Efficacy of antihypertensive treatment based on plasma renin activity: An open label observational study.

BACKGROUND: We investigated the extent of blood pressure (BP) reduction and control (<140/90 mmHg) in patients treated with appropriate or inappropriate drugs according to their plasma renin activity (PRA) level (natriuretic drugs and renin-angiotensin system blockers for low-renin and high-renin hypertension, respectively). PATIENTS AND METHODS: One hundred and seventy Caucasian untreated hypertensive patients (61 females), aged 18-70 years, participated to the study. Patients with secondary hypertension, diabetes or established cardiovascular or renal disease were excluded. The physician prescribed an antihypertensive monotherapy chosen among all drug classes, unaware of patient's PRA levels. We compared effect of an inappropriate or appropriate drug, evaluating BP values after a month of treatment. RESULTS: Rate of BP control was not significantly higher in patients treated with an appropriate drug than the others (38% vs 29%, p=0.24). However, in a regression analysis, final diastolic BP (DBP) was lower in subjects treated with an appropriate drug (beta=-2.84, p=0.03). CONCLUSIONS: The present study does not clearly support the use of PRA in a general population of hypertensive patients to optimize BP control. However, the greater efficacy of a drug appropriate to PRA in reducing DBP may be clinically helpful in young hypertensive patients. Future studies are warranted to evaluate if PRA determination enhances the therapeutic success in patients with predominantly high values of DBP.

Effects of birth weight on spontaneous baroreflex sensitivity in adult life.

BACKGROUND AND AIM: Several epidemiological studies have suggested a link between low birth weight and coronary heart disease; this may be partly due to the association between low birth weight and conventional risk factors. Among the factors involved in the regulation of cardiovascular homeostasis, baroreflexes play a crucial role. The objective of the present study was to investigate if baroreflex sensitivity (BRS) in adulthood is associated with birth weight. METHODS AND RESULTS: Two hundred and eleven adults from Turin, Italy, aged 22-24 years, were examined in a cross sectional survey. Birth weight, blood pressure, pulse rate, family history of hypertension, anthropometric and environmental parameters and spontaneous baroreflex sensitivity were evaluated. In this study we observed a significant increase in baroreflex sensitivity across the tertiles of birth weight, even after correction for gender, blood pressure and heart rate; in a regression model, birth weight was positively and independently associated with BRS; moreover, BRS showed a significant negative correlation with adult pulse rate. CONCLUSION: This finding may be helpful in understanding the association between low birth weight and cardiovascular disease outcome in later life, since baroreflex failure is associated with an increased cardiovascular morbidity and mortality.

CYP11B2 -344T/C gene polymorphism and blood pressure in patients with acromegaly.

CONTEXT: The pathogenesis of increased blood pressure (BP) in acromegaly is unclear, and the role of IGF-I levels and the renin-angiotensin-aldosterone system (RAAS) in this disease remains controversial. OBJECTIVE AND DESIGN: The aim of this study was to investigate the role of gene polymorphisms of the RAAS and involved in sodium handling on BP in acromegaly. SETTING AND PATIENTS: We conducted a multicentric retrospective study that included 100 consecutive patients with acromegaly referred during the period 2000-2003. INTERVENTION: All patients were genotyped for ACE I/D, AGT M235T, CYP11B2 -344T/C, B2R -58T/C, and alpha-adducin G460W polymorphisms. MAIN OUTCOME MEASURE: We assessed the prevalence of hypertension and BP according to the genotype. RESULTS: Patients with the CYP11B2 -344CC genotype displayed a significant increase in the risk of hypertension compared with patients with CT/TT genotypes (odds ratio = 4.0; 95% confidence interval = 1.4-11.6; P = 0.01). Consistently, a significant proportion of patients with the CYP11B2 -344CC genotypes were under antihypertensive treatment (73.1%) compared with patients with the TT/TC genotypes (38.2%; P = 0.003). Patients with the -344CC genotype displayed a significant increase in systolic BP (10.2 +/- 4.3 mm Hg; P = 0.02) but not a significant increase in diastolic BP (2.6 +/- 2.6 mm Hg; P = 0.32) compared with patients with the CT/TT genotype. CONCLUSIONS: We have shown an association of the -344T/C CYP11B2 gene polymorphism with BP in patients affected by acromegaly. These findings suggest that the RAAS is implicated in the pathogenesis of hypertension in acromegaly.

QT interval in patients with primary aldosteronism and low-renin essential hypertension.

INTRODUCTION: QT interval prolongation increases the risk of sudden death in several medical conditions. Patients with primary aldosteronism and salt-sensitive hypertension experience more cardiovascular events than those with normal-renin essential hypertension. QT interval prolongation might represent one of the risk factors for cardiovascular events in these patients. The aim of the present study was to evaluate the QT interval in patients with primary aldosteronism and low-renin essential hypertension (LREH). METHODS: Twenty-seven patients with primary aldosteronism, 17 patients with LREH, 117 patients with essential hypertension and 25 healthy individuals were studied. Plasma aldosterone, plasma renin activity, and aldosterone to plasma renin activity ratio (ARR) were determined. Corrected QT intervals (QTcs) were measured from a 12-lead electrocardiogram. RESULTS: The QTc was longer in primary aldosteronism (434 +/- 23 ms) and LREH (430 +/- 18 ms) compared with essential hypertension (419 +/- 22 ms) and healthy controls (412 +/- 19 ms) (P = 0.0004). The prevalence of QTc longer than 440 ms was higher in primary aldosteronism (48%) and LREH (23%) compared with essential hypertension (11%) and healthy controls (4%) (P < 0.0001). QTc correlated with plasma aldosterone (P = 0.01), ARR (P = 0.02), and diastolic blood pressure (P = 0.01). ARR (P = 0.01) and systolic blood pressure (P = 0.01) were identified as independent predictors of QTc. CONCLUSIONS: We postulate that the elevated aldosterone secretion contributes to the prolongation of the QT interval in patients with primary aldosteronism and LREH through both a depletion of intracellular potassium concentration and higher blood pressure values. QTc measurement might represent one simple, non-invasive and reproducible index to characterize the cardiovascular risk in patients with primary aldosteronism and LREH.