Hypoperfusion Intensity Ratio Correlates with Angiographic Collaterals and Infarct Growth in Acute Stroke with Thrombectomy.

BACKGROUND

The assessment of collaterals before endovascular thrombectomy (EVT) therapy play a pivotal role in clinical decision-making for acute stroke patients.

OBJECTIVE

To investigate the correlation between hypoperfusion intensity ratio (HIR), collaterals on digital subtraction angiography (DSA), and infarct growth in acute stroke patients who underwent EVT therapy.

METHODS

Patients with acute ischemic stroke (AIS) who underwent EVT therapy were enrolled retrospectively. HIR was assessed through magnetic resonance imaging (MRI) and was defined as the Tmax > 10 s lesion volume divided by the Tmax > 6 s lesion volume. Collaterals were assessed on DSA using the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology (ASITN/SIR) scale. Good collaterals were defined as ASITN/SIR score 3-4 and poor collaterals were defined as ASITN/SIR score 0-2. Spearman's rank correlation analysis was used to evaluate the correlation between HIR, collaterals, infarct growth, and functional outcome.

RESULTS

A total of 115 patients were included. Patients with good collateral (n = 59) had smaller HIR (0.29 ± 0.07 vs. 0.52 ± 0.14; t = 10.769, P < 0.001) and infarct growth (8.47 ± 2.40 vs. 14.37 ± 5.28; t = 7.652, P < 0.001) than those with poor collateral (n = 56).

DISCUSSION

The ROC analyses showed that the optimal cut-off value of HIR was 0.40, and the sensitivity and specificity for predicting good collateral were 85.70% and 96.61%, respectively. With the optimal cut-off value, patients with HIR < 0.4 (n = 67) had smaller infarct growth (8.86 ± 2.59 vs. 14.81 ± 5.52; t = 6.944, P < 0.001) than those with HIR ≥ 0.4 (n = 48). Spearman's rank correlation analysis showed that HIR had a correlation with ASITN/SIR score (r = -0.761, P < 0.001), infarct growth (r = 0.567, P < 0.001), and mRS at 3 months (r = -0.627, P < 0.001).

CONCLUSION

HIR < 0.4 is significantly correlated with good collateral status and small infarct growth. Evaluating HIR before treatment may be useful for guiding EVT and predicting the functional outcome of AIS patients.