Abstract WMP8: Imaging Variables as Predictors of Outcome after Intra-Arterial Therapy: The Superiority of Collateral Circulation
Early ischemic changes on CT, collateral circulation, clot location and extension are important determinants of outcome in patients with large artery occlusion (LAO). We compared these variables as predictors of outcome in patients treated with intra-arterial therapy (IAT).
We identified 86 AIS patients who received IAT at our center for LAO (MCA or ICA) from 01/08 to 05/11. Univariate logistic regression analysis was used to identify radiographic variables obtained on (CT/CTA) that predicted poor (mRS 4-6) and good (mRS 0-2) discharge outcomes. The CTA collateral score (CS), from 0 (absent) to 3 (complete), was measured. Spearman’s correlations and ROC curves evaluated the performance of CS against ASPECTS and clot burden score (CBS).
Table 1 shows the baseline characteristics. Patients with CS (0-1) on CTA had a significantly higher odds of a poor outcome (OR 8.96, 95%CI 2.42-33.19, p=0.001); this effect was maintained when using mRS 5-6 (OR 2.77, 95% CI 1.11-6.88, p= 0.03). These results persisted after adjustment for revascularization (TICI ≥ 2) (Table 2). Moreover, patients with good CS (2-3) had a significantly greater odds of independence (mRS 0-2) at discharge (OR 15, CI 95% 1.88-119.8, P=0.01), and was maintained when adjusting for no or only partial revascularization (TICI < 2) (OR 9.36, CI 95% 1.10-79.4, p=0.04). The distribution of mRS demonstrates a shift toward better outcomes in patients with CTA≥2 (figure 1). Although both scores were good predictors of outcome, CS performed better than ASPECTS in identifying patients who have poor or good outcome after IAT (Table 2, figures 2A, 2B and 2C). Clot location or extension measured on CBS did not correlate with clinical outcomes.
Conclusion The status of collaterals on CTA is a pivotal determinant of clinical outcome in patients who undergo IAT for LAO. The collateral score can improve selection for IAT by identifying patients who may benefit and those who may not.
- © 2012 by American Heart Association, Inc.