SAN ANTONIO — Riociguat is associated with improvements in right ventricular (RV) function in patients with pulmonary arterial hypertension(PAH) compared with placebo, according to a study presented at the CHEST Annual Meeting, held October 6-10, 2018, in San Antonio, Texas.
Riociguat improved functional measures such as the 6-minute walk distance (6MWD), World Health Organization functional class, and N-terminal pro-brain natriuretic peptide in the PATENT-1 study (ClinicalTrials.gov Identifier: NCT00810693). The agent also demonstrated improvements in hemodynamic parameters, including pulmonary vascular resistance (PVR) and cardiac index (CI).
“However, mortality in PAH is usually related to RV failure and so we performed a post hoc analysis to determine if riociguat improved hemodynamic parameters of RV function in PATENT-1,” researchers noted.
Patients with PAH and a 6MWD between 150 and 450 m, PVR of >300 dyn⋅s⋅cm−5, and mean pulmonary arterial pressure (mPAP) of ≥25 mm Hg at baseline were enrolled. The investigators randomly assigned patients to either riociguat at up to 2.5 mg 3 times daily (n=254) or placebo (n=126) for a 12-week treatment period. At 12-week follow-up, the researchers performed right heart catheterization, and stroke volume (SV, mL), stroke volume index (SVI, mL/m2), RV work (cardiac output × mPAP × 0.0144), RV work index (CI × mPAP × 0.0144), RV power (mPAP × CI), cardiac efficiency (SV/mPAP), and pulmonary artery (PA) elastance (systolic pulmonary artery pressure/SV) were assessed.
At 12-week follow-up, riociguat was associated with increases in RV work (+0.30 ±0.78), RV work index (+0.17 ±0.46), RV power (+0.05 ±0.12), SV (+10.63 ±13.68), SVI (+6.16 ±7.87), and cardiac efficiency (+0.44 ±0.60) from baseline. Additionally, treatment with riociguat demonstrated a decrease in PA elastance (–0.34 ±0.53). Patients who received placebo had decreases in RV work (–0.10 ±0.94), RV work index (–0.07±0.57), RV power (–0.02±0.15), and SVI (–0.04±9.52) at 12 weeks compared with baseline. Placebo was also associated with increases in PA elastance (+0.02±0.65), SV (+0.33±16.30), and cardiac efficiency (+0.09±0.57).
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