Ambulatory Blood Pressure Monitoring and Cardiovascular Risk in Resistant Hypertensive Women

Background: Few studies have explored the prognostic value of ambulatory blood pressure (ABP) in resistant hypertensive patients, a high-risk group. Objective: To investigate the prognostic value of uncontrolled daytime ABP in resistant hypertensive women. Methods: We followed 382 resistant hypertensive women, aged 24-92 years, from a hypertension unit of a university hospital, for up to 8.9 years (mean 3.9). Patients were classified as controlled (office BP >= 140/90 mmHg and daytime ABP < 135/85 mmHg) or uncontrolled (office BP >= 140/90 mmHg and daytime ABP >= 135/85 mmHg). We analyzed a combined endpoint, consisting of cardiovascular mortality, ischemic heart disease, stroke and nephropathy. Cox proportional hazard models were used to estimate the risk for cardiovascular events, adjusting for potential confounders. Results: The total event rate was 5.0 per 100 women-years. In the controlled and uncontrolled groups, the rates were 3.7 vs. 5.8 events respectively, p=0.06. The relative risks adjusted for age and current smoking status associated with a 10 mmHg increment in systolic ABP were greater than the ones associated with a 5 mmHg increment in diastolic ABP. Non-dipper patients had a higher risk for cardiovascular events than dipper patients (RR = 1.42 (0.87-2.32)), although this association had no statistical significance. Uncontrolled daytime blood pressure (yes/no) was a stronger independent risk factor, 1.67 (1.00-2.78). Conclusions: There was a 67% increase in the risk of a cardiovascular event if daytime ambulatory blood pressure was uncontrolled in women with resistant hypertension. Therefore, it is mandatory to use ABP to evaluate control and to guide therapeutic strategies in resistant hypertensive patients. (Arq Bras Cardiol 2009; 92(6) : 448-453)