Weight gain post-heart transplantation is associated with an increased risk for allograft vasculopathy and rejection

Revisiting Biomarkers of Cardiac Allograft Vasculopathy: Addressing the Achilles Heel of Heart Transplantation

Nearly half of heart transplant recipients will be diagnosed with cardiac allograft vasculopathy (CAV) within five years after transplantation. Advanced CAV can lead to worsening heart failure as well as arrhythmias and sudden cardiac death. The only curative therapy for end-stage CAV is re-transplantation. Current diagnostic methods are invasive and limited by poor sensitivity in early disease. Despite its high prevalence in the post-transplantpopulation, the underlying pathophysiology of this condition has yet to be fully described. It is thought to be primarily related to endothelial dysfunction, immune activation, and cardiometabolic disease. Biomarkers reflecting these underlying processes, particularly endothelial injury and immune activation, have shown early promise in discriminating prevalent CAV. Next-generation sequencing technologies such as proteomic and transcriptomic profiling have also provided further insight into the pathophysiology of CAV through the identification of novel biomarkers. Ultimately, these biomarkers may have a role in not only diagnosing CAV but also highlighting potential targets for disease-specific therapies. In this article, we review the current data for biomarkers in CAV and discuss future directions for biomarker identification..

The Impact of Age and Body Composition on the Agreement between Estimated and Measured GFR in Heart Transplant Recipients

BACKGROUND

Estimated GFR (eGFR) has shown poor agreement with measured GFR (mGFR) in several populations. We investigated the impact of age and body composition on the accuracy and precision of eGFR in heart transplant (HTx) recipients.

METHODS

In a longitudinal, observational, retrospective study design, patients receiving first-time HTx with at least one registered mGFR value within 15 months after HTx and a corresponding plasma creatinine were included. GFR was measured by 51Cr-EDTA and eGFR calculated by creatinine-based CKD-EPI formula.

RESULTS

A total of 150 patients with a total of 723 mGFR measurements were included. During the first year after HTx, mean weight increased by 4.2 kg (CI: 3.2 to 5.1) followed by an annual decrease of 0.35 kg/year (Cl: -0.05 to 0.74). mGFR increased by 7.5 mL/min (Cl: 3.2 to 11.8) the first year but was stable hereafter (0.0 mL/min/year; CI: -1.0 to 1.0). The initial weigh gain and increase in mGFR were most pronounced in patients <45 years. Neither eGFR adjusted nor unadjusted for BSA detected the initial increase in mGFR. At 1 year after HTx, limits of agreement on the Bland-Altman plot were -37.2 to 33.1 mL/min with a bias of -2.1 mL/min (Cl: -5.0 to 0.9). In patients <45 years, eGFR significantly overestimated mGFR by 7.1 mL/min (Cl: 1.0 to 13.2) and showed a significant lower precision than patients >45 years. There was no effect of BMI class, weight, BSA, or change in BMI class on the difference between eGFR and mGFR.

CONCLUSION

eGFR is, on average, accurate but imprecise in HTx patients. The agreement is affected by age but not body composition.

The association between body mass index, exercise capacity, and health-related quality of life in heart transplant recipients

Introduction

Pre-transplant obesity and weight gain after heart transplantation are both associated with increased risk of poor clinical outcomes. We aimed to assess the association between overweight or obesity, exercise capacity, and health-related quality of life in heart transplant recipients.

Methods

This study is based on baseline data from the IronIC trial, in which we randomized 102 heart transplant recipients with iron deficiency to ferric derisomaltose or placebo. We performed cardio pulmonary exercise testing in all participants. To assess quality of life, we used the SF-36v2 questionnaire, using two sum scores: the physical component summary and the mental component summary. A minimal clinically important difference was defined as ≥2 and ≥3 for the physical and the mental component summary, respectively.

Results

24/102 heart transplant recipients (24%) had a body mass index (BMI) ≥30 kg/m2. Peak oxygen consumption was 17.3 ± 4.6 ml/kg/min in the obese group vs. 24.7 ± 6.4 ml/kg/min in the group with a BMI <30 for a between-group difference of 7.4 (95% confidence interval 4.7-10.2) ml/kg/min: p < 0.001. The physical component summary score was on average 5.2 points lower in the patients with a body mass index ≥30 than in the lower weight group (p = 0.04).

Conclusion

Almost a quarter of our heart transplant recipients in long-term follow-up had a BMI ≥30 kg/m2. These patients had substantially lower exercise capacity and lower quality of life in the physical domain.

Long-term changes in body weight and serum cholesterol in heart transplant recipients

INTRODUCTION

Long-term changes in weight and blood lipids beyond 12 months after heart transplantation are largely unknown. We quantified changes in weight, body mass index (BMI), blood cholesterol, and triglycerides in heart transplant recipients (HTRs) during the 36 months after transplantation, and we assessed the influence of statin therapy on these outcomes.

METHODS

Retrospective cohort study of adult HTRs, transplanted 1990-2017, in Queensland, Australia. From each patient's medical charts, we extracted weight, total cholesterol, triglycerides, and statin therapy at four time-points: time of transplant (baseline), and 12-, 24-, 36-month post-transplant. Changes in weight and blood lipids were assessed according to baseline BMI.

RESULTS

Among 316 HTRs, 236 (median age 52 years, 83% males) with available information were included. During the 36 months post-transplant, all patients gained weight (83.5-90.5 kg; p < .001), especially those with baseline BMI < 25.0 km/m2 (67.9-76.2 kg; p < .001). Mean blood cholesterol (4.60-4.90 mmol/L; p = .004) and mean blood triglycerides (1.79-2.18 mmol/L; p = .006) also increased significantly in all patients, particularly in those with baseline BMI ≥ 25.0 km/m2 but the differences were not significant (total cholesterol 4.42-5.13 mmol/L; triglycerides 1.76-2.47 mmol/L). Total cholesterol was highest in patients not taking statins, and levels differed significantly (p = .010) according to statin dosing changes during the 36 months post-transplant.

CONCLUSION

Patients demonstrate significant rises in weight and blood lipids in the 36 months after heart transplantation.