# A Novel and Simple Score to Predict Embolic or Atherosclerotic Middle Cerebral Artery Occlusion Before Mechanical Thrombectomy: AHOC Score

## TL;DR

A new scoring system called AHOC helps predict whether a stroke is caused by embolism or atherosclerosis before mechanical thrombectomy, improving treatment decisions.

## Contribution

The AHOC score is a novel, simple, and validated pre-thrombectomy tool for predicting stroke etiology in acute middle cerebral artery occlusion.

## Key findings

- The AHOC score includes four variables: atrial fibrillation, hyperdense artery sign, stenosis/occlusion in other arteries, and collateral status.
- The AHOC score demonstrated excellent discrimination and calibration in both training and validation cohorts with C-statistics of 0.932 and 0.933 respectively.

## Abstract

The mechanical thrombectomy (MT) strategy obviously differs for acute middle cerebral artery occlusion (MCAO) stroke caused by embolism or atherosclerosis. Our study aimed to develop and validate a simple and universally applicable score for predicting etiology [embolism or intracranial arteriosclerosis (ICAS)] before MT in patients with acute MCAO stroke.

Between November 2019 and September 2022, we retrospectively enrolled eligible patients in our hospital as the training cohort. Additionally, consecutive patients between July 2023 and April 2024 were recruited as the validation cohort. Multivariate logistic regression analysis was used to identify the independent factors associated with etiology in the training group. Each factor was then point assigned based on β‐coefficient, and a risk scoring system was developed. The scoring system was validated through the validation cohort. The C‐statistic, Brier score, and Hosmer‐Lemeshow test were used to assess model discrimination and calibration.

The training group and validation group finally included 277 patients (154 embolism‐MCAO and 123 ICAS‐MCAO) and 101 patients (59 embolism‐MCAO and 42 ICAS‐MCAO), respectively. A scoring system (AHOC score) covering four variables (atrial fibrillation, hyperdense middle cerebral artery sign, stenosis/occlusion in other arteries, and collateral status) was derived to help identify embolism‐MCAO or ICAS‐MCAO. The AHOC score showed good discrimination and calibration in the training cohort (C‐statistic, 0.932 [0.902–0.963]; Brier score, 0.092 [0.070–0.115]; p value of the Hosmer‐Lemeshow test, 0.604) and in the validation cohort (C‐statistic, 0.933 [0.888–0.978]; Brier score, 0.102 [0.067–0.140]; p value of the Hosmer‐Lemeshow test, 0.846). According to the AHOC score, patients with a score of 4–8 were identified as high‐risk for the embolism‐MCAO category. Conversely, a patient with a score of 0–3 was considered high‐risk for the ICAS‐MCAO category.

Our scoring system (AHOC score), consisting of atrial fibrillation, hyperdense middle cerebral artery sign, stenosis/occlusion in other arteries and collateral status, is a valid and applicable model for predicting the etiology in patients with acute MCAO before MT.

This study developed and validated the novel AHOC score, a simple pre‐thrombectomy tool for predicting stroke etiology (embolism vs. intracranial atherosclerosis) in acute middle cerebral artery occlusion. This score integrates four key clinical/imaging variables—atrial fibrillation, hyperdense artery sign, stenosis/occlusion in other arteries, and collateral status—and demonstrates excellent predictive accuracy. It aids in tailoring mechanical thrombectomy strategy by identifying the underlying cause preoperatively.