RESUMO
OBJECTIVE: The prognostic importance of a reduced glomerular filtration rate (GFR) is unsettled in resistant hypertension. The aim was to evaluate GFR and its interaction with microalbuminuria as prognostic predictors in resistant hypertensive patients. METHODS: In a prospective study, 531 resistant hypertensive patients had albuminuria measured and GFR estimated by Cockroft-Gault (eGFRCG) and Modification of Diet in Renal Disease (MDRD; eGFRMDRD) equations. Primary endpoints were a composite of fatal and nonfatal cardiovascular events, all-cause and cardiovascular mortality. Multiple Cox regression assessed the associations between reduced GFR and endpoints, and interaction with microalbuminuria. RESULTS: After a median follow-up of 4.9 years, 72 patients died, 42 from cardiovascular causes; and 96 cardiovascular events occurred. Decreasing grades of eGFRMDRD were predictors of the composite endpoint with hazard ratios of 2.1 [95% confidence interval (CI) 1.1-3.8], 2.2 (1.2-3.9) and 3.5 (1.4-8.7) for the subgroups with eGFR between 60-89, 30-59 and less than 30âmg/min per 1.73âm, respectively. A decreased eGFRCG was predictive of the composite endpoint only in the lowest GFR subgroup (hazard ratio 2.7, 95% CI 1.0-7.1). The lowest eGFR subgroups were also associated with all-cause mortality, regardless of the estimated equation used. The presence of both reduced eGFR and microalbuminuria significantly increased cardiovascular risk in relation to one or another isolated, with hazard ratios of 3.0 (1.7-5.3), 2.9 (1.5-5.5) and 4.6 (2.2-10.0), respectively for the composite endpoint, all-cause and cardiovascular mortality. CONCLUSION: A reduced GFR, mainly estimated by the MDRD equation, is an independent predictor of increased cardiovascular morbidity and mortality in resistant hypertension. The combination of a reduced GFR and increased albuminuria identifies patients with a very high cardiovascular risk.
Assuntos
Albuminúria/complicações , Albuminúria/fisiopatologia , Taxa de Filtração Glomerular , Hipertensão/complicações , Hipertensão/fisiopatologia , Idoso , Anti-Hipertensivos/uso terapêutico , Doenças Cardiovasculares/etiologia , Doenças Cardiovasculares/fisiopatologia , Estudos de Coortes , Intervalo Livre de Doença , Resistência a Medicamentos , Feminino , Humanos , Hipertensão/tratamento farmacológico , Masculino , Pessoa de Meia-Idade , Prognóstico , Modelos de Riscos Proporcionais , Estudos ProspectivosRESUMO
Increased arterial stiffness may be causally related to resistant hypertension. Our objective was to investigate the variables, particularly those derived from ambulatory blood pressure (BP) monitoring (ABPM), associated with increased aortic stiffness in resistant hypertensives. In a cross-sectional study, 600 resistant hypertensive patients without peripheral arterial disease were evaluated. Arterial stiffness was assessed by aortic pulse wave velocity (PWV), and was considered increased if >12 m s(-1). Statistical analyses included multiple linear and logistic regressions to assess the independent correlates of increased aortic stiffness. One hundred and sixty-eight patients (28%) had aortic PWV >12 m s(-1). Patients with increased PWV were older and had a higher prevalence of cardiovascular risk factors than did those patients with low PWV. On ABPM, patients with elevated PWV had higher daytime and night time systolic BP (SBP) and pulse pressures (PP), less nocturnal decrease in SBP and a higher prevalence of non-dipping pattern. On multiple linear regression, the independently associated variables with aortic PWV were age (P<0.001), 24-h PP (P<0.001), high-density lipoprotein (HDL)-cholesterol (P<0.001), microalbuminuria (P<0.001), fasting glycemia (P=0.001) and a decrease in nocturnal SBP (P=0.002). Multivariate logistic regression confirmed these results, with the non-dipping patients having a 72% higher likelihood of presenting with increased aortic stiffness (95% confidence interval: 1.12-2.65, P=0.013). This association was observed in both the reduced and reverted dipping patterns, but not in the extreme dipping pattern. In conclusion, a blunted nocturnal decrease in BP is independently associated with increased aortic stiffness in resistant hypertensive patients. Other independent correlates are older age, diabetes, microalbuminuria, low HDL-cholesterol and a widened 24-h PP.