SPIRONOLACTONE DOES NOT CHANGE 24HR BP CIRCADIAN PATTERN IN RESISTANT HYPERTENSIVE PATIENTS

Abstract

Objective: Resistant hypertension (RHTN) is defined as uncontrolled blood pressure (BP) (clinic BP > = 130/80 mmHg, 24-hr ambulatory BP [ABPM] >= 125/75 mmHg) on 3 or more medications including a diuretic. As previously described by us a novel 24hr circadian BP pattern with a large morning dip and evening surge is seen in RHTN patients whereas patients with non-RHTN lack this 24hr circadian pattern. We aim to study change in 24hr circadian BP pattern in RHTN after Spironolactone therapy as mineralocorticoid receptor antagonist (MRA) are most common antihypertensive medication class used in treatment of RHTN. Design and method: In this prospective evaluation, 27 uncontrolled RHTN patients on medications were recruited from Hypertensive clinic after three or more clinic visits. All patients were evaluated by clinic BP and 24-hour ABPM at baseline visit. 14 patients were RHTN by clinic BP and 24hr ABPM were randomized to Spironolactone 50 mg for 3 months and clinic BP and ABPM were done at end of 3 months of spironolactone therapy. Results: There was no change in 24hr circadian BP pattern from baseline visit to 3months after spironolactone therapyNevertheless, there was decrease in 24hr systolic and diastolic BP by ABPM from baseline visit to 3months after spironolactone therapy of 14.9 ± 20.4 / 8.4 ± 14.1 mmHg (24hr systolic and diastolic BP by ABPM at baseline visit 145.6 ± 13.3 / 80.6 ± 12.5 mmHg to 3months after spironolactone therapy 130.8- ± 18.7 / 72.2 ± 10.3 mmHg, P-value 0.011 and 0.031). Conclusions: Patients with RHTN demonstrate a similar 24-hr circadian BP profile irrespective of BP control by spironolactone therapy characterized by large morning dip followed by a prominent evening surge. This novel profile suggests that RHTN is a distinct phenotype in terms of circadian BP variation and is not affected by BP control by MRA. This wide fluctuation in 24-hr circadian BP pattern would be expected to contribute to the increased cardiovascular and cerebrovascular risk in RHTN patients even after BP control.