The effect of amlodipine on exercise-induced pulmonary hypertension and right heart function in patients with chronic obstructive pulmonary disease.

The aim of the study was to investigate the pulmonary vasodilator effect of the dihydropyridine calcium channel blocker amlodipine in patients with clinically stable chronic obstructive pulmonary disease (COPD) and pulmonary hypertension (PH). Many patients with COPD develop chronic PH and this may predict mortality in this disorder. The treatment with calcium channel blockers is accepted as a therapeutic strategy for primary pulmonary hypertension. In twenty male patients (mean age 57+/-7 years) with clinically stable COPD and PH, we investigated whether amlodipine could effectively decrease pulmonary vascular resistance (PVR) and pulmonary arterial pressure (PAP) and improve right heart function. PAP was recorded by a balloon-tipped thermodilution catheter and cardiac output was determined in triplicate by thermodilution at rest and during exercise. In addition, blood gas values were determined from the capillary blood of the earlobe. All measurements were done under identical conditions before and after 18 days of chronic treatment: with 10 mg amlodipine once daily starting with 5mg in the first week. At a mean maximal achieved workload of 71.3+/-20 Watts, amlodipine achieved a significant reduction in PVR (-13.4%; p<0.01) and PAP (-12.1%; p<0.001) implying an improved right heart function assessed by a significant reduction in mean right atrial pressure (-20.6%; p<0.05). During the action of amlodipine there were no significant changes in pulmonary gas exchange and pulmonary capillary wedge pressure. Amlodipine given as a single daily oral dose of 10mg is a safe and effective pulmonary vasodilator in COPD patients with PH and leads to an improvement in right heart function.