SYNTAX investigator touts trials significance

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Washington, D.C.—Addressing the option of PCI for left main stem coronary artery disease is no longer “taboo,” according to Patrick Serruys, MD, co-principal investigator of SYNTAX, who discussed details of the trial with Cardiovascular Business News last week at the Cardiovascular Researcher Therapies (CRT) 2009 conference.  

Various randomized trials and registries in 2008 have opened the door in the area of the main stem, he said. “People are still discussing the results of these studies, but the door is open,” said Serruys, chief of interventional cardiology at the Thoraxcenter-Erasmus University, the Netherlands. 

The SYNTAX trial, which compared CABG with PCI in patients with three vessel and main stem disease, is important for several reasons, Serruys said. First, it took all comers. Second, there were no inclusion/exclusion criteria. Third, and one of the most important and overlooked aspects of the trial, according to Serruys, the surgeon and interventional cardiologist worked together as a team—“evaluating the angiograms, comorbidities and patient complaints to decide the best course of action for the patients.” 

Surgeons and interventional cardiologists ultimately agreed that about one-third of the patients were better served with CABG. They also agreed that about 200 patients would be better served with PCI. The remaining 1800 patients were randomized to either surgery or PCI. “We used the old motto of Andreas Grunzig, ‘When in doubt, let’s randomize,’” Serruys said.  

The final component of the trial that merits attention, he said, is the development of the SYNTAX score. Not all three main vessel diseases are alike and the SYNTAX score helps to separate the more complex cases from the simpler cases.  

Interestingly, researchers did not develop the SYNTAX score to be a prognostic index. It was meant to help physicians understand the technical complexity of the patient, so they’d be able to anticipate the potential complications. As it turned out, the SYNTAX score has significant prognostic value, “an added bonus.”  

“The big advantage of the SYNTAX score is that it is based on arbitrary points, on raw data, but it was done prospectively before discussing cases with the surgeon and before randomization,” Serruys said.  

Results of the trial showed that patients with low SYNTAX scores (0-22) fared well with PCI. But those with intermediate (23-32) and high (above 33) scores fared better with surgery.  

A survey of 100 medical centers undertaken by Serruys and others in 2003-2004 when they were designing the SYNTAX trial found that in practice, physicians were treating about one-third of patients with three-vessel and left main stem disease with PCI and two-thirds with surgery. “We didn’t know those numbers were legitimate,” Serruys said. “SYNTAX confirmed what was already in practice.” 

Calculating the SYNTAX score can be complicated and time-consuming. To help physicians, SYNTAX researchers will be launching a website in May, in conjunction with EuroPCR, to help automate the process.