Thrombus density predicts successful recanalization with Solitaire stent retriever thrombectomy in acute ischemic stroke

Background Thrombus characteristics, including Hounsfield unit (HU) value to measure density and thrombus volume and length, can predict successful recanalization following IV thrombolysis with recombinant tissue plasminogen activator. Conflicting and limited data exist regarding the value of assessing thrombus properties in acute stroke cases treated with endovascular IA approaches. Methods We retrospectively reviewed cases of anterior circulation acute ischemic stroke in which a Solitaire stent retriever (ev3-Covidien) was the primary treatment device. We measured the following thrombus characteristics: absolute and corrected HU values; thrombus length and volume; clot burden score; and vessel bifurcation involvement. Fisher's exact test and the t test were used to study the association between these clot characteristics and successful recanalization (Thrombolysis in Cerebral Infarction (TICI) score 2b-3). Results We identified 41 patients with anterior circulation stroke treated with the Solitaire stent retriever as the primary treatment device. Successful recanalization (TICI score 2b-3) was achieved in 59% of cases. Higher absolute and corrected HU values were strongly predictive of successful recanalization (49.9 +/- 7.6 vs 43.8 +/- 6.6, p=0.01 for absolute HU values and 1.2 +/- 0.2 vs 1.0 +/- 0.1, p=0.03 for HU ratio in TICI 2b-3 and TICI 0-2a groups, respectively). There was no significant difference between recanalization and non-recanalization groups in the other thrombus characteristics studied. Conclusions In acute stroke treated with Solitaire stent retriever thrombectomy, higher thrombus HU values are predictive of successful recanalization. Such information can be used in decision making when estimating recanalization success rate with different endovascular treatment approaches.