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Combined captopril and hydrochlorothiazide therapy in severe hypertension: long-term haemodynamic changes at rest and
Insights
This study shows that combining captopril and hydrochlorothiazide effectively lowers blood pressure in severe hypertension. The treatment reduced blood pressure at rest and during exercise, with minimal impact on fluid volumes.
Area of Science:
- Cardiology
- Pharmacology
- Hypertension Research
Background:
- Severe essential hypertension often requires combination therapy.
- Captopril, an ACE inhibitor, and hydrochlorothiazide, a diuretic, are commonly used antihypertensives.
- Understanding the chronic hemodynamic effects of this combination is crucial for managing resistant hypertension.
Purpose of the Study:
- To evaluate the long-term hemodynamic effects of combined captopril and hydrochlorothiazide treatment.
- To assess the impact of this combination on blood pressure, cardiac index, and peripheral resistance at rest and during exercise.
- To investigate changes in body fluid volumes with chronic treatment.
Main Methods:
- A cohort of 12 patients with severe, therapy-resistant essential hypertension was studied.
- Intra-arterial blood pressure was measured before and after a mean treatment period of 8.7 months.
- Cardiac index (CI) and body fluid volumes were assessed using dye and radioisotope dilution techniques, respectively.
Main Results:
- Mean arterial pressure (MAP) decreased by 15% at rest and 12% during exercise.
- Total peripheral resistance index (TPRI) decreased by 17% at rest, but did not change significantly during exercise.
- Cardiac index (CI) and stroke index (SI) showed no significant changes at rest but decreased by 15% and 17% during exercise, respectively.
Conclusions:
- Combined captopril and hydrochlorothiazide therapy effectively reduces blood pressure in severe resistant hypertension.
- The antihypertensive effect is maintained during dynamic exercise, though accompanied by a reduction in cardiac output.
- No significant alterations in body fluid volumes were observed with chronic treatment.
Abstract:
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.