Symmetric CTA Collaterals Identify Patients with Slow-progressing Stroke Likely to Benefit from Late Thrombectomy

Presentation collateral patterns and outcomes after endovascular thrombectomy for large vessel occlusion stroke

“…Furthermore, we contend our assessment of collateral patterns has significant advantages compared to other approaches. 12 Among our cohort, the median NIHSS was 18 for malignant patterns, 19 for other, and 11 for symmetric. Other studies corroborate our results, showing that patients with poor collaterals have higher NIHSS.…”

“…Comparing collateral patterns there were no differences in demographics, risk factors, time from last known well, thrombolysis treatment, TICI 2b-3 reperfusion, or sICH. Median NIHSS was 18 (IQR 14-23) for malignant, 19 (IQR [12][13][14][15][16][17][18][19][20][21][22] for other, and 11 (IQR 8-18) for symmetric (p=0.02). Intracranial ICA occlusions were present in 28% of malignant, 3% of other, and 11% of symmetric (p=0.04) (Table 1).…”

“…This may be related to our treatment exclusion of patients with poor ASPECTS or large infarcts since patients with poor collaterals have faster infarct growth. 12 Furthermore, more proximal occlusion locations were more likely to have poor collaterals; ICA occlusions were present in 28% of malignant, 3% of other, and 11% of symmetric. This stands to reason, and early studies have explored the relationship between occlusion location and collateral quality.…”

“…Patterns were determined by visual review of the maximum intensity projection arterial phase CTA images, which were classified as “symmetric”, “malignant”, or “other”. 12 Briefly, a symmetric pattern was defined as contrast visualized with similar or near similar conspicuity of the ischemic compared to the contralateral non-ischemic MCA territory. A malignant pattern was defined as no contrast visualized over at least 50% of the MCA territory at risk.…”

“…11 In patients with LVO not treated with reperfusion therapies, symmetric collateral pattern on CTA had a sensitivity of 87% and a specificity of 94% for 24-hour infarct volume <50 cc. 12 We sought to determine the relationship of presentation simple CTA collateral patterns and outcomes after EVT.…”