HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): George Palmer Syma L. Prince Mitchell J. Magee Phillip Brown Marc Katz Michael J. Mack Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Palmer, G. Articles by Mack, M. J. Search for Related Content PubMed PubMed Citation Articles by Palmer, G. Articles by Mack, M. J. Related Collections Coronary disease

Ann Thorac Surg 2007;83:986-992
© 2007 The Society of Thoracic Surgeons

---

Original Articles: Cardiovascular

Coronary Artery Revascularization (CARE) Registry: An Observational Study of On-Pump and Off-Pump Coronary Artery Revascularization

^a Central Florida Regional Hospital, Sanford, Florida
^b Medical City Dallas Hospital, Dallas, Texas
^c HCA Cardiovascular Care Management Network, Nashville, Tennessee
^d Cardiopulmonary Research Science and Technology Institute, Dallas, Texas

Accepted for publication October 23, 2006.

^_* Address correspondence to Syma L. Prince, RN, Cardiopulmonary Research Science and Technology Institute (CRSTI), 7777 Forest Lane, Ste C-742, Dallas, TX 75230 (Email: sprince{at}crsti.org).

Presented at the Fifty-second Annual Meeting of the Southern Thoracic Surgical Association, Orlando, FL, Nov 10–12, 2005.

Dr Mack discloses that he has a financial relationship with Boston Scientific.

 

	Abstract

Top Abstract Introduction Patients and Methods Results Comment Appendix 1 Appendix 2 Discussion Acknowledgments References

 
Background: The Coronary Artery Revascularization (CARE) study is a multicenter observational registry of coronary revascularization by percutaneous and surgical techniques. As a substudy of this registry, we analyzed the current practice and outcomes of on-pump and off-pump coronary artery bypass graft (CABG) surgery.

Methods: Procedural and outcomes data were prospectively collected for all patients undergoing isolated CABG in eight community-based hospitals in the HCA Hospital System between February 1 and July 31, 2004. Twelve-month follow-up was obtained by patient contact, phone, questionnaire, and the National Death Index.

Results: Isolated coronary artery revascularization procedures were done in 1251 patients, with 12-month follow-up data available on 1149 (91.8%); 654 patients (52.3%) were operated on-pump and 597 (47.7%) had off-pump procedures. On-pump versus off-pump results were mean number of grafts, 3.4 ± 1 versus 2.9 ± 1.2 (p < 0.001); operative mortality, 1.7% versus 1.7% (p = 1.00); permanent stroke, 0.9% versus 0.7% (p = 0.51); reoperation for bleeding, 2.6% versus 1.0% (p = 0.037); prolonged ventilation, 10.0% versus 3.4% (p < 0.001); atrial fibrillation, 23.8% versus 14.9% (p < 0.001); need for transfusion, 51.0% versus 34.9% (p < 0.001); intensive care unit length of stay, 68.1 ± 97.0 hours versus 59.3 ± 109.4 hours (p = 0.16); and hospital length of stay, 7.5 days versus 6.2 days (p < 0.001). At 12 months, there was no difference in total cardiac mortality on-pump versus off-pump (4.9% versus 4.6%, p = 0.88), myocardial infarction (1.0% versus 0.7%, p = 0.76), need for repeat revascularization (2.8% versus 4.1%, p = 0.70), or total overall major adverse cardiac outcomes (8.7 versus 9.4, p = 0.69).

Conclusions: Current approaches to coronary revascularization using both on-pump and off-pump techniques at individual surgeon discretion, which varies significantly in the community setting, leads to acceptable outcomes. Although perioperative complications were less off-pump, mortality was the same, both in the perioperative period and at 12 months. Fewer grafts in the off-pump group appeared to be related to disease burden and not incomplete revascularization. Cardiac death, myocardial infarction, and the need for repeat revascularization were equal at 12 months.

Conventional coronary artery bypass (CCAB) grafting (CABG) has been shown to prolong life and reduce symptoms compared with medical management; however, these benefits are somewhat tempered by the procedural risks, including mortality and significant morbidity. Consequently, off-pump coronary artery bypass (OPCAB) grafting was introduced in the interest of finding safer alternatives. Off-pump surgery avoids some of the major side effects of CCAB [1–8], but concerns have been raised about inadequate revascularization [9] and graft patency [10]. OPCAB and CCAB have now been compared in 37 randomized controlled trials. Two meta-analyses of these trials have also been published, without clear consensus [11–12]; similarly, a recent "consensus" statement from the American Heart Association shows little consensus [13].

The Coronary Artery Revascularization (CARE) study is an observational study of coronary artery bypass and percutaneous coronary intervention (PCI) with the intent to analyze current practice usage and outcomes with both techniques. This study analyzes only the coronary artery bypass arm of the study, defining current practice in the community-based hospitals of the use and outcomes of OPCAB and CCAB surgery.

	Patients and Methods

Top Abstract Introduction Patients and Methods Results Comment Appendix 1 Appendix 2 Discussion Acknowledgments References

 
All patients in eight participating institutions undergoing isolated CABG during a 6-month period from February 1, 2004, through July 31, 2004, were entered into the study for a total of 1251 CAB patients (Appendix 1). The study was conducted in eight non-academic community hospitals in the HCA Hospital System. HCA, Inc (Nashville, TN) is a for-profit hospital company with mainly community-based hospitals in the southern, southeastern, and western United States. All study centers were part of the HCA Cardiovascular Care Management Network, which is a hospital system-wide network to introduce best practices and care pathways to all hospitals within the company. All surgeons in the study centers had received training in and had significant experience in both CCAB and OPCAB. Data were collected prospectively before, during, and after surgery and at 6 and 12 months. The study was observational only, and the choice of operation was at the individual surgeon’s discretion.

The Institutional Review Board of each participating center approved the study as exempt. The database was a customized version extracted from the Society of Thoracic Surgeons (STS) National Adult Cardiac Database (NCD). All definitions were standard STS definitions and are listed in Appendix 2. After on-site data collection, the forms were submitted to a central coordinating center where the data were stored and analyzed.

Longitudinal follow-up was obtained by the study center coordinators who contacted the patients at 6 and 12 months by telephone or mail questionnaire. The clinical outcomes captured included major adverse cardiac events, death, death from cardiac cause, myocardial infarction, and the need for repeat revascularization. Follow-up data forms were submitted to the central coordinating center where they were reviewed and stored in a customized database. In centers where follow-up data collection was problematic, the coordinating center assisted from a central site with obtaining follow-up data.

Statistical Analysis
The data were exported from the database and analyzed with SAS 9.1.3 (SAS Institute, Cary, NC). Continuous variables were compared using t tests. Categoric variables were analyzed using the ² test or the Fisher exact when the number of expected responses in a cell was small.

	Results

Top Abstract Introduction Patients and Methods Results Comment Appendix 1 Appendix 2 Discussion Acknowledgments References

 
The study enrolled 1251 patients undergoing isolated CABG surgery, of which 654 (52.3%) were performed on-pump and 597(47.7%) were off-pump. The use of off-pump techniques varied widely between hospitals (Table 1). Twenty-three patients (3.9%) were converted intraoperatively from off-pump to on-pump and were analyzed on an intention-to-treat basis with the off-pump cohort. Patient demographics, operative status, and risk factors are presented in Table 2. The group that underwent on-pump procedures was at higher risk, with a slightly lower ejection fraction, more frequently having an urgent or emergent operative status, a myocardial infarction within the preceding 7 days, or a previous PCI or CABG procedure.

View larger version (21K): [in this window] [in a new window]   Fig 1. Distribution of coronary artery disease. (One-vessel disease = gray fill; two-vessel disease, white fill; three-vessel disease, black fill.)

Multiple attempts were made to contact all patients at 6 and 12 months postoperatively. Follow-up data were available at 12-months on 1149 (91.8%) of 1251 of the patients. Overall, early, and 12-month adverse cardiac outcomes are summarized in Table 5.

	Comment

Top Abstract Introduction Patients and Methods Results Comment Appendix 1 Appendix 2 Discussion Acknowledgments References

Conclusions from these randomized trials and the meta-analyses demonstrate that OPCAB is a safe alternative to CCAB with respect to mortality, and that with the appropriate use of modern stabilizers, heart positioning devices, and adequate surgeon experience, similar completeness of revascularization and graft patency can be achieved. In addition, OPCAB has been demonstrated to reduce the duration of ventilation and intensive care unit and hospital stay, has reduced resource use, and may minimize mid-term cognitive dysfunction. Further evidence suggests that OPCAB use in high-risk patients significantly reduces perioperative mortality and morbidity. There is also evidence that the two techniques are equivalent in postoperative quality of life for the patients.

The question of superiority of one surgical technique versus the other has not been clearly answered at the highest levels of evidence. It continues to be passionately argued in the medical literature, at major meetings, and in the lay press. We concluded that analysis of real-world outcomes in the community hospital setting by experienced off-pump surgeons would increase the body of evidence on current practice outcomes and the role of each technique.

Although no difference was found between CCAB and OPCAB for operative mortality (1.7% versus 1.7%), the overall operative mortality of 1.7% is significantly less than the STS-NCD mortality of 2.3% in 2004. In addition, all major complications, including reoperation for bleeding, permanent stroke, need for prolonged ventilation, and postoperative atrial fibrillation were less than the comparable outcomes in the STS-NCD.

In this study, overall off-pump surgery was used approximately half the time for isolated CABG, but there was a significant inter-hospital variation in use of off-pump techniques. Despite the evidence mentioned previously and the network in which these surgeons worked, there was still a wide disparity in the use of off-pump techniques. Depending on each surgeon’s individual selection criteria, this approach to all comers generally yielded excellent results. No overall direct correlation could be made between the penetrance of off-pump techniques and early or 1-year outcomes.

Significant concern has been raised about the consistent finding in multiple studies that fewer grafts are performed off-pump compared with on-pump. It is has not been clearly determined whether this is due to selection bias towards patients needing fewer bypasses being performed in the off-pump group versus incomplete revascularization by OPCAB. We have analyzed this issue multiple ways. Significantly fewer grafts were performed in the off-pump group in this study (2.9 versus 3.2), primarily the result of fewer vein graft anastomoses in the off-pump group. However, data from the preoperative angiograms show that the ratio of anastomoses performed to lesions present was the same in both the CCAB and OPCAB groups, indicating that the difference in the numbers of grafts was a patient selection issue, not incomplete revascularization. In addition, the 12-month results showing equal outcomes for death, myocardial infarction, or need for repeat revascularization mitigate against either quality of performance of grafts off-pump or incomplete revascularization being an issue leading to adverse outcomes.

A number of conclusions can be reached from this study. In the community hospital setting, current use of off-pump and on-pump CABG yields excellent outcomes in both groups. With experienced surgeons, approximately 50% of procedures are routinely performed off-pump. Early complications are clearly less in the off-pump group, including reoperation for bleeding, renal failure, ventilation time, atrial fibrillation, and resource utilization, but this may be partly due to a less sick cohort of patients being operated on off-pump. Mortality was equivalent in both the perioperative period and at 12 months postoperatively. At 12 months there was no significant difference in any clinical outcome between on-pump and off-pump CABG. Despite fewer grafts in the off-pump group, cardiac death, myocardial infarction, and need for repeat revascularization were equal at 12 months. An integrated approach to coronary revascularization using both on-pump and off-pump techniques at the individual surgeon’s discretion in the community setting leads to superior outcomes.

A limitation of the study was the inability to obtain clinical follow-up on 8.2% of the patients. This was primarily due to the mobile population in the south and southeastern United States. We do not believe that this significantly impacts the findings of the study because we used the National Death Index and the number lost to follow-up was equal in both groups.

The study is ongoing and we will continue to analyze outcomes on an annual basis.

	Appendix 1

Top Abstract Introduction Patients and Methods Results Comment Appendix 1 Appendix 2 Discussion Acknowledgments References

 

	Appendix 2

Top Abstract Introduction Patients and Methods Results Comment Appendix 1 Appendix 2 Discussion Acknowledgments References

	Discussion

Top Abstract Introduction Patients and Methods Results Comment Appendix 1 Appendix 2 Discussion Acknowledgments References

DR PALMER: Two questions. The basic hypothesis was that we believed there probably would not be a difference. Our initial thought was that the mortality might be different; however, that did not bear out. Your second question in terms of routine either CT angiography or routine angiography was not done unless clinically indicated.

DR JOHN D. PUSKAS (Atlanta, GA): Irv, I rise to kind of address your comments as much as our presenter’s. Your conversation with him a moment ago suggested in a sense that you interpreted this as a negative study, that there was "no difference." I think that is not an accurate or a fair characterization of the results. The results show an important benefit of off-pump coronary bypass surgery, including a variety of end points that patients and referring doctors care about. Given a choice, if you are told as a patient that you can have operation A or operation B that have an equivalent mortality at 30 days and at 1 year, but one will increase your risk of transfusion, a long time with a plastic tube in your mouth, renal failure, hospital length of stay, or atrial fibrillation, and the other will be less risky for all those events, there will be a very short line of people signing up for operation A and a long line of people signing up for operation B. So this is not a negative trial. It is, however, underpowered to be a positive trial for the end point that you are discussing, namely, mortality.

So my question to the presenter, Dr Palmer. Did you do a power analysis to determine what N you would have needed to demonstrate a statistically significant difference in mortality between those two groups? If you had continued your trend of mortality in the off-pump group of 1.7%, in the on-pump group of 2.1%, what N would you need to have achieved a p value of .05 or less? I would submit to you it is a positive trial. If you do it for 2 more years, you will have a significant difference between groups in that end point that you were discussing, Irv, mortality.

DR PALMER: Thank you for your question, Dr Puskas. The power analysis may have been done. I am not aware of it. I do not know the exact number required to make that difference significant at this point.

DR ROBERT S. POSTON (Baltimore, MD): The second conclusion you had there I think is one of the most interesting that I got out of the study, that you could possibly get away with less grafts after off-pump and still have the same outcome. There is an ongoing VA study looking at on- versus off-pump CABG that is specifically trying to answer that question by comparing the number of planned grafts versus the number of grafts that were actually performed to try to get at that question about incomplete revascularization. Did you have any protocol for looking at that? Do you have any idea if there were grafts that you just couldn’t do, or was this a group of patients that just had less targets and that is why they went for off-pump compared to on-pump?

DR PALMER: We did not particularly address that issue. It was left to the discretion of the operating surgeon. There are many things we did not control for. We did not control for clamped versus unclamped surgery in the OPCAB arena; we did not control anticoagulation or level thereof in the OPCAB arena; we didn’t control for type of exposure used or technique of exposure used. We allowed the surgeon to use the best that he could do and using his usual intraoperative, pre-op, and postoperative protocols to achieve what he thought would be the best results.

DR PUSKAS: I think it is important to note that you did not randomize, which is a real-world reality. We don’t generally randomize in the real world, and so these patients were selected or assigned to off-pump or on-pump based on surgeon preference, and each surgeon looked at each patient and tried to do the best thing he could for that patient. And so some of those patients will have been put in the off-pump group because they only needed one or two grafts, and some will be put in the on-pump group because they needed five or six. So I think the number of grafts between groups is appropriately compared if you use a denominator like number of diseased vessels. But simply to compare that number between the two groups in an unrandomized retrospective review and say that one group got under-revascularized compared to the other is not arithmetically correct.

DR PALMER: My statement was not that they were under-revascularized but that the number of grafts was different between the two groups.

	Acknowledgments

Top Abstract Introduction Patients and Methods Results Comment Appendix 1 Appendix 2 Discussion Acknowledgments References

 
This study was funded by unrestricted grants from Guidant, Inc; HCA, Inc; and Medtronic, Inc.

	References

Top Abstract Introduction Patients and Methods Results Comment Appendix 1 Appendix 2 Discussion Acknowledgments References

 

1. Magee MJ, Jablonski KA, Stamou SC, et al. Elimination of cardiopulmonary bypass improves early survival for multivessel coronary artery bypass patients Ann Thorac Surg 2002;73:1196-1203.[Abstract/Free Full Text]
2. Tasdemir O, Vural KM, Karagoz H, Bayazit K. Coronary artery bypass grafting on the beating heart without the use of extracorporeal circulation: review of 2,052 cases J Thorac Cardiovasc Surg 1998;116:68-73.[Abstract/Free Full Text]
3. Mack M, Bachand D, Acuff R, et al. Improved outcomes in coronary artery bypass grafting with beating-heart techniques J Thorac Cardiovasc Surg 2002;124:598-607.[Abstract/Free Full Text]
4. Ascione R, Lloyd CT, Gomes WJ, Caputo M, Bryan AJ, Angelini GD. Beating versus arrested heart revascularization: evaluation of myocardial function in a prospective randomized study Euro J Cardiothorac Surg 1999;15:685-690.[Abstract/Free Full Text]
5. Buffolo E, de Andrade CS, Branco JN, Teles CA, Aguiar LF, Gomes WJ. Coronary artery bypass grafting without cardiopulmonary bypass Ann Thorac Surg 1996;61:63-66.[Abstract/Free Full Text]
6. Puskas JD, Williams WH, Mahoney EM, et al. Off-pump vs conventional coronary artery bypass grafting: early and 1-year graft patency, cost, and quality-of-life outcomes: a randomized trial JAMA 2004;291:1841-1849.[Abstract/Free Full Text]
7. Puskas JD, Williams WH, Duke PG, 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.[Abstract/Free Full Text]
8. van Dijk D, Nierich AP, Jansen EW, et al. Early outcome after off-pump versus on-pump coronary bypass surgery: results from a randomized study Circulation 2001;104:1761-1766.[Abstract/Free Full Text]
9. Caputo M, Reeves BC, Rajkaruna C, Awair H, Angelini GD. Incomplete revascularization during OPCAB surgery is associated with reduced mid-term event-free survival Ann Thorac Surg 2005;80:2141-2147.[Abstract/Free Full Text]
10. Khan NE, De Souza A, Mister R, et al. A randomized comparison of off-pump and on-pump multivessel coronary artery bypass surgery N Engl J Med 2004;350:21-28.[Abstract/Free Full Text]
11. Cheng DC, Bainbridge D, Martin JE, Novick RJ. Does off-pump coronary artery bypass reduce mortality, morbidity, and resource utilization when compared with conventional coronary artery bypass?A meta-analysis of randomized trials. Anesthesiology 2005;102:188-203.[Medline]
12. Wijeysundera DN, Beattie WS, Djaiani G, et al. Off-pump coronary artery surgery for reducing mortality and morbidity J Am Coll Cardiol 2005;46:872-882.[Abstract/Free Full Text]
13. Sellke FW, DiMaio JM, Caplan LR, et al. Comparing on-pump and off-pump coronary artery bypass grafting: numerous studies but few conclusions: a scientific statement from the American Heart Association council on cardiovascular surgery and anesthesia in collaboration with the interdisciplinary working group on quality of care and outcomes research Circulation 2005;111:2858-2864.[Abstract/Free Full Text]
14. The Society of Thoracic Surgeons. Available at www.sts.org. Accessed October 3, 2006.

This article has been cited by other articles:

				J. D. Puskas, P. D. Kilgo, O. M. Lattouf, V. H. Thourani, W. A. Cooper, T. A. Vassiliades, E. P. Chen, J. D. Vega, and R. A. Guyton Off-pump coronary bypass provides reduced mortality and morbidity and equivalent 10-year survival. Ann. Thorac. Surg., October 1, 2008; 86(4): 1139 - 1146. [Abstract] [Full Text] [PDF]

				S. F. Marasco, L. N. Sharwood, and M. J. Abramson No improvement in neurocognitive outcomes after off-pump versus on-pump coronary revascularisation: a meta-analysis Eur. J. Cardiothorac. Surg., June 1, 2008; 33(6): 961 - 970. [Abstract] [Full Text] [PDF]

This Article Abstract Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): George Palmer Syma L. Prince Mitchell J. Magee Phillip Brown Marc Katz Michael J. Mack Permission Requests Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Palmer, G. Articles by Mack, M. J. Search for Related Content PubMed PubMed Citation Articles by Palmer, G. Articles by Mack, M. J. Related Collections Coronary disease