Increasing donor-recipient weight mismatch in pediatric orthotopic heart transplantation does not adversely affect outcome.

Objective: The aim of the study was to show the effect of heart transplant donor-recipient weight mismatch on mortality, right-ventricular (RV) failure, and medium-term control of systemic blood pressure.

Methods: From 2000 to 2008 inclusive, 161 patients undergoing orthotopic heart transplantation at our unit were retrospectively analyzed. The cohort was divided into three groups of similar size depending on the tertile ranges of the donor-recipient weight ratio. Median follow-up was 4.81 years. Donor-recipient body weight ratio was analyzed with respect to intubation time, time in intensive care unit (ITU), development of RV failure, medium-term survival, and freedom from medium-term hypertension.

Results: The median age was 115 months (23 days to 18 years), at a median weight of 26.9 kg (3-88 kg) at transplant. Median donor-recipient weight ratio was 1.61 (0.62-3.25). Mean intubation time was 448 h (SD 749.2), mean time in the ITU 302.7 h (SD 617.8). On linear regression, these were not related to donor-recipient weight ratio. A total of 38 patients (23.6%) developed postoperative RV failure. Nearly one-fifth (18.9) of patients in the lowest tertile group developed RV failure. In the middle tertile group, 24.5% developed RV failure and 28.8% in the upper tertile of weight mismatch, although this was not statistically significant (p = 0.48). On survival analysis, there was a higher mortality among those with the lowest tertile of mismatch (log-rank p = 0.04), but there was no difference in midterm survival on condition of survival to discharge (log-rank p = 0.14). There was also no association between weight ratio and freedom from medium-term hypertension as measured on serial 24-h ambulatory blood pressure monitoring (log-rank p = 0.39). There were nine patients in whom the weight mismatch was 3 or greater. There was no association between this 'extreme' mismatch group and either midterm mortality (p = 0.76) or freedom from hypertension (p = 0.62), but this was associated with the need for postoperative extracorporeal membrane oxygenator (ECMO) support (p < 0.01).

Conclusions: Our current policy involves accepting a maximum donor-recipient weight ratio of 3. These encouraging findings cautiously justify this policy, in an era when marginal donors are increasingly sought.