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Published on: September 22, 2020
Aortic manipulation proxy score predicts early stroke after isolated coronary artery bypass grafting: an
Haitham Abu Khadija1, Mohammad Alnees2,3, Nizar Abu Hamdeh2
1Heart Center, Kaplan Medical Center, Rehovot, Affiliated with the Hebrew University, Jerusalem, Israel.
Insights
A new Aortic Manipulation Proxy (AMP) score helps predict stroke risk after coronary artery bypass grafting (CABG). This score uses routine data to assess procedural complexity and improve patient risk stratification.
Area of Science:
- Cardiovascular Surgery
- Neurology
- Health Services Research
Background:
- Stroke is a significant complication following coronary artery bypass grafting (CABG).
- Intraoperative aortic manipulation and embolization are common causes of post-CABG stroke.
- A simple, scalable method to estimate procedural complexity and embolic risk is lacking.
Purpose of the Study:
- To develop and evaluate the Aortic Manipulation Proxy (AMP) score.
- To predict 30-day stroke risk after isolated CABG using routinely collected variables.
Main Methods:
- Retrospective international multicenter cohort study of 6,818 adults undergoing isolated CABG.
- Development of the AMP score using routinely documented operative variables.
- Cox proportional hazards models and AUC analysis to assess stroke prediction and incremental value.
Main Results:
- Higher AMP scores correlated with increased 30-day stroke risk.
- The AMP score independently predicted stroke (HR 1.46 per 1-SD increase).
- Adding AMP to clinical models improved stroke prediction discrimination (AUC 0.731 vs. 0.707).
Conclusions:
- The AMP score is independently associated with 30-day stroke after CABG.
- AMP provides incremental risk stratification beyond conventional factors.
- The AMP score may aid early postoperative risk assessment, requiring external validation.
Background:
Stroke remains a devastating complication after coronary artery bypass grafting (CABG), often related to intraoperative aortic manipulation and embolization. However, no simple and scalable surrogate exists to approximate procedural complexity and embolic risk using routinely collected variables. We developed and evaluated the Aortic Manipulation Proxy (AMP) score for predicting 30-day stroke after isolated CABG.
Methods:
We conducted a retrospective international multicenter cohort study including 6,818 adults undergoing isolated CABG. The primary outcome was 30-day postoperative stroke (n = 133; 1.95%). The AMP score was constructed from routinely documented operative variables. Associations were assessed using Cox proportional hazards models stratified by center. Discrimination was evaluated using the area under the receiver operating characteristic curve (AUC), and incremental predictive value was examined using ΔAUC and decision curve analysis. Sensitivity analysis, excluding postoperative atrial fibrillation and internal validation using bootstrap resampling, was performed.
Results:
Higher AMP scores were associated with a graded increase in 30-day stroke risk. In center-stratified models, AMP independently predicted stroke per 1-SD increase (HR 1.46; 95% CI, 1.23-1.73; p < 0.001) and per 2-unit increase (HR 1.62; 95% CI, 1.30-2.01; p < 0.001). Kaplan-Meier analysis demonstrated stepwise separation across AMP tertiles (log-rank p = 0.005). Addition of AMP to a clinical model modestly improved discrimination (AUC 0.731 vs. 0.707; ΔAUC = 0.024; p = 0.021) and demonstrated improved net benefit across clinically relevant thresholds. Findings were consistent in sensitivity analyses and bootstrap validation.
Conclusions:
In a large multicenter CABG cohort, the AMP score was independently associated with 30-day stroke and provided incremental risk stratification beyond conventional clinical factors. As a pragmatic surrogate derived from routinely available data, the AMP score may support early postoperative risk assessment, although external validation is warranted.
