High prevalence of cardiac and extracardiac target organ damage in refractory hypertension

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Abstract
Target organ damage (TOD) in chronically treated hypertensives is related to effective blood pressure (BP) control. The aim of this study was to evaluate the prevalence of cardiac and extracardiac TOD in patients with refractory hypertension (RH) compared with well-controlled treated hypertensives (C). Fifty-four consecutive patients with RH (57 ± 10 years), selected according to WHO/ISH guidelines definition, and 51 essential hypertensives (55 ± 10 years) with satisfactory BP control obtained by association therapy, underwent the following procedures: (1) clinic BP measurement; (2) blood sampling for routine chemistry examinations; (3) 24 h urine collection for microalbuminuria; (4) non-mydriatic retinography; (5) echocardiogram; (6) carotid ultrasonogram. In order to exclude ‘office resistance’ (defined as clinic BP > 140/90 mmHg and average 24 h BP ≤ 125/79 mmHg), all patients with RH were subjected to 24-hour ambulatory BP monitoring. Both groups were similar for age, gender, body surface area, smoking habit and duration of hypertension, glucose, creatinine and lipid levels. By definition, clinic BP was significantly higher in RH than C (161 ± 19/96 ± 9 versus 127 ± 6/80 ± 5 mmHg, respectively, P < 0.01). The increased prevalence of left ventricular hypertrophy (LVH) and carotid intima–media (IM) thickening (40 versus 12%, P < 0.01, according to a non-gender-specific partition value of 125 g/m2 ; and 36 versus 14%, P < 0.01, according to IM thickness ≥1.0 mm, respectively); a higher prevalence of carotid plaques (65 versus 32%, P < 0.05), a more advanced retinal involvement (grade II and III, 73 and 5% versus 38 and 0%, P < 0.01) and a greater albumin urinary excretion (22 ± 32 mg/24 h versus 11 ± 13 mg/24 h, P < 0.01) were found in RH compared to C. Our study suggests that RH is a clinical condition associated with a high prevalence of TOD at cardiac, macro- and microvascular level and consequently with high absolute cardiovascular risk, which needs a particularly intensive therapeutic approach aimed to normalize BP levels and to induce TOD regression.