Association of Pulmonary Artery Compliance and Adverse Cardiac Events

Pulmonary artery compliance (PAC), the ratio of stroke volume to pulmonary artery pulse pressure, reflects the pulsatile component of right ventricular afterload. While lower PAC is associated with right heart failure (HF) and death in patients with pulmonary arterial hypertension, the association of PAC with clinical outcomes among individuals with a broader range of cardiopulmonary comorbidities is unclear.

We examined consecutive ambulatory and hospitalized patients undergoing clinically indicated right heart catheterization at a single center between 2005 and 2016. Multivariable Cox models were used to investigate the association of PAC with clinical outcomes including HF hospitalization and mortality. Analyses were stratified by presence and absence of pulmonary hypertension (PH) and by PH hemodynamic subtype.

Among 7966 patients (mean age 63 years, 39% women), median PAC was 3.29 (IQR 2.19, 4.70) mL/mmHg. PAC was significantly inversely associated with mortality (HR 0.59 per 1-SD higher PAC, 95% CI 0.56, 0.63) and HF hospitalization (HR 0.56, 95% CI 0.52, 0.59) across the whole sample and among those with PH (mortality: HR 0.69, 95% CI 0.64, 0.74, HF: HR 0.65, 95% CI 0.61, 0.70) and without PH (mortality: HR 0.74, 95% CI 0.66, 0.84, HF: HR 0.72, 95% CI 0.61, 0.85). Similarly, PAC was associated with mortality across all PH subtypes: precapillary PH (HR 0.56, 95% CI 0.48, 0.65), combined PH (HR 0.75, 95% CI 0.66, 0.86) and isolated post-capillary PH (HR 0.88, 95% CI 0.79, 0.98).

Among patients undergoing clinically indicated right heart catheterization, lower PAC is associated with adverse outcomes irrespective of presence or absence of PH. Our findings support potential clinical utility of PAC in risk stratification across a broad spectrum of cardiopulmonary disease.