Extracorporeal Membrane Oxygenation in the Perioperative Care of the Lung Transplant Patient

Which strategy is better for lung transplantation: Cardiopulmonary bypass or extracorporeal membrane oxygenation?

Background: In lung transplantation surgery, extracorporeal life support (ECLS) is essential for safety. Various support methods, including cardiopulmonary bypass (CPB) and off-pump techniques, are used, with extracorporeal membrane oxygenation (ECMO) gaining prominence. However, consensus on the best support strategy is lacking.Purpose: This article reviews risks, benefits, and outcomes of different support strategies in lung transplantation. By consolidating knowledge, it aims to clarify selecting the most appropriate ECLS modality.Research Design: A comprehensive literature review examined CPB, off-pump techniques, and ECMO outcomes in lung transplantation, including surgical results and complications.Study Sample: Studies, including clinical trials and observational research, focused on ECLS in lung transplantation, both retrospective and prospective, providing a broad evidence base.Data Collection and/or Analysis: Selected studies were analyzed for surgical outcomes, complications, and survival rates associated with CPB, off-pump techniques, and ECMO to assess safety and effectiveness.Results: Off-pump techniques are preferred, with ECMO increasingly vital as a bridge to transplant, overshadowing CPB. However, ECMO entails hidden risks and higher costs. While safer than CPB, optimizing ECMO postoperative use and monitoring is crucial for success.Conclusions: Off-pump techniques are standard, but ECMO's role is expanding. Despite advantages, careful ECMO management is crucial due to hidden risks and costs. Future research should focus on refining ECMO use and monitoring to improve outcomes, emphasizing individualized approaches for LT recipients.

A two-circuit strategy for intraoperative extracorporeal support during single lung transplantation in a patient bridged with venovenous extracorporeal membrane oxygenation

Venovenous extracorporeal membrane oxygenation is increasingly used as a bridging strategy in decompensating patients awaiting lung transplantation. Various approaches for continuing support intraoperatively have been previously described. A two-circuit strategy that uses the in situ venovenous extracorporeal membrane oxygenation circuit supplemented with peripheral cardiopulmonary bypass allows for diversion of native cardiac output away from the transplanted lung as well as seamless continuation of venovenous extracorporeal membrane oxygenation postoperatively.

The effect of allograft ischemic time on outcomes following bilateral, single, and reoperative lung transplantation

OBJECTIVE

To determine whether allograft ischemic times affect outcomes following bilateral, single, and redo lung transplantation.

METHODS

A nationwide cohort of lung transplant recipients from 2005 through 2020 was examined using the Organ Procurement and Transplantation Network registry. The effects of standard (<6 hours) and extended (≥6 hours) ischemic times on outcomes following primary bilateral (n = 19,624), primary single (n = 688), redo bilateral (n = 8461), and redo single (n = 449) lung transplantation were analyzed. A priori subgroup analysis was performed in the primary and redo bilateral-lung transplant cohorts by further stratifying the extended ischemic time group into mild (≥6 and <8 hours), moderate (≥8 and <10 hours), and long (≥10 hours) subgroups. Primary outcomes included 30-day mortality, 1-year mortality, intubation at 72 hours' posttransplant, extracorporeal membrane oxygenation (ECMO) support at 72 hours' posttransplant, and a composite variable of intubation or ECMO at 72 hours' posttransplant. Secondary outcomes included acute rejection, postoperative dialysis, and hospital length of stay.

RESULTS

Recipients of allografts with ischemic times ≥6 hours experienced increased 30-day and 1-year mortality following primary bilateral-lung transplantation, but increased mortality was not observed following primary single, redo bilateral, or redo single-lung transplants. Extended ischemic times correlated with prolonged intubation or increased postoperative ECMO support in the primary bilateral, primary single, and redo bilateral-lung transplant cohorts but did not affect these outcomes following redo single-lung transplantation.

CONCLUSIONS

Since prolonged allograft ischemia correlates with worse transplant outcomes, the decision to use donor lungs with extended ischemic times must consider the specific benefits and risks associated with individual recipient factors and institutional expertise.

Perioperative Circulatory Support and Management for Lung Transplantation: A Case-Based Review

Lung transplantation (LTx) historically was performed with cardiopulmonary bypass (CPB) or Off-pump. Recent data suggest an increased interest in extracorporeal membrane oxygenation (ECMO) as perioperative circulatory support by many lung transplantation centers worldwide. However, there are no established guidelines for anesthetic management for LTx. We present a patient with a history of systemic sclerosis and interstitial lung disease complicated by acute onset of systemic pulmonary hypertension and right heart failure undergoing LTx. We aim to discuss perioperative circulatory support, including ECMO bridge to LTx, and how best to consider the varied intraoperative strategies of CPB vs ECMO vs off-pump during LTx, intraoperative maintenance, and coagulation management.

Perioperative Outcomes During Double-Lung Transplantation and Retransplantation in Cystic Fibrosis Patients: A Monocentric Cohort Study

OBJECTIVE

Life expectancy for lung-transplant patients, especially those with cystic fibrosis (CF), is leading increasingly to more retransplantations.

DESIGN

Retrospective monocentric cohort study.

SETTING

Foch University Hospital, Suresnes, France.

PARTICIPANTS

CF patients having had a primary double-lung transplantation (pLgTx) or a retransplantation (reLgTx) from 2012 to 2021.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

The authors compared the main intraoperative and early postoperative features between pLgTx (n = 258) and reLgTx (n = 24). Demographic characteristics were similar. No patients with retransplantations had a preoperative bridge with extracorporeal membrane oxygenation (ECMO); however, 23 patients had it in the pLgTx group (p = 0.24). Patients with retransplants had longer second graft ischemic time (p = 0.02), larger intraoperative bleeding volume (p = 0.001) and blood transfusion (p = 0.009 for packed red blood cells), increased blood lactate concentrations (p = 0.002), and higher norepinephrine dose at end-surgery (p = 0.001). Extracorporeal membrane oxygenation was used during surgery in 94 patients in the pLgTx group and 12 patients in the reLgTx group (p = 0.39). Extracorporeal membrane oxygenation could not be weaned after surgery in 55 patients in the pLgTx group and 4 in the reLgTx group (p = 0.54). Despite worse preoperative renal function in the reLgTx group (p < 0.001), there was no difference concerning renal replacement therapy in the intensive care unit between groups (p = 0.08). There were no differences between groups concerning the main complications, including primary graft dysfunction. Although the difference was not statistically different (p = 0.17), mortality was 3 times higher in the reLgTx group.

CONCLUSIONS

Intraoperative period of retransplantation was more convoluted but had a similar ECMO profile to primary transplantation. In addition, the early postoperative period was similar.

Extracorporeal membrane oxygenation support for lung transplantation: Initial experience in a single center in China and a literature review

Background

Extracorporeal membrane oxygenation (ECMO) is a versatile tool associated with favorable outcomes in the field of lung transplantation (LTx). Here, the clinical outcomes and complications of patients who underwent LTx with ECMO support, mainly prophylactically both intraoperatively and post-operatively, in a single center in China are reviewed.

Methods

The study cohort included all consecutive patients who underwent LTx between January 2020 and January 2022. Demographics and LTx data were retrospectively reviewed. Perioperative results, including complications and survival outcomes, were assessed.

Results

Of 86 patients included in the study, 32 received ECMO support, including 21 who received prophylactic intraoperative use of ECMO with or without prolonged post-operative use (pro-ECMO group), while the remaining 54 (62.8%) received no external support (non-ECMO group). There were no significant differences in the incidence of grade 3 primary graft dysfunction (PGD), short-term survival, or perioperative outcomes and complications between the non-ECMO and pro-ECMO groups. However, the estimated 1- and 2-year survival were superior in the pro-ECMO group, although this difference was not statistically significant (64.1% vs. 82.4%, log-rank P = 0.152; 46.5% vs. 72.1%, log-rank P = 0.182, respectively). After regrouping based on the reason for ECMO support, 30-day survival was satisfactory, while 90-day survival was poor in patients who received ECMO as a bridge to transplantation. However, prophylactic intraoperative use of ECMO and post-operative ECMO prolongation demonstrated promising survival and acceptable complication rates. In particular, patients who initially received venovenous (VV) ECMO intraoperatively with the same configuration post-operatively achieved excellent outcomes. The use of ECMO to salvage a graft affected by severe PGD also achieved acceptable survival in the rescue group.

Conclusions

Prophylactic intraoperative ECMO support and post-operative ECMO prolongation demonstrated promising survival outcomes and acceptable complications in LTx patients. Particularly, VV ECMO provided safe and effective support intraoperatively and prophylactic prolongation reduced the incidence of PGD in selected patients. However, since this study was conducted in a relatively low-volume transplant center, further studies are needed to validate the results.

Recipient Comorbidities for Prediction of Primary Graft Dysfunction, Chronic Allograft Dysfunction and Survival After Lung Transplantation

Since candidates with comorbidities are increasingly referred for lung transplantation, knowledge about comorbidities and their cumulative effect on outcomes is scarce. We retrospectively collected pretransplant comorbidities of all 513 adult recipients transplanted at our center between 1992–2019. Multiple logistic- and Cox regression models, adjusted for donor-, pre- and peri-operative variables, were used to detect independent risk factors for primary graft dysfunction grade-3 at 72 h (PGD3-T72), onset of chronic allograft dysfunction grade-3 (CLAD-3) and survival. An increasing comorbidity burden measured by Charleston-Deyo-Index was a multivariable risk for survival and PGD3-T72, but not for CLAD-3. Among comorbidities, congestive right heart failure or a mean pulmonary artery pressure >25 mmHg were independent risk factors for PGD3-T72 and survival, and a borderline risk for CLAD-3. Left heart failure, chronic atrial fibrillation, arterial hypertension, moderate liver disease, peptic ulcer disease, gastroesophageal reflux, diabetes with end organ damage, moderate to severe renal disease, osteoporosis, and diverticulosis were also independent risk factors for survival. For PGD3-T72, a BMI>30 kg/m2 was an additional independent risk. Epilepsy and a smoking history of the recipient of >20packyears are additional independent risk factors for CLAD-3. The comorbidity profile should therefore be closely considered for further clinical decision making in candidate selection.

Ethical considerations during a pioneering surgical procedure: porcine cardiac xenotransplantation

Preclinical advances in life-sustaining porcine cardiac xenotransplantation from donor pigs to baboons have paved the way for the performance of porcine cardiac xenotransplantation in a human. This procedure was performed with emergency use authorisation granted by the United States Food and Drug Administration under the umbrella of investigational new drug use on compassionate grounds. The patient was denied candidacy for durable mechanical circulatory support and heart transplantation as a result of non-adherence to medical advice.

Successful porcine cardiac xenotransplantation in humans will significantly increase the availability of potential donor organs for long-term management of end-stage heart failure. Human porcine cardiac xenotransplantation is associated with ethical conflicts encompassing multiple ethical principles which are not mutually exclusive and are sometimes conflicting. This article focuses on some of the ethical conflicts encountered in relation to the use of mechanical circulatory support, pretransplant evaluation, shared decision making during informed consent, infectious disease risk, preclinical and clinical testing, and the role of regulatory bodies during performance of the first human porcine cardiac xenotransplantation.

An increase in human trials of xenotransplantation procedures is imminent. Potential ethical conflicts associated with xenotransplantation should be addressed appropriately.

Complications of an uncovered metallic tracheal stent managed by veno-venous extracorporeal membrane oxygenation: a case report

Airway stents are primarily inserted for the management of airway obstruction associated with an inoperable malignancy and are rarely indicated in benign disease. We outline the complications associated with tracheal stents and describe the use of veno-venous extracorporeal membrane oxygenation (V-V ECMO) to facilitate open tracheal surgery in an apnoeic patient who had an uncovered metallic tracheal stent left in place for an inappropriately long period. Computerised tomography imaging of the neck and thorax provided information for operative planning and described of the stent in addition to the extensive granulation tissue at the distal end of the stent. Veno-venous extracorporeal membrane oxygenation was used to facilitate open tracheal surgery, removal of the tracheal stent and formation of a surgical tracheostomy. Prolonged use of an uncovered metallic airway stent in younger patients with benign disease may lead to the stent being difficult to remove. There may be an accumulation of granulation tissue with the risk of airway obstruction.

Intraoperative support during lung transplantation

The role of intraoperative mechanical support during lung transplantation (LTx) is essential to provide a safe hemodynamic and ventilatory status during critical intraoperative events. This hemodynamic and ventilatory stability is vital to minimize the odds of suboptimal outcomes, especially considering that, due to the scarcity of donors and the fact that more and more patients with significant comorbidities are being considered for this therapy, a more aggressive approach is often needed by the transplant centers. Hence, the attenuation of any potential injury that can happen during this complex event is paramount. While a thorough assessment of the donor and optimization of postoperative care is pursued, certainly protective intraoperative management would also contribute to better outcomes. Understanding each patient’s underlying anatomy and cardiopulmonary physiology, associated with awareness of critical events during a complicated procedure like LTx, is essential for a precise indication and safe use of support. Cardiopulmonary bypass (CPB) and veno-arterial extracorporeal membrane oxygenation (VA ECMO) have been the most common approaches used, with the latter gaining popularity more recently and we have used VA ECMO exclusively for the last decade. New technologies certainly contributed to more liberal use of VA ECMO intraoperatively, enabling a protecting and physiologic environment for the newly implanted grafts. In this setting, potential prophylactic use for lung protection during a critical period is also considered.

Outcomes following lung re-transplantation in patients with cystic fibrosis

PURPOSE

We examined cystic fibrosis (CF) patients and compared their clinical status at the time of primary versus double lung re-transplantation (re-DLTx) in order to better understand lung retransplant practice patterns.

METHODS

We performed a retrospective analysis of the UNOS Database identifying CF patients ≥18 years old undergoing re-DLTx (5/4/2005 and 12/4/2020). Baseline and clinical variables at the primary and re-DLTx were compared utilizing the paired student t-test. Graft survival was defined as time from surgery to retransplant and analyzed using Kaplan-Meier estimates.

RESULTS

277 CF patients who underwent re-DLTx experienced a significantly worse 5-year survival when compared to the primary DLTx cohort (47.9% vs 58.8%, p = 0.00012). The following differences were observed comparing CF re-DLTx group to their primary DLTx: higher LAS score at the time of listing (50.66 vs 42.15, p < 0.001) and transplant (62.19 vs 48.20, p < 0.001), and increase LAS from the time of listing to transplant (+12.22 vs +7.23, p = 0.002). While serum albumin and total bilirubin were similar, CF patients had a higher creatinine (1.05 vs 0.74, p < 0.001), dialysis (4.4% vs 0.6%, p < 0.001), ECMO bridge to transplant rates (7.6% vs 4.0%, p < 0.001), and higher oxygen requirements (5.95 vs 3.93, p < 0.001) at the time of listing for a re-DLTx.

CONCLUSION

Compared to their initial transplant, CF patients experience significant clinical decline in renal, cardiac, and pulmonary function at the time of lung retransplantation. This may indicate that an earlier evaluation and rehabilitation process may be necessary to identify patients earlier for lung retransplantation prior significant clinical decline.

Lung Disease-Related Pulmonary Hypertension

Patients with advanced lung disease can develop pulmonary hypertension and succumb to right ventricular failure/cor pulmonale. Patients with pulmonary hypertension owing to chronic lung disease, or World Health Organization group 3 pulmonary hypertension, are more limited and carry a high risk of mortality. Adjunctive therapies remain the cornerstones of treatment. Recent evidence suggests that inhaled pulmonary vasodilator therapy can be helpful in patients with pulmonary hypertension owing to interstitial lung disease. Lung transplantation may be the only life-saving option in select patients, whereas palliative care and hospice should be sought for those who are not candidates as the disease progresses.

Outcome of Bridge to Lung Transplantation With Extracorporeal Membrane Oxygenation in Pediatric Patients 12 Years and Older

BACKGROUND

There is a reluctance to using extracorporeal membrane oxygenation (ECMO) as a bridge to lung transplantation in the pediatric population. Pediatric patients between ages 12 and 18 years are eligible for acuity-based lung transplantation using the Lung Allocation Score and may be suitable for adult allografts, increasing the donor pool and thus leading to a successful bridge to lung transplantation.

METHODS

The United Network for Organ Sharing dataset was queried for primary lung transplantation in pediatric patients (12-18 years) from 2005 to 2016. Groups were divided into those who were on ECMO (bridged [BG]) and not on ECMO (nonbridged [NBG]) at the time of listing for lung transplant.

RESULTS

The groups comprised 16 BG and 375 NBG patients. Fourteen BG patients (88%) survived the first 30 days. One-year (83.3% vs 86.2%, P = .78) and 3-year (66.7% vs 55.1%, P = .57) survivals were similar in the BG and NBG groups, respectively. Donors in the BG group were more likely to be adults. The median wait-list times were shorter (10.5 [interquartile range {IQR}, 11] vs 93 [IQR, 221] days, P < .001), with a higher Lung Allocation Score (89.8 vs 36.6, P < .001) and similar median ischemic times (5.19 [IQR, 2.32] vs 5.34 [IQR, 1.92] hours, P = .85) in the BG group compared with the NBG group. The median post-transplant length of stay was longer in the BG group (33 [IQR, 31] vs 17 [IQR, 12] days, P = .007) and was the only factor predictive of 3-year mortality. Longer wait-list time had a higher mortality in the BG group.

CONCLUSIONS

ECMO as a bridge to lung transplantation is a reasonable strategy in pediatric patients aged ≥ 12 years with acceptable operative mortality and similar 1- and 3-year survival compared with nonbridged patients despite higher acuity. Bridged patients were more likely to receive adult donor lungs.