The effects of short term administration of captopril on coronary hemodynamics in the presence and absence of chronic activation of the renin-angiotensin system were studied in 10 mild essential hypertensive patients with no evidence of ischemic disease. Coronary blood flow (CBF) was measured by the thermodilution technique, intraarterial blood pressure was monitored centrally, and plasma renin activity (PRA) levels were determined before and after 1 week of diuretic therapy (six patients. Group A). CBF was reduced and coronary vascular resistance (CVR) increased by chronic furosemide 50 mg/day compared to the placebo treatment (four patients. Group B). Blood pressure, heart rate, and rate-pressure product were comparable with and without activation. Forty-five minutes after 25 mg oral captopril, mean aortic pressure fell, CBF rose, and CVR and rate-pressure product were reduced in patients with an activated renin-angiotensin system (RAS), while profiles were insignificantly modified in the nonactivated group. PRA was increased by diuretic therapy. No correlation exists between PRA and CVR independent of RAS activation. These data indicate that short term converting enzyme inhibition (CEI) in the presence of RAS activation augments CBF by direct effect on coronary resistance, and is associated with a reduction in rate-pressure product. Further studies are needed to determine whether or not these effects are maintained long term, and to clarify the action of diuretic alone on coronary hemodynamics. A nonlinear relationship between angiotensin II and PRA may account for the observed lack of correlation with CVR.
|Journal||Journal of Cardiovascular Pharmacology|
|Publication status||Published - 1987|
- Converting enzyme inhibition
- Coronary blood flow
ASJC Scopus subject areas
- Cardiology and Cardiovascular Medicine