The impact of comorbidity burden on outcomes following endovascular thrombectomy for acute ischemic stroke: A nationwide prospective observational study

Introduction: Patients with substantial comorbidity burden are underrepresented in clinical trials on endovascular thrombectomy (EVT), despite being common in clinical routine care. Therefore, analysis of observational data is needed to evaluate how increasing comorbidity burden affects procedural success rate, complication rate, and clinical outcome following EVT.Patients and methods: We conducted a register-based observational study involving pre-stroke functionally independent patients treated with EVT in Sweden 2015-2021. Comorbidity burden was assessed using the Charlson Comorbidity Index (CCI) and categorized as no (CCI 0), moderate (CCI 1), severe (CCI 2), and very severe (CCI >= 3). The primary outcome was favorable 90-day outcome (modified Rankin Scale 0-2). Secondary outcomes included successful recanalization, and peri- and postoperative complications.Results: Of 4735 included patients, 40% had no comorbidity (CCI 0), 15% had moderate (CCI 1), 21% had severe (CCI 2), and 24% had very severe comorbidity burden (CCI >= 3). The yearly proportion of patients with very severe comorbidity burden increased from 16% to 30% during the study period. Increasing comorbidity levels were associated with decreased odds ratio (OR) of favorable outcome compared to patients without comorbidity: CCI 1 adjusted OR (aOR) 0.64, 95% CI 0.57-0.85; CCI 2 aOR 0.59, 95% CI 0.47-0.74; and CCI >= 3 aOR 0.38, 95% CI 0.30-0.47, but there were no significant differences in successful recanalization rates. Patients with CCI 2 had higher OR for perioperative and postoperative complications (OR 1.43, 95% CI 1.09-1.88, and OR 1.41, 95% CI 1.15-1.71), and patients in the CCI >= 3 group had higher OR of postoperative complications (OR 1.34, 95% CI 1.14-1.67), compared to patients in the CCI 0 group. Successful recanalization was associated with favorable functional outcome in all CCI-groups.Discussion and conclusion: Severe and very severe comorbidity burden are increasingly common among EVT-treated patients in routine healthcare and are linked to poorer outcomes. However, our results suggest that successful EVT is associated with functional independency, also in patients with severe and very severe comorbidity burden.