E-129 Thrombectomy in distal vessel occlusion: MCA M2–3 junction and beyond

Introduction/Purpose Since 2012, our team of neurointerventional physicians have performed over 600 intracranial arterial thrombectomies with stent-retrievers. Thrombectomy in the ICA and M1 segments has been shown in randomized trials to reduce permanent disability and is now the standard of care. The time window has continued to expand. However, less is known about outcomes for thrombectomy performed in distal branches, such as near the M2–3 junction or within the M3 segments. Current guidelines state that thrombectomy in these locations may be performed in carefully selected patients, however data is limited. Materials and methods A retrospective review of our stroke database from 2012–2018 was undertaken to find cases of MCA interventions involving the distal third of the M2 insular segment or the M3 opercular segment. Isolated ICA, M1 and proximal M2 branch occlusions, as well as proximal occlusions that resulted in distal emboli post-thrombectomy, were excluded. Patients were selected for intervention based on noncontrast CT head, CTA, CT perfusion results; onset time; and clinical exam. Distal vessel thrombectomies were performed with the use of a stent-retriever device. Pre-intervention scans were compared to post-intervention scans to evaluate degree of infarct. The baseline and discharge National Institute of Health Stroke Scale, and the modified Rankin Scale at 90 days were used to evaluate the degree of residual deficits. Results A total of 43 patients met the inclusion criteria. Mean age was 69.4 (IQR 60.5–82). 23 (53.5%) were female. Thrombus was categorized as being located completely within the M3 segment in 21 cases (48.8%) and spanning the M2-M3 junction in 22 cases. 6 patients (14.0%) presented with tandem vessel occlusions involving the ICA or a proximal MCA segment, or proximal occlusion that had moved distally between CTA and angiography. 18 patients received intravenous tPA (41.9%). 42 cases were treated with a stent-retriever, and 1 case was treated with intra-arterial tPA. Multiple devices were used, however all were 3–4 mm in diameter, and 39 were 15–20 mm in length. 3 cases used a 4x40 mm device. The mean number of passes with a device was 1.2 (range 1–3). Near or complete reperfusion (mTICI score 2b or greater) was achieved in 40 cases (93.0%). Median initial NIHSS on presentation was 10.5 (IQR 7.8–18). Median discharge NIHSS was 2 (IQR 1–5.3). Initial and discharge NIHSS was not available in 3 patients. 90-day mRS was 0–2 in 17 patients (48.6% of those available) and 3–6 in 18 patients (51.4% of those available). 90-day mRS was not available in 9 patients (18.6% of total), mostly in the earliest cases found in the database. 3 cases of intraparenchymal hemorrhage occurred (7.0%), 2 of which were symptomatic including 1 resultant death. Conclusion Distal middle cerebral artery thrombectomy with stent-retriever devices is achievable and can be safe and technically effective. Randomized controlled trials have not been performed to determine if thrombectomy in or distal to the M2-3 junction is more beneficial than other techniques, such as aspiration thrombectomy, intravenous thrombolysis, or maximum medical therapy. Disclosures B. Donegan: None. J. Loeb: None. C. Martin: None. W. Holloway: None. J. Halpin: None. N. Akhtar: None.