Surgery or stent? Gap is narrowing

September 26, 2002

London UK - The results of the Surgery or Stent trial appearing in this week's issue of the Lancet show that bypass surgery provides more complete revascularization and a lower rate of repeat revascularization compared with stent-assisted angioplasty in patients with multivessel disease[1]. However, the advent of the drug-eluting stent is going to strengthen the case for angioplasty as an alternative to bypass surgery for such patients, experts say.

One-year results from the Surgery or Stent trial (SoS) were first reported at the ACC meeting in Orlando in 2001. The study was designed to compare CABG surgery with stent-assisted angioplasty in more than 900 patients with multivessel disease deemed suitable for revascularization by either strategy, and the full 2-year data are published this week. Of patients undergoing angioplasty, 21% (n=101) required repeat revascularizationthe primary end pointcompared with just 6% (n=30) in the CABG group after 2 years (hazard ratio 3.85; p<0.0001). The incidence of death or Q-wave myocardial infarctionboth secondary outcomeswas similar in both groups, but all-cause mortality was lower in the CABG group, at just 2% compared with 5% in the stent-assisted angioplasty patients.

"The use of coronary stents has reduced the need for repeat revascularization when compared with previous studies that use balloon angioplasty, though the rate remains significantly higher than in patents managed with CABG," the SoS authors say.

Three major randomized trials of surgery vs angioplasty with stent implantation have been conductedSoS, ARTS, and ERACI IIand the results at long-term follow-up have been consistent in terms of the rates of repeat revascularizations and in the percentage of patients having complete revascularization (for example, 50% in the angioplasty arm in 1 of the trials, ERACI II, compared with 85% among the CABG patients).

Restenosis is only part of the equation

But interventional cardiology is a fast-moving field, and since SoS and the other 2 studies were conducted there have been major advancesnot least the introduction of the drug-eluting stent as well as much greater use of GP IIb/IIIa inhibitors during angioplasty procedures.

The SIRIUS trial with the sirolimus-eluting stent and TAXUS II with the paclitaxel-eluting stent, reported at the TCT meeting this week, have impressed, with many observers saying the findings are revolutionary and will undoubtedly change the practice of interventional cardiology. As reported by heartwire , the SIRIUS investigators showed a 91% reduction of in-stent restenosis with the use of a sirolimus-eluting stent compared with bare metal stents; restenosis was reduced from 35.4% to 3.2% in a population that the researchers point out was purposely enriched with those patients most prone to restenosis, including 40% of patients who had multivessel disease.

However, one of the principal investigators of SoS, Dr Rod Stables (Cardiothoracic Center, Liverpool, UK), pointed out to heartwire that, "there's more to it than restenosis." Drug-eluting stents are "an excellent solution to restenosis," he says, but angioplasty plus a stent "does not always result in complete revascularization, and drug-eluting stents do not address this problem. Even before restenosis has a chance to be a factor, surgery is already ahead," he commented.

 
Even before restenosis has a chance to be a factor, surgery is already ahead.
 
Surgery preferred for complex anatomy

And in an editorial in the Lancet accompanying the SoS paper[2], Drs William W O'Neill and Cindy Grines (William Beaumont Hospital, Royal Oak, MI) agree: "Surgical treatment still results in more complete revascularization, [and] surgery is likely to remain as the preferred choice for complex anatomical subsets."

Stables says the question of whether to perform angioplasty or surgery on a patient with multivessel disease can be illustrated by imagining 2 overlapping circles, 1 of which represents the patients in whom it is obvious that angioplasty is the best route to take and the other which represents the evident surgical candidates. The overlap between the 2 is the gray area, patients in whom it is debatable as to which strategy will be the best, he says. He said that, on a personal level, he usually has no problem reaching agreement with the surgeons as to which is the most appropriate strategy, but this is not always the case.

 
Surgery is likely to remain as the preferred choice for complex anatomical subsets.
 

One of the subgroups in whom there will be much debate is diabetics. Previously, it was thought that surgery was by far the best option for this group of patients, who make up 40% to 50% of those currently having bypass operations. But now the SIRIUS results have shown that repeat revascularizations were reduced from around 50% with bare stents to 18% with the eluting stent. SoS has a diabetes subgroup that has not yet reported, but Stables would not reveal any of these data to heartwire . What will no doubt be required to provide a definitive answer to this question is a randomized study comparing angioplasty using drug-eluting stents with CABG in diabetes patients.

Drug-eluting stents hold promise

Despite the obvious benefits of surgery seen to date in the randomized trials, there is a consensus that the goal posts are moving. O'Neill and Grines say in their editorial: "The improving safety and durability of angioplasty will mean that the gap in choices between the 2 approaches will continue to narrow." The safety of percutaneous intervention in multivessel revascularization "is established," they note, and "in-hospital mortality is 1% or less for elective procedures. In addition, the risk of need for emergency bypass has been nearly eliminated, [and] mortality at 1-to-2 year follow-up also appears to be low."

 
The gap in choices between the 2 approaches will continue to narrow.
 

And the SoS authors themselves agree that "PCI, and to a lesser extent, coronary surgery, are rapidly evolving specialties." SoS investigators reported only limited use of GP IIb/IIIa antiplatelet agents, and further advantage might be gained with the more long-term use of clopidogrel, they note. And "the development and more widespread application of a drug-eluting stent holds the promise of a significant reduction in restenosis and revascularization rates."

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