Right ventricular undersizing is associated with increased 1-year mortality

Right heart hemodynamic management is critical, because many post-heart transplantation (HTx) complications are related to right ventricular (RV) failure. However, current guidelines on size and sex matching rely primarily on weight matching, with recent literature using total ventricular mass (TVM), which places less emphasis on the impact of RV mass (RVM) matching. The aim of the present study was to analyze the relationship of RVM matching and survival after HTx.

We performed the retrospective analysis using the UNOS database of adult HTx performed between January 1997 and December 2017. Previously validated equations were used to calculate TVM and RVM. The percent difference in ventricular mass in the donor and recipient pair was used for the size mismatch. All donor-recipient pairs were divided into 4 RVM groups by their mismatch ratio. We analyzed RVM matching and explored how RVM undersizing impacted outcomes. The primary outcome measure was 1-year survival; secondary outcomes measured included stroke and dialysis within 1 year and functional status.

A total of 38,740 donor-recipient pairs were included in our study. The 4 RVM match groupings were as follows: <0%, 0% to 20%, 20% to 40%, and >40%. Utilization of donors who were older and of female sex resulted in greater RVM undersizing. Survival analysis demonstrated patients with RVM undersizing had worse 1-year survival (P < .001). RVM undersizing was an independent predictor of higher 1-year mortality (hazard ratio, 1.23; 95% confidence interval, 1.11 to 1.34; P < .001). RVM undersizing was also associated with higher rates of dialysis within 1-year of transplantation and poorer postoperative functional status.

RVM undersizing is an independent predictor for worse 1-year survival. Donors who are older and female have lower absolute predicted RVM and may be predisposed to RVM undersizing. RVM-undersized transplantation requires careful risk/benefit considerations.