Outcomes of endovascular thrombectomy for ischaemic stroke among nonagenarians with and without pre-existing dependency.

Background: Our aim was to compare the outcomes of treatment with endovascular thrombectomy for pre-stroke dependent versus pre-stroke independent among the very elderly ≥90 years.

Methods: A retrospective cohort study was performed on 106 patients ≥90 years who underwent endovascular thrombectomy for ischaemic stroke in Western Australia between June 2016 and September 2021. Patient, stroke and procedural details along with inpatient progress and outcome at 90 days were recorded. Patients were divided into Group A (pre-stroke modified Rankin Scale 0-2) and Group B (pre-stroke modified Rankin Scale >2). Primary outcome measure was functional status at 90 days post-stroke, with favourable clinical outcome defined as a 90-day mRS category equal to the patients' respective pre-stroke mRS category. Secondary outcome measures include successful reperfusion, symptomatic intracranial haemorrhage, hospital length-of-stay, change in accommodation to an aged care facility, and mortality during admission, at 90 days and one year.

Results: 61 patients were allocated to Group A and 45 to Group B. There was none with pre-stroke mRS 5. Group B had more pre-existing cognitive impairment, aged care facility residents, higher median age and lower Alberta Stroke Program Early CT Score. For primary outcome measure, 38 % of patients in Group A and 49 % in Group B achieved a favourable clinical outcome. The difference was not significant (p=0.3408). For secondary outcome measures, Group B had a significantly higher 90-day mortality rate at 47 % versus 24 % in Group A (p=0.03). All other secondary outcome measures were similar between the two groups. These include the rate of successful reperfusion and symptomatic intracranial haemorrhage, hospital length-of-stay, new transition into an aged care facility, inpatient mortality rate and 1-year mortality rate.

Conclusion: When treated with endovascular thrombectomy for ischaemic stroke, nonagenarians with pre-existing dependency achieved a rate of favourable functional outcome comparable with their independent peers, although they also had higher 90-day mortality rate.