Pressure-dimension index: A novel “morphologic-functional” index of right ventricle that predicts short-term survival after left ventricular assist device implantation

Background: Right ventricular failure (RVF) after left ventricular assist device (LVAD) implantation is a major cause of postoperative morbidity and mortality. Despite the availability of multiple imaging parameters, none of these parameters had adequate predictive accuracy for post-LVAD RVF. Aim: To study whether right ventricular pressure-dimension index (PDI), which is a novel echocardiographic index that combines both morphologic and functional aspects of the right ventricle, is predictive of post-LVAD RVF and survival. Methods: 49 cases that underwent elective LVAD implantation were retrospectively analyzed using data from an institutional registry. PDI was calculated by dividing systolic pulmonary artery pressure to the square of the right ventricular minor diameter. Cases were categorized according to tertiles. Results: Patients within the highest PDI tertile (PDI>3.62 mmHg/cm2) had significantly higher short-term mortality (42.8%) and combined short-term mortality and definitive RVF (50%) compared to other tertiles (p<0.05 for both, log-rank p for survival to 15th day 0.014), but mortality was similar across tertiles in the long-term follow up. PDI was an independent predictor of short-term mortality (HR:1.05–26.49, p=0.031) and short-term composite of mortality and definitive RVF (HR:1.37–38.87, p=0.027). Conclusions: Increased PDI is a marker of an overburdened right ventricle. Heart failure patients with a high PDI is at risk for short-term mortality following LVAD implantation.