Effect of age on lipid profiles in pediatric heart transplant recipients

Obesity and dyslipidemia predict cardiac allograft vasculopathy and graft loss in children and adolescents post-heart transplant: A PHTS multi-institutional analysis

BACKGROUND

Obesity and dyslipidemia afflict children of all ages. We explored the prevalence of obesity and dyslipidemia in pediatric heart transplant (HT) recipients and its effects on cardiac allograft vasculopathy (CAV) and survival.

METHODS

This study included primary HT recipients (≤18 years) transplanted between 01/1996 and 12/2018 included in the Pediatric Heart Transplant Society database. Obesity was categorized according to WHO/CDC guidelines and dyslipidemia according to the National Cholesterol Education Program. Kaplan-Meier analyses for CAV and graft loss stratified for BMI and lipid panels were generated and risk factors identified using multivariate analyses.

RESULTS

Among 6291 HT patients (median age [range] at HT = 4.3 [0.6-12.8] years; 45% Female; 68% White), 56% had a normal BMI at HT. Obese patients at HT had an increased risk for graft loss (HR 1.19, 95% CI 1.01-1.4, p = .04). Poor total cholesterol (TC), LDL-C, and TG were associated with the risk of both CAV (HR 1.79, p < .0001; HR 1.65, p = .0015; HR 1.53, p < .0001, respectively) and graft loss (HR 1.58, p = .0008; HR 1.22, p = .04; HR 1.43, p = .0007, respectively).

CONCLUSIONS

Pediatric patients who are obese at the time of HT and dyslipidemic at 1 year post-HT are at an increased risk for CAV and graft loss. Preventative interventions may reduce morbidity and mortality among this cohort.

Cardiovascular health in pediatric heart transplant patients

BACKGROUND

Ideal "cardiovascular health" (CVH)-optimal diet, exercise, nonsmoking, BMI, BP, lipids, and glucose-is associated with healthy longevity in adults. Pediatric heart transplant (HT) patients may be at risk for suboptimal CVH.

METHODS

Single-center retrospective study of HT patients 2003-2014 who survived 1 year post-transplant. Five CVH metrics were collected at listing, 1, 3 and 5 years post-transplant (diet and exercise were unavailable). CVH was scored by summing individual metrics: ideal = 2, intermediate = 1, and poor = 0 points; total scores of 8-10 points were considered high (favorable). CVH was compared between HT patients and the US pediatric population (GP) utilizing NHANES 2007-2016. Logistic regression was performed to examine the association of CVH 1 year post-transplant with a composite adverse outcome (death, re-listing, coronary vasculopathy, or chronic kidney disease) 3 years post-transplant.

RESULTS

We included 110 HT patients (median age at HT: 6 years [range 0.1-21]) and 19,081 NHANES participants. CVH scores among HT patients were generally high at listing (75%), 1 (74%), 3 (87%) and 5 (76%) years post-transplant and similar to GP, but some metrics (e.g., glucose) were worse among HT patients. Among HT patients, CVH was poorer with older age and non-Caucasian race/ethnicity. Per 1-point higher CVH score, the demographic-adjusted OR for adverse outcomes was 0.95 (95% CI, 0.7-1.4).

CONCLUSIONS

HT patients had generally favorable CVH, but some metrics were unfavorable and CVH varied by age and race/ethnicity. No significant association was detected between CVH and adverse outcomes in this small sample, but study in a larger sample is warranted.

Calcineurin inhibitor sparing in paediatric solid organ transplantation : managing the efficacy/toxicity conundrum

Despite their efficacy, the calcineurin inhibitors (CNIs) ciclosporin and tacrolimus carry a risk of debilitating adverse effects, especially nephrotoxicity, that affect the long-term outcome and survival of children who are given organ transplants. Simple reduction in dosage of CNI has little or no long-term benefit on their adverse effects, and complete withdrawal without threatening graft outcome may only be possible after liver transplantation. Until the last decade, the only option was to increase corticosteroid and/or azathioprine doses, which imposed additional long-term hazards. Considered here are the emerging generation of new agents offering an opportunity for improving long-term graft survival, minimizing CNI-related adverse events and ensuring patient well-being.A holistic, multifaceted strategy may need to be considered - initial selection and optimized use and monitoring of immunosuppressant regimens, early recognition of indicators of patient and graft dysfunction, and, where applicable, early introduction of CNI-sparing regimens facilitating CNI withdrawal. The evidence reviewed here supports these approaches but remains far from definitive in paediatric solid organ transplantation. Because de novo immunosuppression uses CNI in more than 93% of patients, reduction of CNI-related adverse effects has focused on CNI sparing or withdrawal.A recurring theme where sirolimus and mycophenolate mofetil have been used for this purpose is the importance of their early introduction to limit CNI damage and provide long-term benefit: for example, long-term renal function critically reflects that at 1 year post-transplant. While mycophenolic acid shows advantages over sirolimus in preserving renal function because the latter is associated with proteinuria, sirolimus appears the more potent immunosuppressant but also impairs early wound healing. The use of CNI-free immunosuppressant regimens with depleting or non-depleting antibodies plus sirolimus and mycophenolic acid needs much wider investigation to achieve acceptable rejection rates and conserve renal function. The adverse effects of the alternative immunosuppressants, particularly the dyslipidaemia associated with sirolimus, needs to be minimized to avoid replacing one set of adverse effects (from CNIs) with another. While we can only conjecture that judicious combinations with the second generation of novel immunosuppressants currently in development will provide these solutions, a rationale of low-dose therapy with multiple immunosuppressants acting by complementary mechanisms seems to hold the promise for efficacy with minimal toxicity until the vision of tolerance achieves reality.

Low HDL-C predicts the onset of transplant vasculopathy in pediatric cardiac recipients on pravastatin therapy

The levels and protein/lipid compositions of major lipoprotein particles of 19 pediatric cardiac transplant recipients (4-18 yr of age) were studied in this prospective, open clinical follow-up study before and at one yr of pravastatin therapy (10 mg/day). The recipients were grouped into those with (n = 6; group A) and those without (n = 13; group B) angiographically detectable vasculopathy. Twenty-one pediatric non-transplant controls were studied at baseline. At baseline, the group A recipients had 29% lower HDL-C concentrations (p = 0.031) and 29% higher apoB-100/apoA-I ratios (p = 0.034) than the group B recipients. At one yr of pravastatin, the respective figures were 29% (p = 0.013) and 33% (p = 0.005). Compared with the healthy pediatric controls, the transplant recipients had significantly higher serum TG before pravastatin [median (range): 1.3 mmol/L (0.6-3.2) vs. 0.7 mmol/L (0.3-2.4), p = 0.0002] and at one yr [1.3 mmol/L (0.5-3.5) vs. 0.7 mmol/L (0.3-2.4), p = 0.0004]. The baseline apoB-100/apoA1 ratios of the recipients were 33% higher (p = 0.005). In conclusion, low HDL-C and high apoB-100/apoA-I ratio were associated with angiographically detectable vasculopathy. Even though pravastatin effectively lowered the TC and LDL-C and improved compositional properties of LDL and HDL(2) particles, it failed to normalize the elevated TG and, in some patients, to prevent the progression of transplant vasculopathy.

Immunosuppression in pediatric solid organ transplantation: opportunities, risks, and management

The pediatric transplant community stands at a time of unprecedented choice of immunosuppressive agents - and with a legacy of morbidity from those agents used in the previous two decades. This review considers the clinical utility and side-effect profiles of immunosuppressants used widely in current practice (e.g., glucocorticoids, azathioprine, ciclosporin, tacrolimus, mycophenolate, and sirolimus) and those agents which are in increasing use or in evaluation (e.g., IL-2 receptor antibodies, everolimus, FTY720, LEA29Y, and deoxyspergualin). Further consideration is given to the wider drug interactions likely during the use of new immunosuppressant regimens and to our growing awareness of the influences of genetic heterogeneity on drug efficacy and handling. Finally, we consider the new demands being placed on the use of drug monitoring to regulate dosage of this new repertoire of immunosuppressants.