Pulmonary Vasodilator Monotherapy in PAH Improves Exercise Capacity, Study Reports

Monotherapy given to patients with congenital heart defects associated with pulmonary arterial hypertension, or PAH-CHD, improved their exercise capacity more than a combined therapy, researchers report. The study, “Effect of dual pulmonary vasodilator therapy in pulmonary arterial hypertension associated with congenital heart disease: a retrospective analysis,” was published in the journal Open Heart.

Patients burdened with heart defects may develop pulmonary arterial hypertension (PAH) as a second condition. Pulmonary hypertension is a serious condition characterized by high blood pressure in the arteries that supply blood to the lungs (pulmonary arteries), with vessels becoming narrowed, blocked, or destroyed. This leads to an increase in blood pressure in the arteries (because blood flow is compromised). It is estimated to occur in 10 percent of cases of heart defects.

Most PAH patients are initially treated with monotherapy, although more recent guidelines recommend combining drugs from different classes in patients who fail to respond adequately to initial therapy.

Researchers performed a retrospective single-center analysis of adults with PAH-CHD who received bosentan or sildenafil monotherapy, or dual bosentan and sildenafil therapy. The study outcomes determined symptomatic improvements, assessed in terms of exercise capacity and survival from treatment initiation, in the different treatment conditions. In total, the study included 82 patients, followed from January 2007 to January 2014.

Out of the 82 patients, 29 had Down syndrome. Regarding the therapeutic approach, 54 PAH-CHD patients received bosentan monotherapy (65.8%), 16 sildenafil monotherapy (19.5%), and 12 combined therapy (14.6%). Patients were treated for 2.5 years, with the exception of 38 patients who were treated for a longer period (4.1 years).

Authors observed that oral PAH-specific therapies significantly increased exercise capacity (determined by the mean 6 min walk distance test, 6MWD) in the first six months of treatment, and stabilized that capacity for up to two years. For both Down and non-Down syndrome patients, bosentan monotherapy also increased and led to a stabilization of 6MWD.

Investigators, in this study performed in real-life clinical settings, concluded that for the majority of the patients, monotherapy with a PAH-specific drug led to improvements in exercise capacity, and the benefits were sustained through time. Among the small percentage of patients who required the dual therapy, such an approach prevented further deterioration in exercise capacity, but had no effect on improving 6MWD.