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Ann Thorac Surg 1999;67:1545-1546
© 1999 The Society of Thoracic Surgeons
a Division of Cardiothoracic Surgery, Medical College of Wisconsin, Milwaukee, Wisconsin, USA
Address reprint requests to Dr Olinger, Division of Cardiothoracic Surgery, Medical College of Wisconsin, 9200 W Wisconsin Ave, Milwaukee, WI 53226
How does the heart surgeon as an informed advisor respond today to the patient who says, "I saw on television that having my valve fixed through a short incision is better. Is that true? What would you advise?" "Minimally invasive," "midCAB," "opCAB"—each term reflects technically innovative alterations of traditional, well-established cardiac operations, developed and practiced by skilled surgeons with widely heralded but arguably substantiated claims of superiority. What is true? What should we advise?
In this issue of the Annals, Aris and colleagues report their prospective randomized evaluation of aortic valve replacement performed through ministernotomy versus traditional median sternotomy [1]. They sought to determine whether these different approaches to the same operation resulted in differences in clinical outcome as assessed by aortic cross-clamp and pump times, mortality, blood loss, pain, pulmonary function, cosmesis, and incidence of atrial fibrillation. Two patients died in each group of 20 patients. The two deaths in the ministernotomy group might have been contributed to by the incision. The authors don’t speculate to this effect even though the ministernotomy was converted to sternotomy in both patients, presumably to facilitate efforts to resolve intraoperative complications that led to mortalities. Differences between groups failed to reach statistical significance for any of the end-points being assessed.
As the authors admit, this study is weakened by relative lack of statistical power. Had there been 100 patients in each arm, superiority of ministernotomy or of median sternotomy might have been proven to statistical satisfaction with respect to end-points examined. In discussion of their presentation of this study, the authors implied that use of the ministernotomy became less attractive to the investigators as the study progressed. In a situation where investigators become disenamored of one arm of a nonblinded study for whatever reason, it is difficult to drive the trial to completion without bias. This is particularly true of and is an irreducible difficulty in systematic evaluation of techniques. Nonetheless, if a clinical study is to have more than anecdotal meaning vis-a-vis its results, it must be designed with appropriate statistical power and carried to fruition. Without more scientific rigor, it is not possible to draw definitive conclusions one way or another about "betterness."
Despite these drawbacks to the contribution of Aris and associates [1], the singular importance of their effort is their commitment to their patients, to their peers, and to the public to ask the question about superiority and to attempt to evaluate it systematically. They responded as have representatives of our specialty responded in the past to internal and external inquisition regarding efficacy of alternative therapies being examined in the public eye. Cardiac surgeons collaborated with cardiologists in the VA Cooperative Trial and the CASS trial to test efficacy of coronary artery bypass versus medical therapy [2, 3], and more recently in the BARI trial to test efficacy of coronary artery bypass versus angioplasty [4]. These prospective randomized studies have had their detractors, but the conclusions of substance have allowed surgeons and cardiologists alike to give patients informed advice and to treat with conviction. Sound data have become the basis for further questions and for further advances.
Surgeons have also been openly critical of our colleagues in cardiology as rapid technical evolutions in catheter-based interventional therapy have eroded our patient base and dug into our pockets. Cardiologists, on the other hand, have completed numerous prospective randomized trials to test the efficacy of various reperfusion strategies, of various angioplastic devices, of advanced platelet inhibition on reperfusion, and early patency with angioplastic revascularization, and to examine many of these variables relative to intermediate rates of restenosis. Based on data from such trials, they now speak and treat with more confidence and with more credibility.
What do we know about our latest technical "wrinkles?" My view is that we don’t know enough to support the claims that are driving a thriving surgical and industrial marketplace. It’s time for prospective randomized trials performed by experienced groups of surgeons with patient volumes adequate to achieve appropriate statistical power to answer questions about minimally invasive direct coronary artery bypass (mid-CAB), off pump coronary artery bypass (opCAB,) and minimal incisions that are relevant in particular to morbidity and to early and late functional results, along with cost and appropriate aspects of patient satisfaction. These trials must utilize contemporaneous controls. Case matching may fail to account for biases inherent in practitioners attempting to prove points that may garner market advantage. Case matching, furthermore, may not employ the same "fast tracking" methodologies that are now commonplace in most cardiac surgical centers and that clearly affect outcome for some end-points claimed to gain advantage through techniques that are minimal.
Appropriate issues to address for midCAB and opCAB include:
Appropriate issues to address for minimal incisional approaches to valve surgery include:
Each of these questions can be addressed without denial of definitive therapy. The diseases being treated are common, and each surgeon should be capable of performing either operative approach in a two-armed study. Patient accrual thereby could be rapid. Prospective randomized trials are feasible in many circumstances without additional expense. Questions about adequacy and safety of revascularization are important enough to warrant additional expense when long-term results could impact on patient well-being for 10 to 15 years or longer. The debate over these issues has been raging in private and is increasingly public with well-respected surgeons speaking eloquently on both sides [5–8]. These examples of persuasive comment go far beyond my remarks in illustrating the multiplicity of questions that remain unanswered.
Borst and Gründeman [8] allude to two randomized trials that have been funded by the Netherlands National Health Insurance Council to evaluate opCAB against conventional CAB and against stenting. Both apparently will include angiographic evaluation at 1 year. The results of these trials will be eagerly awaited. To my knowledge, no such trials have been initiated in the United States, where marketing forces may be having more impact. Such trials are unlikely to be initiated by surgical groups with understandable vested interests in these innovations. Yet the very surgeons who have worked through the learning curves and now support these techniques are the most capable of testing efficacy in a prospective randomized fashion. Is there a potential role for organized thoracic surgery, through its societies, to promote and to assist in organization of such trials?
Perhaps these concerns are irrelevant in the big picture of rapidly advancing technology, little more than the quibbling of surgical curmudgeons. Perhaps our patients’ concerns over the claims referred to are frivolous. I don’t think so. Without informed advice, there is no informed consent, and that is the point of departure for every operative journey.
References
This article has been cited by other articles:
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  B. Murtuza, J. R. Pepper, R. DeL Stanbridge, C. Jones, C. Rao, A. Darzi, and T. Athanasiou Minimal Access Aortic Valve Replacement: Is It Worth It? Ann. Thorac. Surg., March 1, 2008; 85(3): 1121 - 1131. [Abstract] [Full Text] [PDF]
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