Effect of intravenous thrombolysis on patients with middle cerebral artery infarction of different lesions

Objective To investigate the effect of intravenous recombinant tissue plasminogen activator (rt-PA) thrombolysis on patients with middle cerebral artery (MCA) infarction of different lesions and to analyze the influencing factors of clinical prognoses. Methods Seventy-five patients with acute infarction in the MCA territory were consecutively collected in our hospital from January 2013 to December 2016, and all patients underwent intravenous rt-PA thrombolysis within 4.5 h time window. The sites of MCA were classified into origin of the MCA (type I), MCA trunk distal to the lenticulostriate arteries (type II) and branches of the MCA (type III). Early symptom improvement was defined as 24 h National Institutes of Health Stroke Scale (NIHSS) scores decreased≥4 or down to 0 after intravenous thrombolysis. Clinical data, NIHSS scores on admission and after intravenous thrombolysis, ratio of patients enjoying early symptom improvement, ratio of hemorrhagic transformation, mortality rate within 7 d of intravenous thrombolysis and modified Rankin scale (mRS) scores 90 d after intravenous thrombolysis were obtained and compared among the three groups. And according to mRS scores 90 d after intravenous thrombolysis, the patients were divided into good prognosis group and poor prognosis group; Logistic regression analysis was used to confirm the different prognoses of patients with MCA infarction of different lesions. Results Among the 75 enrolled patients, 22 (29.3%) were classified as type I, 16 (21.3%) as type II and 37 (49.3%) as type III. Type I patients (n=6, 27.3%) had significantly lower ratio of patients with early symptom improvement than type II patients (n=11, 68.8%) and type III patients (n=25, 67.5%, P<0.05). Type I patients had significantly higher ratio of symptomatic intracranial hemorrhage, higher mortality rate within 7 d of intravenous thrombolysis and higher mRS scores 90 d after intravenous thrombolysis than type II patients and type III patients (P<0.05). After 90 d of follow up, good prognosis was found in 56 patients (74.7%) and poor prognosis in 19 patients (25.3%); the sites of MCA lesions, thrombolysis time, and NIHSS scores on admission and 24 h after intravenous thrombolysis between the two groups were significantly different (P<0.05). Multivariate Logistic analysis revealed that sites of MCA lesions (OR=2.633, 95%CI: 1.119-6.197, P=0.027), thrombolysis time (OR=7.603, 95% CI: 1.561-37.043, P=0.012), and NIHSS scores on admission (OR=3.622, 95%CI: 1.068-12.285, P= 0.039) were the risk factors of prognoses. Conclusions Different lesion sites of MCA may indicate different effects and prognoses in patients with intravenous thrombolysis. And, MCA lesion sites, thrombolysis time and NIHSS scores on admission are independent risk factors for prognoses in cerebral infarction patients with intravenous thrombolysis. Key words: Cerebral infarction; Middle cerebral artery; Lesion; Intravenous thrombolysis; Prognosis