EuroSCORE refines the predictive ability of SYNTAX score in patients undergoing left main percutaneous coronary intervention.

Background: Whether SYNTAX score should be used as a stand-alone tool or whether its performance may be improved by the parallel use of clinical scores focusing on comorbidities, such as EuroSCORE, is a matter of debate.

Methods: A combined risk model including both clinical and angiographic information was developed, and its performance tested on a contemporary population of 255 patients with left main disease undergoing percutaneous coronary intervention (PCI). A global risk classification (GRC) system was created by combination of SYNTAX score and EuroSCORE strata, and new classes of risk were defined.

Results: When EuroSCORE was fitted into the SYNTAX score model, c-statistic increased from 0.681 to 0.732 for the prediction of cardiac mortality. The likelihood ratio test for the significance of adding the EuroSCORE term to the model was chi(2) = 4.109 (P = .043) with a net reclassification improvement of 26% (P = .002). GRC showed the best prediction and discriminative ability in terms of two-year cardiac mortality (HR 3.40, 95% CI 1.79-6.43, P < .001; c-statistic 0.756) as compared with SYNTAX score (HR 2.87, 95% CI 1.35-6.10, P = .006; c-statistic 0.747) and EuroSCORE (HR 3.04, 95% CI 1.41-6.57, P = .005; c-statistic 0.708) alone.

Conclusions: We found a significant improvement in the prediction of cardiac mortality with the inclusion of EuroSCORE in a SYNTAX score-based model. The degree of reclassification between treatment threshold categories indicates that clinical and angiographic information are both important for assessing individual risk of patients undergoing left main PCI.