Collaterals at Angiography and Outcomes in the Interventional Management of Stroke (IMS) III Trial

Abstract

Background and Purpose: Endovascular strategies provide unique opportunity to correlate angiographic measures of collateral circulation at the time of endovascular therapy. We conducted systematic analyses of collaterals at conventional angiography on recanalization, reperfusion and the clinical outcomes in the endovascular treatment arm of the Interventional Management of Stroke (IMS) III Trial. Methods: Prospective evaluation of angiographic collaterals was conducted via central review of subjects treated with endovascular therapy in IMS III (n=331). Collateral grade prior to endovascular therapy was assessed with the ASITN/SIR scale, blinded to all other data. Statistical analyses investigated the association between collaterals with baseline clinical variables, angiographic measures of recanalization, reperfusion and clinical outcomes. Results: Adequate views of collateral circulation to the ischemic territory were available in 276/331 (83%) subjects. Collateral grade was strongly related to both recanalization of the occluded arterial segment (p=0.0016) and downstream reperfusion (p<0.0001). Multivariable analyses confirmed that robust angiographic collateral grade was a significant predictor of good clinical outcome (mRS≤2) at 90 days (p=0.0353), adjusted for age, history of diabetes, NIHSS strata, and ASPECTS. The relationship between collateral flow and clinical outcome may depend on the degree of reperfusion. Conclusions: More robust collateral grade was associated with better recanalization, reperfusion, and subsequent better clinical outcomes. These data, from the largest endovascular trial to date, suggest that collaterals are an important consideration in future trial design.

Impact of Time-to-Reperfusion on Outcome in Patients with Poor Collaterals

“…[5][6][7][8][9][10][11] Also, the ORT in intra-arterial treatment was a main determinant factor in predicting favorable outcome. 3,4 Regarding collateral flow and ORT as determinant factors of favorable outcome, reperfusion of Ͼ300 minutes from onset in a poor collateral group was associated with decreased odds of clinical improvement and favorable outcome from a small retrospective cohort.…”

“…3,4 However, the effect of reperfusion on outcome can vary on the basis of the extent of collateral flow. [5][6][7][8][9][10][11] Baseline collateral flow, which is an important determinant of clinical recovery, can mitigate potential injury to ischemic brain tissue. 12 Before adequate reperfusion occurs, the penumbral area can continue to be salvageable depending on the robustness of collateral flow, and its impact on infarct growth and subsequent clinical outcome may be time-dependent, along with reperfusion status.…”

Thrombus Characteristics Are Related to Collaterals and Angioarchitecture in Acute Stroke

“…Collateral status and symptom onset to CT time were independent variables in model 1; this model also includes a two-way interaction term between collateral status and symptom onset to CT time. Collateral status was trichotomized into good (regional leptomeningeal score 17-20), intermediate (11)(12)(13)(14)(15)(16), and poor (0-10) for these analyses. 12 Model 2a used logistic regression with the hyperdense sign as a dependent variable, clot length and onset to CT time as independent variables, and a two-way multiplicative interaction term between the independent variables.…”

Assessment of Collateral Status by Dynamic CT Angiography in Acute MCA Stroke: Timing of Acquisition and Relationship with Final Infarct Volume

“…1,3,4 DSA is considered the criterion standard for visualization of the collateral circulation. However, DSA is currently reserved for part of the thrombectomy procedures and has no role in the diagnostic work-up of patients with acute ischemic stroke.…”