In addition to being effective vasodilators, angiotensin-converting enzyme inhibitors (ACEIs)
and angiotensin receptor blockers (ARBs) exert neurohumoral inhibitory actions, such as the
inhibition of vascular remodeling and smooth muscle cell proliferation and the amelioration
of endothelial dysfunction. These beneficial effects, render those agents appropriate for use
in the treatment of pulmonary hypertension. However, data regarding the use of ACEIs or ARBs
in the treatment of PHT are limited. In this study, efficacy of an ARB, losartan was compared
with those of the calcium channel blocker, nifedipine in the treatment of pulmonary
hypertension using echocardiographic, 6-minute walk test (6MWT), cardiopulmonary exercise
test, and endothelin-1 levels.Losartan is as effective as nifedipine for reducing Doppler
echocardiographically measured PAP and improving exercise capacity on 6MWT and CPET. However
the short-term use of losartan or nifedipine had no statistically significant effect on
endothelin-1 levels in patients with PHT.