National Heart, Lung, and Blood Institute and American Association for Thoracic Surgery Workshop Report: Identifying collaborative clinical research priorities in lung transplantation

Development of the Lung Transplant Frailty Scale (LT-FS)

BACKGROUND

Existing measures of frailty developed in community dwelling older adults may misclassify frailty in lung transplant candidates. We aimed to develop a novel frailty scale for lung transplantation with improved performance characteristics.

METHODS

We measured the short physical performance battery (SPPB), fried frailty phenotype (FFP), Body Composition, and serum Biomarkers representative of putative frailty mechanisms. We applied a 4-step established approach (identify frailty domain variable bivariate associations with the outcome of waitlist delisting or death; build models sequentially incorporating variables from each frailty domain cluster; retain variables that improved model performance ability by c-statistic or AIC) to develop 3 candidate "Lung Transplant Frailty Scale (LT-FS)" measures: 1 incorporating readily available clinical data; 1 adding muscle mass, and 1 adding muscle mass and research-grade Biomarkers. We compared construct and predictive validity of LT-FS models to the SPPB and FFP by ANOVA, ANCOVA, and Cox proportional-hazard modeling.

RESULTS

In 342 lung transplant candidates, LT-FS models exhibited superior construct and predictive validity compared to the SPPB and FFP. The addition of muscle mass and Biomarkers improved model performance. Frailty by all measures was associated with waitlist disability, poorer HRQL, and waitlist delisting/death. LT-FS models exhibited stronger associations with waitlist delisting/death than SPPB or FFP (C-statistic range: 0.73-0.78 vs. 0.57 and 0.55 for SPPB and FFP, respectively). Compared to SPPB and FFP, LT-FS models were generally more strongly associated with delisting/death and improved delisting/death net reclassification, with greater improvements with increasing LT-FS model complexity (range: 0.11-0.34). For example, LT-FS-Body Composition hazard ratio for delisting/death: 6.0 (95%CI: 2.5, 14.2), SPPB HR: 2.5 (95%CI: 1.1, 5.8), FFP HR: 4.3 (95%CI: 1.8, 10.1). Pre-transplant LT-FS frailty, but not SPPB or FFP, was associated with mortality after transplant.

CONCLUSIONS

The LT-FS is a disease-specific physical frailty measure with face and construct validity that has superior predictive validity over established measures.

Intraoperative Support for Primary Bilateral Lung Transplantation: A Propensity-Matched Analysis

BACKGROUND

Single-center studies support benefits of venoarterial extracorporeal membrane oxygenation (VA-ECMO) as a method of intraoperative support. Propensity-matched data from a large cohort, however, are currently lacking. Therefore, our goal was to compare outcomes of intraoperative VA-ECMO and cardiopulmonary bypass (CPB) during bilateral lung transplantation (LTx) with a propensity analysis.

METHODS

We performed a retrospective analysis of 795 consecutive primary adult LTx patients (June 1, 2011-December 26, 2020) using no intraoperative support (n = 210), VA-ECMO (n = 150), or CPB (n = 197). Exclusion criteria included LTx on venovenous-ECMO, single/redo LTx, ex vivo lung perfusion, and concomitant solid-organ transplantation or cardiac procedure. Propensity analysis was performed comparing patients who underwent intraoperative CPB or VA-ECMO.

RESULTS

The propensity CPB group required more blood products at 72 hours (P = .02) and longer intensive care unit length of stay (P < .001) and ventilator dependence days (P < .001). There were no differences in cerebrovascular accident (P = 1), reintubation (P = .4), dialysis (P = .068), in-hospital mortality (P = .33), and 1-year (P = .67) and 3-year (P = .32) survival. The CPB group had a higher incidence of grade 3 primary graft dysfunction at 72 hours (P < .001). Neither support strategy was a predictor of 1- and 3-year mortality in our multivariable model (VA-ECMO, P = .72 and P = .57; CPB, P = .45 and P = .91, respectively).

CONCLUSIONS

Intraoperative VA-ECMO during lung transplantation was associated with fewer postoperative blood transfusions, shorter length of mechanical ventilation, and lower incidence of a grade 3 primary graft dysfunction at 72 hours. Although there were some differences in the postoperative course between the VA-ECMO and CPB groups, support type was not associated with differences in survival.

The Intersection of Aging and Lung Transplantation: its Impact on Transplant Evaluation, Outcomes, and Clinical Care

Purpose

Older adults (age ≥ 65 years) are the fastest growing age group undergoing lung transplantation. Further, international consensus document for the selection of lung transplant candidates no longer suggest a fixed upper age limit. Although carefully selected older adults can derive great benefit, understanding which older adults will do well after transplant with improved survival and health-related qualiy of life is key to informed decision-making. Herein, we review the epidemiology of aging in lung transplantation and its impact on outcomes, highlight selected physiological measures that may be informative when evaluating and managing older lung transplant patients, and identify directions for future research.

Recent Findings

In general, listing and transplanting older, sicker patients has contributed to worse clinical outcomes and greater healthcare use. Emerging evidence suggest that measures of physiological age, such as frailty, body composition, and neurocognitive and psychosocial function, may better identify risk for poor transplant outcomes than chronlogical age.

Summary

The evidence base to inform transplant decision-making and improvements in care for older adults is small but growing. Multipronged efforts at the intersection of aging and lung transplantation are needed to improve the clinical and patient centered outcomes for this large and growing cohort of patients. Future research should focus on identifying novel and ideally modifiable risk factors for poor outcomes specific to older adults, better approaches to measuring physiological aging (e.g., frailty, body composition, neurocognitive and psychosocial function), and the underlying mechanisms of physiological aging. Finally, interventions that can improve clinical and patient centered outcomes for older adults are needed.

Sleep quality, depressive symptoms, and transplant outcomes: Follow-up analyses from the ADAPT prospective pilot study

BACKGROUND

Previous studies suggested that depressive symptoms and sleep quality may be important for long-term clinical outcomes following cardiothoracic transplant. Few studies, however, have systematically examined objective markers of these behavioral factors among ambulatory transplant recipients, or their association with clinical outcomes.

METHODS

We examined sleep quality and depressive symptoms with subsequent clinical outcomes (hospitalizations and death) in a sample of 66 lung or heart transplant recipients using a single-center, prospective cohort study. Recipients were assessed at approximately 6 months post-transplant and completed one week of actigraphy assessment to examine sleep quality and self-report measures of mood (Centers for Epidemiologic Studies of Depression [CESD]). Recipients were followed for clinical outcomes.

RESULTS

At 6-months following transplantation, recipients spent the majority of daytime activity at a sedentary level (61% of daily activity [SD = 10]) and elevated depressive symptoms were common (subclinical = 17%, mild = 12%, or moderate = 8%). Over a median follow-up of 4.5 years (IQR = 0.9, 5.1), 51 participants (77%) had at least one unplanned hospitalization and 11 (17%) participants died. In addition, sleep efficiency measurements suggested that a subset of participants exhibited suboptimal sleep (mean efficiency = 87% [SD = 7]). Poorer sleep quality, indexed by lower sleep efficiency and greater sleep fragmentation, was associated with greater depressive symptoms (r's = 0.37-0.50, P < .01). Better sleep quality at 6-months (HR = 0.75 [0.60, 0.95], P = .015), including sleep efficiency (HR = 0.74 [0.56, 0.99], P = .041) and sleep fragmentation (HR = 0.71 [0.53, 0.95], P = .020) were associated with lower risk of hospitalization or death. Compared with individuals without elevated depressive symptoms or sleep difficulties, individuals with either factor (HR = 1.72 [1.05, 2.81], P = .031) or both factors (HR = 2.37 [1.35, 4.18], P = .003) exhibited greater risk of clinical events in adjusted analyses.

CONCLUSIONS

Sleep quality is associated with depressive symptoms among cardiothoracic transplant recipients and enhances the prognostic association between biobehavioral risk factors and clinical outcomes.

Factors affecting complications development and mortality after single lung transplant

Lung transplantation (LT) is a life-saving therapeutic procedure that prolongs survival in patients with end-stage lung disease. Furthermore, as a therapeutic option for high-risk candidates, single LT (SLT) can be feasible because the immediate morbidity and mortality after transplantation are lower compared to sequential single (double) LT (SSLTx). Still, the long-term overall survival is, in general, better for SSLTx. Despite the great success over the years, the early post-SLT period remains a perilous time for these patients. Patients who undergo SLT are predisposed to evolving early or late postoperative complications. This review emphasizes factors leading to post-SLT complications in the early and late periods including primary graft dysfunction and chronic lung allograft dysfunction, native lung complications, anastomosis complications, infections, cardiovascular, gastrointestinal, renal, and metabolite complications, and their association with morbidity and mortality in these patients. Furthermore, we discuss the incidence of malignancy after SLT and their correlation with immunosuppression therapy.

Extracorporeal Membrane Oxygenation as a Bridge to Lung Transplant: Considerations for Critical Care Nursing Practice

TOPIC

Candidates waiting for lung transplant are sicker now than ever before. Extracorporeal membrane oxygenation has become useful as a bridge to lung transplant for these critically ill patients.

CLINICAL RELEVANCE

Critical care nurses must be prepared to care for the increasing number of lung transplant patients who require this advanced support method.

PURPOSE OF PAPER

To provide critical care nurses with the foundational knowledge essential for delivering quality care to this high-acuity transplant patient population.

CONTENT COVERED

This review describes the types of extracorporeal membrane oxygenation (venovenous and venoarterial), provides an overview of the indications and contraindications for extracorporeal membrane oxygenation, and discusses the role of clinical bedside nurses in the treatment of patients requiring extracorporeal membrane oxygenation as a bridge to lung transplant.