Abstract 198: Relationship Between 24 Hour Infarct Volume And Clinical Outcomes In IMS 3

Background: Prospective, core lab adjudication of 24 hour post randomization head CT in IMS3 enabled analysis of the association between 24 hour infarct volume (24HRIV) and clinical outcomes in patients randomized to IV tPA alone or IV/IA approach. Methods: Manually calculated volumes of hypodense areas deemed acute and found within the affected territory on the IMS 3 follow-up CT scans expressed in cc were termed 24HRIV. These were correlated with several variables of interest in the IMS3 database including clinical outcomes expressed as modified Rankin score (mRS), baseline NIHSS (bNIHSS), follow-up NIHSS at 24 hours (fNIHSS), treatment allocation and occlusion location assessed on baseline CTA. Results: Of the 656 randomized patients, 502 (76.5%) had available 24HRIV’s and were included in the analysis. Good outcomes (defined as mRS 0-2) were noted in 197 (39.2%) of patients. Mean (median) 24HRIV in patients with favorable outcomes was 24.2 (12.2) cc vs. 115 (75.11) cc in those with unfavorable outcomes (p< 0.00001). A strong correlation was noted between the 24HRIV and clinical outcomes across the entire spectrum of the mRS scale (Figure1). Mean (median) 24HRIV’s were not significantly different in the IV vs IV/IA group 76.8 (34.5) vs 84.8 (37.8) cc, p= 0.38. No differences in 24HRIV were noted between IV and IV/IA groups in patients with ICA occlusion on baseline CTA (mean 24HRIV 125.8 vs 123.8 cc's respectively, p=0.9) or MCA occlusion (mean 24HRIV 54.4 vs 54.6 cc's respectively, p=0.9). A strong correlation was found between 24HRIV and fNIHSS (spearman rho=0.7, p<0.0001). Conclusions: In IMS 3, a significant correlation between 24 hour infarct volume on CT and clinical outcomes both at 24 hours and at 90 days was demonstrated. No significant differences in 24 hour infarct volumes were noted between the IV and the IV/IA group, suggesting that endovascular reperfusion strategies utilized during IMS3 overall lacked added effectiveness compared to IV t-PA alone. ![][1] [1]: /embed/graphic-1.gif