The primary aims of the research are to evaluate, in patients presenting with posterior artery occlusion (PCA), whether favorable outcome would be superior for EVT compared to Medically Management (MM), inclusive of intravenous thrombolysis (IVT), as measured by:~90-day modified Rankin Scale (mRS) ordinal shift or~decrease in NIH Stroke Scale/Score (NIHSS) by two points at 24 hours or at hospital discharge~The secondary aims are to evaluate in patients presenting with PCA occlusion, other outcome and safety metrics:~90-day functional independence, mRS 0-2~90-day excellent outcome, mRS 0-1~Visual field recovery (none, partial, complete) by 90-days~rate of reperfusion by modified thrombolysis in cerebral infarction (TICI) scale grade~any intracranial hemorrhage~symptomatic intracranial hemorrhage~mortality~In subgroup analysis, the investigators aim to identify subgroups that may confer differential treatment benefit by:~location of occlusion on the PCA segment (P1, P2, P3)~NIHSS strata (0-6, 7-15,>16)~time from symptom onset to treatment (0 to <6h vs 6-24h)~posterior circulation (PC) Acute Stroke Prognosis Early Computed Tomography Score (ASPECTS)~visual field defect on presentation~The investigators hypothesize that greater benefit in outcomes would be seen in EVT treated patients with higher NIHSS, more proximal PCA occlusion, higher PC ASPECTS scores, and shorter time from symptom onset to treatment.
For this retrospective study, the investigators will collect and analyze data of patients who presented with posterior artery occlusion and underwent mechanical thrombectomy (the type of endovascular stroke treatment) and intravenous thrombolysis (the type of non-endovascular stroke treatment).~The electronic health records will be queried for the demographic, medical history, and outcomes data of all patients with posterior cerebral artery occlusion who underwent mechanical thrombectomy, intravenous thrombolysis (IVT), or medical management.