Evaluation of the ASPIRANT trial

Several pathophysiological, clinical, and therapeutic features of resistant hypertension are far from being clearly defined. This is the case also for the efficacy of aldosterone receptor antagonists as an add-on treatment of resistant hypertension. The Addition of Spironolactone in Patients with Resistant Arterial Hypertension (ASPIRANT) trial evaluated, with a double-blind, placebo-controlled design, the effects of low-dose (25 mg/day) spironolactone as compared with placebo on clinic and ambulatory blood pressure in 117 resistant hypertensive obese patients, already under treatment with at least four antihypertensive drugs. The primary study endpoint was the achievement of a statistically significant difference in the systo-diastolic blood pressure reduction during the daytime period between the spironolactone-treated and the placebo-treated group. The results show that aldosterone blockade was associated with a significant reduction in clinic, 24-h and daytime systolic (but not in diastolic) blood pressure as compared with the placebo-treated group, the systo-diastolic blood pressure difference between the two treatment regimens amounting to 5.4/1.0 mmHg. Although a number of limitations weaken some of the study conclusions, ASPIRANT trial provides the first controlled evidence on the blood pressure-lowering effects of low-dose spironolactone in resistant hypertensive patients.