Introduction: Time is brain; time is muscle. Faster endovascular reperfusion is associated with better outcome for both acute ischemic stroke due to large vessel occlusion (AIS-LVO) and ST-elevation myocardial infarction (STEMI). However, their relative pace of benefit gain with accelerated time has not been systematically investigated.
Methods: We performed a systematic literature search to identify all multi center studies (RCTs and registries) between 2000-2015 reporting relation between onset to reperfusion (OTR) and clinical outcome for AIS-LVO, or onset to balloon (OTB) and clinical outcome for STEMI. Study sample size weighting was used to produce a combined estimate of outcome change associated with every 15 min reduction in total ischemia time.
Results: Systematic search identified 11 AIS-LVO studies with 611 patients and 8 STEMI studies with 15,827 patients. Across AIS-LVO trials, median OTRs were 132 to 440 minutes; across STEMI trials median OTBs were 75 to 330 minutes. Among all clinical outcomes (Table), the one most responsive to faster treatment was functional independence at 90 days for AIS-LVO: for which every 15 min acceleration in OTR, 37 more of 1000 treated patients achieved functional independence. Degree of mortality reduction with faster treatment was relatively similar for both AIS-LVO and STEMI; for every 15 min acceleration, 2-6 more of 1000 treated patients survived. MI recurrence was insensitive to treatment times. For AIS-LVO, speedier treatment was also associated with reduced intracranial hemorrhage (ICH), with 19 fewer ICHs per 1000 patients with every 15 min acceleration.
Conclusion: Considering important dichotomous clinical outcomes, accelerating onset to endovascular reperfusion time has 7-fold greater benefit in acute ischemic stroke than in acute myocardial infarction. As the nervous system has greater eloquence, functional diversity, and sensitivity to ischemia, time is more brain than muscle.