Hemodynamic Response to Oral Vasodilator Therapy in Systemic Sclerosis-Related Pulmonary Hypertension

Abstract

Purpose: Although classified as group 1 pulmonary arterial hypertension (PAH), patients with systemic sclerosis-related pulmonary hypertension (SSc-PH) experience poorer clinical response to PAH therapy and increased mortality compared to those with idiopathic PAH. Due to heterogeneity in phenotypes, identifying patients likely to respond to therapy is challenging. The goal of this study was to determine clinical factors associated with hemodynamic response, defined by a > 20% reduction in pulmonary vascular resistance on repeat right heart catheterization.

Methods: We applied a time-to-event model using a retrospective cohort of 39 patients with precapillary SSc-PH, defined by a mean pulmonary artery pressure of ≥ 25 mmHg and pulmonary arterial wedge pressure (PAWP) ≤ 15 mmHg on right heart catheterization.

Results: Patients with PAWP ≤ 8 mmHg were nearly fourfold more likely to achieve a hemodynamic response compared to those with PAWP > 8 mmHg (HR 3.88; 95% CI: 1.20, 12.57); each 1 mmHg increase in PAWP was associated with a decreased hazard for hemodynamic response (HR 0.84; 95% CI: 0.70, 1.00).

Conclusion: In patients with precapillary SSc-PH, PAWP was associated with time to hemodynamic response, suggesting the importance of subclinical cardiac disease in determining hemodynamic response to oral vasodilator therapy.

Keywords: Cardiac hemodynamics; Pulmonary arterial hypertension; Pulmonary vasodilators; Scleroderma.

Figure 1.. Unadjusted (A) and Adjusted (B) Hazard Ratios for Hemodynamic Response by Pulmonary Arterial Wedge Pressure.

In both models, the point estimate for the hazard ratio of PAWP is plotted with the 95% CI. Based on this value, it appears that a PAWP of ≤ 8 mmHg is the highest PAWP to maintain a 95% CI above 1 for time to hemodynamic response.