Global and regional hemodynamic effects of ramipril in congestive heart failure

Global and regional hemodynamic changes were assessed in 11 patients with congestive heart failure following the introduction of the novel angiotensin-converting enzyme inhibitor (ACEI), ramipril. All patients were stabilized on digitalis, furosemide, and a fixed diet, central hemodynamics and hormones having been stable over 2 control days. Ramipril resulted in significant falls in converting enzyme activity, angiotensin II, and aldosterone, with a rise in renin. Changes in regional blood flow were assessed 2 h following the first dose of ramipril at the time of maximal increase in global cardiac output (+27%, p less than 0.05), but prior to the maximal fall in systemic arterial pressure. Despite the fall in systemic arterial pressure, blood flow increases were noted in the renal (+93%, p less than 0.05), coronary (+10%), and cerebral (+5%) regions, while forearm blood flow was unchanged. Glomerular filtration rate fell (29%) and was associated with small rises of plasma creatinine and acute sodium retention. After 7 weeks of therapy we noted improvement in functional class (p less than 0.05), exercise time, and left ventricular ejection fraction. We conclude that during inhibition of angiotensin-converting enzyme activity by ramipril in patients with congestive heart failure, blood flow to the kidneys, heart, and brain is increased or preserved despite hypotension. Long-term therapy is associated with beneficial clinical effects.