Renin levels and cardiovascular morbidity in essential hypertension. A prospective study

Renin levels and cardiovascular morbidity: a prospective study of the effect of beta-adrenergic blocking drugs

A 3-year prospective study was undertaken to evaluate the relationship between plasma renin activity levels and the incidence of cardiovascular complications in white patients with uncomplicated essential hypertension treated with various beta-adrenergic blocking agents (oxprenolol, pindolol, propranolol, sotalol and timolol). During the follow-up study, 4 (5.9%) of 68 treated patients and 10 (41.7%) of 24 non-treated patients (p less than 0.001) developed cardiovascular complications. The cardiovascular events occurred more frequently in patients with low renin activity levels and in patients with severe hypertension (diastolic blood pressure above 120 mmHg). An increase in plasma renin activity levels was observed following cardiovascular complications in both groups of patients. No cases of myocardial infarction occurred among the treated patients, while 5 cases (3 fatal) of proven myocardial infarction occurred among the non-treated patients. The results of this study suggest that low plasma renin activity levels have no "protective effect" on the incidence of cardiovascular complications in patients with essential hypertension. The fact that no cases of myocardial infarction were observed among patients treated with various beta-adrenergic blocking drugs suggests that these drugs may have a "cardioprotective" effect on ischaemic heart disease in patients with essential hypertension. This hypothesis should be confirmed by further trials.