SAN ANTONIO — Patients with treatment-resistant hypertension and hyperaldosteronism have higher ambulatory blood pressures and less white-coat hypertension than do those with resistant hypertension and normal aldosterone levels, Dr. Eduardo Pimenta said at a meeting of the Council for High Blood Pressure Research.
This may explain, in part, the finding in prior observational studies that hypertensives with hyperaldosteronism seem to have a greater risk of cardiovascular events than do equally hypertensive patients with normal aldosterone. It is well established that higher ambulatory blood pressure (BP) values and less white-coat hypertensive effect are associated with increased risk of cardiovascular events both in the general hypertensive population and in those with resistant hypertension, noted Dr. Pimenta of the University of Alabama, Birmingham.
Recent studies show that hyperaldosteronism plays a greater role in resistant hypertension than was historically thought to be the case. Dr. Pimenta reported on 252 consecutive patients referred for resistant hypertension (BP in excess of 140/90 mm Hg despite concurrent use of at least three drugs). Patients were on an average of 4.2 antihypertensive agents.
Of the 252 patients, 59 (23%) had hyperaldosteronism (plasma renin activity below 1.0 ng/mL per hour, and urinary aldosterone excretion of at least 12 mcg/24 hours). All discontinued spironolactone and other drugs affecting aldosterone at least 6 weeks prior to ambulatory BP monitoring.
The average in-office BP of the study participants was 160/89.4 mm Hg, with no significant difference between those with and without hyperaldosteronism. Despite the closely similar in-office BP in the two groups, those with high aldosterone had significantly higher daytime, nighttime, and 24-hour systolic and diastolic BP.
Moreover, the prevalence of white-coat hypertension—as defined by high BP in the clinic but a daytime ambulatory BP less than 135/85 mm Hg—was only 5% in resistant hypertensives with hyperaldosteronism, vs. more than 35% in those with normal aldosterone, Dr. Pimenta said at the meeting, sponsored by the American Heart Association.