SYNTAX trial

SYNTAX trial
Name	SYNTAX trial
Acronym	SYNTAX
Phase	Randomized controlled trial
Design	Multicenter, investigator-initiated, randomized
Condition	Coronary artery disease
Interventions	Percutaneous coronary intervention; Coronary artery bypass grafting
Enrollment	1,800+ patients
Start date	2005
Primary outcome	Major adverse cardiac or cerebrovascular events
Follow up	up to 10 years

SYNTAX trial

The SYNTAX trial was a multicenter randomized clinical study comparing outcomes of percutaneous coronary intervention and coronary artery bypass grafting for patients with complex coronary artery disease. Initiated in the mid-2000s, the study enrolled patients with de novo three-vessel disease or left main coronary artery disease and informed guideline deliberations among cardiology and cardiac surgery societies. Major European and North American cardiovascular centers, professional societies, and regulatory agencies used the trial to evaluate revascularization strategies across heterogeneous patient populations.

Background

The trial emerged from collaboration among leading institutions including European Society of Cardiology, American College of Cardiology, Society of Thoracic Surgeons, and academic centers such as Royal Brompton Hospital, Milan Heart Institute, and Cleveland Clinic. Investigators sought to resolve debates highlighted by prior studies like BARI trial, CASS trial, and observational registries from Framingham Heart Study cohorts. Key clinical figures and trialists from University of Leuven, University College London, and Harvard Medical School contributed to protocol development. Regulatory stakeholders such as European Medicines Agency and Food and Drug Administration watched outcomes for implications on device approvals and reimbursement policies across England, Germany, and the United States.

Methods

SYNTAX randomized patients with complex anatomic coronary lesions to treatment by contemporary percutaneous coronary intervention using drug-eluting stents or coronary artery bypass grafting performed by cardiac surgeons. The trial used a validated anatomic scoring system developed by investigators at centers including Erasmus Medical Center and Leiden University Medical Center to quantify lesion complexity; the score informed both enrollment and stratification. Randomization procedures were overseen by coordinating centers at Imperial College London and University of Barcelona, with imaging adjudication by core laboratories at institutions such as Mayo Clinic and Mount Sinai Hospital. Primary endpoints—composite measures of death, myocardial infarction, stroke, and repeat revascularization—were assessed by independent clinical events committees including representatives from Society for Cardiovascular Angiography and Interventions and European Association for Cardio-Thoracic Surgery.

Results

Initial publications reported differential outcomes favoring coronary artery bypass grafting for patients with higher anatomic complexity, while percutaneous coronary intervention showed competitive results in lower-complexity cohorts. Key outcome papers from investigators affiliated with St. Bartholomew's Hospital, Karolinska Institutet, and Johns Hopkins University described event rates at one year and three years, with subsequent reports extending to five years and beyond. The trial’s main reports demonstrated higher rates of repeat revascularization after percutaneous coronary intervention and comparable or lower mortality with coronary artery bypass grafting in specified subgroups. Meta-analyses that pooled SYNTAX data with trials such as EXCEL trial and NOBLE trial were discussed at meetings organized by European Society for Cardio-Thoracic Surgery and American Heart Association.

Subgroup analyses and long-term outcomes

Investigators published prespecified and post-hoc subgroup analyses examining patients with left main disease, diabetes mellitus, chronic kidney disease, and advanced age; authors hailed from University of Oxford, University of Toronto, and John Radcliffe Hospital. Long-term follow-up up to ten years, coordinated with registries at Swedish Coronary Angiography and Angioplasty Registry and national databases in Spain and Italy, clarified durable differences in repeat procedures and survival. Analyses by anatomical SYNTAX score tiers influenced decision algorithms debated at consensus conferences held by European Society of Cardiology and American College of Cardiology Foundation; experts from Royal College of Surgeons and British Cardiovascular Society participated in guideline panels referencing these results.

Safety and adverse events

Safety analyses reported peri-procedural myocardial infarction, stroke, wound complications, graft occlusion, and device-related events adjudicated by independent committees including clinicians from Guy's and St Thomas' NHS Foundation Trust, Charité – Universitätsmedizin Berlin, and Cedars-Sinai Medical Center. Percutaneous coronary intervention was associated with fewer early surgical-site complications but higher rates of repeated target-vessel intervention, while coronary artery bypass grafting showed risks linked to sternotomy and graft patency. Device- and procedure-specific safety signals informed regulatory reviews by European Medicines Agency and payer assessments across health systems in France and Netherlands.

Impact on clinical practice and guidelines

Results from the study shaped revascularization recommendations in guideline documents issued by European Society of Cardiology, American College of Cardiology, and American Heart Association, and influenced shared decision-making tools used in clinics at Mount Sinai Hospital, Royal Papworth Hospital, and Christie Hospital. Cardiac multidisciplinary teams at tertiary centers including Massachusetts General Hospital, University Hospital Zurich, and Sheffield Teaching Hospitals integrated trial-derived algorithms and the anatomic scoring system into pathway development. Health technology assessment bodies such as National Institute for Health and Care Excellence reviewed cost-effectiveness models that incorporated SYNTAX outcomes, affecting reimbursement policies and clinical audit standards across United Kingdom and Scandinavia.

Category:Cardiology clinical trials