) expert panel was to review the existing literature and establish recommendations about the use of MCS before, during, and after lung transplantation. METHODS: The AATS CPSC assembled an expert panel of 16 lung transplantation physicians who developed a consensus document of recommendations. The panel was broken into subgroups focused on preoperative, intraoperative, and postoperative support, and each subgroup performed a focused literature review. These subgroups formulated recommendation statements for each subtopic, which were evaluated by the entire group. The statements were then developed via discussion among the panel and refined until consensus was achieved on each statement. RESULTS: The expert panel achieved consensus on 36 recommendations for how and when to use MCS in lung transplantation. These recommendations included the use of veno-venous extracorporeal membrane oxygenation (ECMO) as a bridging strategy in the preoperative setting, a preference for central veno-arterial ECMO over traditional cardiopulmonary bypass during the transplantation procedure, and the benefit of supporting selected patients with MCS postoperatively. CONCLUSIONS: Achieving optimal results in lung transplantation requires the use of a wide range of strategies. MCS provides an important mechanism for helping these critically ill patients through the peritransplantation period. Despite the complex nature of the decision making process in the treatment of these patients, the expert panel was able to achieve consensus on 36 recommendations. These recommendations should provide guidance for professionals involved in the care of end-stage lung disease patients considered for transplantation.

Reflux Surgery in Lung Transplantation: A Multicenter Retrospective Study.

BACKGROUND: Aspiration has been associated with graft dysfunction after lung transplantation, leading some to advocate for selective use of fundoplication despite minimal data supporting this practice. METHODS: We performed a multicenter retrospective study at 4 academic lung transplant centers to determine the association of gastroesophageal reflux disease and fundoplication with bronchiolitis obliterans syndrome and survival using Cox multivariable regression. RESULTS: Of 542 patients, 136 (25.1%) underwent fundoplication; 99 (18%) were found to have reflux disease without undergoing fundoplication. Blanking the first year after transplantation, fundoplication was not associated with a benefit regarding freedom from bronchiolitis obliterans syndrome (hazard ratio [HR], 0.93; 95% CI, 0.58-1.49) or death (HR, 0.97; 95% CI, 0.47-1.99) compared with reflux disease without fundoplication. However, a time-dependent adjusted analysis found a slight decrease in mortality (HR, 0.59; 95% CI, 0.28-1.23; P = .157), bronchiolitis obliterans syndrome (HR, 0.68; 95% CI, 0.42-1.11; P = .126), and combined bronchiolitis obliterans syndrome or death (HR, 0.66; 95% CI, 0.42-1.04; P = .073) in the fundoplication group compared with the gastroesophageal reflux disease group. CONCLUSIONS: Although a statistically significant benefit from fundoplication was not determined because of limited sample size, follow-up, and potential for selection bias, a randomized, prospective study is still warranted.

Prone ex vivo lung perfusion protects human lungs from reperfusion injury.

BACKGROUND: We previously reported beneficial effects of prone positioning during ex vivo lung perfusion (EVLP) using porcine lungs. In this study, we sought to determine if prone positioning during EVLP was beneficial in human donor lungs rejected for clinical use. METHODS: Human double lung blocs were randomized to prone EVLP (n = 5) or supine EVLP (n = 5). Following 16 h of cold storage at 4°C and 2 h of cellular EVLP in either the prone or supine position. Lung function, compliance, and weight were evaluated and transplant suitability determined after 2 h of EVLP. RESULTS: Human lungs treated with prone EVLP had significantly higher partial pressure of oxygen/fraction of inspired oxygen (P/F) ratio [348 (291-402) vs. 199 (191-257) mm Hg, p = 0.022] and significantly lower lung weight [926(864-1078) vs. 1277(1029-1483) g, p = 0.037] after EVLP. 3/5 cases in the prone group were judged suitable for transplant after EVLP, while 0/5 cases in the supine group were suitable. When function of upper vs. lower lobes was evaluated, prone EVLP lungs showed similar P/F ratios and inflammatory cytokine levels in lower vs. upper lobes. In contrast, supine EVLP lungs showed significantly lower P/F ratios [68(59-150) vs. 467(407-515) mm Hg, p = 0.012] and higher tissue tumor necrosis factor alpha levels [100.5 (46.9-108.3) vs. 39.9 (17.0-61.0) ng/ml, p = 0.036] in lower vs. upper lobes. CONCLUSIONS: Prone lung positioning during EVLP may optimize the outcome of EVLP in human donor lungs, possibly by improving lower lobe function.

Right Internal Thoracic Artery Patency Is Affected More by Target Choice Than Conduit Configuration.

BACKGROUND: Although coronary artery bypass grafting using bilateral internal thoracic arteries (ITA) maximizes long-term survival, knowledge of the effect of different right ITA (RITA) inflow configurations on graft patency is limited. We have compared RITA occlusion among these configurations and identified its risk factors while adjusting for outflow coronary target location. METHODS: From January 1972 to January 2016, of 7092 patients undergoing bilateral ITA grafting at a single center, 1331 received one ITA to the left anterior descending coronary artery and had one or more evaluable postoperative coronary angiograms: 835 (63%) in situ, 496 free RITA grafts (311 [63%] originating from aorta; 98 [20%] left ITA [LITA], 76 [15%] saphenous vein graft, 11 [2%] radial graft). RITA occlusion reported on 1983 angiograms performed a median of 5.8 years later was estimated using nonlinear mixed-effects longitudinal modeling. RESULTS: RITA patency was 90% at 1 year, 87% at 5 years, and 86% at 10 and 15 years. At 15 years, in situ RITA patency was 91% and free RITA patency from aorta was 91%, LITA 89%, and saphenous vein graft 77%. After adjusting for coronary target location and degree of stenosis, occlusion was similar in free RITAs from aorta (P = .15), LITA (P = .4), saphenous vein grafts (P = .13), and in situ RITAs. However, RITAs grafted to the left anterior descending coronary artery had fewer occlusions (P < .001), with patency similar to LITAs. CONCLUSIONS: Among patients with bilateral ITA grafting requiring interval coronary angiography, long-term RITA patency was high and independent of its inflow configuration. Therefore, priority should be a RITA configuration optimizing its reach to important coronary targets, including the left anterior descending coronary artery.

Trends, risk factors, and outcomes of post-operative stroke after heart transplantation: an analysis of the UNOS database.

BACKGROUND: Post-operative stroke increases morbidity and mortality after cardiac surgery. Data on characteristics and outcomes of stroke after heart transplantation (HTx) are limited. METHODS AND RESULTS: We conducted a retrospective analysis of the United Network for Organ Sharing (UNOS) database from 2009 to 2020 to identify adults who developed stroke after orthotropic HTx. Heart transplant recipients were divided according to the presence or absence of post-operative stroke. The primary endpoint was all-cause mortality. A total of 25 015 HT recipients were analysed, including 719 (2.9%) patients who suffered a post-operative stroke. The stroke rates increased from 2.1% in 2009 to 3.7% in 2019, and the risk of stroke was higher after the implantation of the new allocation system [odds ratio 1.29, 95% confidence intervals (CI) 1.06-1.56, P = 0.01]. HTx recipients with post-operative stroke were older (P = 0.008), with higher rates of prior cerebrovascular accident (CVA) (P = 0.004), prior cardiac surgery (P < 0.001), longer waitlist time (P = 0.04), higher rates of extracorporeal membrane oxygenation (ECMO) support (P < 0.001), left ventricular assist devices (LVADs) (P < 0.001), mechanical ventilation (P = 0.003), and longer ischaemic time (P < 0.001). After multivariable adjustment for recipient and donor characteristics, age, prior cardiac surgery, CVA, support with LVAD, ECMO, ischaemic time, and mechanical ventilation at the time of HTx were independent predictors of post-operative stroke. Stroke was associated with increased risk of 30 day and all-cause mortality (hazard ratio 1.49, 95% CI 1.12-1.99, P = 0.007). CONCLUSIONS: Post-operative stroke after HTx is infrequent but associated with higher mortality. Redo sternotomy, LVAD, and ECMO support at HTx are among the risk factors identified.

Pleural space management after lung transplant: Early and late outcomes of pleural decortication.

BACKGROUND: Pleural complications after lung transplant may restrict allograft expansion, requiring decortication. However, its extent, indications, risk factors, and effect on allograft function and survival are unclear. METHODS: From January 2006 to January 2017, 1,039 patients underwent primary lung transplant and 468 had pleural complications, 77 (16%) of whom underwent 84 surgical decortications for pleural space management. Multivariable time-related analysis was performed to identify risk factors for decortication. Mixed-effect longitudinal modeling was used to assess allograft function before and after decortication. RESULTS: Cumulative number of decortications per 100 transplants was 1.8, 7.8, and 8.8 at 1 month, 1 year, and 3 years after transplant, respectively. Indications for the 84 decortications were complex effusion in 47 (56%), fibrothorax in 17 (20%), empyema in 11 (13%), and hemothorax in 9 (11%). Thoracoscopic operations were performed in 52 (62%) and full lung re-expansion was achieved in 76 (90%). Complications occurred after 30 (36%) decortications, with 15 pulmonary complications (18%), including 2 patients requiring extracorporeal support due to worsening function. Ten reinterventions occurred via thoracentesis (2), tube thoracostomy (1), and reoperation (7). In-hospital and 30-day mortality was 5.2% (n = 4/77). Forced expiratory volume in 1 second increased from 50% to 60% within the first year after decortication, followed by a slow decline to 55% at 5 years. Postdecortication survival was 87%, 68%, and 48% at 1, 3, and 5 years, respectively. CONCLUSIONS: Despite high risk of reoperative surgery, decortication after lung transplant allows salvage of pleural space and graft function with a reasonable morbidity profile.

Natural History of Pleural Complications After Lung Transplantation.

BACKGROUND: Despite advances in lung transplantation, 5-year survival remains at 56%. Although the focus has been on chronic lung allograft dysfunction and infection, pleural complications in some may contribute to adverse outcomes. Therefore, we determined (1) the prevalence of, and risk factors for, pleural complications after lung transplantation and (2) their association with allograft function and mortality. METHODS: From 2006 to 2017, 1039 adults underwent primary lung transplantation at Cleveland Clinic in Cleveland, Ohio. Multivariable analyses were performed in the multiphase mixed longitudinal and hazard function domains to identify risk factors associated with allograft function and survival. RESULTS: A total of 468 patients (45%) had pleural complications, including pleural effusion in 271 (26%), pneumothorax in 152 (15%), hemothorax in 128 (12%), empyema in 47 (5%), and chylothorax in 9 (1%). Risk factors for pleural complications within the first 3 months included higher recipient-to-donor weight ratio, lower recipient albumin, and recipient-to-donor race mismatch; risk factors extending beyond 3 months included older age, hypertension, smoking history, lower lung allocation score, and donor death from anoxia. Cardiopulmonary bypass and previous thoracic interventions were not risk factors in patients with pleural effusions who were treated with thoracentesis only, and forced expiratory volume in 1 second improved after drainage; however, repeat percutaneous or surgical interventions did not impart a similar benefit. Pleural complications were associated with worse survival. CONCLUSIONS: Pleural complications are common after lung transplantation and are associated with worse allograft function and survival. These complications are likely secondary to other underlying clinical problems. Malnourishment and size mismatch are modifiable risk factors.

Bilateral sequential lung transplantation: technical aspects.

The surgical technique for lung transplantation has evolved dramatically over the last three decades. Significant improvements in short term outcomes in the early years of lung transplantation were due, in large part, to techniques developed to reduce airway anastomotic complications in single lung transplantation. Following development of the technique of en bloc double lung transplantation, evolution to the bilateral sequential technique further reduced airway complications for double lung transplantation. More recently, some programs have utilized the en bloc double lung transplant technique with bronchial artery revascularization to aid airway healing and potentially improve short- and long-term outcomes. The experience with bronchial artery revascularization remains limited to a few series, with the technique having not been widely adopted by most lung transplant programs. With the implementation of priority allocations schemes in many countries, patients with higher risk profiles are being prioritized for transplantation which results in more complex procedures in fragile recipients with multiple comorbidities. This includes the increased need for concomitant cardiac procedures as well as performing lung transplantation after prior cardiothoracic surgery. Different surgical approaches have been described for bilateral sequential lung transplantation with or without intra-operative mechanical circulatory support (MCS), such as sternotomy, clamshell (bilateral anterior thoracotomies with transverse sternotomy), and bilateral thoracotomy incisions. Herein, we aim, not only to describe the various surgical approaches for double lung transplantation, but to provide a comprehensive review of other aspects related to the recipient pathology and different anatomical variants as well as handling technical challenges that might be encountered during the procedure.

The Effect of Blood Transfusion in Lung Donors on Recipient Survival.

BACKGROUND: Blood transfusion can have detrimental effects on the pulmonary system, leading to lung injury and respiratory decompensation with subsequent increased morbidity and mortality in surgical and critically ill patients. How much of this effect is carried from a lung donor to transplant recipient is not fully understood, raising questions regarding transplant suitability of lungs from transfused donors. METHODS: United Network for Organ Sharing data were reviewed. Lung transplants from adult donors and known donor transfusion status were included; multiorgan transplants and retransplants were excluded. Recipient mortality was evaluated based on donor and recipient characteristics using a Kaplan-Meier survival estimate, Cox proportional hazards, and logistic regression models. We further assessed whether recipient mortality risk modified the donor transfusion effect. RESULTS: From March 1996 to June 2017, 20,294 transplants were identified. Outcome analysis based on transfusion status showed nonsignificant difference in 1-year mortality (P = .214). Ninety-day recipient mortality was significantly higher with transfusion of >10 units (U) vs 1-10 U or no transfusion (8.5%, 6.1%, and 6.0%, respectively, P = .005). Multivariable analysis showed increased 90-day mortality with transfusion of >10 U compared to no transfusion (odds ratio 1.62, P < .001), whereas 1-10 U showed no difference (odds ratio 1.07, P = .390). When stratified by recipient transplant risk, transfusion of >10 U was associated with increased mortality even with the lowest-risk recipients, while transfusion of 1-10 U showed no mortality increase even in the highest-risk recipients. CONCLUSIONS: Donor transfusion of >10 U of blood was associated with increased 90-day recipient mortality even in low-risk transplants. This risk should be considered when evaluating donor lungs.

Ventricular assist device bridging with gender-mismatch increases rejection and decreases survival following a heart transplant.

OBJECTIVES: Survival is poor following an orthotopic heart transplant with gender-mismatched donors and recipients. Patients bridged to an orthotopic heart transplant with a ventricular assist device (VAD) frequently become sensitized. We hypothesized that the combination of VAD bridging and gender-mismatch may result in greater rejection and poorer survival. METHODS: Data were obtained from the United Network of Organ Sharing database. Patients were divided into 4 groups: (i) VAD recipients who received a heart from a gender-matched donor (VAD-M); (ii) VAD recipients who received a heart from a gender-mismatched donor (VAD-MM); (iii) noVAD recipients who received a heart from a gender-matched donor (noVAD-M); and (iv) noVAD recipients who received a heart from a gender-mismatched donor (noVAD-MM). Rejection episodes within 1-year post-transplant and transplant survival were compared in VAD-M versus VAD-MM and noVAD-M versus noVAD-MM groups, respectively. RESULTS: Between January 2000 and June 2017, of 33 401 adult patients who underwent heart transplants, 8648, 2441, 12 761 and 4992 patients were identified as VAD-M, VAD-MM, noVAD-M and noVAD-MM, respectively. Rejection within 1-year post-transplant occurred in 23.3% and 27.3% of the VAD-M and VAD-MM groups, respectively (P < 0.01) and in 21.8% and 23.6% of the noVAD-M and noVAD-MM groups (P = 0.02), respectively. In an adjusted survival analysis, the VAD-MM group showed significantly worse survival than the VAD-M group (P < 0.01), whereas there was no significant difference between the noVAD-M and noVAD-MM groups (P = 0.21). CONCLUSIONS: Our results indicated that the combination of VAD bridging and gender-mismatch caused greater rejection and worse survival following a transplant. Further study is necessary to prove comparable post-transplant survival of gender-matched or -mismatched recipients without VAD bridging.

Hyperinflation With Pulmonary Dysfunction in Donor Lungs With Smoking History During Lung Perfusion.

BACKGROUND: Donor lungs with smoking history are perfused in ex vivo lung perfusion (EVLP) to expand donor lung pool. However, the impact of hyperinflation of perfused lungs in EVLP remains unknown. The aim of this study was to investigate the significance of hyperinflation, using an ex vivo measurement delta VT, during EVLP in smoker's lungs. MATERIALS AND METHODS: Seventeen rejected donor lungs with smoking history of median 10 pack-years were perfused for 2 h in cellular EVLP. Hyperinflation was evaluated by measuring delta VT = inspiratory - expiratory tidal volume (VT) difference at 1 h. All lungs were divided into two groups; negative delta VT (n = 11, no air-trapping pattern) and positive delta VT (n = 6, air-trapping pattern). Transplant suitability was judged at 2 h. By using lung tissue, linear intercept analysis was performed to evaluate the degree of hyperinflation. RESULTS: The positive delta VT group had significantly lower transplant suitability than the negative delta VT group (16 versus 81%, P = 0.035). The positive delta VT group was significantly associated with lower partial pressure of oxygen/fraction of inspired oxygen ratio ratio (278 versus 356 mm Hg, P = 0.049), higher static compliance (119 versus 98 mL/cm H2O, P = 0.050), higher lung weight ratio (1.10 versus 0.96, P = 0.014), and higher linear intercept ratio (1.52 versus 0.93, P = 0.005) than the negative delta VT group. CONCLUSIONS: Positive delta VT appears as an ex vivo marker of ventilator-associated lung hyperinflation of smoker's lungs during EVLP.