Introduction Acute ischemic stroke (AIS) still remains one of the top leading causes of morbidity and mortality in the United States. In 2007, the DESTINY trial demonstrated lower mortality rates in patients with large hemispheric strokes following hemicraniectomy. 7 years later, the MR CLEAN trial showed improved outcomes in AIS following endovascular mechanical thrombectomy (MT) when compared to intravenous tPA alone. However, during the enrollment period for this trial there remains limited data regarding the effects of MT on the need for hemicraniectomy.

Methods A retrospective analysis of the Nationwide Inpatient Sample (NIS) between 1998–2015 was performed. Patients with an ICD-9-CM diagnosis code indicating an anterior circulation ischemic stroke (433.11, 434.01, 434.11, and 434.91) were included. Patients with an ICD-9-CM diagnosis code indicating trauma, neoplasm, SAH/aneurysm, posterior circulation ischemic stroke, or abscess (191.x, 198.3, 324.0, 430, 433.01, 433.21, 437.3, 437.5, 437.6, 443.24, 747.81, 800.xx, 801.xx, 851.xx, 852.xx, 853.xx, and 854.xx) were excluded. In order to limit the analysis to AIS, patients who did not have the ICD-9-CM procedure code of tPA (99.10) were excluded. Those patients who underwent thrombectomy (39.74) and hemicraniectomy (01.24, 01.25, 01.39, 01.53, and 01.59) were also indentified. Logistic regression model was used to analyze the effect of thrombectomy on rates of hemicraniectomy in patients with AIS who received tPA.

Results A total of 59,703 patients in the NIS were identified as having an acute anterior circulation ischemic stroke that subsequently received tPA. 3597 patients were also identified as having undergone MT and 606 patients were found to have undergone hemicraniectomy as well. Logistic regression model demonstrated that patients who underwent MT were significantly more likely to undergo hemicraniectomy (OR 4.52, 95% CI 3.72–5.49, p<0.001).

Conclusions Although MT has proven to be an effective treatment for AIS, it appears that prior to MR CLEAN, patients who underwent MT had a higher likelihood of requiring a hemicraniectomy during the same hospital admission. Since MTs were not standardized prior to 2014, the variability in procedural technique could ultimately cause unreliable degrees of recanalization and thus lead to varied outcomes. Therefore, the effect of MT on hemicraniectomy rates in patients with AIS warrants further investigation following the advent of standardized thrombectomy techniques.

Disclosures E. Luther: None. D. McCarthy: None. R. Starke: None.