Combined captopril and hydrochlorothiazide therapy in severe hypertension: long-term haemodynamic changes at rest and during exercise.

Captopril is an orally active converting enzyme inhibitor lowering blood pressure (BP) in different types of hypertension. A combination of captopril and a diuretic is often used in the treatment of severe hypertension. We have examined the chronic haemodynamic effect of combined captopril and hydrochlorothiazide treatment at rest and during 50 and 100 W dynamic exercise in 12 patients with severe therapy resistant essential hypertension. Blood pressure was measured intra-arterially before and after a mean treatment period of 8.7 months. Cardiac index (CI) was measured by dye dilution (Cardiogreen) and body fluid volumes by radioisotope dilution techniques. During rest sitting BP was reduced by 31/17 mmHg (15%) from a pretreatment value of 205/119 mmHg. Total peripheral resistance index (TPRI) fell 17% whereas CI, heart rate (HR) and stroke index (SI) did not show any significant changes. The fall in mean arterial pressure (MAP) was slightly less during exercise (12%) and the BP reduction was associated with a fall in CI and SI of 15 and 17%, respectively and no fall in TPRI. No significant changes were observed in body fluid volumes.