Pressure-dimension index and left ventricular sphericity index following HeartMate II and HeartMate 3 implantation.

Abstract

This study aimed to compare the changes in the left ventricle (LV) and right ventricle (RV) geometry and performance after the implantation of HeartMate II (HMII) and HeartMate 3 (HM3). In addition, we investigated whether the echocardiographic parameters LV sphericity index (LVSI) and the novel pressure-dimension index (PDI) can predict post-operative right ventricular failure (RVF). Between 2012 and 2020, 46 patients [HMII (n=22) and HM3 (n=24)] met the study's criteria and had echocardiography tests pre-operatively, 6 and 12months post-operatively. The LVSI and PDI were calculated together with the standard LV and RV echocardiographic parameters. The mean follow-up was 24±7months. In both groups, the LV end-diastolic diameter (LVEDD) significantly decreased 12months post-operatively compared with the pre-operative values (HMII: 6.4±1.4cm vs. 5.7±0.9cm, P=0.040; HM3: 6.7±1.3cm vs. 5.5±0.9cm, P<0.01, respectively). RV function 12months post-operatively was better in the HM3 group than in the HMII group, as indicated by a significantly higher RV fractional area change (RVFAC) in the HM3 group than in the HMII group 12months post-operatively (35±12% vs. 26±16%, P=0.039), significantly higher tricuspid annular plane systolic excursion (TAPSE) in the HM3 group 12months post-operatively compared with the HMII group (13.9±1.9mm vs. 12.0±2.1mm, P=0.002), and the tissue Doppler estimated tricuspid annular systolic velocity (TASV) was also significantly higher in the HM3 group 12months post-operatively compared with the HMII group (11.5±2.7mm/s vs. 9.9±1.5mm/s, P=0.020). The LVSI value was significantly higher 12months post-operatively in the HMII group than in the HM3 group (1.2±0.4 vs. 0.8±0.2, P=0.001, respectively), indicating worse geometric changes. The PDI decreased 12months post-operatively in the HM3-group compared with the baseline (3.4±1.4mmHg/cm2 vs. 2.0±0.8mmHg/cm2, P<0.001). In the univariate and multivariate analyses, only the pre-operative PDI was a predictor of post-operative RVF [odds ratio: 3.84 (95% CI: 1.53-18.16, P=0.022)]. The area under the curve for pre-operative PDI was 0.912. The 2year survival was significantly better in the HM3 group (log-rank, P=0.042). The design of HM3 offered better geometrical preservation of the LV and enabled normal PDI values, leading to improved RV function, as indicated by better RVFAC, TAPSE, and TASV values. The use of pre-operative PDI as an additional tool for established risk scores might offer a better pre-operative predictor of RVF.