Pulse Pressure Is an Age-Independent Predictor of Stroke Development After Cardiac Surgery

Abstract

Chronologic age is a strong predictor of adverse outcomes after cardiac surgery. The variability in age-related cardiovascular changes suggests that age may not be the most accurate predictor of adverse perioperative outcomes. Vascular stiffness has emerged as an important surrogate of vascular aging. In a retrospective review, we investigated the value of vascular stiffness, as assessed by brachial pulse pressure (PP) measurements, in predicting stroke in 703 patients (63.4% men and 36.6% women). Patients were followed for 348+/-215 days after cardiac surgery. We used a multivariable logistic model and unadjusted and adjusted Cox proportional-hazard models to assess the probability of stroke and the hazards of stroke over time. Stroke patients had a significantly higher PP (81.2 mm Hg versus 64.5 mm Hg; P=0.0006). In the logistic regression model, PP was an independent predictor of stroke development (unadjusted odds ratio: 1.35; 95% CI: 1.13 to 1.62, for every 10-mm Hg increase in PP; P=0.001). In the unadjusted and adjusted Cox models, PP again predicted stroke (hazard ratio: 1.32; 95% CI: 1.12 to 1.57; hazard ratio: 2.62; 95% CI: 1.49 to 4.60, respectively; P=0.001 for both) for every 10 mm Hg increase in PP. Age, gender, and diabetes were not independent predictors of stroke. Ejection fraction was inversely related to stroke in the adjusted model. Kaplan-Meier estimates and corresponding log-rank test indicated that the probability of stroke-free survival function was significantly lower (P=0.0067) in patients with PP >72 mm Hg versus <72 mm Hg. This analysis suggests that indices of vascular stiffness could be important predictors of neurologic complications.