Two Studies Look at Predictive Value of SYNTAX Score

June 25, 2010—In the Journal of the American College of Cardiology: Cardiovascular Interventions, Young-Hak Kim, MD, et al published findings from a study aimed to validate the SYNTAX (Synergy Between Percutaneous Coronary Intervention With Taxus and Cardiac Surgery) score representing angiographic complexity after unprotected left main coronary artery (ULMCA) revascularization (2010;3:612–623). The investigators calculated the SYNTAX scores for 1,580 patients in a large multicenter registry who underwent percutaneous coronary intervention (PCI) (n = 819) or coronary artery bypass graft (CABG) (n = 761) for ULMCA stenosis. The outcomes of interests were 3-year incidences of major adverse vascular events (MAVE), including death, Q-wave myocardial infarction, and stroke, and major adverse cardiac and cerebrovascular events (MACCE), including MAVE and target vessel revascularization of ULMCA.

The investigators reported that the incidence of 3-year MAVE was 6.2% in the lowest (23), 7.1% in the intermediate (23–36), and 17.4% in the highest (> 36) SYNTAX score tertile groups after PCI (P = .01). However, the incidences of MAVE in the CABG group and MACCE in the PCI and CABG groups did not differ among the SYNTAX tertiles. In subgroups, the MAVE (P = .005) and MACCE (P = .007) rates, according to the SYNTAX score tertiles, were significantly different in patients receiving drug-eluting stents, not in those receiving bare-metal stents. When compared with the clinical EuroSCORE (European System for Cardiac Operative Risk Evaluation), the C-indexes of SYNTAX score and EuroSCORE were 0.59 and 0.67, respectively, for discrimination of MAVE and 0.53 and 0.57, respectively, for MACCE.

The investigators concluded that the angiographic SYNTAX score seems to play a partial role in predicting long-term adverse events after PCI for ULMCA stenosis, and that a complementary consideration of patient's clinical risk might improve the predictive ability of risk score.

Also in the Journal of the American College of Cardiology: Cardiovascular Interventions, Shao-Liang Chen, MD, et al published findings from a study that aimed to compare the NERS (New Risk Stratification) and SYNTAX scores for prognostication after stenting of unprotected left main stenosis in a real-world setting (2010;3:632–641). In contrast to existing systems, the NERS score encompasses clinical, procedural, and angiographic characteristics, the investigators stated.

As detailed by the investigators, the NERS score was derived from 260 patients with unprotected left main stenosis who underwent PCI and tested in 337 patients in a consecutive left main registry (66.55 ± 10.49 years, 78.9% men) undergoing PCI in a prospective, multicenter trial. Six-month clinical and angiographic follow-up was obtained in 100% and 88.9% of patients, respectively. The primary endpoint was major adverse cardiac events (MACE), encompassing myocardial infarction, all-cause death, and target vessel revascularization. Receiver-operator characteristic (ROC) curve was generated for the comparison of NERS versus SYNTAX scores.

The investigators reported that the NERS score consisted of 54 variables (17 clinical, 4 procedural, and 33 angiographic). A NERS score 25 demonstrated a sensitivity and specificity of 92% and 74.1% (MACE as state variable), respectively, significantly higher than SYNTAX intermediate risk (20.5% and 25.4%) or SYNTAX higher risk (70.5% and 35.2%; P for all < .001). At follow-up, myocardial infarction, cardiac death, and target vessel revascularization occurred in 3%, 5.6%, and 13.1% of patients, respectively, for a composite MACE of 26%. A NERS score of 25 (hazard ratio, 1.13; 95% confidence interval [CI], 1.11–1.16; P < .001) was the only independent predictor of cumulative MACE and stent thrombosis at follow-up (odds ratio, 31.04; 95% CI, 19.36–67.07; P < .001).

The investigators concluded that the NERS score was more predictive of MACE than the SYNTAX score; however, further study is needed to address their relative roles in assessment for appropriateness of CABG versus PCI for ULMCA stenosis.