Ethnic Differences in Outcomes of Endovascular Thrombectomy in New Zealand

INTRODUCTION: Stroke is a leading cause of morbidity and mortality in New Zealand, with ethnic disparities known to exist. Endovascular thrombectomy (EVT) has proven efficacy in reducing or preventing disability for stroke patients, but little is known about ethnic differences in functional outcomes following EVT in New Zealand. METHODS: A retrospective nationwide registry-based study was conducted, including all patients who underwent EVT between 1st January 2011 through to 31st December 2023 in New Zealand. Demographic, clinical and procedural data were obtained from the National Stroke Register. Primary outcomes were mortality at 7 days and dichotomised modified Rankin Scale (mRS) at 90 days. Subgroup analysis compared patients presenting directly to EVT-capable centres with those requiring transfer. RESULTS: 2852 EVT patients were included (68.7% European, 14.6% Māori, 7.4% Pacific, 8.4% Asian and 1.0% Other). Non-Europeans presented at younger ages and with greater vascular risk factors. Functional outcomes and 7-day mortality rates did not differ significantly by ethnicity. Odds of symptomatic intracranial haemorrhage (sICH) were greater in Māori (aOR 3.01, 1.42-6.38, p = 0.004), Pacific peoples (3.40, 1.22-9.53, p = 0.02) and Asian (aOR 3.57, 1.57-8.15, p = 0.002) patients compared to Europeans. Nearly half of patients (46.5%) initially presented to non-EVT capable centres; although EVT was delayed, functional and mortality outcomes remained similar. CONCLUSION: This nationwide study found no significant ethnic disparities in functional outcomes or 7-day mortality following EVT, though sICH was more likely in non-Europeans. Despite treatment delays, patients initially presenting to non-EVT capable centres achieved comparable functional outcomes to those presenting directly to EVT centres.