Correspondence
Minimally Invasive Bypass Surgery
N Engl J Med 2002; 347:2165-2168December 26, 2002
- Article
To the Editor:
In the clinical trial reported by Diegeler et al. (Aug. 22 issue),1 surgery was much more effective than stenting with regard to the prospectively established end point of a major adverse cardiac event (which occured in 31 percent of the patients in the stenting group vs. 15 percent in the surgery group, P=0.02) and with regard to freedom from angina (79 percent in the surgery group vs. 62 percent in the stenting group, P=0.03). Nonetheless, the authors conclude that “stenting yields excellent short-term results.” Are they referring to a time point earlier than six months? If so, where are the comparative data?
Furthermore, they show no data to support their statement that both surgery and stenting “are effective,” since there were no controls who received no intervention or who received medical therapy alone. The authors turn to other studies2,3 to justify the absence of a nonintervention control group. However, neither these randomized, prospective studies nor a follow-up study4 demonstrated the effectiveness of angioplasty as compared with medical therapy. Surgery was shown to be effective.3,4 Readers may be surprised at the absence of randomized, controlled trials demonstrating the effectiveness of angioplasty or stenting as compared with standard medical therapy.
I hope that the authors of both the article and the accompanying Perspective (MacGillivray and Vlahakes5) will agree that a large, randomized clinical trial comparing stenting with standard medical therapy is long overdue. Are we really improving the health of the American public with the widespread application of highly technological and expensive health care? Are we doing harm? Let us try to find out using the scientific method and fulfilling our commitment to evidence-based medicine.
5 ReferencesFrank W. LoGerfo, M.D.
Beth Israel Deaconess Medical Center, Boston, MA 02215
flogerfo@caregroup.harvard. edu 1
Diegeler A ,Thiele H ,Falk V , et al. Comparison of stenting with minimally invasive bypass surgery for stenosis of the left anterior descending coronary artery. N Engl J Med 2002;347:561-566
Full Text | Web of Science | Medline2
Parisi AF, Folland ED, Hartigan P. A comparison of angioplasty with medical therapy in the treatment of single-vessel coronary artery disease.N Engl J Med 1992;326:10-6.
3
Hueb WA ,Bellotti G ,de Oliveira SA , et al. The Medicine, Angioplasty, or Surgery Study (MASS): a prospective, randomized trial of medical therapy, balloon angioplasty or bypass surgery for single proximal left anterior descending artery stenoses. J Am Coll Cardiol 1995;26:1600-1605
CrossRef | Web of Science | Medline4
Hueb WA ,Soares PR ,Almeida de Oliviera S , et al. Five-year follow-up of the Medicine, Angioplasty, or Surgery Study (MASS): a prospective, randomized trial of medical therapy, balloon angioplasty, or bypass surgery for single proximal left anterior descending coronary artery stenosis. Circulation 1999;100:Suppl II:II-1075
MacGillivray TE ,Vlahakes GJ . Angioplasty versus minimally invasive bypass surgery. N Engl J Med 2002;347:551-552
Full Text | Web of Science | Medline
To the Editor:
Diegeler et al. compared stenting with minimally invasive bypass surgery for stenosis of the left anterior descending coronary artery. Outcome after stenting is strongly affected by the morphology of the lesion1; in short, high-risk (type C) lesions have a significantly higher rate of restenosis than low-risk (type A or B) lesions. Seventy-five percent of the stenting group in the study by Diegeler et al. had a low-risk lesion, whereas 25 percent had a high-risk lesion. In their high-risk group, the authors found a high rate of restenosis (56 percent) after stenting. By contrast, the results of surgery are not affected by the morphology of the lesion, and surgery yields excellent patency rates. Therefore, this study underestimates the benefit of surgery over stenting in high-grade lesions of the left anterior descending coronary artery.
In a comparable study, we also found a significantly better six-month patency rate after surgery as compared with stenting in 102 patients who all had a high-risk lesion in the proximal left anterior descending coronary artery.2 In addition, surgery resulted in a higher rate of three-year survival free of major adverse events than did stenting and in better anginal status at three years.3
We believe that in the proximal left anterior descending coronary artery, low-risk lesions should be treated by means of angioplasty with or without stenting, and high-risk lesions should be treated with surgery. Additional studies are needed to clarify whether recent improvements in stenting (i.e., the use of glycoprotein IIb/IIIa blockers and drug-eluting stents) will change this strategy.
3 ReferencesDerk J. Drenth, M.D.
Nic J.G.M. Veeger, M.Sc.
Piet W. Boonstra, M.D., Ph.D.
University Hospital Groningen, 9700RB Groningen, the Netherlands
p.w. boonstra@thorax. azg. nl 1
Smith SC Jr ,Dove JT ,Jacobs AK , et al. ACC/AHA guidelines for percutaneous coronary intervention (revision of the 1993 PTCA guidelines) -- executive summary: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (Committee to Revise the 1993 Guidelines for Percutaneous Transluminal Coronary Angioplasty) endorsed by the Society for Cardiac Angiography and Intervention. Circulation 2001;103:3019-3041
Web of Science | Medline2
Drenth DJ ,Winter JB ,Veeger NJ , et al. Minimally invasive coronary artery bypass grafting versus percutaneous transluminal coronary angioplasty with stenting in isolated high-grade stenosis of the proximal left anterior descending coronary artery: six months' angiographic and clinical follow-up of a prospective randomized study. J Thorac Cardiovasc Surg 2002;124:130-135
CrossRef | Web of Science | Medline3
Drenth DJ ,Veeger NJGM ,Winter JB , et al. A prospective randomized trial comparing stenting with off-pump coronary surgery for high-grade stenosis in the proximal LAD: 3-years follow-up. J Am Coll Cardiol 2002;40:1955-1960
CrossRef | Web of Science | Medline
To the Editor:
As Diegeler et al. state, the minimally invasive direct coronary-artery bypass procedure is not free of complications. Their article reports that two patients died during follow-up, one while exercising strenuously; in one case, rupture of the left-internal-thoracic-artery graft was observed at autopsy.
Good mobilization of the artery used for grafting is a prerequisite to adequate routing of the graft during this type of surgery for the prevention of excessive tension that may occur at the level of the anastomosis. We have reported on two cases in which the left internal thoracic artery was avulsed from the anastomosis with the left anterior descending coronary artery1,2 after the Valsalva maneuver and chest compressions for cardiopulmonary resuscitation. Our reports, together with that of Diegeler et al., should be added to a long list of anecdotal and unreported cases of arterial avulsion after minimally invasive direct coronary-artery bypass.
We have reconsidered the technique of harvesting the left internal thoracic artery for such bypass operations and have attempted to find alternative ways to achieve adequate thoracic-artery length even in the most difficult cases. In our last series of minimally invasive bypasses, we routinely harvested the left internal thoracic artery endoscopically using a robotically enhanced system. Given that Diegeler et al. are recognized as one of the leading groups in the field of robotic heart surgery, they could apply routine robotic harvesting of the left internal thoracic artery to the traditional minimally invasive bypass. Surgical innovation inevitably carries new sets of challenges. Those who are learning to perform this bypass operation may use robotic technology to harvest the left internal thoracic artery in order to prevent unexpected deadly complications.
2 ReferencesGiuseppe D'Ancona, M.D.
Hratch Karamanoukian, M.D.
Center for Less Invasive and Robotic Heart Surgery, Buffalo, NY 14203
lisbon5@yahoo.com 1
McMahon J ,Bergsland J ,Arani DT ,Salerno TA . Avulsion of the left internal mammary artery after minimally invasive coronary bypass. Ann Thorac Surg 1997;63:843-845
CrossRef | Web of Science | Medline2
Ricci M ,Karamanoukian H ,D'Ancona G ,Bergsland J ,Salerno TA . Avulsion of the left internal mammary artery graft after minimally invasive coronary surgery. Ann Thorac Surg 2001;71:1401-1402
CrossRef | Web of Science | Medline
To the Editor:
Diegeler et al. compared the results of minimally invasive bypass surgery for stenosis of the proximal left anterior descending coronary artery with angioplasty and stenting without the use of glycoprotein IIb/IIIa inhibitors. The authors conclude that the two procedures have similar results and that the surgery has favorable results in cases of complicated lesions. The well-established Evaluation of 7E3 for the Prevention of Ischemic Complications (EPIC)1 and Evaluation in PTCA to Improve Long-Term Outcome with Abciximab GP IIb/IIIa Blockade (EPILOG)2 studies and their derivatives have demonstrated a significant reduction in the incidence of death, acute myocardial infarction, and the need for revascularization at 30 days, 6 months, and 3 years of follow-up with the use of abciximab after angioplasty. The benefits were observed among high-risk as well as low-risk patients. Ellis et al.3 demonstrated an absolute reduction of risk in patients with more complex lesions (type B2 or C) than in patients with morphologically simple lesions (type A or B1) after the use of abciximab. In my opinion, with such evidence supporting the administration of platelet glycoprotein IIb/IIIa inhibitors, the use of these agents should be mandatory in the context of this type of trial, and their absence could bias the results in favor of the surgical procedure.
3 ReferencesRobert E. Dragu, M.D.
Rambam Medical Center, Haifa 31096, Israel
r_dragu@rambam.health. gov. il 1
The EPIC Investigators
Full Text | Web of Science | Medline2
The EPILOG Investigators
Full Text | Web of Science | Medline3
Ellis SG ,Lincoff AM ,Miller D , et al. Reduction in complications of angioplasty with abciximab occurs largely independently of baseline lesion morphology. J Am Coll Cardiol 1998;32:1619-1623
CrossRef | Web of Science | Medline
To the Editor:
The Perspective by MacGillivray and Vlahakes presents a very conservative view of the issue and (appropriately) warns that the outcomes of all less invasive procedures must be judged against the “gold standard” of conventional coronary-artery bypass grafting with cardiopulmonary bypass. MacGillivray and Vlahakes err, however, in stating that no prospective, randomized comparisons of conventional coronary-artery bypass grafting and “off-pump” coronary-artery bypass grafting have been performed. Indeed, three such studies have been conducted and reported.
The first two, in England1 and the Netherlands,2 randomized patients selected for absence of disease in the left circumflex artery, since such disease presents greater technical difficulty for off-pump bypass. The third, conducted at Emory University,3 randomized all comers; the patients were entirely unselected according to coronary anatomy. Only those who had emergency cases or who declined randomization were excluded. All three studies found remarkably similar results. In terms of all end points measured, the results with off-pump bypass were either equal or superior to those obtained with conventional coronary-artery bypass grafting with cardiopulmonary bypass. Indeed, the off-pump procedure showed striking benefits in terms of reduced release of myocardial enzymes, reduced duration of intubation, reduced length of stay, reduced rates of transfusion, and reduced cost. In end points that occur infrequently (death, myocardial infarction, and stroke), no significant differences were found between groups in any of the studies, because they had limited statistical power. In some of these infrequent end points, however, there were trends in favor of off-pump bypass. Unique to the Emory study was the inclusion of cardiac catheterization to document similar completeness of revascularization and postoperative graft patency in both groups.
Taken together, these three randomized studies demonstrate the safety and efficacy of off-pump coronary-artery bypass grafting, when it is performed by an experienced physician. Moreover, they demonstrate that there are significant benefits to patients from the application of this technique.
3 ReferencesWilliam C. Wood, M.D.
Emory University School of Medicine, Atlanta, GA 303221
Angelini GD ,Taylor FC ,Reeves BC ,Ascione R . Early and midterm outcome after off-pump and on-pump surgery in Beating Heart Against Cardioplegic Arrest Studies (BHACAS 1 and 2): a pooled analysis of two randomised controlled trials. Lancet 2002;359:1194-1199
CrossRef | Web of Science | Medline2
van Dijk D ,Nierich AP ,Jansen EWL , et al. Early outcome after off-pump versus on-pump coronary bypass surgery: results from a randomized study. Circulation 2001;104:1761-1766
CrossRef | Web of Science | Medline3
Puskas JD, Williams WH, Duke PG, et al. Off-pump coronary artery bypass grafting (OPCAB) provides complete revascularization while reducing myocardial injury, transfusion requirements and length of stay (LOS): a prospective randomized comparison of 200 unselected patients having OPCAB versus conventional CABG. J Thorac Cardiovasc Surg (in press).
Author/Editor Response
The authors reply:
To the Editor: We agree with LoGerfo that our study showed only data on the effectiveness of either stenting, with excellent short-term results and low periprocedural complications, or surgery with reduction of angina. We had no control group that did not have an intervention. Indeed, it would be desirable to perform a large, randomized clinical trial comparing medical therapy with interventional or surgical approaches involving state-of-the-art techniques, since there are only a few reports with rather small numbers of patients.1,2 However, it might be difficult to persuade patients with severe angina pectoris to continue to receive medical treatment alone. In addition, lesions in the proximal left anterior descending artery are associated with a significantly worse prognosis than lesions at any other location, which might also limit the ability of researchers to perform such a randomized study.3
In our study, the morphology of the lesion was a strong predictor of restenosis after stenting. Contrary to the statement of Drenth et al., more than 80 percent of our study patients had a lesion with a high risk of restenosis if their definition of “high risk” is applied (a type B or C lesion). Thus, the study populations and restenosis rates after stenting were quite similar in their study and ours, although they did not report the rates of restenosis after stenting according to the morphology of the lesion.4 We disagree with the strategy of stratifying the randomization of patients to surgery or stenting according to the morphology of the lesion. In the light of a mortality rate of 4 percent after minimally invasive bypass surgery, as reported by Drenth et al., a strategy based solely on the morphologic appearance of the target vessel cannot be justified. Additional variables must be taken into account, such as the size of the vessel, the age of the patient, left ventricular function, and coexisting diseases. In this context, additional procedures such as the administration of platelet IIb/IIIa inhibitors in patients undergoing stenting or adequate harvesting of the left internal thoracic artery,5 which can be performed well with a robotically enhanced system, should be used to improve outcome.
5 ReferencesHolger Thiele, M.D.
Friedrich W. Mohr, M.D.
Gerhard Schuler, M.D.
University of Leipzig Heart Center, 04289 Leipzig, Germany
schug@medizin.uni-leipzig. de 1
Hueb WA ,Bellotti G ,de Oliveira SA , et al. The Medicine, Angioplasty, or Surgery Study (MASS): a prospective, randomized trial of medical therapy, balloon angioplasty or bypass surgery for single proximal left anterior descending artery stenoses. J Am Coll Cardiol 1995;26:1600-1605
CrossRef | Web of Science | Medline2
Parisi AF, Folland ED, Hartigan P. A comparison of angioplasty with medical therapy in the treatment of single-vessel coronary artery disease.N Engl J Med 1992;326:10-6.
3
Califf RM ,Tomabechi Y ,Lee KL , et al. Outcome in one-vessel coronary artery disease. Circulation 1983;67:283-290
CrossRef | Web of Science | Medline4
Drenth DJ ,Winter JB ,Veeger NJ , et al. Minimally invasive coronary artery bypass grafting versus percutaneous transluminal coronary angioplasty with stenting in isolated high-grade stenosis of the proximal left anterior descending coronary artery: six months' angiographic and clinical follow-up of a prospective randomized study. J Thorac Cardiovasc Surg 2002;124:130-135
CrossRef | Web of Science | Medline5
Mohr FW ,Falk V ,Diegeler A , et al. Computer-enhanced “robotic“ cardiac surgery: experience in 148 patients. J Thorac Cardiovasc Surg 2001;121:842-853
CrossRef | Web of Science | Medline
Author/Editor Response
The intended message of our Perspective was that all methods of myocardial revascularization should be critically analyzed not only for technical feasibility and periprocedural safety, but also for long-term graft patency and survival benefit to patients. The initial contention (and hope) was that avoidance of cardiopulmonary bypass would decrease the risks associated with coronary surgery. Centers have reported the safe performance of off-pump coronary-artery bypass grafting of multiple vessels; in-hospital angiographic patency rates have been similar in trials of conventional coronary-artery bypass grafting and off-pump coronary-artery bypass grafting. However, no clinical trial examining long-term graft patency and patient survival has been published. Although the Emory group is examining one-year angiographic follow-up, the results have not yet been reported. The published trials, including those cited by Dr. Wood, do not demonstrate any significant difference (let alone superiority) in mortality, rate of stroke, or rate of end-organ dysfunction between conventional coronary-artery bypass grafting and off-pump coronary-artery bypass grafting; these are the major issues of concern for those of us who treat patients with coronary artery disease. For patients undergoing coronary-artery bypass, decreased time to extubation, length of stay in the intensive care unit, and length of hospital stay are interesting findings that vary not only among institutions, but also within institutions over time; changes in these variables alone do not constitute dramatic improvements.
Regardless of our impressions and contentions, the analysis of myocardial-revascularization techniques should include critical assessment of the risks and benefits to patients in the short term and the long term. As Sir Peter Medawar once stated, “the intensity of the conviction that a hypothesis is true has no bearing on whether it is true or not.”
Thomas E. MacGillivray, M.D.
Gus J. Vlahakes, M.D.
Massachusetts General Hospital, Boston, MA 02114
