Abstract 12538: Pulmonary Arterial Capacitance after Left Ventricular Assist Device Implantation
Background: Left ventricular assist device (LVAD) improves pulmonary vascular resistance (PVR), which reflects the resistive load. However, the response of the pulmonary arterial capacitance (PAC), which represents the pulsatile load, is not clear. While the normally fixed relationship between PVR and PAC is shifted in the presence of elevated left sided filling pressures, it is unclear whether normalization of pulmonary capillary wedge pressure (PCWP) with LVAD implantation is associated with complete normalization of PAC. The goal of our study is to determine whether decrease in PCWP after LVAD results in improved PAC.
Methods: Right heart catheterization and other hemodynamic were collected and analyzed both pre and post (within 48-72 hours) LVAD implantation on a cohort of 69 patients with end stage systolic heart failure.
Results: After LVAD, the PVR to PAC relationship curve was shifted (Figure 1), which was largely driven by the decrease in PCWP (each 5 mm Hg decrease in PCWP was associated with an increase in PAC by 0.52 L·mmHg-1, p ≤ 0.0001). Mean PAC increased (2.09 to 3.76 L·mmHg-1, p ≤ 0.0001) and mean PCWP decreased (23 to 15 mm Hg, p 3.8 mL·mmHg-1). Predictors of failure to normalize PAC included a pre-operative PCWP ≤ 18, (OR 0.21, 95 % CI 0.04 - 0.91, p ≤0.05) and low pre-operative PAC (OR 0.07, 95 % CI .02-.31, p ≤0.0001 for the lowest pre-op PAC quartile). Pre-operative trans-pulmonary gradient, PVR, and cardiac index were not predictive of abnormal post-operative PAC.
Conclusion: Acute unloading of the left ventricle resulted in an immediate increase in PAC, relative to resistive load, which is driven mainly by a decrease of PCWP. However, in a subset, PAC is elevated independently of PCWP. Longitudinal studies will be needed to determine the effects of LVAD implantation on PAC over time and its prognostic implications.
- © 2013 by American Heart Association, Inc.