Atherosclerosis and Unsuccessful Recanalization in Acute Stroke Patients

Unsuccessful recanalization rates in acute ischemic stroke patients range between 8-18%. Currently, there are no models to predict thrombectomy reperfusion success with current thrombectomy techniques. We aimed to describe the clinical and radiological features of patients with unsuccessful thrombectomy (UT) and its association with intracranial atherosclerosis (ICAD). A cohort of 413 consecutive, adult, thrombectomy patients admitted to two comprehensive stroke centers were reviewed from 2014 to 2017. Patients with anterior circulation large vessel occlusions (LVOs) and a thrombolysis in cerebral infarction (TICI) score of ≤2a were selected. Demographics, clinical and imaging data were obtained from electronic medical records. Head CT, CT angiography and digital subtraction angiography (DSA) images were reviewed by one independent investigator to evaluate ASPECTS score, vessel calcifications, clot burden score and CTA and DSA collateral score. Proposed causes of UT were categorized based on angiography evaluation by two independent neurointerventionalists. Analysis was performed using descriptive frequency analysis and univariate logistic regression models. A total of 87 low TICI score (≤2a) patients from 413 procedures were included. The median age was 74 years (IQR 58.5-84) and 58% were female. The most common comorbidity was hypertension (73.5%), followed by hyperlipidemia (46%). TICI score of 0 was found in 23% (N=20), 1 in 9.2% (N=8), and 2a in 67.8% (N=59). The inpatient mortality rate was 19.5% (17/87). Out of the remaining 70 patients, 78.5% (N=55) had a 3-month follow up modified Rankin Scale (mRS) of 3-6. The most common proposed cause of poor revascularization in our study was presence of ICAD [29.9% (n=32) of patients]. In our cohort of UT patients with ICAD, 68.8% (N=22) had TICI 2a score with majority (96.8%) having a 3 months mRS of 3-6. Patients with ICAD had 7.3% increased odds of having angiographic collateral score of 5 (p=0.035) and 15.2% increased odds of having an absence of hyperdense MCA in noncontrast CT scan (p=0.003). ICAD is frequently found in patients that undergo UT. Identification of radiological predictors of ICAD may be helpful to consider alternative revascularization strategies for LVOs.