Allopurinol and Blood Pressure Variability Following Ischemic Stroke and Transient Ischemic Attack: A Secondary Analysis of XILO-FIST

Background Blood Pressure Variability (BPV) is associated with cardiovascular risk and serum uric acid level. We investigated whether BPV is lowered by allopurinol and whether it is related to markers of cerebral small vessel disease. Methods We used data from a randomised, double-blind, placebo-controlled trial of two years allopurinol treatment after recent ischemic stroke or transient ischaemic attack. Visit-to-visit BPV was assessed using brachial blood pressure (BP) recordings. Short-term BPV was assessed using ambulatory BP monitoring (ABPM) performed at 4 weeks and 2 years. Brain MRI was performed at baseline and 2 years. BPV measures were compared between the allopurinol and placebo groups and with white matter hyperintensity progression. Results 409 participants were included (205 allopurinol; 204 placebo) were included in analyses of visit-to-visit BPV and there were no significant differences between groups. 196 participants were included in analyses of short-term BPV at week 4. Two measures were reduced by allopurinol: the standard deviation (SD) of systolic BP (by 1.30mmHg (95% confidence interval (CI) 0.18–2.42, p=0.023)); and the average real variability (ARV) of systolic BP (by 1.31mmHg (95% CI 0.31–2.32, p=0.011)). There were no differences in other measures at week 4 or in any measure at 2 years. Conclusions Allopurinol treatment did not affect visit-to-visit BPV in people with recent ischemic stroke or TIA. Two BPV measures were reduced at week 4 by allopurinol but not at 2 years. Allopurinol is unlikely to lead to an important reduction in BPV in people with ischemic stroke or TIA.