Long-term prognostic implications of visit-to-visit blood pressure variability in patients with ischaemic stroke

Abstract

Background: Both blood pressure (BP) and its variability (BPV) are established risk factors for the development of atherosclerotic diseases and are associated with an increased risk of cardiovascular and all-cause mortality. The long-term prognostic implications of out-patient clinic visit-to-visit BPV among patients with ischaemic stroke are nevertheless unknown. Methods: We prospectively followed up the clinical outcome of 632 consecutive ischaemic stroke patients without atrial fibrillation. The mean BP and BPV, as determined by the coefficient of variation of the systolic and diastolic BP, were recorded during a mean of 12 ± 6 outpatient clinic visits. Results: The mean age of the patients was 71 ± 11 years. After a mean of 76 ± 18 month’s follow-up, 161 (26%) patients died, 35% (56/161) were due to cardiovascular causes. 16% and 5% developed recurrent stroke and acute coronary syndrome (ACS), respectively. After adjusting for mean systolic BP and confounding variables, patients with a high systolic BPV were at significantly greater risk of cardiovascular mortality (hazard ratio [HR] = 2.36; 95% confidence interval [CI], 1.02-5.49; P < 0.05). A high systolic BPV also predicted all-cause mortality after adjusting for mean systolic BP (HR = 1.79; 95% CI, 1.16-2.75; P < 0.05). There was no association between systolic BPV with non-fatal recurrent stroke nor non-fatal ACS. A raised diastolic BPV did not predict recurrent non-fatal stroke, non-fatal ACS nor mortality. Conclusions: Visit-to-visit systolic BPV predicts long-term all-cause and cardiovascular mortality in patients with ischaemic stroke without atrial fibrillation, independent of other conventional risk factors including average BP control.