The International Society for Heart and Lung Transplantation (ISHLT): 2024 infection definitions for durable and acute mechanical circulatory support devices

Infections remain a significant concern in patients receiving mechanical circulatory support (MCS), encompassing both durable and acute devices. This consensus manuscript provides updated definitions for infections associated with durable MCS devices and new definitions for infections in acute MCS, integrating a comprehensive review of existing literature and collaborative discussions among multidisciplinary specialists. By establishing consensus definitions, we seek to enhance clinical care, facilitate consistent reporting in research studies, and ultimately improve outcomes for patients receiving MCS.

Influence of cardiac diagnosis on outcomes of pediatric heart-lung transplantation

OBJECTIVE

Pediatric Heart-lung transplant (HLTX) is performed for endstage congenital heart disease (CHD) with irreversible pulmonary hypertension or non-congenital heart disease (NCHD) with end-stage heart and lung disease. CHD could influence the outcomes of HTLX due to increased complexity of the operation as compared to NCHD. In this study we evaluated the influence of cardiac diagnosis on outcomes of pediatric HTLX.

METHODS

The UNOS database (1987-2022) was queried for primary HTLX in patients <18 years. The data were extracted for demographics, pretransplant characteristics, post-transplant outcomes, and analyzed for the impact of cardiac diagnosis on post-transplant outcomes. Standard statistical tests were used. Survival was compared using the Kaplan-Meier method.

RESULTS

Ninety of the 213 patients who underwent HLTX had CHD. There were no demographic differences. Heart listing status was similar but with a higher LAS score for NCHD. NCHD had higher pre-operative life support use (mechanical ventilation, inotropes or dialysis) but the use of ECMO as a bridge to transplantation was similar. Wait-list times were longer for CHD. The ischemic times were similar. Post-transplant dialysis, stroke, prolonged mechanical ventilation, and rejection were similar. Survival at 30-days, 1-year, and long-term survival at 17 years was similar. Non-survivors at 30-days post-transplant were on life support, used ECMO as a bridge, had lower wait-list times, longer ischemic times and had strokes. Non-survivors at 1-year had similar factors in addition to a higher dialysis use.

CONCLUSION

Cardiac diagnosis had no impact on outcomes after Pediatric HLTX. Patients on life support or ECMO before transplantation were transplanted faster but with lower survival.

Trends and Outcomes of Combined Heart-Kidney and Heart-Lung Transplantation Over the Past Two Decades

INTRODUCTION

Combined heart-kidney transplantation (HKTx) and combined heart-lung transplantation (HLTx) remain the definitive therapy for patients with end-stage heart failure with concomitant end-stage renal or lung failure. We sought to study trends and outcomes of HKTx and HLTx over the last two decades.

METHODS

The United Network for Organ Sharing registry was used to identify all adult patients (aged >18 y) who underwent HKTx and HLTx between 2001 and 2021. Patients were divided into 5-y groups by the year of transplantation (2001-2006, 2007-2011, 2012-2016, and 2017-2021). Primary outcome was 1-y posttransplantation mortality. Kaplan-Meier and multivariable Cox proportional hazards models were used for unadjusted and risk-adjusted survival analyses, respectively.

RESULTS

A total of 2301 HKTx and 567 HLTx patients were included. Between 2001 and 2021, HKTx volume increased from 25 to 344 patients (P < 0.001) and centers performing HKTx increased from 19 to 76 (P < 0.001). On unadjusted analysis, 1-y survival after HKTx improved from 86.7% in 2001-2006 to 89.0% in 2017-2021 (log-rank, P = 0.005). On risk-adjusted analysis, the hazard ratio of 1-y mortality for 2017-2021 was 0.62 (0.39-1.00, P = 0.048) compared with that for 2001-2006. Between 2001 and 2021, HLTx volume increased from 21 to 43 patients (P < 0.001) and centers performing HLTx increased from 12 to 20 (P = 0.047). On unadjusted analysis, 1-y survival after HLTx improved from 68.9% in 2001-2006 to 83.9% in 2017-2021 (log-rank, P = 0.600). On risk-adjusted analysis, the hazard ratio of 1-y mortality for 2017-2021 was 0.37 (0.21-0.67, P = 0.001) compared with that for 2001-2006.

CONCLUSIONS

Over the last two decades, HKTx volume substantially increased and HLTx experienced resurgent growth. One-year survival persistently improved for both procedures, especially over the past 5 y.

Pediatric heart transplantation: Looking forward after five decades of learning

Heart transplantation has become the standard of care for pediatric patients with end-stage heart disease throughout the world. Since the first transplant was performed in 1967, the number of transplants has grown dramatically with 13 449 pediatric heart transplants being reported to The International Society of Heart and Lung Transplant (ISHLT) between January 1992 and June 30, 2018. Outcomes have consistently improved over the last few decades, specifically short-term outcomes. Most recent survival data demonstrate that recipients who survive to 1-year post-transplant have excellent long-term survival with more than 60% of those who were transplanted as infants being alive 25 years later. Nonetheless, the rates of graft loss beyond the first year have remained relatively constant over time; driven primarily by our poor understanding and lack of treatments for chronic allograft vasculopathy (CAV). Acute rejection, CAV, graft failure, and infection continue to be the major causes of death within the first 5 years post-transplant. In addition, renal dysfunction, malignancy, and the need for re-transplantation remain as significant issues that require close follow-up. Looking forward, key challenges include improving donor utilization rates (including donation after cardiac death (DCD) and the use of ex vivo perfusion devices), the development of non-invasive biomarkers for rejection, efforts to mitigate the long-term effects of immunosuppression, and prevention of CAV. It is not possible to cover the entire evolution of pediatric heart transplantation over the last five decades, but in this review, we hope to touch on key observations, lessons learned, and practice changes that have advanced the field, as well as glance ahead to the next decade.

Right lower lung midline herniation as a rare complication in an infant with heart-lung transplantation: A case report

BACKGROUND

Lung herniation is a rare complication of heart-lung transplantation that can be fatal owing to vascular compromise and airway obstruction. To date, only five cases of lung herniation related to heart-lung transplantation have been reported in the literature; however, to the best of our knowledge, this is the first worldwide report of heart-lung transplantation-related lung herniation in an infant.

METHODS

We describe the case of lung herniation as a rare heart-lung transplantation-related complication in an infant. A 12-month-old female baby developed severe bronchopulmonary dysplasia with severe pulmonary hypertension, and she underwent extracorporeal membrane oxygenation for cardiac collapse and lung support. Then, we performed heart-lung transplantation to manage the irreversible deterioration of her lung function. After the heart-lung transplantation, we found the radiological abnormalities persisted on follow-up chest radiographs until the 13th postoperative day diagnosed as lung herniation of the right lower lobe on chest computed tomography.

RESULTS

After the relocation of the herniated lung, the clinical condition of the patient improved, and the patient is currently growing without any respiratory symptoms.

CONCLUSIONS

In this case report, we emphasize that clinical awareness and high suspicion of this rare complication are needed for early diagnosis and proper treatment to prevent post-transplantation morbidity and mortality related to potential ischemic injury.

Heart-Lung Transplantation From Donation After Circulatory Death Using Mobile Normothermic Regional Perfusion

Combined heart-lung transplant (HTLx) is the most durable treatment available for end-stage heart and lung failure. Many patients are unable to receive combined organs due to organ availability and allocation policies prioritizing separate heart or lung transplantation. While an average of 45 HTLxs have been performed per year in the United States half the listed patients do not receive organs. Recently, donation after circulatory death (DCD) utilizing normothermic regional perfusion (NRP) has been utilized for heart allografts with excellent results, and here, we present a case utilizing mobile NRP to procure a heart and lung block from a circulatory death donor and successful implantation for a recipient in a separate center.

Prognosis factors in heart-lung transplantation: 30 years experience in a reference center

INTRODUCTION

Heart-lung transplantation has shown a progressive decrease in the number of procedures. There is a lack of information about this field in Spain. The main goal of this study is to analyze the experience of a national reference hospital.

METHODS

We performed a retrospective study of a historical cohort of heart-lung transplanted patients in a single center, during a 30 years period (from 1990 to 2021). The associations between variables were evaluated using the χ2 test or Fisher's exact test. Survival was analyzed using the Kaplan-Meier method. Differences were evaluated using the log-rank test and multivariate analysis with the Cox method.

RESULTS

A decrease in the number of procedures performed in the last decade was observed [2000-2009: 19 procedures (44.2%); 2010-2021: 15 procedures (34.8%)]. Early postoperative mortality was 23.3%, falling to 13.3% from 2010. In-hospital mortality was 41%, falling to 33% from 2010. Main factors related to higher mortality: previous thoracic surgery, corticosteroid therapy, extracorporeal circulation (ECLS) greater than 200 min, ischemia time greater than 300 min, and tracheal dehiscence (p < 0.005). Overall survival at one, five, and ten years was 58%, 44.7%, and 36.1%, respectively. Factors associated with lower survival rates: previous thoracic surgery, male donor, extracorporeal circulation greater than 200 min, ischemia time greater than 300 min, tracheal dehiscence and weight difference (p < 0.005).

CONCLUSIONS

There has been a progressive decrease in the number of heart-lung transplantations, being more evident in the last decade, but showing an improvement in both mortality and survival.

Revised Heart Allocation Policy Improved Waitlist Mortality and Waiting Time With Maintained Outcomes in En-Bloc Heart-Lung Transplant Candidates and Recipients

The revised United Network for Organ Sharing heart allocation policy was implemented in October 2018. Using a national transplant database, this study evaluated the transplant rate, waitlist mortality, waiting time, and other outcomes of en-bloc heart-lung transplantation recipients. Adult patients registered on the national database for heart-lung transplants before and after the policy update were selected as cohorts. Baseline characteristics, transplant rates, waitlist mortality, waiting times, and other outcomes were compared between the two periods. In total, 370 patients were registered for heart-lung transplants during the pre- and post-periods. There were significantly higher transplant rates, shorter waitlist times, and substantially reduced waitlist mortality in the post-period. Registered patients waitlisted in the post-period had significantly higher utilization of intra-aortic balloon pumps, extracorporeal membrane oxygenation, and overall life support, including ventricular assist devices. Transplant recipients had significantly longer ischemic times, increased transport distances, and shorter waiting times before transplantation in the post-policy period. Transplant recipients held similar short-term survival before and after the policy change (log-rank test, p = 0.4357). Therefore, the revised policy significantly improved access to en-bloc heart-lung allografts compared with the prior policy, with better waitlist outcomes and similar post-transplant outcomes.

Double-lung versus heart-lung transplantation for end-stage cardiopulmonary disease: a systematic review and meta-analysis

We compared posttransplant outcomes following double-lung transplantation (DLTx) and heart-lung transplantation (HLTx), based on a search of PubMed, Cochrane Library, and Embase, from inception to March 8, 2022, for studies that report outcomes of these procedures. We then performed a meta-analysis of baseline characteristics and posttransplant outcomes. Subgroup analyses were implemented according to indication, publication year, and center. This study was registered on PROSPERO (number CRD42020223493). Ten studies were included in this meta-analysis, involving 1230 DLTx patients and 1022 HLTx patients. The DLTx group was characterized by older donors (P = 0.04) and a longer allograft ischemia time (P < 0.001) than the HLTx group. The two groups had comparable 1-year, 3-year, 5-year, 10-year survival rates (all P > 0.05), with similar results identified in subgroup analyses. We found no significant differences in 1-year, 5-year, and 10-year chronic lung allograft dysfunction (CLAD)-free survival, length of intensive care unit stay and hospital stay, length of postoperative ventilation, in-hospital mortality, or surgical complications between the groups (all P > 0.05). Thus, DLTx provides similar posttransplant survival to HLTx for end-stage cardiopulmonary disease. These two procedures have a comparable risk of CLAD and other posttransplant outcomes.

Heart transplantation using donation after circulatory death in the United States

OBJECTIVES

Heart donation after circulatory death was recently reintroduced in the United States with hopes of increasing donor heart availability. We examined its national use and outcomes.

METHODS

The United Network for Organ Sharing database was used to identify validated adult patients undergoing heart transplantation using donation after circulatory death donors (n = 266) and donation after brain death donors (n = 5998) between December 1, 2019, and December 31, 2021, after excluding heart-lung transplants. Propensity score matching was used to create more balanced groups for comparison.

RESULTS

The monthly percentage of donation after circulatory death heart transplant increased from 2.5% in December 2019 to 6.8% in December 2021 (P < .001). Twenty-two centers performed donation after circulatory death heart transplants, ranging from 1 to 75 transplants per center. Four centers performed 70% of the national volume. Recipients of donation after circulatory death hearts were more likely to be clinically stable (80.4% vs 41.1% in status 3-6, P < .001), to have type O blood (58.3% vs 39.9%, P < .001), and to wait longer after listing (55, interquartile range, 15-180 days vs 32, interquartile range, 9-160 days, P = .003). Six-month survival was 92.1% (95% confidence interval, 91.3-92.8) after donation after brain death heart transplants and 92.6% (95% confidence interval, 88.1-95.4) after donation after circulatory death heart transplants (hazard ratio, 0.94, 95% confidence interval, 0.57-1.54, P = .79). Outcomes in propensity-matched patients were similar except for higher rates of treated acute rejection in donation after circulatory death transplants before discharge (14.4% vs 8.8%, P = .01). In donation after circulatory death heart recipients, outcomes did not differ based on the procurement technique (normothermic regional perfusion vs direct procurement and perfusion).

CONCLUSIONS

Heart transplantation with donation after circulatory death donors has short-term survival comparable to donation after brain death transplants. Broader implementation could substantially increase donor organ availability.

Heart transplant offers are less likely to be accepted on weekends, holidays, and conferences

BACKGROUND

The existence of a "weekend effect" in heart transplantation (HTx) is understudied. The present study sought to determine whether the odds of (HTx) offer acceptance differed for adult and pediatric candidates depending upon the day on which the offer occurred.

METHODS

United Network for Organ Sharing data were used to identify all HTx offers to adult (listing age ≥18) and pediatric candidates from 2000-2019. Odds of offer acceptance were studied, comparing weekends, holidays, and conferences (Society of Thoracic Surgeons [STS], American Association for Thoracic Surgery [AATS], International Society for Heart and Lung Transplantation [ISHLT]) to "baseline" (all other days). Multivariable binary logistic regression analyses were performed to determine independent predictors of offer nonacceptance, controlling for the impacts of program transplant volume, region, and candidate characteristics.

RESULTS

A total of 323,953 offers occurred - 298,405 to adults and 25,548 to pediatric candidates. Clinically significant differences did not exist in donor or candidate characteristics between baseline or other events. The number of offers per day was stable throughout the year for both adults (p = 0.191) and pediatrics (p = 0.976). In adults, independently lower odds of acceptance existed on weekends (OR 0.88 [95% CI 0.84-0.92]), conferences in aggregate (0.86 [0.77-0.95]), and holidays in aggregate (0.81 [0.72-0.91]). In children, independently lower odds of acceptance were seen on weekends (0.88 [0.79-0.98]), during STS (0.46 [0.25-0.83], and during Christmas (0.32 [0.14-0.76]).

CONCLUSIONS

The day on which a HTx offer occurs significantly impacts its likelihood of acceptance. Further work can determine the impacts of human behavior or resource distribution, but knowledge of this phenomenon can inform efforts to ensure ideal organ allocation throughout the year.

Circovirus Hepatitis Infection in Heart-Lung Transplant Patient, France

In March 2022, a 61-year-old woman in France who had received a heart-lung transplant sought treatment with chronic hepatitis mainly characterized by increased liver enzymes. After ruling out common etiologies, we used metagenomic next-generation sequencing to analyze a liver biopsy sample and identified an unknown species of circovirus, tentatively named human circovirus 1 (HCirV-1). We found no other viral or bacterial sequences. HCirV-1 shared 70% amino acid identity with the closest known viral sequences. The viral genome was undetectable in blood samples from 2017-2019, then became detectable at low levels in September 2020 and peaked at very high titers (1010 genome copies/mL) in January 2022. In March 2022, we found >108 genome copies/g or mL in the liver and blood, concomitant with hepatic cytolysis. We detected HCirV-1 transcripts in 2% of hepatocytes, demonstrating viral replication and supporting the role of HCirV-1 in liver damage.

A comparison of outcomes after lung transplantation between European and North American centers

BACKGROUND

With advancements in basic science and clinical medicine, lung transplantation (LT) has evolved rapidly over the last three decades. However, it is unclear if significant regional variations exist in long-term outcomes after LT.

METHODS

To investigate potential differences, we performed a retrospective, comparative cohort analysis of adult patients undergoing deceased donor single or double LT in North America (NA) or Europe between January 2006 and December 2016. Data up to April 2019 were abstracted from the International Society for Heart and Lung Transplantation (ISHLT) Thoracic Organ Registry. We compared overall survival (OS) between North American and European LT centers in a propensity score matched analysis.

RESULTS

In 3,115 well-matched pairs, though 30-day survival was similar between groups (NA 96.2% vs Europe 95.4%, p = 0.116), 5-year survival was significantly higher in European patients (NA 60.1% vs Europe 70.3%, p < 0.001).

CONCLUSIONS

This survival difference persisted in a sensitivity analysis excluding Canadian patients. Prior observations suggest that these disparities are at least partly related to better access to care via universal healthcare models prevalent in Europe. Future studies are warranted to confirm our findings and explore other causal mechanisms. It is likely that potential solutions will require concerted efforts from healthcare providers and policymakers.

Focused Update on Pulmonary Hypertension in Children-Selected Topics of Interest for the Adult Cardiologist

Pulmonary hypertensive vascular disease (PHVD), and pulmonary hypertension (PH), which is a broader term, are severe conditions associated with high morbidity and mortality at all ages. Treatment guidelines in childhood are widely adopted from adult data and experience, though big differences may exist regarding aetiology, concomitant conditions and presentation. Over the past few years, paediatric aspects have been incorporated into the common guidelines, which currently address both children and adults with pulmonary hypertension (PH). There are multiple facets of PH in the context of cardiac conditions in childhood. Apart from Eisenmenger syndrome (ES), the broad spectrum of congenital heart disease (CHD) comprises PH in failing Fontan physiology, as well as segmental PH. In this review we provide current data and novel aspects on the pathophysiological background and individual management concepts of these conditions. Moreover, we focus on paediatric left heart failure with PH and its challenging issues, including end stage treatment options, such as mechanical support and paediatric transplantation. PH in the context of rare congenital disorders, such as Scimitar Syndrome and sickle cell disease is discussed. Based on current data, we provide an overview on multiple underlying mechanisms of PH involved in these conditions, and different management strategies in children and adulthood. In addition, we summarize the paediatric aspects and the pros and cons of the recently updated definitions of PH. This review provides deeper insights into some challenging conditions of paediatric PH in order to improve current knowledge and care for children and young adults.

Characteristics and Outcomes of Patients Undergoing Combined Organ Transplantation (from the United Network for Organ Sharing)

Studies have shown that highly selected patients who underwent combined heart-kidney (HK) and heart-liver transplants (HLv) have short- and long-term outcomes comparable to those observed in primary heart transplantation (HT). Adults patients with stage D heart failure that underwent combined HK, HLv, and heart-lung (HL) were identified in the United Network for Organ Sharing registry from 1991 to 2016, with follow-up through March 2018. We conducted inverse probability of treatment weighting survival analysis of long-term survival stratified by type of combined organ transplant, accounting for donor, recipient, and operative characteristics. We identified 2,300 patients who underwent combined organ transplant (HK 1,257, HLv 212, HL 831). HL recipients were more likely white (77%), women (58%), with congenital heart disease (44.5%), and longer waiting list time (median 195 days). HK transplant increased significantly during the study period where as HL decreased significantly. Median survival was 12.2 years for HK (95% confidence intervals [CI] 10.8 to 12.8), 12 for HLv (95% CI 8.6 to 17.6) but significantly lower at 4.5 years for HL (95% CI 3.6 to 5.8). Combined HK and HLv transplantation rates are increasing and long-term survival is comparable to primary HT, unlike HL which is associated with decreasing trends and significantly lower survival.