Background and Purpose: It remains unclear how experience influences outcomes after the advent of stent-retriever technology. We studied the relationship between site experience and outcomes in the TRevo ACute Ischemic StroKe (TRACK) multicenter registry.
Methods: The 24 sites that enrolled patients in the TRACK registry were trichotomized into: low volume (enrolling 1-23 cases, less than 2 cases/ month), medium volume (24-47 cases, 2-4 cases/ month), and high volume sites (> 48 cases, > 4 cases/ month). Demographics, baseline features, and key prognostic presentation characteristics were compared across the three volume strata.
Results: The 624 TRACK registry patients were divided into three sub groups: low (n=188 patients, 30.1%), medium (n=175, 28.1%), and high (n=261, 41.8%) volume centers. There were no significant differences in terms of age (mean, 66±16 vs. 67±14 vs. 65±15, p=0.2), baseline NIHSS (mean, 17.6±6.5 vs. 16.8±6.5 vs. 17.6±6.9, p=0.43) or site of occlusion across the 3 groups. Times from stroke onset to groin puncture were shorter in the medium volume sites (310 min) but similar in the low vs. high volumes sites (397 vs. 378 min). Higher efficiency and better outcomes were seen in higher volumes sites as demonstrated by faster times from groin puncture to reperfusion (mean, 89 vs. 82 vs. 65 min, p<0.0001), lower general anesthesia usage (60% vs. 70% vs. 59%, p=0.06), higher balloon guide catheter use (40% vs. 36% vs. 59%, p=<0.0001), higher reperfusion rates (mTICI ≥2b, 75.8% vs. 79.4% vs. 83.9%, p=0.10), and higher rates of good outcome (90-day mRS≤2, 39% vs. 50% vs. 53.4%, p=0.02). There were no appreciable differences in sICH (4.5% vs. 9.8% vs. 7.3%, p=0.2) or 90-day mortality (20.3% vs. 25% vs. 17.1%, p=0.2). After adjustments in multivariate analysis, there were significantly higher chances of achieving good outcomes in high vs. low volume (OR: 1.7, 95%CI 1.04-2.75, p=0.035) and medium vs. low volume (OR: 1.8, 95%CI 1.1-2.9, p=0.03) centers but there were no significant differences between high and medium volume centers (p=0.84).
Conclusions: Clinical volumes have a significant influence in terms of efficiency and outcomes across stroke centers.