Blood Flow Kinetic Energy of Right Ventricular Outflow Tract: A Marker for Right Ventricular Global Systolic Function

Abstract

Purpose Right ventricular (RV) failure remains a major concern in heart failure (HF) patients undergoing LVAD surgery. We aimed to measure flow kinetic energy (KE) of the RV outflow tract (OT) - a new marker of RV global systolic function - and assess its relationship to well-established echocardiographic and hemodynamic parameters of RV performance in heart failure (HF) and LVAD pts. Methods Twenty-one subjects were prospectively enrolled: 12 HF pts (2 NYHA Class II and 10 Class IV), 3 HeartMate II (HMII) and 6 healthy controls (C). Echocardiographic parameters of RV function (TAPSE, St’, Et’, IVA, MPI) and RV inflow-outflow color Doppler images were recorded on all pts. Invasive hemodynamic parameters of RV function and RV failure risk score (RVFRS) were collected in all Class IV pts. KE-RVOT was derived from color Doppler images using a vector flow mapping proprietary software, Echo VFM® (Cardio Flow Design, Tokyo, Japan) (Figure). Kruskal-Wallis test was performed for comparison of each group. Correlation between KE-RVOT and echocardiographic/hemodynamic parameters as well as RVFRS was assessed by linear regression analysis. Results KERVOT (Median ± IQR) was higher in C (56.98 [37.63 to 97.21] mW/m) than in Class II HF (26.60 [26.14 to 27.05] mW/m, p<0.05) and further declined in Class IV HF (7.45 [4.87 to 10.46] mW/m, p<0.05)). LVAD therapy partially restored KE-RVOT (23.17 [9.77 to 25.03] mW/m, p<0.05)) to levels similar to Class II HF (Figure). KE-RVOT was significantly related to TAPSE, St’, CVP/PCWP, and PAPi (r = 0.5887, 0.6671, -0.6942, and 0.7899, respectively, all p<0.05) but not to RVFRS. Conclusion KE-RVOT, a novel noninvasive measure of RV function, strongly correlates with well-established markers of RV performance. The utility of KE-RVOT in prediction of RV failure post LVAD requires further study. Right ventricular (RV) failure remains a major concern in heart failure (HF) patients undergoing LVAD surgery. We aimed to measure flow kinetic energy (KE) of the RV outflow tract (OT) - a new marker of RV global systolic function - and assess its relationship to well-established echocardiographic and hemodynamic parameters of RV performance in heart failure (HF) and LVAD pts. Twenty-one subjects were prospectively enrolled: 12 HF pts (2 NYHA Class II and 10 Class IV), 3 HeartMate II (HMII) and 6 healthy controls (C). Echocardiographic parameters of RV function (TAPSE, St’, Et’, IVA, MPI) and RV inflow-outflow color Doppler images were recorded on all pts. Invasive hemodynamic parameters of RV function and RV failure risk score (RVFRS) were collected in all Class IV pts. KE-RVOT was derived from color Doppler images using a vector flow mapping proprietary software, Echo VFM® (Cardio Flow Design, Tokyo, Japan) (Figure). Kruskal-Wallis test was performed for comparison of each group. Correlation between KE-RVOT and echocardiographic/hemodynamic parameters as well as RVFRS was assessed by linear regression analysis. KERVOT (Median ± IQR) was higher in C (56.98 [37.63 to 97.21] mW/m) than in Class II HF (26.60 [26.14 to 27.05] mW/m, p<0.05) and further declined in Class IV HF (7.45 [4.87 to 10.46] mW/m, p<0.05)). LVAD therapy partially restored KE-RVOT (23.17 [9.77 to 25.03] mW/m, p<0.05)) to levels similar to Class II HF (Figure). KE-RVOT was significantly related to TAPSE, St’, CVP/PCWP, and PAPi (r = 0.5887, 0.6671, -0.6942, and 0.7899, respectively, all p<0.05) but not to RVFRS. KE-RVOT, a novel noninvasive measure of RV function, strongly correlates with well-established markers of RV performance. The utility of KE-RVOT in prediction of RV failure post LVAD requires further study.