Aim: It is not well known if lowering systolic blood pressure (SBP), analyzed by 24 h ambulatory blood pressure (ABP), has limits in order to be CV protective. The aim of the study was to evaluate, by (ABP), if lowering SBP is associated with a non-J shape curve of decrease of cardiovascular events (CV) strokes (AVC) and coronary events (DC).Design and method:
Casual and ABP were obtained in 1200 hypertensive patients (HTA, 645 female) ageing 51 ± 12 years, BMI 27 ± 5 Kg/m2, 24 systolic blood pressure 133,3 ± 16 mmHg, under stabilized therapy without previous cardiovascular (CV) events. Presence or absence of CV events were followed 11,8 ± 5,1 years and analyzed by a Cox hazard model adjusted for confounding variables and by survival curves of Kaplan Meier free of events.Results:
There were 133 deaths and 251 cardiovascular fatal and non-fatal events (147 strokes, 67 coronary events, 37 other CV events) during 21,2 years of follow-up (mean 11,8 ± 5,1 years).Results:
After adjustment for age, BMI, gender, casual BP, antihypertensive treatment and diabetes, when we analyzed in the same Cox multivariate the deciles of 24 hours SBP distribution in relation to global cardiovascular events, strokes, coronary events had a positive correlation with those type of events, respectively HR 1,17 (95%CI 1,07-1,29; p < 0.001), 1,22 (95%CI 1,22 (1,08 –1,35; p < 0,001), 1,27 (95%CI 1,04-1,57; p < 0.03). When we analyzed the survival curves of Kaplan Meier free of events the deciles of 24 hours SBP in relation to global cardiovascular events, strokes, coronary events those within the higher deciles had the worst prognosis, respectively for CV events log ranK 52,8 p < 0.000 Breslow 66,7 p < 0.000, Stroke log rank 62,1 p < 0.000 Breslow 73,5 p < 0,000, and coronary events log rank 15,9 p < 0,03 Breslow p < 0,05.Conclusions:
IIn our Portuguese sample of patients with treated hypertension, lowering systolic blood pressure has a positive effect in terms of cardio-cerebrovascular events. No J curve was observed suggesting that in our sample the “lower is the better”.