Two-Year SYNTAX Data Presented for Boston Scientific's Taxus Express for PCI

September 2, 2009—Boston Scientific Corporation (Natick, MA) announced 2-year data from its SYNTAX (Synergy Between Percutaneous Coronary Intervention [PCI] With Taxus and Cardiac Surgery) clinical trial comparing PCI using the company's Taxus Express paclitaxel-eluting coronary stent system to coronary artery bypass graft (CABG) surgery. The overall results demonstrated no statistically significant difference between PCI and CABG in the composite safety endpoint (all-cause death, stroke, and myocardial infarction [MI]). The company made the announcement at the annual European Society of Cardiology Congress in Barcelona, Spain.

Boston Scientific stated that these results reinforce the 1-year SYNTAX data and show impressive outcomes for PCI in patients with complex coronary anatomy, the majority of whom are normally treated with CABG surgery. The findings build on the company's earlier data and provide additional support for PCI as a viable treatment option for many of these challenging patients.

A unique study group in the PCI field, all of the patients in the SYNTAX trial have left main and/or three-vessel coronary disease. The company advised that the safety and effectiveness of the Taxus Express stent system have not been established in patients with left main or three-vessel disease. In the trial, mean stent use was 4.6 stents per patient, with one patient having 14 stents implanted. By contrast, the average number of stents implanted in a PCI patient in everyday practice is 1.5. In addition, the study included 33% of patients with > 100-mm stented length, 71% with bi- or trifurcations, 27% with chronic total occlusions, and 39% with left main disease.

The results showed comparable safety profiles for the two treatment groups at 2 years, with a combined rate of all-cause death, stroke, and MI of 10.8% for PCI and 9.6% for CABG (P = .44). The rate of stroke was 1.4% for PCI as compared to 2.8% for CABG (P = .03), while MI was 5.9% for PCI and 3.3% for CABG (P = .01). The rate of all-cause death was 6.2% for PCI and 4.9% for CABG (P = .24).

The overall major adverse cardiovascular or cerebrovascular event (MACCE) rate, including all-cause death, stroke, MI, and repeat revascularization, was significantly higher for PCI (23.3% as compared to 16.4% for CABG; P = .0002), driven largely by the anticipated higher rate of revascularization in the PCI group (17.4% as compared to 8.6% for CABG; P < .0001), with the difference narrowing in the second year of follow-up. Most patients requiring repeat revascularization in the PCI group were successfully treated with another PCI.

The trial results were also analyzed based on the SYNTAX score, which demonstrated no statistically significant difference in MACCE for patients in the lower two terciles—those with low lesion complexity (19.4% for PCI and 17.4% for CABG; P = .63) and moderate lesion complexity (22.8% for PCI and 16.4% for CABG; P = .06). For patients in the upper tercile (ie, those with the most complex disease), there was a significant increase in MACCE for PCI patients as compared to CABG (28.2% as compared to 15.4%; P = .001).

The SYNTAX score is a novel angiographic tool used to measure the complexity of coronary artery disease based on nine anatomic criteria, including lesion frequency, complexity, and location. Higher SYNTAX scores indicate patients with more complex disease and increased treatment challenges. The SYNTAX score Web site allows cardiologists and cardiac surgeons to characterize a patient's anatomical complexity, which can be used in combination with a physician's clinical judgment, to help determine the best revascularization option, the company noted.

In related news, in Circulation: Cardiovascular Interventions, Davide Capodanno, MD, et al published a study on the usefulness of the SYNTAX score for predicting clinical outcome after percutaneous coronary intervention of unprotected left main coronary artery disease (2009;2:302-308). The investigators concluded that the SYNTAX score is a useful tool to predict cardiac mortality and MACCE in patients undergoing percutaneous revascularization of the left main coronary artery.

In the Journal of the American College of Cardiology: Cardiovascular Interventions, Dr. Capodanno et al published a study on the usefulness of the SYNTAX score to select patients with left main coronary artery disease to be treated with CABG (2009;2:731-738). The investigators concluded that a SYNTAX score threshold of 34 may usefully identify a cohort of patients with left main disease who would benefit most from surgical revascularization in terms of mortality.