Since its first publication, the SYNTAX score has been used and validated in several subsets of lesions and populations. Despite some concerns about its reproducibility between cardiologists and its power of discrimination, the SYNTAX score remains the most powerful angiographic tool to predict events after percutaneous coronary intervention. Knowledge and mastering of the SYNTAX score definitions is of paramount importance and is the first step to an adequate stratification. This short article presents the different steps of the scoring system of SYNTAX score and focuses on the variables with the highest interobserver variability.
Accurate characterisation of coronary artery disease (CAD) anatomy based on the diagnostic angiogram is essential to select the optimal strategy of revascularisation. Recently, the SYNTAX score generated a great amount of interest because of its ability to risk-stratify and discriminate outcomes of patients with complex CAD undergoing percutaneous coronary intervention (PCI) as compared to coronary artery bypass graft surgery.1–3 Additionally, it has been validated in different clinical settings of patients undergoing PCI, as well as in various subsets of lesions.4–11 Thus, SYNTAX score is a pioneer anatomical-based risk score that aids in the decision-making process. However, assessment of the SYNTAX score relies on pure visual interpretation of lesion severity and other semi-quantitative and subjective variables, which for even simple measures may be inaccurate. Although some studies report acceptable reproducibility when determined by angiographic core laboratory technicians,2 concerns remain regarding its reproducibility, especially among ‘SYNTAX-score naive’ or inappropriately trained cardiologists.12 The recent introduction of a ‘functional SYNTAX score’ that incorporates ischaemia-producing lesions as determined by fractional flow reserve (FFR), has brought some hope by better risk-stratifying of patients.13 Moreover, a limitation of the SYNTAX score relies on the fact that the score algorithm does not entail any clinical variable. Co-morbidities are known to impact early outcomes of patients undergoing revascularisation. Accordingly, to address the relative lack of discrimination and predictability of the pure SYNTAX score, some attempts to combine clinical variables into the SYNTAX score were reported recently. The ‘clinical SYNTAX score’, a combination of ACEF and SYNTAX score strata, parsimoniously combines three strong clinical predictors of clinical outcome (i.e., age, creatinine and ejection fraction). An alternative approach combines the SYNTAX score and the EuroSCORE, the so-called ‘Global risk classification’.14–16 Overall, their findings underline the potential importance of the interplay between clinical and angiographic data in predicting clinical outcomes after PCI.
Although the precise training requirements to optimise the performance of cardiologists using the SYNTAX score are unknown, some recent published data suggest that training beyond the standard on-line tutorial (www.syntaxscore.com) is warranted if the full clinical potential of the SYNTAX score is to be realised.12 The aim of this short article is to overview the basics and essentials of the SYNTAX score assessment, to ensure appropriate reading and, therefore, improve its reproducibility between readers.
- Sianos G, Morel MA, Kappetein AP, et al., The SYNTAX score: an angiographic tool grading the complexity of coronary artery disease, EuroIntervention, 2005;1:219–27.
- Serruys PW, Onuma Y, Garg S, et al., Assessment of the SYNTAX score in the SYNTAX study, EuroIntervention, 2009;5:50–6.
- Serruys PW, Morice MC, Kappetein AP, et al., Percutaneous coronary intervention versus coronary-artery bypass grafting for severe coronary artery disease, N Engl J Med, 2009;360:961–72.
- Valgimigli M, Serruys PW, Tsuchida K, et al., Cyphering the complexity of coronary artery disease using the SYNTAX score to predict clinical outcome in patients with three-vessel lumen obstruction undergoing percutaneous coronary intervention, Am J Cardiol, 2007;99:1072–81.
- Capodanno D, Capranzano P, Di Salvo ME, et al., Usefulness of SYNTAX score to select patients with left main coronary artery disease to be treated with coronary artery bypass graft, JACC Cardiovasc Interv, 2009;2:731–8.
- Capodanno D, Di Salvo ME, Cincotta G, et al., Usefulness of the SYNTAX score for predicting clinical outcome after percutaneous coronary intervention of unprotected left main coronary artery disease, Circ Cardiovasc Interv, 2009;2:302–8.
- Wykrzykowska JJ, Garg S, Girasis C, et al., Value of the SYNTAX score for risk assessment in the all-comers population of the randomized multicenter leaders (limus eluted from a durable versus erodable stent coating) trial, J Am Coll Cardiol, 2010;56:272–7.
- Palmerini T, Genereux P, Caixeta A, et al., Prognostic value of the SYNTAX score in patients with acute coronary syndromes undergoing percutaneous coronary intervention: analysis from the acuity (acute catheterization and urgent intervention triage strategy) trial, J Am Coll Cardiol, 2011;57:2389–97.
- Garg S, Sarno G, Girasis C, et al., A patient-level pooled analysis assessing the impact of the SYNTAX (synergy between percutaneous coronary intervention with taxus and cardiac surgery) score on 1-year clinical outcomes in 6,508 patients enrolled in contemporary coronary stent trials, JACC Cardiovasc Interv, 2011;4:645–53.
- Garg S, Serruys PW, Silber S, et al., The prognostic utility of the SYNTAX score on 1-year outcomes after revascularization with zotarolimus- and everolimus-eluting stents: a substudy of the resolute all comers trial, JACC Cardiovasc Interv, 2011;4:432–41.
- Magro M, Nauta S, Simsek C, et al., Value of the SYNTAX score in patients treated by primary percutaneous coronary intervention for acute st-elevation myocardial infarction: the mi-SYNTAX score study, Am Heart J, 2011;161:771–81.
- Genereux P, Palmerini T, Caixeta A, et al., Syntax score reproducibility and variability between interventional cardiologists, core laboratory technicians, and quantitative coronary measurements, Circ Cardiovasc Interv, 2011;4:553–61.
- Nam CW, Mangiacapra F, Entjes R, et al., Functional SYNTAX score for risk assessment in multivessel coronary artery disease, J Am Coll Cardiol, 2011;58:1211–8.
- Capodanno D, Miano M, Cincotta G, et al., Euroscore refines the predictive ability of SYNTAX score in patients undergoing left main percutaneous coronary intervention, Am Heart J, 2010;159:103–9.
- Capodanno D, Caggegi A, Miano M, et al., Global risk classification and clinical SYNTAX (synergy between percutaneous coronary intervention with taxus and cardiac surgery) score in patients undergoing percutaneous or surgical left main revascularization, JACC Cardiovasc Interv, 2011;4:287–97.
- Girasis C, Garg S, Raber L, et al., Syntax score and clinical SYNTAX score as predictors of very long-term clinical outcomes in patients undergoing percutaneous coronary interventions: a substudy of sirolimus-eluting stent compared with paclitaxel-eluting stent for coronary revascularization (SIRTAX) trial, Eur Heart J, 2011 32(24):3115–27.