Left Atrial Pressure Pulsatility Attenuates Pulmonary Vascular Compliance in Heart Failure

Abstract

It has been demonstrated that elevations in mean pulmonary artery wedge pressure (PAWPm) yield a leftward and downward shift of the pulmonary arterial compliance (PAC)-pulmonary vascular resistance (PVR) hyperbolic curve suggesting that higher PAWPm augments RV pulsatile relative to resistive load and may contribute to RV dysfunction. However, the PAWPm comprises an integration of both the steady and the pulsatile pressure occurring during the heart circle. In the current study we sought to address the differential impact of the steady and pulsatile components of PAWPm on the PAC-PVR relationship. The study population consisted of 192 patients with hemodynamic findings indicating heart failure (HF) defined as elevated PAWPm at rest or during exercise. Figure 1 illustrates the method used to measure the steady and pulsatile components of PAWPm. The PAC and PVR were hyperbolically and inversely associated and the subgroup of patients with PAWPm above the median (18 mmHg) showcased a shift of the curve fit downwards and to the left. As illustrated in Figure 2a and 2b, the group of patients with steady PAWP (PAWPs) above the median (16.7 mmHg) demonstrated a slight shift of the PAC-PVR fit curve downwards and to the left. On the other hand, there was a clear downward and leftward shift of the PVR-PAC curve fit for the patient cohort with higher pulsatile PAWP (PAWPp) component (3.5 mmHg). Higher pulsatile rather than steady PAWP component changes significantly the PVR-PAC relationship in patients with HF.