Abstract 89: Mechanical Thrombectomy Or Medical Management Alone For Isolated Posterior Cerebral Artery Occlusion. An International Multicentric Observational Study.

Introduction:
Whether endovascular therapy (EVT) added on best medical management (BMM, including intravenous thrombolysis [IVT] if indicated), as compared to BMM alone, is beneficial in acute ischemic stroke (AIS) with isolated posterior cerebral artery occlusion is unknown.

Methods:
We conducted a multicenter international observational study of consecutive AIS patients admitted within 6hrs from last seen well in 26 stroke centers in France, Switzerland and USA with isolated proximal posterior cerebral artery strokes (P1 or P2 occlusions) and treated either with EVT+BMM or BMM alone. Propensity score with inverse probability of treatment weighting was used to account for baseline between-groups differences. The primary outcome was 3-month good functional outcome (modified Rankin score [mRS] 0-2). Secondary outcomes were excellent functional outcome (mRS 0-1) and symptomatic intracranial hemorrhage (sICH) at 24hrs. We searched for an interaction between treatment group and (1) occlusion site (P1
vs
. P2), (2) NIHSS score (<10
vs.
≥10), and (3) IVT use.

Results:
Overall, 810 AIS patients were included (180 and 630 in the EVT+BMM and BMM alone groups, respectively). Median age was 74yo (IQR 63-83), 352 (44%) were female, median NIHSS was 6 (IQR 4-10), 594 (73%) received IVT, and occlusion site was P1 in 205 (25%) and P2 in 605 (75%) patients. Baseline clinical and radiological data were similar between the 2 groups following propensity-score weighting. EVT was not associated with good (adjusted OR=0.86; 95%CI: 0.67-1.09;
P
=0.21) or excellent (adjusted OR=1.10; 95%CI: 0.87-1.39;
P
=0.42) functional outcome but was associated with higher risk of sICH (OR=2.71; 95%CI: 1.41-5.21;
P
=0.003). No interaction was found between EVT effect and (1) NIHSS score, (2) occlusion site, or (3) IVT use for either outcome.

Conclusion:
In our population of AIS patients with isolated P1 or P2 occlusion, EVT was not associated with higher rates of good or excellent functional outcome as compared to BMM alone. However, EVT was associated with higher rates of sICH. Randomized trials are warranted.