Background and Objective Mechanical Thrombectomy (MT) is standard treatment for acute ischemic stroke due to large vessel occlusion (LVO). However, extent of preventability of these strokes is generally not addressed. This study analyzes stroke preventability for patients treated with MT for LVO.

Subjects and Methods We conducted retrospective analyses of stroke patients treated with MT for LVO at UC Irvine Medical Center from June 2008 to March 2019. We obtained data including age, NIH Stroke Scale (NIHSS) at onset, and (beginning in 2015) 90-day outcome measured by modified Rankin Scale (mRS). We used the Stroke Preventability Score (SPS, 0–10 points) from our prior work (JAMA Neurology 2016, 73:186), based on how well patients had been treated given their hypertension, hyperlipidemia, atrial fibrillation, and prior stroke history. We examined associations of SPS with age, NIHSS at onset, and mRS.

Results For 301 patients treated with MT for LVO, mean ± standard error of age was 60±0.1 years (range 18–97) and NIHSS was 17±0.4 (range 0–37, n=282); one-third (n=96) were male. SPS was calculated for 273 patients, with mean±SE 2.1±0.1 (range 0–8). Over two-thirds (n=184, 67%) demonstrated some degree of preventability (SPS 1 or higher), while 23% (n=64) showed high stroke preventability (SPS 4 or higher). Among those with high SPS, atrial fibrillation with no treatment was seen in 54 (85.7%) patients. Among 119 patients with mRS data, stroke preventability was associated with age (66±2.5, 69±2.4 and 79±1.7 years for no, low and high SPS, respectively; p<0.002). Stroke preventability was also associated with NIHSS at onset (15±1.3, 16±0.9, and 20±1.4 for no, low and high preventability, respectively; p<0.04). SPS was significantly correlated with age (r=0.33, p<0.0002), NIHSS (r=0.29, p=0.002), and mRS (r=0.22, p=0.02). The partial correlation coefficient for SPS remained significant after adjusting for age and NIHSS.

Conclusion Nearly one-quarter of patients, with LVO treated with MT, presented with strokes that were highly preventable. High stroke preventability tended to be seen in older patients, patients with more severe deficits, and (to a lesser extent) patients with poor outcome. Severe LVO strokes with the worst outcome (post-mechanical thrombectomy) tended to be the most preventable strokes. While most acute stroke treatment efforts focus on streamlining workflow, these findings demonstrate the enduring importance of stroke prevention in this patient population. These findings raise the question whether resources for treatment of acute stroke are being directed toward patients whose strokes are the most preventable.

Disclosures S. Suzuki: None. B. Nguyen: None. I. Yuki: None. J. Xu: None. M. Fisher: None.