Objective: To explore the independent predictors of internal borderzone (IBZ) infarcts in patients with atherosclerotic middle cerebral artery stenosis/occlusion (MCAS).
Methods: A total of 167 hospitalized patients with atherosclerotic MCAS during January 2008 and March 2014 were retrospectively analyzed. They were divided into "with IBZ group" (n = 55) and "without IBZ group" (n = 112) according to the findings of magnetic resonance images (MRI). Their clinical data were collected including demographics, traditional vascular risk factors, stenotic degree of MCA and other cerebral supply arteries, TICI grading for antegrade blood flow, ASITN/SIR grading for collateral circulation and other variables. The intra-group data were compared by univariate analysis. Variables with P < 0.1 were included into multivariate Logistic regression model for obtaining the independent predictors of IBZ. Two models were established including either TICI-grading or stenotic degree of MCAS due to close correlations between two variables.
Results: There were 45 females and 122 males with a mean age of 54 ± 12 years. Variables with a P value <0.1 in univariate analysis included relatively low blood pressure (P = 0.006), stenotic degree of MCAS (P = 0.012), TICI-grading (P = 0.003), history of hypertension (P = 0.055) and ASITN-grading (P = 0.067). In multivariate model I, independent predictors of IBZ included TICI-grading (OR 4.310, 95%CI 1.698-10.869, P = 0.002), history of hypertension (OR 0.458, 95%CI 0.224-0.936, P = 0.032), relatively low blood pressure (OR 3.848; 95%CI 1.345-7.983, P = 0.039). In multivariate model II, independent predictors of IBZ included stenotic degree of MCAS (P = 0.006; severe vs moderate: OR 4.796, 95%CI 1.676-13.729, P = 0.003; occlusion vs moderate: OR 5.537, 95%CI 1.846-16.603, P = 0.002). The two models had a similar area under the curve (AUC) of receiver operating curve (ROC) of 0.702 (95%CI 0.618~0.787, P < 0.001) and 0.709 (95%CI 0.626-0.792, P < 0.001).
Conclusion: Severe stenosis or total occlusion of MCA, impairment of antegrade blood flow and relatively low blood pressure are the independent risk factors of IBZ. And history of hypertension is a protective fact or of IBZ in patients with MCAS.