Abstract 204: Non-dipper Pattern Is Associated With Urinary Metanephrines In Patients With Refractory Hypertension
Refractory hypertension (HTN) is an extreme phenotype of treatment-resistant HTN and is defined as blood pressure (BP) ≥140/90 mm Hg on ≥5 antihypertensive drug classes including a diuretic and mineralocorticoid antagonist.
Observational data indicate that African Americans, males, body mass index, kidney function, and diabetes are associated with refractory HTN. Available BP data of refractory HTN are based on clinic or in-home evaluations. Less is known about ambulatory blood pressure (ABP) levels, circadian patterns and pathophysiologic mechanisms.
Aim: Prospective study of ABP levels, nocturnal BP fall, and urinary (U-) 24-hour metanephrines as index of sympathetic activity.
Methods: Over a 2 year period, 44 subjects were prospectively enrolled (15 subjects with refractory HTN matched with 29 controlled resistant hypertensive subjects who served as comparator group). All subjects underwent 24-ABP monitoring (ABPM) and U-24-hour metanephrines testing.
Results: Subjects with refractory HTN were on more antihypertensive drugs (6±1 vs 4.1±1.1, p≤ 0.05) and had significantly higher 24-hour systolic BP(SBP) (174±20.2 vs 139.8±16.3 mm Hg, p=0.0017), higher 24-hour diastolic BP (DBP) (94.7±19.8 vs 75.7±11.8 mm Hg, p=0.006), higher daytime SBP (178.1±97.4 vs 141±15.7 mm Hg, p=0.0046), higher daytime DBP (97.4±19.8 vs 77.2±11.4 mm Hg, p=0.007), higher nighttime SBP (165.2±19.2 vs 133.5±19.8 mm Hg, p=0.0002), and higher nighttime DBP (87.7±16.5 vs 70.2±15.1 mm Hg, p=0.007). Analysis of circadian patterns revealed significant increase in non-dipper pattern, defined as nocturnal BP fall of 0-10%, in subjects with refractory HTN (53.3 % (8 of 15) vs 14.3 % (3 of 28), p=0.0267). Biochemical analysis of U-24-hr fractionated metanephrines revealed significantly higher levels in refractory compared to controlled resistant HTN indicative of higher sympathetic activity (U-24-h total metanephrines (592.2 ±246.9 vs 409.3±167.0 μg, p=0.021, and U-24-h total normetanephrines 464.4 ±250.2 vs 309.8±147.6 μg, p=0.039).
These findings suggest that increased sympathetic activity may play a role in treatment failure and may promote blunted nocturnal BP fall in refractory hypertension.
Author Disclosures: T. Dudenbostel: None. M.C. Acelajado: None. P. Li: None. S. Oparil: None. D.A. Calhoun: None.
- © 2014 by American Heart Association, Inc.