Background: Endovascular treatment (EVT) is an effective treatment in strokes with persistent large artery occlusion despite previous intravenous thrombolisis (IVT) as rescue treatment. Performing computer tomography angiography (CTA) before IVT could allow early activation of neurointerventional teams; however routine CTA could delay unnecessary door-to-needle time of IVT and may be infeasible.
Methods: We reviewed stroke code activations between May 2011 and June 2015 in our comprehensive stroke center and divided into groups based on NIHSS and patency of arterial occlusion according to non-enhanced CT on admission (dense artery sign or dot sign) and baseline CTA. We assessed patients treated with IVT and selected to EVT according to results in CTA post-IVT. We analyze percentage of recanalization or migration of thrombus after IVT alone and variables associated to successful treatment.
Results: Of 2856 stroke codes registered during the study period 1810 were diagnosis of ischemic strokes. We treated 520 patients with IVT, 202 had a radiological evidence of large artery occlusion (55%M1, 32% M2, 5%TICA, 5%ICA, 3% basilar). Thirty-two percent of patients showed changes in CTA carried out after IVT(17% successfully recanalized, 15% distal migration of thrombus) so they were not selected to endovascular treatment. There were significant difference between M1 and M2 occlusion regarding changes in CTA after IVT (23% vs 70%; p<0.001). In multivariate logistic regression a baseline score NIH<10 was associated with higher percentage of recanalization with rtPA despite signs of large vessel occlusion (78% vs 32%; p:0.001). In receiver operating characteristic analysis higher baseline NIH was associated with persistent occlusion after IVT (area under curve=0.79;95% CI, 0.6-0.9; P:0.001) with optima threshold of 10 ( Sensivity 84%, Specificity 74%).
Conclusions: We consider defer CTA angiography until after IVT in stroke code patients with moderate clinical impairment (NIH<10) or M2-segment occlusion, because they achieve a high percentage of arterial recanalization. CTA previous IVT could be unnecessary, provide unreliable information and delay IVT in that clinical group but could be useful to plan EVT in patients with higher NIH scores.