To identify the risk factors for post thrombectomy hemorrhagic transformation (HT).

Mechanical thrombectomy (MT) has become the current standard of care for large vessel occlusion stroke but is associated with an increased risk of HT.  Recent studies have identified thrombolysis in cerebral infarction (TICI) score, Alberta stroke program early CT score (ASPECTS), and blood glucose (BG) levels as predictors of symptomatic intracerebral hemorrhage (sICH). This study aims to validate similar variables and outcomes in our MT cohort.

We retrospectively reviewed all MT patients who were treated at a single comprehensive stroke center from 12/2016 to 7/2019. Variables included initial NIHSS, blood glucose, initial systolic blood pressure, age, gender, IV tPA, time from door to recanalization, and TICI score. Outcome measures were HT on post-procedure or 24-hour post-tPA head CT/MRI as well as modified Rankin scale (mRS) upon discharge.

Among 74 patients (68.8 ± 14 years, men 47.3%), 9 (12.2%) experienced hemorrhagic transformation after thrombectomy. Average admitting NIHSS was significantly higher in the HT group (22 vs 16.8, p=0.041). TICI 3 after MT was protective for HT (OR 0.078, 95% CI 0.009-0.663). IV tPA (OR 3.86, 95% CI 1.448-10.326) was associated with good neurological outcome at discharge (mRS <=2), but HT was not (OR 0.114, 95% CI 0.013-0.964). Patients with mRS <=2 upon discharge were younger (65.2±12 vs 71.9±15, p=0.04) and had lower initial BG (124±45.8 vs 157±69.6, P=0.02).

TICI 3 score, decreased NIHSS, and lower BG were associated with less HT and better outcomes in our MT cohort.  Admitting NIHSS >= 20 may be a reasonable threshold to predict HT after MT.  Our findings are consistent with the TICI-ASPECTS-glucose (TAG) score to predict sICH; however, we used initial NIHSS as a surrogate for ASPECTS.  Further studies may utilize additional quantitative measures such as CTP data to predict HT.