Heterotopic heart transplant: is there an indication in the continuous flow ventricular assist device era?

Heterotopic heart transplantation (HHTx) is a therapeutic option in heart failure patients with fixed elevated pulmonary hypertension. However, survival is poorer in HHTx recipients, and with improving results in continuous flow ventricular assist devices (VADs), many patients can be bridged to allow normalization of pulmonary artery pressures, making them orthotopic heart transplant (OHTx) candidates. Thus, the aim of this study was to analyse the survival of our HHTx cohort and compare them with our VAD bridge patients.

A retrospective review of 342 heart transplant patients (315 OHTx and 27 HHTx) performed at our institution over 15 years was compared with 124 bridge-to-transplant VAD patients over the same time period, of whom 69 received an OHTx. Pulmonary artery pressures before and after VAD implant were analysed. Survival was analysed using both univariate and multivariate analyses.

HHTx recipients were significantly older, and the donor allografts were older, smaller and had longer ischaemic times than the OHTx cohort. Comparison of the VAD types implanted (pulsatile vs continuous) showed significantly longer time supported on the continuous devices with significantly fewer deaths than the pulsatile devices. The continuous devices were successful in reducing pulmonary artery pressures pretransplant. The HHTx cohort had a significantly poorer survival than the OHTx cohort (P=0.002). Survival on a continuous device and then OHTx was significantly better than either HHTx or pulsatile device support.

The main indication for HHTx, namely fixed elevated pulmonary hypertension in heart failure patients, can be safely and effectively treated by continuous flow bridge to transplant with superior survival.