Abstract
Background:
Early neurological deterioration occurs in one third of mild ischemic strokes primarily due to the presence of a visible intracranial vessel occlusion. We studied the clinical and vascular occlusive patterns, thrombus characteristics and recanalization rates in patients with mild ischemic stroke and a visible intracranial vessel occlusion.
Methods:
We studied patients enrolled in the INTERRSeCT multi-center prospective study of acute ischemic strokes with visible intracranial occlusions. We compared the clinical, thrombus characteristics and recanalization rates between two groups, 1) mild ischemic NIHSS≤5 and 2) moderate/severe strokes NIHSS >5, with or without IV alteplase treatment. Vessel imaging with CT angiography (CTA) was initiated within 12 hrs of symptom onset followed by repeat imaging with CTA or cerebral angiogram (before endovascular therapy; EVT) within 4 +/- 2 hrs.
Results:
Among 575 patients with a visible intracranial occlusion, 12.9% had mild strokes with similar patient characteristics compared to the moderate/severe stroke group. Residual flow grades were similar between the two groups (residual flow grades I-II, 21% vs 19%). The mild stroke group had longer symptom-onset-to -CT (240 vs 167 min, p=0.02) and -CTA (246 vs 172 min, p=0.02) times, longer CT to needle time (35 vs 26 min, p<0.01), more distal occlusions (49% in M2 of the middle cerebral artery), lower clot burden scores 9 (6-9) vs 6 (4-9) (p<0.001), better collateral flow (9.1 vs 7.6, p=0.001) and no association between residual flow grade and recanalization. The mild stroke group was less likely to receive IV alteplase (62% vs 84%), but more likely to recanalize (rAOL2b and 3) with (46% vs 29%) and without (38% vs 26%) IV alteplase.
Conclusion:
Some thrombus characteristics that predict recanalization in more severe strokes do not predict recanalization in mild strokes, such as residual blood flow through intracranial occlusions, though they have similar cardiovascular risk factors. Less than half of patients with mild strokes recanalized with IV alteplase which was associated with longer decision-making times suggesting that more aggressive use of thrombolytics and/or EVT may be viable treatment options in this population.