Hematoma Evacuation and Risk of Subsequent Ischemic Stroke and Coronary Ischemic Events: MISTIE III and ATACH-2 Analysis

BACKGROUND Nontraumatic intracerebral hemorrhage (ICH) especially in deep locations is independently associated with a long-term increased risk of major arterial ischemic events. Minimally invasive surgery (MIS) has differential impact on outcomes by location. Whether ischemic events modify outcomes after MIS and the influence of ICH location is poorly understood. METHODS We pooled individual patient data from the MISTIE III and ATACH-2 trials. The exposure was ICH location (deep vs. lobar). The outcome was a symptomatic, clinically overt ischemic stroke or coronary ischemic event. We evaluated the association between ICH location and risk of an ischemic event using Cox regression analyses after adjustment for demographics, vascular comorbidities, and ICH characteristics. We investigated whether ischemic events modified the impact of effective MIS, defined as end of treatment volume (EOT) <15 mL, on modified Rankin scale (mRS) 0-3 at one year in MISTIE III using logistic regression. RESULTS Of 1470 ICH patients median hematoma volume was 17.3 mL (interquartile range, 7.2–35.7) and 1186 (80.7%) were deep. During a median follow-up of 110 days (iqr 110-365), 70 ischemic events occurred, 60 (5.0% cumulative incidence) in patients with deep ICH and 10 after lobar ICH (cumulative incidence 3.2%). In adjusted analyses, deep ICH location was associated with an increased risk of ischemic events (hazard ratio, 2.3 [95% CI, 1.1–4.8]), but MIS was not. In the full MISTIE cohort, in patients without ischemic events during follow-up, MIS with EOT<15 mL was significantly associated with favorable one year outcome (OR 1.90 (95% CI: 1.16-3.12; P for interaction = 0.04). There was no effect modification for deep location (P for interaction = 0.128). For lobar ICH, EOT ICH volume <15 mL with MIS was associated with good outcome regardless of ischemic events. CONCLUSIONS In a heterogeneous cohort of patients with ICH, deep ICH location was associated with increased risk of ischemic events over the short term, but this appears to have low impact on one-year outcomes with successful surgery.