View article

In an attempt to produce substantial reductions in pulmonary arterial pressure and pulmonary vascular resistance in patients with primary pulmonary hypertension, a new treatment strategy using high doses of calcium channel-blocking drugs was developed. Thirteen patients were given an initial test dose of 60 mg diltiazem or 20 mg nifedipine followed by consecutive hourly doses until a 50% fall in pulmonary vascular resistance and 33% fall in pulmonary arterial pressure was achieved or untoward side effects developed. The initial drug challenges failed to produce significant reductions in mean pulmonary arterial pressure or pulmonary vascular resistance. In eight of 13 patients, continued hourly doses produced a reduction in mean pulmonary arterial pressure of 48% (61 to 35 mm Hg, p less than .01) and a reduction in pulmonary vascular resistance of 60% (15 to 6 units, p less than .01). These patients were …