Analysis of Stroke Occurring in the SYNTAX Trial Comparing Coronary Artery Bypass Surgery and Percutaneous Coronary Intervention in the Treatment of Complex Coronary Artery Disease

Study Questions:

What are stroke rates in the SYNTAX (SYNergy Between PCI With TAXUS and Cardiac Surgery) trial’s randomized and registry cohorts of patients being treated with coronary artery bypass grafting (CABG) or percutaneous coronary intervention (PCI) for treatment of de-novo three-vessel and/or left main coronary artery disease (CAD)?


This was a post-hoc analysis of the SYNTAX trial, a prospective, international, randomized trial with parallel nested registries (CABG registry: n = 1,077, of which n = 644 were followed for 5 years; PCI registry: n = 198) designed to assess clinical outcomes after PCI with Taxus Express stents compared with outcomes after CABG for the treatment of complex CAD. In the randomized cohort of SYNTAX, all strokes were confirmed by a local neurologist and adjudicated by a clinical events committee. In the parallel nested registries, strokes were site-reported but not adjudicated.


At 4 years of follow-up, 31 CABG (3.7%) and 19 PCI (2.3%) patients experienced 33 and 20 strokes post-randomization, respectively (p = 0.062). After CABG, a large proportion of strokes occurred acutely (0-30 days: 9 of 33). Most strokes in the PCI arm occurred >30 days following the procedure (18 of 20); 15% of randomized and 18.6% of registry CABG patients underwent off-pump surgery. There were no differences in rates of strokes in the trial (3.6% vs. 3.5% with on-pump), nor in the registry (5.3% vs. 4.0% with on-pump). Atrial fibrillation and/or atrial flutter during follow-up were comparatively low and reported in 3.4% (31 of 903) after PCI and in 7.9% (71 of 897) after CABG.


In a post-hoc analysis of the SYNTAX trial, the overall incidence of stroke was low, and while there appears to be a risk of periprocedural stroke with CABG, the overall risk for stroke seems to converge for PCI and CABG at 4 years of follow-up.


The authors presented a post-hoc analysis of the SYNTAX trial that generally presents reassuring statistics about the hazard of stroke during 4-year follow-up after CABG or PCI for complex CAD. In this analysis, the overall incidence of stroke was similar at 4 years for both methods of revascularization. These results are contrary (as acknowledged by the authors) to those reported in the recent FREEDOM (Future Revascularization Evaluation in Patients With Diabetes Mellitus: Optimal Management of Multivessel Disease) trial, in which there was a significant increase in stroke at 5-year follow-up after CABG as compared with PCI in a population of diabetics with multi-vessel CAD. Future studies should clarify the differential stroke risk following PCI and CABG in patients with complex CAD, and ultimately determine operative strategies that may reduce the rate of stroke following surgical coronary revascularization.

Keywords: Registries, Coronary Artery Disease, Stroke, Follow-Up Studies, Coronary Artery Bypass, Cardiac Surgical Procedures, Angioplasty, Diabetes Mellitus, Atrial Flutter, Stents, Percutaneous Coronary Intervention

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