Predicted Heart Mass (PHM) Ratio for Size Matching in Heart Transplant Post LVAD

Abstract

<h3>Purpose</h3> Recent studies point towards donor/recipient predicted heart mass (PHM) ratio as an emerging metric for size matching. Our study examines if PHM ratio is a better marker than weight ratios in size matching for heart transplant, specifically in post LVAD patient population. <h3>Methods</h3> 11,891 patients with LVAD who received heart transplants between the years 1997 to 2020 in the Scientific Registry of Transplant Recipient's database were analyzed. We compared 5 size match metrics including Donor/recipient ratios of weight, height, BMI, BSA and PHM. We divided each metric into 3 equally sized groups. Univariate and multivariate cox proportional hazard models for one year mortality was calculated. <h3>Results</h3> On multivariate analysis, patients in the undersized group with PHM ratios of less than 0.82 had hazards ratio of 1.3 (95% CI, 1.08-1.6; p-0.001), suggestive of increased mortality in post LVAD patients. There was no difference in one year survival between matched (PHM ratio 0.82-1.2) and oversized group (PHM ratio>1.2). Under-sizing or oversizing based on other metrics of weight, BMI, BSA or height were not predictive of outcomes at one year. <h3>Conclusion</h3> Donor/recipient PHM ratio is emerging as a better metric in size matching in heart transplant than weight ratios. When size matching for heart transplant post LVAD, PHM ratio < 0.82 confers higher mortality within a year post transplant. Oversizing of PHM >1.2 does not afford any advantage in heart transplant post LVAD.