Deriving a Simple Clinical Predictive Score for Posterior Circulation Ischemic Stroke (PCS-SCORE)

TL;DR

This paper introduces PCS-SCORE, a clinical scoring tool to identify high-risk patients for posterior circulation ischemic stroke using simple bedside features.

Contribution

The novel contribution is the derivation of a practical, highly specific clinical score for early detection of posterior circulation strokes.

Findings

The PCS-SCORE achieved an AUC of 0.76 with high specificity (87.9%) at a threshold >3.

Increasing the score threshold to >4 improved specificity to 94.4%.

The tool is designed for use in prehospital and resource-limited settings to aid rapid triage.

Abstract

Posterior circulation ischemic stroke (PCS) accounts for up to 25% of all ischemic strokes but remains frequently under-recognized due to atypical symptoms and poor representation in conventional stroke scales. Early diagnosis is critical yet challenging. This study aimed to derive a pragmatic clinical scoring tool, the PCS-SCORE, to identify patients at high risk of PCS based solely on bedside features.

We retrospectively analyzed 5163 patients from a prospective stroke registry, including 1571 with -confirmed PCS. Key predictors were identified through multivariable logistic regression and lasso modeling. Variables were weighted according to regression coefficients and clinical relevance. The final PCS-SCORE (0-9 points) included: diabetes (1 point), hypertension (1), male sex (1), double/blurred vision (2), vertigo with vomiting (2), and incoordination (2).

At a score threshold >3, the PCS-SCORE achieved an area under the curve (AUC) of 0.76, with 87.9% specificity and 43.4% sensitivity. Raising the threshold to >4 increased specificity to 94.4% (sensitivity 27.9%). Higher scores corresponded with progressively increased likelihood of PCS, enabling confident identification of high-risk patients.

The PCS-SCORE is a simple, highly specific bedside tool for early detection of posterior circulation strokes. Its rule-in strength makes it especially useful in prehospital settings, resource-limited environments, and crowded emergency departments. Prospective validation is ongoing.

Posterior circulation ischemic stroke (PCS) represents up to a quarter of all ischemic strokes but is often missed because symptoms can be atypical and current stroke scales under-represent these cases. Prompt recognition is crucial for timely treatment, yet diagnosis remains challenging, particularly in prehospital or resource-limited settings. This study set out to develop a practical, easy-to-use clinical scoring tool—the PCS-SCORE—designed to identify patients at high risk of PCS based entirely on bedside findings. Researchers retrospectively reviewed data from a prospective stroke registry containing 5,163 patients, of whom 1,571 had confirmed PCS. Predictive factors were identified using multivariable logistic regression and lasso modeling. Each factor was assigned a point value based on statistical weight and clinical significance. The final PCS-SCORE ranges from 0 to 9 points and includes six predictors: diabetes mellitus (1 point), hypertension (1 point), male sex (1 point), double or blurred vision (2 points), vertigo with vomiting (2 points), and incoordination (2 points). Performance analysis showed that at a threshold score greater than 3, the PCS-SCORE achieved an area under the curve (AUC) of 0.76, with 87.9% specificity and 43.4% sensitivity. Increasing the threshold to greater than 4 improved specificity to 94.4%, though sensitivity decreased to 27.9%. Importantly, higher PCS-SCORE values correlated with a markedly increased probability of PCS, supporting its utility as a “rule-in” diagnostic aid. It’s high specificity makes it particularly useful for quickly identifying likely PCS cases, helping clinicians prioritize further imaging and urgent intervention. This is especially valuable in crowded emergency departments, rural or low-resource hospitals, and prehospital environments where rapid triage decisions are critical. In conclusion, the PCS-SCORE is a simple, bedside clinical tool with strong potential to improve early detect.

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