Angiotensin-converting enzyme inhibition and radial artery compliance in patients with congestive heart failure

Congestive heart failure is characterized by a clear-cut impairment of arterial compliance of medium-sized arteries, but whether this alteration is irreversible or can be favorably affected by cardiovascular drugs currently used in congestive heart failure treatment is unknown. We studied 9 congestive heart failure patients (New York Heart Association class II; age, [mean±SEM] 60.7±3.3 years) receiving diuretic and digitalis treatment in whom arterial compliance was assessed at the level of the radial artery by an echotracking device capable of measuring the arterial diameter along the entire cardiac cycle. Beat-to-beat arterial blood pressure was concomitantly measured by a Finapres device that allowed diameter-pressure curves and compliance-pressure curves (Langewouters' formula) to be calculated for the entire systolic-diastolic blood pressure range. Arterial compliance was expressed as the area under the compliance-pressure curve normalized for pulse pressure (compliance index). Data were collected before and after 4 and 8 weeks of oral administration of benazepril (10 mg/day). Ten healthy subjects were studied before and after an observational period of 4 weeks (5 subjects) or 8 weeks (5 subjects), and 9 age-matched mildly essential hypertensive subjects studied before and after 4 to 12 weeks of benazepril administration served as control subjects. In congestive heart failure patients, baseline compliance index was significantly less than in normotensive and hypertensive subjects. However, the compliance index showed a marked increase after 4 weeks of benazepril administration (+95.7±24.9%, P<.05); the increase was also marked after 8 weeks of angiotensin-converting enzyme inhibitor treatment (+77.7±4.2%, P<.05). At this time the compliance values of the congestive heart failure patients were not different from those of the healthy and hypertensive groups, in which the observational period and angiotensin-converting enzyme inhibitor administration, respectively, had brought no change in compliance. Similar results were observed when compliance index was calculated for the blood pressure range shared by the three groups (isobaric compliance). These data provide the first evidence that the impairment of arterial compliance occurring in congestive heart failure can be favorably affected by the addition of an angiotensin- converting enzyme inhibitor to the treatment regimen. This has favorable implications for the cardiovascular functions adversely affected by a reduced arterial compliance (eg, cardiac work and oxygen consumption, coronary perfusion, and arterial baroreflex).