Clinical Implications of the SYNTAX Study

Clinical Implications of the SYNTAX Study

Garg Scot , Serruys Patrick
Interventional Cardiology Volume 4 Issue 1
Published: November 2009
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Recent years have seen an ongoing debate as to whether coronary artery bypass graft (CABG) surgery or percutaneous coronary intervention (PCI) is the most appropriate revascularisation strategy for patients with coronary heart disease (CAD). The Synergy between Percutaneous Coronary Intervention with TAXUS and Cardiac Surgery (SYNTAX) study was conducted with the intention of defining the specific roles of each therapy in the management of de novo three-vessel disease or left main CAD. Interim results after 12 months show that PCI leads to significantly higher rates of major adverse cardiac or cerebrovascular events compared with CABG (17.8 versus 12.4; p=0.002), largely owing to increased rates of repeat revascularisation. However, CABG was much more likely to lead to stroke. Interestingly, categorisation of patients by severity of CAD complexity according to the SYNTAX score has shown that there are certain patients in whom PCI can yield results that are comparable to, if not better than, those achieved with CABG. Careful clinical evaluation and comprehensive assessment of CAD severity, alongside application of the SYNTAX score, can aid practitioners in selecting the most suitable therapy for each individual CAD patient.

Coronary artery disease (CAD) is the predominant cause of heart disease and the leading cause of death worldwide. In recent decades revolutionary treatments have been developed and ushered in for its management. Following its introduction in 1968, coronary artery bypass (CABG) surgery rapidly became established as the standard of care for treatment of CAD.1 In 1977, Andreas Gruntzig performed the first percutaneous coronary intervention (PCI), which was seen as an innovative non-surgical alternative to CABG.2 Since their inception, both techniques have undergone significant developments that have reduced rates of morbidity and mortality despite the increasing age and prevalence of co-morbidities in the patient population receiving revascularisation.3 Advances in cardiac surgeryinclude off-pump CABG, enhanced myocardial preservation, improvements in anaesthesia, pre-operative risk assessment and post-operative care, and an increased use of arterial conduits, which have reduced the rate of graft occlusion.4–7 In patients treated with PCI, improvements in technology and antiplatelet therapy coupled with landmark studies8–10 have effectively led to the replacement of balloon angioplasty with coronary artery stenting, which is the current preferred method of PCI.

The selection of appropriate therapy for CAD has been the subject of continuing debate for many years. Several studies comparing the use of bypass surgery and coronary bare-metal stents (BMS) in patients with multivessel disease have revealed higher rates of repeat revascularisation at five years in patients treated with BMS, while those patients treated with CABG have higher rates of stroke. Nevertheless, overall survival has been comparable between both groups.11–17 However, seminal improvements in treatment options have now rendered these studies historical in their applicability to contemporary practice. The introduction of drug-eluting stents (DES) has greatly enhanced the PCI approach to managing CAD, with demonstrated superiority in reducing restenosis over their bare-metal predecessors while maintaining similar rates of death and myocardial infarction (MI).18–21 These reductions in restenosis and re-intervention have also been reproduced in patients with multivesssel disease22,23 and left main disease,24–26 such that the use of PCI has expanded to the treatment of patients with severe CAD.27 Nevertheless, to date the use of PCI in this patient population has not been supported by adequate data from evidence-based medicine or sufficiently powered randomised clinical trials.27 Indeed, current guidelines state that CABG remains the gold standard and treatment of choice for patients with severe CAD, including three-vessel disease and left main CAD.28

The SYNTAX Study
The Synergy between Percutaneous Coronary Intervention with TAXUS and Cardiac Surgery (SYNTAX) study was designed to assess the optimum revascularisation strategy for patients with de novo three-vessel or left main CAD.29 To avoid criticism that patients enrolled would be non-representative of real-world patient cohorts, the SYNTAX trial adopted an all-comers design in which all eligible patients with de novo three-vessel or left main CAD were included.

Keywords:
Coronary heart disease, coronary artery bypass graft, percutaneous coronary intervention, drug-eluting stents, SYNTAX, SYNTAX score

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