Prime Time: Is there an Optimal VAD Duration Prior to Heart Transplant in Children? Restricted; Files Only

Butto, Arene (Spring 2023)

Permanent URL: https://etd.library.emory.edu/concern/etds/nc580n99m?locale=en%5D
Published

Abstract

Purpose: Early pediatric ventricular assist device (VAD) studies showed high adverse event (AE) rates within one month after VAD implant, prompting heart transplant (Tx) soon after VAD surgery. However, recent data indicate that shorter VAD durations are associated with worse post-Tx outcomes. We compared outcomes of patients bridged to Tx with <30 vs. ≥30 days of VAD support by assessing both VAD and Tx risk factors.

Methods: We merged data from children in the PediMACS and Pediatric Heart Transplant Study registries. Inverse probability of treatment weighting using propensity scores (PS) was used to control for potential confounders, including age at VAD implant, recipient blood type, cardiac diagnosis (cardiomyopathy, congenital heart disease, myocarditis), VAD support type (left, right, single, and biventricular VAD), allosensitization, and pre-Tx mechanical ventilation and vasoactive support. The primary endpoint was one-year post Tx mortality.

Results: Among 271 patients, there were 60 in the <30 days and 211 in the ≥30 days groups. Baseline and VAD characteristics were similar. The ≥30 days group had higher prevalence of blood type O and allosensitization. At Tx, the <30 days group had more mechanical ventilation (34% vs. 7%, p<0.001) and vasoactive use (60% vs. 24%, p<0.001 vs. ≥30 days). There were 187 VAD AEs in the first 30 days after implant. The overall weighted AE rate per patient was lower in the <30 days group than in the ≥30 days group (0.42 vs. 0.78, p=0.02). There were 2 deaths in the <30 days group and 13 in the ≥30 days group (log-rank p=0.38). A PS-weighted Cox proportional hazards model, adjusted for 30-day AE rate while on VAD support, demonstrated a non-significant mortality hazard ratio of 0.43 for the <30 days vs. ≥30 days group (95% CI 0.07-2.70, p=0.37).

Conclusion: VAD support durations <30 days were associated with a non-significant lower post-Tx mortality after accounting for illness severity and VAD AEs in children bridged to Tx with VAD. The effect size must be interpreted with caution due to the small event number but raises important questions regarding the need for a mandatory waiting period prior to Tx in VAD patients.

Table of Contents

Table of Contents

Thesis 1

Introduction 1

Methods 5

Results 8

Discussion 10

Limitations 12

Conclusions 12

References 13

Tables and Figures 19

Table 1: Baseline Characteristics Between VAD Duration Groups 19

Table 2: Adverse Event Rate in First 30 Days of VAD Support 21

Table 3: Laboratory Studies Between Groups at 30 Days Post-VAD 22

Table 4: Weighted Cox Proportional Hazards Model for One-Year Post-Transplant Mortality 23

Supplemental Table 1: Baseline Characteristics with Unadjusted and Adjusted SMD 24

Supplemental Table 2. Laboratory Values Pre-VAD Implant 25

Supplemental Table 3. Post-Transplant Length of Stay 26

Supplemental Table 4. Cumulative Incidence of Infection, Rejection, and Renal Failure in First Year Post-Transplant 27

Figure 1. Weighted Kaplan-Meier Plot of One-Year Post-HTx Mortality by VAD Duration 28

Figure 2. Cumulative Incidence of Infection in First Year Post-Transplant 29

Figure 3. Cumulative Incidence of Rejection in First Year Post-Transplant 30

Figure 4. Cumulative Incidence of Renal Failure in First Year Post-Transplant 31

 

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