How We Estimate the Risk of Bypass Surgery (CABG) and Angioplasty/Stent (PCI)

Coronary artery disease (CAD-cholesterol buildup in the of the heart arteries) can decrease blood flow to the heart muscle causing in some patients an increased risk of death and in others causing distressing  symptoms (like angina or shortness of breath).

Two possible treatments for CAD are coronary artery bypass surgery (CABG) and balloon angioplasty/stent called percutaneous coronary intervention (PCI).

There are a number of methods of estimating the risk of CABG and PCI in an indivdual who is considering about one these treatment methods.

Four risk estimators in wide use are the EuroSCORE, the SYNTAX score, the NCDR CathPCI risk score,  and the Society of Thoracic Surgeons (STS) score.

The EuroSCORE is a method of predicting operative mortality from CABG. The EuroSCORE II interactive calculator is online at

The SYNTAX score is an independent predictor of major adverse cardiac events in patients undergoing PCI. However, it depends on careful interpretation of the coronary angiograms and so is limited to use by physicians who are experts in reading coronary angiography. The website is outstanding and has an excellent tutorial on how to use the Syntax Score which physicians will find very helpful. The site is available at

The NCDR CathPCI risk score is a useful risk predictor for patients undergoing PCI. It is shown in Table 4  of the article “Contemporary  Mortality Risk Prediction for Percutaneous Coronary Intervention: . . .” published  in J. Am. Coll. Cardiol. 2010;55;1923-1932 available at: I have not been able to find an online risk calculator for this. If you know of one please comment or email me. Table 4 in the article will work but it is kind of inconvenient.

The Society of Thoracic Surgery (STS) Score is a risk predictor for CABG. The online STS risk calculator is available at: The online risk calculator is outstanding and worth visiting for any physician or patient interested in CABG.

Of course, all these risk scores are just estimates and you and your doctor will have to add in clinical judgment. But they are a good start.

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