To evaluate the relationship between atherogenic index of plasma (AIP) and CTA collaterals in LVO stroke patients who underwent EVT.

Cerebral collateral status strongly influences infarct progression and outcomes in acute ischemic stroke. The AIP, calculated as log10(triglyceride / HDL-cholesterol), reflects the balance between pro- and anti-atherogenic lipoproteins and may serve as a surrogate marker of endothelial dysfunction. While AIP is an established risk factor for coronary artery disease (CAD), its role in stroke remains unclear.

In this cross-sectional study, patients with internal carotid or middle cerebral artery occlusion who had a CTA within 24 hours of symptom onset were included. Collaterals were classified as symmetrical, malignant, or other. AIP was calculated using the formula: log (triglycerides / HDL-cholesterol). The discriminatory value of AIP to predict poor collaterals was assessed using receiver-operating characteristic curves with 2,000 bootstrap replicates for confidence intervals (CI). Multivariable logistic regression adjusted for age, sex, NIHSS score, hypertension,  diabetes, creatinine, ejection fraction and smoking examined the association between high AIP and poor collaterals.

AIP moderately predicted poor collateral circulation (AUC = 0.619, 95% CI 0.535–0.699; p < 0.001) with an optimal cut-off of 0.56 (sensitivity 75.0%, specificity 46.9%). High AIP was associated with increased odds of poor collaterals, particularly among patients with NIHSS ≥ 18 (OR 2.89, 95% CI 1.23–6.79; p = 0.015), LV EF < 60% (OR 5.28, 95% CI 1.55–18.04; p = 0.008), and current smokers (OR 4.67, 95% CI 1.01–21.53; p = 0.048). No significant interactions were observed across subgroups (p-int > 0.05 for all).

Elevated AIP is independently associated with impaired cerebral collaterals on CTA in acute ischemic stroke, especially among patients with higher stroke severity, reduced cardiac function, and active smoking. High AIP may serve as a useful biomarker for vascular fragility and collateral failure in AIS patients undergoing EVT.