The final session of the CRF-sponsored Third Annual Left Main and Bifurcation Summit, held June 4-5, 2009, in New York, NY, tackled a controversial issue: Does angioplasty with stenting have a legitimate role in the treatment of left main coronary artery disease?
This artery supplies blood to a crucial area of the heart, and significant narrowing there signals a poor prognosis. Traditionally, the “left main” has been forbidden territory for angioplasty, mainly because of poor early results with the technique combined with bare-metal stents. More recently, however, the advent of drug-eluting stents has encouraged exploration of a catheter-based approach to this vessel in certain kinds of patients.
Drs. Martin B. Leon and Michael J. Mack Debate Over the Data
Evidence for the relative merits of surgery vs. stenting was the focus of a lively debate between CRF founder and chairman emeritus Martin B. Leon, MD, of Columbia University Medical Center (New York, NY), and cardiac surgeon Michael J. Mack, MD, of Baylor Heart Hospital (Dallas, TX). Dr. Leon championed the cause of upgrading the current recommendation for stenting—which now essentially advises “steer clear”—while Dr. Mack defended bypass surgery as the gold standard of treatment.
Dr. Leon began by pointing out that the complications of surgery are by no means trivial. Aside from being more invasive, and thus requiring a longer, more arduous recovery, coronary bypass carries a significant risk of stroke and cognitive deficits. Moreover, when vein grafts are used, over time they can become clogged, leading to dangerous complications.
Reviewing contemporary studies comparing surgery and drug-eluting stents, Dr. Leon said that when the focus is on so-called hard clinical endpoints, such as death, heart attack, and stroke, “there really is nothing that differentiates importantly CABG from [angioplasty].” Angioplasty with stenting appears superior to surgery in terms of stroke risk, while the need for repeat procedures clearly favors surgery.
It’s All in the SYNTAX
Looming over the debate were results from the large, randomized SYNTAX trial, reported last year, which pitted bypass surgery against angioplasty with paclitaxel-eluting stents in patients with left main or multivessel disease. SYNTAX’s message appeared to be that at one year, angioplasty did not measure up to surgery. But
Dr. Leon cautioned that no single trial can be considered definitive.
He noted that the SYNTAX patients were skewed toward very complex coronary anatomy and the treatment practices in the trial were sometimes substandard. Even so, he said, looking at just left main patients, there was no difference between bypass and angioplasty in terms of death or heart attack rates, a highly significant benefit with angioplasty for stroke rates, and a nonsignificant difference favoring angioplasty for the combined rate of death, stroke, and heart attack. Only when patients who had two- or three-vessel disease were taken into account did the trend favor bypass surgery, and that was driven by the need for repeat procedures. Furthermore, looking through the lens of the SYNTAX score, which stratifies patients according to risk, the individual endpoints all favored angioplasty for a broad range of scores. Only patients at highest risk fared better with bypass surgery in terms of death rates and need for repeat procedures.
For his part, Dr. Mack responded that all of the SYNTAX score subgroups were too small to allow solid conclusions to be drawn. In addition, he noted, although at one year death rates for angioplasty and bypass surgery were similar, there are hints from longer follow-up in SYNTAX registry patients that over time, survival might come to favor surgery. Some have claimed that choosing bypass surgery over angioplasty comes down to trading the need for repeat procedures for an increased risk of stroke, Dr. Mack observed. But closer inspection of the timing of strokes suffered by bypass patients in SYNTAX shows that most were probably not due to surgery.
Dr. Mack conceded, however, that the evidence for angioplasty deserves a second look and asserted that the SYNTAX score may be the most helpful outcome of the trial. Moreover, he said, the trial served as a model for collaboration between surgeons and interventional cardiologists in evaluating patients and deciding on the most appropriate treatment.
