Researchers have discovered that a decreased mean pulmonary arterial pressure (mPAP) of 35 mmHg or less can significantly improve clinical outcomes in patients with pulmonary arterial hypertension (PAH) of various etiologies, according to a study published in Vascular Pharmacology.
PAH is characterized by a rise in precapillary pressure, resulting in remodeling of the pulmonary vasculature. The mainstay of treatment for PAH remains vasodilation and a reduction in right ventricular afterload.
“Until now [mPAP] was never considered a possible therapeutic target, mainly because randomized controlled trials of vasodilators showed marginal reduction in mPAP with the active drug compared with placebo,” the authors of the study wrote.
However, current treatment regimens have been observed to significantly lower mPAP. Recent studies demonstrate that a significant reduction in mPAP can lead to reverse remodeling of the right ventricle and improve long-term survival.
Read more about PAH epidemiology
The authors of the study hence decided to investigate if lowering mPAP could have a meaningful impact on clinical outcomes. They recruited 267 patients with PAH of various etiologies, including idiopathic, hereditary, drug-induced, and toxin-induced PAH. Participants continued to receive targeted drugs based on the therapeutic strategy initiated at the time of diagnosis.
Among the 267 participants, 239 underwent right heart catheterization. The research team monitored the reduction in mPAP compared to baseline and compared clinical outcomes.
“A mPAP ≤35 mmHg during follow-up was identified by [receiver operating characteristic] analysis (Youden index method) as the best cutoff value for survival prediction,” the authors of the study reported.
In addition, the research team observed that an mPAP of less than 25 mmHg could be achieved in roughly 25% of patients with PAH. This was especially the case in patients administered parenteral prostanoids, compared to those receiving oral medications.
“Our results suggest that reduction of mean pulmonary pressure has important prognostic implication in idiopathic, hereditary and drug and toxin-induced PAH,” the authors wrote.
Badagliacca R, Vizza CD, Lang I, et al. Pulmonary pressure recovery in idiopathic, hereditary and drug and toxin-induced pulmonary arterial hypertension: determinants and clinical impact. Vascul Pharmacol. Published online September 1, 2022. doi:10.1016/j.vph.2022.107099