Stents May Be Better After One Year, But One Year Is Not Lifelong
To the Editor:
I read with great interest the article titled “Randomized comparison between stenting and off-pump bypass surgery in patients referred for angioplasty.”1 I congratulate Eefting and associates on publishing first-ever randomized comparison of stenting and off-pump coronary artery surgery.
The clinical effectiveness of the percutaneous revascularization techniques combined with the considerable morbidity associated with conventional coronary artery bypass grafting (CABG) provided the impetus for exploring alternative approaches to surgical revascularization. Two such approaches are coronary stenting and off-pump CABG (OPCAB). The clinical goals of these approaches are interrelated and include the following (in order of importance): (1) achieving graft patency rates equal or superior to those of conventional CABG (avoid repeated revascularization), (2) decreasing incisional pain and discomfort (reduce invasiveness), (3) facilitating a more rapid return to normal activity levels (reduce invasiveness), (4) reducing the length of hospital stay (decrease complications), and (5) decreasing cost. Despite tremendous enthusiasm on the part of surgeons and interventional cardiologists, patients, industry, and the media, widespread adoption will not occur until stenting and OPCAB are validated through the explicit and conscientious assessment of current best evidence.
The study of Eefting et al1 concludes that stenting rather than off-pump surgery, can be recommended as a first-choice revascularization strategy in selected patients because at 1 year, stenting was more cost-effective than off-pump surgery while maintaining comparable cardiac outcome and quality of life. In an era in which the future of coronary artery surgery is threatened by the emergence of drug-eluting stents, the conclusion of this study has definitely added to the existing euphoria that stents spell the beginning of the end for coronary artery surgery. However, what is more important are the limitations of this study. Eefting and colleagues1 themselves admit that the point estimates of the (cost) effectiveness may lack precision because of sample size, risk profile of the population, number of events, and duration of follow-up. Also, the open design may have affected the assessment of outcome, such as revascularization, angina, and quality of life. In addition, despite the computerized randomization procedure, subtle differences between the populations cannot be ruled out. With respect to the population, patients with in-stent restenosis were excluded because of the potentially refractory nature of this disorder, for which stent reimplantation was not considered an appropriate therapy. Moreover, circumflex disease is no longer a contraindication for OPCAB.2–5
My humble message to the authors as well as readers of this article is that, although this was a randomized control trial and the conclusions sound very attractive, one year is not lifelong, especially when the problem of in-stent restenosis stands unsolved.
We are not concerned that the Octostent Study spells the beginning of the end of coronary surgery. That study concerns a randomized comparison in which 280 patients referred for angioplasty with a low risk were enrolled. The pitfalls of the translation of such a study to daily practice are well known. The limitations specific for the Octostent Study have been discussed and are summarized by Dr Raja.
The follow-up period was, indeed, 1 year. During further follow-up, more repeat revascularizations in stented patients are conceivable and may ultimately favor bypass surgery. The long-term follow-up of the Benestent 1 Study, however, disclosed that the original benefit of stenting remained unchanged at 5 years, and the survival curves reveal that most of the events occur within the first year after the procedure.1 Kimura et al2 found that after the first 14 months, freedom from repeat intervention of the target lesion reached a plateau at 85% to 81% over 1 to 8 years with a sustained clinical benefit up to 11 years.
We did not use a drug-eluting stent. An impressive further reduction in repeat revascularization and improvement in event-free survival in comparison to the bare metal stent have been documented in a broad spectrum of patients.3 Randomized comparisons between drug-eluting stents and coronary surgery are under way. One may reasonably expect a similar or identical event-free survival after surgery and angioplasty.
Surgical techniques are evolving as well. However, they will remain much more invasive and less patient friendly than catheter-based revascularization. Despite the outstanding long-term clinical results when using arterial grafts, complete arterial revascularization is a technical dream but not yet a reality.4 Most grafts are still venous in type, and their fate is well known.5 Also, the patency of both the arterial and venous grafts may be inferior when using novel surgical techniques.5
We, therefore, believe that the future of coronary revascularization will be dominated by the catheter-based approach. In this respect, we concur with Dr Raja’s thoughts. A joint venture of the surgeon with the interventional cardiologist most likely will occur. We are currently evaluating a novel anastomosis technique in the porcine model for which stent technology was essential in its development. The concept is to implant the mammary artery on the left anterior descending artery by a combined limited surgical and catheter-based approach.