Abstract WP29: National Patterns of Stroke Mechanical Thrombectomy Before and After the 2015 American Stroke Association Focused Update Endovascular Treatment Guidelines
Introduction: Positive pivotal trials followed by guideline endorsement can be a major driver of change in US national medical practice patterns. We therefore analyzed national trends in the use and outcomes of mechanical thrombectomy (MT) for acute ischemic stroke (IS) due to large vessel occlusion before and after the 2015 publication of pivotal trials and the US guideline update. Methods: We analyzed the National Inpatient Sample from 2012-2016. IS and MT patients were identified using ICD-9 and ICD-10. The primary efficacy outcome measure was discharge to home, which strongly correlates with mild disability at discharge. Safety outcomes include in-hospital mortality and in-hospital medical complications. Results: Between 2012-2016, 2,394,550 discharges had diagnosis of IS, 39,150 (1.6%) underwent MT. The number and proportion of IS patients undergoing MT rose from 4,910/452,905 (1.1%) in 2012 to 11,860/509,215 (2.3%) in 2016. The largest increase occurred between 2014, when 6,460 stroke patients were treated with MT, and 10,280 in 2015. Comparing the pre (Q1 2012-Q4 2014) and post (Q4 2015 - Q4 2016) RCT/Guideline epochs, in addition to increased MT rates, the proportion of MT patients who received IV-tPA decreased (46% to 24%, p<0.001). Rates of mild disability outcome increased from 17% to 20% (p=0.04), while mortality decreased from 17.7% to 15% (p=0.03). The odds of pulmonary embolism, urinary tract infection, and pneumonia reduced, while intracranial hemorrhage, sepsis, deep venous thrombosis, shock, and cardiac arrest were unchanged. Conclusion: In US, thrombectomy treatment for acute ischemic stroke increased rapidly and substantially in frequency following publication of positive clinical trials and a US guideline update in 2015, accompanied by improved functional outcomes and reduced peri-procedural mortality.