External validation of the OAC3-PAD risk score after endovascular revascularisation
Kevin Pelicon1, Klemen Petek1, Anja Boc1,2
1Department of Vascular Diseases, University Medical Centre Ljubljana, Slovenia.
Insights
The OAC3-PAD bleeding risk score shows potential for identifying high-risk patients with peripheral arterial disease (PAD) after endovascular revascularisation, though it requires further refinement for precise risk stratification. This study validates its use in this specific patient group.
Area of Science:
- Vascular Surgery
- Cardiology
- Clinical Risk Prediction
Background:
- The OAC3-PAD bleeding risk score was developed to assess bleeding risk in peripheral arterial disease (PAD) patients.
- Its performance in patients treated exclusively with endovascular revascularisation has not been previously validated.
- External validation is crucial for this specific patient cohort undergoing endovascular procedures.
Purpose of the Study:
- To externally validate the OAC3-PAD bleeding risk score in patients with PAD treated solely with endovascular revascularisation.
- To assess the score's performance in discriminating bleeding risk within this specific patient population.
Main Methods:
- Retrospective observational study of PAD patients treated with endovascular revascularisation over five years.
- Performance evaluation of the Cox proportional hazards (CPH) model using calibration, discrimination, and scaled Brier score.
- Calculation of OAC3-PAD score, risk group classification, Kaplan-Meier curves, and log-rank tests for discrimination.
Main Results:
- The OAC3-PAD score demonstrated adequate discrimination but poor calibration (scaled Brier score: 3.27%).
- Among 1,434 patients, 2.3% experienced major bleeding events.
- The score differentiated between lower and higher risk groups but not within these pairs (e.g., low vs. low-to-moderate).
Conclusions:
- The OAC3-PAD score effectively discriminates between low and high bleeding risk patients post-endovascular revascularisation.
- While not perfectly stratifying into four groups, it shows utility in identifying patients at significantly different bleeding risks.
- The score may serve as a valuable tool for predicting major bleeding events in this specific PAD patient cohort.
Abstract:
Background: The OAC3-PAD bleeding risk score was developed to assess the bleeding risk in patients with peripheral arterial disease (PAD), however its performance in patients treated exclusively with endovascular revascularisation has not yet been tested. We aimed to externally validate the bleeding risk score for this patient cohort. Patients and methods: A retrospective observational study, analysing the data of all PAD patients successfully treated with endovascular revascularisation in a single centre within a five-year period. The performance of the Cox proportional hazards (CPH) model, upon which the OAC3-PAD bleeding risk score is based, was tested using calibration methods, discrimination, and a scaled Brier score for overall performance. The OAC3-PAD bleeding risk score was calculated for all patients, classifying them into the four respective risk groups. Kaplan-Meier curves were plotted for all risk groups and discrimination was tested using log-rank tests. Results: While discrimination of the CPH model was adequate, calibration of the model was poor and the scaled Brier score was 3.27% (95% CI 0.65%-4.40%). Of the 1,434 patients, 33 (2.3%) experienced a major bleeding event. The frequency of bleeding was 0.4% in the low risk group (3/736 patients), 0.8% in the low-to-moderate risk group (2/243 patients), 5.8% in the moderate-to-high risk group (15/258 patients), and 6.6% in the high risk group (13/197 patients). The OAC3-PAD score successfully discriminated each of the two lower bleeding risk groups from one of the two higher risk groups, but failed to discriminate among the two lower risk groups and the two higher risk groups, respectively. Conclusions: Although the OAC3-PAD score did not stratify patients into the four respective risk groups, it allowed discrimination between the low risk patients and the high risk patients. It could therefore become a useful tool for predicting major bleeding events in patients with PAD after endovascular revascularisation.
