The renin-angiotensin system and the heart: beyond 2000

Meta-Analysis of effectiveness or lack thereof of angiotensin-converting enzyme inhibitors for prevention of heart failure in patients with systemic hypertension

We undertook a meta-analysis of large, randomized controlled trials in hypertensive subjects that compared angiotensin-converting enzyme (ACE) inhibitors with different classes of antihypertensive drugs. Compared with subjects randomized to drugs different from ACE inhibitors, those treated with ACE inhibitors did not show a different risk of congestive heart failure (CHF) (odds ratio 1.03, 95% confidence interval 0.96 to 1.12, p = 0.407). The degree of protection from CHF associated with the use of ACE inhibitors showed a nonsignificant trend to increase with age and the degree of blood pressure control. Thus, the hypothesis that ACE inhibitors are superior to other antihypertensive drugs for prevention of CHF in hypertension remains unproven.

Anticipatory blood pressure responses to exercise are associated with left ventricular mass in Finnish men: Kuopio Ischemic Heart Disease Risk Factor Study

BACKGROUND

Exaggerated cardiovascular reactivity to psychological demands may contribute to the development of left ventricular (LV) hypertrophy. We examined the cross-sectional association between anticipatory blood pressure (BP) responses to bicycle exercise and LV mass in the Kuopio Ischemic Heart Disease Risk Factor Study, a population-based epidemiological sample.

METHODS AND RESULTS

Among 876 men from 4 age cohorts (ages 42, 48, 58, and 64 years), we collected echocardiographic assessments of LV mass along with measures of BP response taken before bicycle ergometry testing. Anticipatory BP responses were positively associated with LV mass, with significant associations only among younger (age <50 years) subjects with elevated resting pressures (3-way interactions for anticipatory BP x age x resting pressure for systolic and diastolic BP, all P:<0.05; for younger subjects with elevated systolic BP, P:<0. 01; and for younger subjects with elevated diastolic BP, P:<0.001). Among these subgroups, exaggerated anticipatory BP responses (top quartile) were associated with an incremental increase in LV mass of 10% or greater, corrected for body surface area. Results remained significant after adjusting for age, education, salt consumption, and resting BP, and the pattern of findings was maintained among men with no previous history of cardiovascular disease.

CONCLUSIONS

The tendency to show exaggerated pressor responses to psychological demands may be a significant independent correlate of LV mass, especially among young men with high resting pressures. This is the first study to examine such associations in a middle-aged population sample.

The renin-angiotensin system in essential hypertension: associations with cardiovascular risk

The importance of the renin-angiotensin system (RAS) in blood pressure regulation is well established. High RAS activity has also been implicated in connection with elevated cardiovascular risk in patients with essential hypertension. Data from epidemiological studies have related high plasma renin levels in essential hypertensive patients to cardiovascular complications. However, whether renin itself is a risk factor of cardiovascular events or just acts as a marker for other risk factors still remains to be elucidated. Several possible mechanisms that could be responsible for the association between elevated RAS activity and cardiovascular risk are reviewed. The concept of high RAS activity being a cardiovascular risk factor is strongly supported by results from large clinical studies showing the beneficial effects of angiotensin-converting enzyme inhibitors and angiotensin II receptor blockers in congestive heart failure and hypertension. Knowing more about the exact mechanisms of the association between high RAS activity and cardiovascular complications would enable us to profile the treatment of high blood pressure more specifically to improve outcome in individuals or groups of patients.

Hemodynamic effect of endothelin antagonists in dogs with myocardial infarction

The hemodynamic effects of enalapril, an angiotensin-converting enzyme inhibitor, BQ-123, a selective ETA receptor antagonist, and bosentan, a nonselective ETA and ETB receptor antagonist, were studied in dogs 4 weeks after myocardial infarction (MI) produced by ligation of the left anterior descending coronary artery. Reduced arterial pressure and total peripheral resistance after administration of analapril, BQ-123, and bosentan revealed that both the renin-angiotensin system and endothelin participate in maintenance of cardiovascular function in chronic MI.