Correlation Between Intraventricular Pressure Difference and Indexed Flow of a Left Ventricular Assist Device.

ABSTRACT

OBJECTIVES: There is no definitive parameter for left ventricular (LV) preload in patients with a continuous-flow left ventricular assist device (LVAD). The intraventricular pressure difference (IVPD) is the maximum pressure difference between the mitral valve and LV apex during diastole; and, in past studies, the IVPD was influenced by volume loading. The authors hypothesized that IVPD in LVAD patients correlates with indexed LVAD flow and that IVPD can serve as a novel parameter of LV preload in this population. DESIGN: A single-center, retrospective, observational study. SETTING: A tertiary-care hospital from August 2019 to July 2020. PARTICIPANTS: Sixteen ramp tests for adjustment of LVAD pump speed in 14 adult patients undergoing continuous-flow LVAD implantation. INTERVENTIONS: Measurement of IVPD during ramp tests. MEASUREMENTS AND MAIN RESULTS: LVAD flow and IVPD were measured at each LVAD pump speed during the ramp test for the adjustment of LVAD pump speed after patients came off cardiopulmonary bypass during LVAD implantation. A straight, longitudinal view of the left atrium and left ventricle was obtained, and the pressure difference between the mitral valve and LV apex during diastole was measured by transesophageal echocardiography. The maximum pressure difference during diastole was recorded as IVPD. The relationship between indexed LVAD flow (LVAD flow/body surface area) and IVPD was assessed by a multivariate nonlinear regression analysis with the Huber-White sandwich estimator. IVPD correlated with indexed LVAD flow (p < 0.001). CONCLUSIONS: IVPD is a useful indicator of LV preload during LVAD implantation.