Different contribution of SBP and DBP variability to vascular events in patients with stroke

BACKGROUND: High blood pressure variability (BPV) is a novel risk factor for cardiovascular disease. However, the heterogeneity of systolic blood pressure variability (SBPV) and diastolic blood pressure variability (DBPV) for different vascular events remains unclear. This study aims to investigate whether SBPV or DBPV has different contribution to vascular events in patients with acute ischaemic stroke (IS) or transient ischaemic attack (TIA). METHODS: Data from the BOSS (blood pressure and clinical outcome in TIA or IS) study were examined for vascular events at 3-month and 1-year follow-up. BPV was defined as the SD and coefficient of variation (CV) of day-to-day measurements within 3 months after IS/TIA. Vascular events include cardiovascular events (myocardial infarction, unstable angina, cardiac death and congestive heart failure) and cerebrovascular events (ischaemic or haemorrhagic stroke). Logistic regression model was used to test the associations between BPV and vascular events. RESULTS: Of 2325 patients with IS or TIA, 103 (4.43 %) experienced a recurrent stroke and 64 (2.75 %) had cardiovascular events within 3 months. Day-to-day SBPV was only associated with stroke recurrence (BPV(SD): OR, 1.72, 95% CI 1.09 to 2.71; BPV(CV): 1.86, 95% CI 1.19 to 2.92), but not cardiovascular events (BPV(SD): 1.67, 95% CI 0.94 to 2.94; BPV(CV): 1.51, 95% CI 0.86 to 2.64). However, DBPV seems to be related to both stroke (BPV(SD): 1.60, 95% CI 1.02 to 2.49; BPV(CV): 1.53, 95% CI 0.99 to 2.37) and cardiovascular events (BPV(SD): 2.48, 95% CI 1.37 to 4.48; BPV(CV): 1.92, 95% CI 1.09 to 3.36). Similar results were found at 1 year. CONCLUSIONS: For patients with IS/TIA, stroke recurrence was associated with both SBPV and DBPV; however, cardiovascular events seem to be only related to DBPV.