J Thorac Cardiovasc Surg 2004;127:301
© 2004 The American Association for Thoracic Surgery
Reply to the editor
John D. Puskas, MD
Associate Professor of Surgery (Cardiothoracic), Emory University, Crawford Long Hospital, Atlanta, GA 30308, USA
Drs Ascione and Angelini have written to emphasize the contributions they have previously made in conducting and reporting randomized clinical trials of off-pump coronary artery bypass grafting (CABG) versus CABG with cardiopulmonary bypass (CPB). Indeed, these authors and their coworkers have made numerous contributions to our understanding of patient outcomes with these two surgical techniques. Among their contributions is a series of publications reporting various outcome variables from two groups of selected patients randomized to undergo OPCAB or conventional CABG/CPB. As they have noted in their own letter to the Editor, the first of these groups of patients was selected to exclude those requiring grafts to the distal branches of the left circumflex artery, whereas the second group was selected to exclude patients with previous stroke and renal failure, as these were considered potentially confounding variables. Both studies reported important advantages of OPCAB over conventional CABG/CPB and were landmark publications. Neither rigorously documented the completeness of revascularization. Indeed, BHACAS 2 reported that 70% of CPB patients versus 56% of OPCAB patients had 3 grafts or more; this difference (the manuscript does not state whether this was a statistically significant difference) was especially noted in grafts to the lateral wall of the left ventricle. The mean number of grafts per patient in each group was not reported.1
In the SMART trial,2 my coauthors (to each of whom I am grateful) and I sought to demonstrate that OPCAB could be safely applied to the general population of patients referred for elective surgical coronary revascularization and that an equivalently optimal revascularization could be achieved in both groups. Patients were not excluded on the basis of any coronary anatomy, ventricular dysfunction, or comorbidities, including prior stroke or renal failure. Indeed we believed it important to randomize "all comers," and we did so. Thus, this trial compared outcomes among truly unselected patients referred for nonemergency CABG. (Among the numerous demographic variables tracked, incidence of prior stroke was regrettably different between the randomized groups. This is a simple function of sample size.) We believed it important to document the optimal revascularization that should be performed for each patient before randomization. The grafts actually performed were then compared with those intended, creating a formal index of completeness of revascularization (ICOR), which was found to be virtually identical between groups. The ICOR was also similar between groups for the lateral wall of the left ventricle, documenting that OPCAB with modern stabilizing devices could provide complete revascularization of all areas of the heart in unselected patients. Other end points, including serum levels of myocardial enzymes, transfusion requirement, and length of stay, strongly favored the OPCAB group, consistent with the findings of previous randomized trials in selected patients.
We look forward to reporting angiographic graft patency and longer term outcomes from these randomized cohorts as those data become available, building on the important foundation that Drs Ascione, Angelini,1 Van Dijk,3 Diegeler,4 Czerny,5 Zamvar,6 and others have laid.
"I prefer nothing more than that I should be true to myself and they to themselves."
—Julius Caesar, letter to Cicero, quoted in Cicero, Letters to Atticus, 9.16.2.
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References
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- 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 (CHACAS 1 and 2): a pooled analysis of two randomized controlled trials. Lancet. 2002;359:1194–1199
- Puskas JD, Williams WH, Duke PG, Staples JR, Glas KE, Marshall JJ, et al. Off-pump coronary artery bypass grafting provides complete revascularization with reduced myocardial injury, transfusion requirements, and length of stay: a prospective randomized comparison of two hundred unselected patients undergoing off-pump versus conventional coronary artery bypass grafting. J Thorac Cardiovasc Surg. 2003;125:797–808
- Van Dijk D, Nierich AP, Jansen EWL, Nathoe HM, Suyker WJ, Diephuis JC, et al. Early outcome after off-pump versus on-pump coronary bypass surgery: results from a randomized study. Circulation. 2001;104:1761–1766
- Diegeler A, Hirsch R, Schneider F, Schilling LO, Falk V, Rauch T, et al. Neuromonitoring and neurocognitive outcome in off-pump versus conventional coronary bypass operation. Ann Thorac Surg. 2000;69:1162–1166
- Czerny M, Baumer H, Kilo J, Zuckermann A, Grubhofer G, Chevtchik O, et al. Complete revascularization in coronary artery bypass grafting with and without cardiopulmonary bypass. Ann Thorac Surg. 2001;71:165–169
- Zamvar V, Williams D, Hall J, Payne N, Cann C, Young K, et al. Assessment of neurocognitive impairment after off-pump and on-pump techniques for coronary artery bypass graft surgery: prospective randomized controlled trial. BMJ. 2002;325:1268–1271
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