Does pulmonary vasoconstriction play an important role in patients with primary pulmonary hypertension? A skeptic's view of vasodilator therapy.

Despite isolated reports of dramatic hemodynamic and clinical improvement over the past 30 years, most patients with primary pulmonary hypertension fail to benefit from treatment with vasodilator drugs and many develop serious adverse reactions. The failure of this approach strongly suggests that pulmonary vasoconstriction does not play an important role in the pathogenesis of this disorder.