Noninvasive assessment of hemodynamic improvement during chronic vasodilator therapy in obliterative pulmonary hypertension.

The ability to treat selected patients with obliterative pulmonary hypertension (OPH) with vasodilator therapy has been clearly demonstrated. However, the dangers involved in their use in patients who fail to have a beneficial response have also been well documented. A major problem in the management of these patients has been the lack of an easily measurable, noninvasive index of alterations in cardiopulmonary status that could be used at relatively frequent intervals to monitor the response to therapy. We have studied the utility of changes in noninvasively assessed exercise performance to predict changes in pulmonary vascular tone. In 10 patients with OPH, we compared symptom-limited oxygen consumption (o2ex) and oxygen pulse (o2/heart rate) at o2ex (O2 Pex) determined during progressive treadmill exercise with invasive measurements of cardiovascular function during steady-state supine bicycle submaximal exercise prior to and 8 wk after initiation of vasodilator therapy with nifedipine or diltiazem. Af...