Impact of Donor Obesity on Outcomes After Orthotopic Heart Transplantation

Outcomes of Heart Transplantation Using a Temperature-controlled Hypothermic Storage System

BACKGROUND

The SherpaPak Cardiac Transport System is a novel technology that provides stable, optimal hypothermic control during organ transport. The objectives of this study were to describe our experience using the SherpaPak system and to compare outcomes after heart transplantation after using SherpaPak versus the conventional static cold storage method (non-SherpaPak).

METHODS

From 2018 to June 2021, 62 SherpaPak and 186 non-SherpaPak patients underwent primary heart transplantation at Stanford University with follow-up through May 2022. The primary end point was all-cause mortality, and secondary end points were postoperative complications. Optimal variable ratio matching, cox proportional hazards regression model, and Kaplan-Meier survival analyses were performed.

RESULTS

Before matching, the SherpaPak versus non-SherpaPak patients were older and received organs with significantly longer total allograft ischemic time. After matching, SherpaPak patients required fewer units of blood product for perioperative transfusion compared with non-SherpaPak patients but otherwise had similar postoperative outcomes such as hospital length of stay, primary graft dysfunction, inotrope score, mechanical circulatory support use, cerebral vascular accident, myocardial infarction, respiratory failure, new renal failure requiring dialysis, postoperative bleeding or tamponade requiring reoperation, infection, and survival.

CONCLUSIONS

In conclusion, this is one of the first retrospective comparison studies that evaluated the outcomes of heart transplantation using organs preserved and transported via the SherpaPak system. Given the excellent outcomes, despite prolonged total allograft ischemic time, it may be reasonable to adopt the SherpaPak system to accept organs from a remote location to further expand the donor pool.

Interaction between donor obesity and prolonged donor ischemic time in heart transplantation

BACKGROUND

The purpose of the study was to determine the impact of donor obesity on outcomes following heart transplantation in the setting of routine (<4 h) and prolonged (≥4 h) organ ischemic times.

METHODS

Retrospective review of the 2000-2020 United Network for Organ Sharing Database was performed to identify adult heart transplant recipients and donors. Nearest-neighbor propensity score matching by donor obesity was performed separately among routine and prolonged cohorts, with Kaplan-Meier survival estimates used to assess survival at 5 years following transplantation.

RESULTS

A total of 43,304 heart transplant recipients were included in analysis, with 15,925 (36.8 %) receiving obese donor hearts. After propensity-score matching, 30-day mortality and 5-year survival following transplantation were not statistically different between recipients of obese and non-obese donor hearts when organ ischemic times were routine. In the setting of prolonged organ ischemic times, those receiving obese donor hearts experienced lower 30-day mortality (5.1 % vs 6.7 %, p = 0.04) and improved 5-year survival (74.9 % vs 71.2 %, p < 0.01) compared to non-obese donor hearts.

CONCLUSIONS

Recipients of obese donor hearts experienced improved outcomes compared to those receiving non-obese donor hearts when organ ischemic times exceeded 4 h. These findings suggest that the detrimental impact of prolonged organ ischemic time may be attenuated by donor obesity.

Predicted heart mass for size matching in obese heart transplant donors and recipients

INTRODUCTION

Predicted heart mass (PHM) was neither derived nor evaluated in an obese population. Our objective was to evaluate size mismatch using actual body weight or IBW-adjusted PHM on mortality and risk assessment.

METHODS

We conducted a retrospective cohort study of adult recipients with BMI ≥30 kg/m² or recipients of donors with BMI≥30 kg/m² from the ISHLT registry. We used multivariable Cox proportional hazard models to evaluate 30 day and 1-year mortality. The 2 models were compared using net reclassification index.

RESULTS

10,817 HT recipients, age 55 (IQR 46-62) years, 23% female, BMI 31 kg/m² (IQR 28-33) were included. Donors were age 34 (IQR 24-44) years, 31% female, and BMI 31 kg/m² (IQR 26-34). There was a significant non-linear association between mortality and actual PHM but not IBW-adjusted PHM. Undersizing using actual PHM was associated with higher 30-day and 1-year mortality (p<0.01), not seen with IBW-adjusted PHM. Actual PHM better risk classified 0.6% (95% CI 0.3-0.8%) patients compared to IBW-adjusted PHM.

CONCLUSION

Actual PHM can be used for size matching when assessing mortality risk in obese recipients or recipients of obese donors. There is no advantage to re-calculating PHM using IBW to define candidate risk at the time of organ allocation. This article is protected by copyright. All rights reserved.

Post-Transplant Extracorporeal Membrane Oxygenation for Severe Primary Graft Dysfunction to Support the Use of Marginal Donor Hearts

Severe primary graft dysfunction (PGD) is the leading cause of early postoperative mortality following orthotopic heart transplantation (OHT). Veno-arterial extracorporeal membrane oxygenation (VA-ECMO) has been used as salvage therapy. This study aimed to evaluate the outcomes in adult OHT recipients who underwent VA-ECMO for severe PGD. We retrospectively reviewed 899 adult (≥18 years) patients who underwent primary OHT at our institution between 1997 and 2017. Recipients treated with VA-ECMO (19, 2.1%) exhibited a higher incidence of previous cardiac surgery (p = .0220), chronic obstructive pulmonary disease (p = .0352), and treatment with a calcium channel blocker (p = .0018) and amiodarone (p = .0148). Cardiopulmonary bypass (p = .0410) and aortic cross-clamp times (p = .0477) were longer in the VA-ECMO cohort and they were more likely to have received postoperative transfusion (p = .0013); intra-aortic balloon pump (IABP, p < .0001), and reoperation for bleeding or tamponade (p < .0001). The 30-day, 1-year, and overall survival after transplantation of non-ECMO patients were 95.9, 88.8, and 67.4%, respectively, compared to 73.7, 57.9, and 47.4%, respectively in the ECMO cohort. Fourteen (73.7%) of the ECMO patients were weaned after a median of 7 days following OHT (range: 1-12 days). Following OHT, VA-ECMO may be a useful salvage therapy for severe PGD and can potentially support the usage of marginal donor hearts.

Risk factors and outcomes of BK viremia among deceased donor kidney transplant recipients based on donor characteristics

INTRODUCTION

BK polyomavirus (BKV) is a common infection among kidney transplant recipients (KTR). Risk factors and outcomes based on donor characteristics remain largely unknown.

METHODS

In this study, we aimed to analyze the impact of donor factors through a paired kidney analysis. We included 289 pairs of adult deceased donor transplants (578 KTRs total); each pair had received kidneys from the same donor. Recipient pairs were divided into three groups: "no BK group" if neither KTR developed BK viremia (n = 336), "discordant" if the only one did (n = 176), and "concordant" if both did (n = 66). Acute rejection (AR), graft failure, and BK nephropathy (BKN) were outcomes of interest.

RESULTS

Donors in the concordant group were younger, had lower kidney donor profile index (KDPI), and were less likely to be donor after circulatory death (DCD). In multivariate analyses, KTRs who had a donor with a higher body mass index (BMI) (hazard ratio (HR): 0.97; 95% confidence interval (CI): 0.95-0.99; p = .009) were less likely to develop BKV. Concordance was not associated with AR (HR: 0.83; 95% CI: 0.51-1.34; p = .45), graft failure (HR: 1.77; 95% CI: 0.42-7.50; p = .43), or BKN (HR: 1.02; 95% CI: 0.51-2.03; p = .96).

DISCUSSION

Our study suggests lower donor BMI is associated with BKV infection, and concordance or discordance between paired kidney recipients is not associated with poor outcomes.

The Stanford experience of heart transplantation over five decades

AIMS 

Since 1968, heart transplantation has become the definitive treatment for patients with end-stage heart failure. We aimed to summarize our experience in heart transplantation at Stanford University since the first transplantation performed over 50 years ago.

METHODS AND RESULTS 

From 6 January 1968 to 30 November 2020, 2671 patients presented to Stanford University for heart transplantation, of which 1958 were adult heart transplantations. Descriptive analyses were performed for patients in 1968-95 (n = 639). Stabilized inverse probability weighting was applied to compare patients in 1996-2006 (n = 356) vs. 2007-19 (n = 515). Follow-up data were updated through 2020. The primary endpoint was all-cause mortality. Prior to weighting, recipients in 2007-19 vs. those in 1996-2006 were older and had heavier burden of chronic diseases. After the application of stabilized inverse probability weighting, the distance organ travelled increased from 84.2 ± 111.1 miles to 159.3 ± 169.9 miles from 1996-2006 to 2007-19. Total allograft ischaemia time also increased over time (199.6 ± 52.7 vs. 225.3 ± 50.0 min). Patients in 2007-19 showed superior survival than those in 1996-2006 with a median survival of 12.1 vs. 11.1 years.

CONCLUSION 

In this half-century retrospective descriptive study from one of the largest heart transplant programmes in the USA, long-term survival after heart transplantation has improved over time despite increased recipient and donor age, worsening comorbidities, increased technical complexity, and prolonged total allograft ischaemia time. Further investigation is warranted to delineate factors associated with the excellent outcomes observed in this study.

Center-Level Variations in Maximum Recipient Body Mass Index in Heart Transplantation

This study explored center-level variations in maximum recipient body mass index (BMI) and the associated impact of morbid obesity on outcomes of orthotopic heart transplantation (OHT). Using the United Network for Organ Sharing (UNOS) database, we examined adults (≥18 years) who underwent OHT between 2010 and 2018. Centers performing <10 OHTs per year were excluded. Recipients were stratified by BMI: <35, 35-38, 38 to 40, >40 kg/m2. Kaplan-Meier analysis was utilized to model survival and Cox regression analysis was utilized for adjusted analysis of 1-year mortality. A total of 17,821 candidates underwent OHT with 1,330 having a BMI >35kg/m2. Among 84 centers, a mean of 92.06% of recipients per center had a BMI<35 with 5.87%, 1.01%, and 1.06% of recipients having BMIs of 35 to 38, 38 to 40, and >40 at each center, respectively. A total of 5, 54, 17, and 8 centers had maximum recipient BMIs of <35, 35 to 38, 38 to 40, and >40 kg/m2, respectively. Centers performing OHT on recipients with higher BMIs displayed higher overall OHT volume (p = 0.002). Rates of post-transplant dialysis (p <0.001) and stroke (p = 0.008) were higher with increased BMI and length of stay was significantly longer (p <0.001). Following risk-adjustment, BMI 35 to 38 (HR 1.19) was not associated with increased risk of 1-year mortality although BMI 38 to 40 (HR 1.80, p = 0.007) and >40 (HR 2.85, p <0.001) were associated. In conclusion, most centers in the United States have a maximum recipient BMI of 35 to 38 for OHT, which appears justified as the risk of 1-year mortality increases with BMI >38.

How Big Is Too Big?: Donor Severe Obesity and Heart Transplant Outcomes

BACKGROUND

As the population becomes increasingly obese, so does the pool of potential organ donors. We sought to investigate the impact of donors with body mass index ≥40 (severe obesity) on heart transplant outcomes.

METHODS

Single-organ first-time adult heart transplants from 2003 to 2017 were evaluated from the United Network for Organ Sharing database and stratified by donor severe obesity status (body mass index ≥40). Demographics were compared, and univariate and risk-adjusted analyses evaluated the relationship between severe obesity and short-term outcomes and long-term mortality. Further analysis evaluated the prevalence of severe obesity within the pool of organ donation candidates.

RESULTS

A total of 26 532 transplants were evaluated, of which 939 (3.5%) had donors with body mass index ≥40, with prevalence increasing over time (2.2% in 2003, 5.3% in 2017). Severely obese donors more likely had diabetes mellitus (10.4% versus 3.1%, P<0.01) and hypertension (33.3% versus 14.8%, P<0.01), and 67.4% were size mismatched (donor weight >130% of recipient). Short-term outcomes were similar, including 1-year survival (10.6% versus 10.7%), with no significant difference in unadjusted and risk-adjusted long-term survival (log-rank P=0.67, hazard ratio, 0.928, P=0.30). Organ donation candidates also exhibited an increase in severe obesity over time, from 3.5% to 6.8%, with a lower proportion of hearts from severely obese donors being transplanted (19.5% versus 31.6%, P<0.01).

CONCLUSIONS

Donor severe obesity was not associated with adverse post-transplant outcomes. Increased evaluation of hearts from obese donors, even those with body mass index ≥40, has the potential to expand the critically low donor pool.

Relation of Length of Survival After Orthotopic Heart Transplantation to Age of the Donor

We aim to evaluate the impact of donor age on the outcomes in orthotropic heart transplantation recipients. The United Network for Organ Sharing database was queried for adult patients (age; ≥60) underwent first-time orthotropic heart transplantation between 1987 and 2019 (n = 18,447). We stratified the cohort by donor age; 1,702 patients (9.2%) received a heart from a donor age of <17 years; 11,307 patients (61.3%) from a donor age of 17 ≥, < 40; 3,525 patients (19.1%) from a donor age of 40 ≥, < 50); and 1,913 patients (10.4%) from a donor age of ≥50. There was a significant difference in the survival likelihood (p < 0.0001) based on donor's age-based categorized cohort, however, the median survival was 10.5 years in the cohort in whom the donor was <17, 10.3 years in whom the donor was 17 ≥, < 40, 9.4 years in whom the donor was 40 ≥, < 50, and 9.0 years in whom the donor was ≥ 50. Additionally, there was no significant difference in the episode of acute rejection (p = 0.19) nor primary graft failure (p = 0.24). In conclusion, this study demonstrated that patients receiving hearts from the donor age of ≥50 years old showed slight inferior survival likelihood, but appeared to be equivalent median survival.

Impact of Donor Obesity on Outcomes After Orthotopic Heart Transplantation

Background

The impact of donor obesity on the outcome of orthotopic heart transplantation has not been studied. The aim of this study was to investigate the impact of donor obesity on the outcomes of adult orthotopic heart transplantation recipients.

Methods and Results

Data were obtained from the United Network for Organ Sharing database. All adult (age ≥18 years) patients undergoing orthotopic heart transplantation from 2000 through 2016 were included (n=31 920). We stratified the cohort by donor body mass index (BMI); 13 015 patients (40.8%) received a heart from a normal‐weight donor (BMI 18.5–24.9), 11 271 patients (35.3%) received a heart from an overweight donor (BMI 25.0–29.9), 4910 patients (15.4%) received a heart from an obese donor (BMI 30.0–34.9), and 2724 patients (8.5%) received a heart from an extremely obese donor (BMI ≥35). The cohort of obese donors was older, included a higher incidence of diabetes mellitus, and had a higher creatinine. Our data also showed that the recipients of obese donor grafts were older, had a higher BMI, creatinine, percentage of diabetes mellitus, and longer total waiting period. There was no significant difference detected in the survival likelihood (P=0.08) of patients based on a donor's BMI‐based categorized cohort. There were no significant differences found in the overall survival probability among 4 groups in the adjusted survival analyses (P=0.25).

Conclusions

This study demonstrated that patients receiving higher BMI donor hearts might not be subjected to an increased risk of death, at least during the short term after transplant, compared with those using the normal‐weight donors.

[Left ventricle myocardium hypertrophy of donor heart: the results and outlook]

Left ventricular hypertrophy - is one of the most frequent structural changes in the heart. This article is devoted to the assessment of modern views on the causes of myocardial hypertrophy of the donor heart, indications and contraindications for the heart trans‑ plantation, the outlook of expanding the pool of effective donors through the use of these hearts. Here are considered the issues of post-transplantation remodeling of the donor heart myocardium, The pathogenesis features, the nascence risk and possibilities of drug regulation of the transplanted heart's myocardial hypertrophy of the left ventricle.