Widening clinical applications of the SYNTAX Score

The SYNTAX Score (http://www.syntaxscore.com) has established itself as an anatomical based tool for objectively determining the complexity of coronary artery disease and guiding decision-making between coronary artery bypass graft (CABG) surgery and percutaneous coronary intervention (PCI). Since the landmark SYNTAX (Synergy between PCI with Taxus and Cardiac Surgery) Trial comparing CABG with PCI in patients with complex coronary artery disease (unprotected left main or de novo three vessel disease), numerous validation studies have confirmed the clinical validity of the SYNTAX Score for identifying higher-risk subjects and aiding decision-making between CABG and PCI in a broad range of patient types. The SYNTAX Score is now advocated in both the European and US revascularisation guidelines for decision-making between CABG and PCI as part of a SYNTAX-pioneered heart team approach. Since establishment of the SYNTAX Score, widening clinical applications of this clinical tool have emerged. The purpose of this review is to systematically examine the widening applications of tools based on the SYNTAX Score: (1) by improving the diagnostic accuracy of the SYNTAX Score by adding a functional assessment of lesions; (2) through amalgamation of the anatomical SYNTAX Score with clinical variables to enhance decision-making between CABG and PCI, culminating in the development and validation of the SYNTAX Score II, in which objective and tailored decisions can be made for the individual patient; (3) through assessment of completeness of revascularisation using the residual and post-CABG SYNTAX Scores for PCI and CABG patients, respectively. Finally, the future direction of the SYNTAX Score is covered through discussion of the ongoing development of a non-invasive, functional SYNTAX Score and review of current and planned clinical trials.