Endomyocardial biopsy in the heterotopic heart transplant patient

Better together: a reappraisal of heterotopic heart transplantation

Heterotopic heart transplantation (HHT) is rare in the modern era. When used as a biologic left ventricular assist, HHT provides pulsatile flow, supports the left ventricle with a physiologic cardiac output, responds to humoral stimuli, and with modern immunosuppression may offer long-term untethered survival. This study was undertaken to compare survival of HHT with orthotopic heart transplantation (OHT) to assess its viability in the modern era. In the United Network for Organ Sharing database, from January 1999 to December 2020, there were 27691 bicaval OHT, 13836 biatrial OHT, 1271 total OHT, and 51 HHT with sufficient follow-up. Survival was analyzed using restricted mean survival time (RMST) through 4 years as the outcome. In the first 4 years after transplant, compared with HHT, differences in RMST were 0.1 years (99% CI: -0.4 to 0.5 years) for bicaval OHT, 0.0 years (99% CI: -0.4 to 0.5 years) for biatrial OHT, and 0.0 years (99% CI: -0.5 to 0.4 years) for total OHT. In this cohort, survival was indistinguishable between HHT and OHT recipients in the first four years. Thus, HHT might be a viable alternative to durable mechanical circulatory assist particularly with size mismatched grafts or for patients with refractory pulmonary hypertension.

A case of heterotopic heart transplant as a "biologic left ventricular assist" in restrictive cardiomyopathy

Heterotopic heart transplant (HHT) has traditionally been thought of as creating 2 parallel circulations. We present a case of using the donor heart as a "biologic left ventricular assist" (bio-LVA). The heterotopic technique used consisted of 4 anastomoses: the donor heart pulmonary artery (PA) to the native heart right atrium, the superior vena cava to superior vena cava, the left atrium to left atrium, and the aorta to aorta. A 9-year-old boy with restrictive cardiomyopathy, a PA pressure of 85/53 mmHg, received a HHT because he would probably not be able to tolerate an orthotopic heart transplant secondary to elevated PA pressure. He is currently alive 14 years post-transplantation.

Hybrid pulmonary artery conduit angioplasty for heterotopic heart transplantation

Heterotopic heart transplantation is rare in clinical practices. It carries technical difficulty not only during transplantation procedures, but also in the postoperative surveillance. We report two cases of heterotopic heart transplantation, which were complicated by pulmonary artery conduit stenosis within 2 years. We applied a less invasive approach combining cardiovascular surgeons with an interventional cardiologist. Through the donor heart right ventricular outflow tract, we performed balloon angioplasty and stent deployment. An excellent angiographic result with minimal residual pressure gradient was achieved in both patients.

Heterotopic Heart Transplantation: An Expanding Role in the Twenty-First Century?

BACKGROUND

Heterotopic heart transplantation was first performed in humans in 1974, the main advantage being the continuing function of the patient's native heart, in the event of life-threatening acute rejection. The effect of cyclosporine on acute rejection saw the heterotopic transplantation technique wane. Our unit revisited heterotopic transplantation in response to a growing number of waiting list patients with high pulmonary artery pressures. We also anticipated an increased cardiac allograft utilization, and improvement of our waiting list times.

METHODS

We retrospectively analyzed 151 patients undergoing heart transplantation by our unit between August 1997 and September 2003. Twenty received allografts in the heterotopic position. This cohort was compared with the 131 contemporary orthotopic heart transplant recipients with respect to their outcomes.

RESULTS

The indication for transplantation was ischemic cardiomyopathy in 14 (70%) of the heterotopic cohort and 47 (36%) of the orthotopic cohort (p = 0.004), and dilated cardiomyopathy in 3 (15%) and 48 (37%) in the heterotopic and orthotopic groups, respectively (p = 0.06). Heterotopic recipients were significantly older than orthotopic recipients, and they had higher pulmonary artery pressures. The heterotopic donors were also older and the ischemic times were longer. A subgroup analysis was made among those patients who had high pulmonary artery pressures as these groups were better matched. Major morbidity in the heterotopic heart transplantation group consisted of reversible allograft dysfunction in 4 patients, renal dysfunction requiring hemofiltration in 3 patients, profound myopathy in 4 patients, and cerebrovascular events in 2 patients. There were two early deaths in the heterotopic transplant group and eight in the orthotopic group (p = 0.87). Kaplan-Meier survival analysis of survival was performed.

CONCLUSIONS

Heterotopic heart transplantation is a viable transplant option for selected high-risk heart transplant recipients in spite of somewhat poorer outcomes.

Selection of patients and techniques of heart transplantation

Cardiac transplantation remains the primary therapeutic choice for most patients under 65 years of age with advanced heart failure who remain symptomatic despite maximal medical therapy. Cardiac transplantation should be reserved for those patients most likely to benefit in terms of both life expectancy and quality of life. The concept of survival benefit margin must be balanced with the principles of utility in the selection process. A critical component of outcomes research for advanced heart failure will be the generation of accurate data and analyses which predict long-term survival and quality of life with various therapeutic modalities. Patients with multiple comorbidities have inferior survival and might be considered for alternative therapies. We currently recommend the bicaval techniques as the transplant technique of choice except in small infants and children.