Hypertension before and after posterior circulation infarction: analysis of data from the South London Stroke Register.

BACKGROUND: Postmortem data have shown that blood pressure before death correlates more closely with a narrowing of the vertebral arteries than any other vessel studied. This study explores a possible association between hypertension, both before and after posterior circulation infarction (POCI) compared to anterior circulation infarction (ACI). METHODS: Patients with a first-ever stroke enrolled in the South London Stroke Register between 2000 and 2006 were included. Chi-square tests and multivariable logistic regression were used to compare risk factors including hypertension, sex, smoking history, diabetes, and hypercholesterolemia in patients with POCI compared to ACI. Chi-square testing was used to compare the incidence of newly diagnosed hypertension after POCI and ACI. Absolute blood pressure readings recorded before stroke and 7 days after stroke were also compared between groups. RESULTS: On multivariable analysis, POCI was significantly associated with male sex (odds ratio [OR] 2.24; 95% confidence interval [CI] 1.55-3.22; P < .001) and hypertension (OR 1.69; 95% CI 1.15-2.50; P = .008). After stroke, patients with POCI were more likely to be newly diagnosed with hypertension during a 1-year follow-up period (OR 2.15; 95% CI 1.20-3.86; P = .009) and as an inpatient (OR 3.27; 95% CI 1.49-7.13; P = .002). Systolic blood pressure was significantly higher in the POCI group before stroke (152 v 146 mm Hg; P = .027). Diastolic blood pressure was significantly higher 7 days poststroke (81 v 74 mm Hg; P = .01) in patients not previously diagnosed with hypertension. CONCLUSIONS: This study has shown a significant association between hypertension before and after POCI compared to ACI. We believe further investigation with brainstem imaging and recordings of sympathetic nervous system activity after stroke is warranted.