Distance to Thrombus in Endovascular Treatment of Middle Cerebral Artery M1 Occlusion Predicts Recanalization Success and Clinical Outcome

The occlusion site of the cerebral artery can help to determine recanalization success, treatment and prognosis in acute stroke patients. In current studies, different measurement techniques and different length values have been considered. We aimed to determine the relationship between the location of occlusion and recanalization success following endovascular therapy of acute middle cerebral artery (MCA) M1 occlusion.

This study was conducted from January 2015 to March 2019. The “M1 distance-to-thrombus length” was determined on curve-linear reformat reconstruction of the MCA, and measured from the center of internal carotid artery (ICA) bifurcation to the beginning of the thrombus on digital subtraction angiography (DSA). A successful recanalization was defined as ≥ modified thrombolysis in cerebral infarction (mTICI) 2b and full recanalization as mTICI 3. Evaluation of patients at the end of the third month was carried out with modified Rankin Scale (mRS) and mortality.

We eventually included 95 patients treated with endovascular therapy. The patients with distance to thrombus (DT) ≤13.2 mm showed significantly higher rates of full recanalization (AUC = 0.639 ± 0.06; P=0.014, 95% confidence interval [CI]). Additionally, DT could predict successful recanalization with an AUC of 0.639. The possibility to distinguish unsuccessful recanalization cases after the endovascular treatment by considering DT had 85.7% sensitivity (95% CI). Of the 82 (86.3%) patients who were treated with successful recanalization (≥mTICI 2b), 46 (48.4%) achieved mRS (0–3) and 38 (40%) expired at the end of the 3 months.

Shorter DT was associated with higher rate of full recanalization (mTICI 3) after endovascular therapy. Having a longer DT reduces the chance of successful recanalization without distal embolism. However, there was no statistically significant effect for DT on a favorable outcome at third months or mortality with endovascular treatment of MCA M1 occlusions.