Long-term Effects of Nitrendipine on Hemodynamics and Oxygen Transport in Patients with Cor Pulmonale

Abstract

Recent studies have suggested that vasodilators may acutely improve pulmonary hemodynamics in patients with chronic obstructive pulmonary disease and cor pulmonale, but the effects of long-term therapy have not been assessed. We evaluated the hemodynamic and gas exchange effects of nitrendipine, a calcium channel blocker with a cardiovascular profile similar to nifedipine, acutely and after five days and six weeks of therapy in eight patients with stable COPD and cor pulmonale. After six weeks, nitrendipine significantly decreased both mean pulmonary artery pressure (40.4 +/- 10.3 to 31.2 +/- 6.6 mm Hg, p less than 0.01) and pulmonary vascular resistance (6.8 +/- 3.9 to 3.0 +/- 1.1 units, p less than 0.01), while cardiac index increased (2.4 +/- 0.8 to 3.6 +/- 1.0 L/min/m2, p less than 0.001). Despite a fall in arterial PO2 (53.1 +/- 18.7 to 45.5 +/- 11.3 mm Hg, p = NS), systemic oxygen transport increased by over 30 percent (843 +/- 284 to 1,111 +/- 373 ml/min, p less than 0.05). Systemic arterial pressure, pulmonary capillary wedge pressure, and heart rate were unchanged. Despite these hemodynamic changes, three patients died from complications of their underlying disease while receiving long-term therapy after eight, nine, and ten months. These preliminary findings suggest that long-term vasodilator therapy can result in persistent hemodynamic improvement in some patients with cor pulmonale secondary to COPD, although the impact of this form of therapy on survival remains to be clarified.