Eur J Cardiothorac Surg 1998;14:59-63
© 1998 Elsevier Science NL
Elimination of cardiopulmonary bypass: a prime goal in reoperative coronary artery bypass surgery1
Jacob Bergsland,
Saira Hasnain,
Thomas Z. Lajos,
Tomas A. Salerno
Center for Less Invasive Cardiac Surgery, The Buffalo General Hospital, State University of New York at Buffalo, New York, USA
Received 30 September 1997;
received in revised form 1 April 1998;
accepted 7 April 1998.
Corresponding author. Center for Less Invasive Cardiac Surgery, Department of Surgery, Buffalo General Hospital, 100 High Street,;Buffalo NY 14203,;USA;
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Abstract
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Objective: The purpose of this study was to evaluate morbidity and mortality in reoperative coronary artery bypass surgery using the New York State database. Methods: Patients undergoing reoperative coronary artery bypass between January-1995 and December 1996 were included. Patients were operated using cardiopulmonary bypass (CPB group, n=184) or without cardiopulmonary bypass (non-CPB group, n=105) by surgeon preference. Groups were compared for preoperative risk factors, postoperative mortality and major complications. Results: Crude mortality was lower in the non-CPB group, despite a higher expected mortality, resulting in a risk-adjusted mortality of 1.3% versus 2.7% for the CPB group (NS). Of non-CPB patients, 91.4% were without complications, while only 72.1% of CPB patients (P<0.0001) were complication-free. Major complications were significantly reduced in non-CPB patients compared to CPB patients: stroke 0% versus 3.8% (P<0.04), cardiovascular complications 4.8% versus 15.8% (P<0.005), other major complications 1.9% versus 10.4% (P<0.007). Postoperative IABP support was needed in 1.9% of the non-CPB group patients and in 14.2% of the CPB group (P<0.0007). Conclusions: The main object of reoperative CABG is to relieve symptoms, since the survival benefit of the procedure has not been demonstrated. Performance of reoperative coronary artery bypass surgery without cardiopulmonary bypass significantly reduces morbidity. We conclude that cardiopulmonary bypass should be avoided whenever possible in reoperative coronary bypass surgery.
Key Words: Coronary artery bypass • Cardiopulmonary bypass • Mortality • Complication
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Introduction
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Coronary artery bypass surgery (CABG) has been performed for 30 years and is one of the most common surgical procedures in Western Europe and United States. It is estimated that 400 000 primary coronary operations are performed in the US alone every year. As larger numbers of patients with previous CABG develop progression of disease, the dilemma of treating patients with progression of arteriosclerosis in graft conduits and native vessels is becoming increasingly important. In contrast to the situation for primary CABG, definite survival benefit of reoperative CABG has not been demonstrated. The morbidity and mortality of reoperation is considerable when publications from carefully-controlled databases are reviewed. The prime challenge for the clinician in reoperative CABG is to relieve symptoms, with low mortality and complication rate.
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Materials and methods
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CABG was only occasionally performed without cardiopulmonary bypass (CPB) in our institution until 1995. In the past, the procedure was used only when there were strong contraindications to cannulation and CPB, such as extensively-calcified aorta, bleeding diathesis, severe peripheral vascular disease, etc. Recently, we have used the approach much more commonly for patients with relative contraindications to CPB and in cases where in the surgeon's opinion, there is no need for CPB. At present, the authors perform 80–90% of all CABG operations without CPB.
The present study involved all patients undergoing reoperative CABG (redo) in 1995 and 1996. All cardiac cases in New York state (NYS) are entered on a central database controlled by the State Department of Health. Demographic data, cardiac and other risk-factors, surgical methods and postoperative complications and deaths are entered in this central database, which is processed by the state. Data is subject to state verification and, therefore, considered highly reliable. The statistical methods have been reported extensively
[1]
[2].
The CPB group included all patients undergoing redo CABG using CPB, and the non-CPB group included all patients having surgery without CPB. Selection to treatment group was by surgeon choice. The demographic characteristics and preoperative risk factors are summarized in Table 1 and Table 2. As can be seen from these tables, the two groups were similar in most respects, although there were significantly more transmural infarctions preoperatively in the CPB group. This did not result in a lower ejection fraction however. There were also more smokers in the CPB group. The risk profile is utilized to calculate expected mortality
[1]. The crude and expected mortalities are used to calculate risk-adjusted mortality (RAM). RAM is considered the most important quality indicator by the Department of Health. Length of hospital stay is not a part of the NYS database but recorded by our institution with a number of other hospital data.
All patients in the CPB group had standard median sternotomy. In most cases aortic and right-atrial cannulations were performed, although occasionally femoral cannulation was utilized. Aortic cross-clamping and cardioplegia were used routinely. Cardioplegia was generally cold-crystalloid or blood, by surgeon choice, administered antegradely and/or retrogradely. In non-CPB cases, median sternotomy was the most common incision, but the left anterior small thoracotomy (LAST) approach as described by Calafiore
[3] was used in 16 cases for revascularization of the left anterior descending coronary artery (LAD).
Formal left thoracotomy for grafting of the circumflex coronary artery and a lower partial sternotomy incision for gastro-epiploic revascularization of the right coronary were used in a small number of cases. The surgical strategy in the non-CPB group was to revascularize the most important vessels. In a few instances it was deliberately decided to use an integrated approach combining surgical and interventional therapies to obtain more complete revascularization
[4].
Internal mammary arteries and saphenous veins were routinely used for grafting. Occasionally, radial and gastro-epiploic arteries were utilized. In non-CPB patients, grafting was done using a proximal snare and intraluminal occluders to interrupt blood flow. A surgical blower
[5] was always utilized to optimize visualization. Short-acting beta-blocking agents were administered, to facilitate the distal anastomosis. In the later part of the series, mechanical stabilization became available
[3] and was used to optimize suturing conditions.
In the non-CPB group, intra-operative verification of graft patency was utilized. Vascular Doppler and/or transit-time measurements were performed and non-functioning grafts revised. Grafts were revised when mean flow was low or diastolic flow minimal or absent. Heparin was given in a dose of 3 mg/kg in the CPB group and 1 mg/kg in the non-CPB group. Heparin was fully reversed when CPB was used but partly or not at all in non-CPB patients.
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Statistical Analysis
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The groups were compared using chi-square test of significance. For univariate analysis the correlation coefficient was used for testing linear relationships. The risk-adjusted (indirectly standardized) mortality rate for a subgroup of the entire population is defined to be the standardized mortality ratio (actual mortality rate divided by the expected mortality rate), multiplied by the population mortality rate. The expected mortality rate for a group is calculated by aggregating the predicted probability of individual patients to a group level. The predicted probability of death is calculated as P=1/1+e-z.
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Results
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The operative mortality is shown in Table 3. As can be seen the expected mortality was higher in non-CPB patients, indicating selection of higher-risk patients for surgery without CPB. This may be due to referral patterns and the more liberal acceptance of high-risk patients to non-CPB surgery. Crude mortality was identical between groups and RAM was, therefore, lower in the non-CPB group. These differences were, however, not statistically significant.
The postoperative complications are outlined in
Fig. 1
,
Fig. 2 ,
Fig. 3
,
Fig. 4
and
Fig. 5
. Only 72.1% of CPB patients escaped major complications while 91.4% of the non-CPB group were complication-free (
Fig. 1). Cardiovascular complications were significantly higher in the CPB group, as were all other complications. Stroke was seen in 3.8% of the CPB patients, while no patient done without CPB had a stroke (Fig, 3). IABP was required in almost 15% of CPB patients but in only 1.5% of the non-CPB group (
Fig. 5). The number of grafts was lower in the non-CPB group (1.2 grafts pr patient vs. 2.7 grafts per patient in the CPB group) reflecting a different treatment philosophy. Interestingly, the perioperative myocardial infarction rate was lower in the non-CPB patients despite the `incomplete revascularization'.
Mean length of stay after the surgical procedure was 9.1 days in CPB patients and 5.0 days in the non-CPB group.
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Discussion
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Reoperative CABG is becoming increasingly common in cardiac surgery. Patients referred for reoperation are usually older, with more multisystem disease, than patients undergoing the first operation. In addition, left ventricular function and distal vessels are usually of poorer quality. The results of redo CABG are, therefore, worse in most reported series
[6]
[7] compared to first-time operations. In single-institution series, results may be better due to strict selection criteria. In the NYS database redo operations have higher risk than first time surgical procedures.
To our knowledge there has not been any controlled study demonstrating a clear survival-benefit of reoperative CABG. The main indications for such operations must, therefore, be relief of symptoms and improvement in quality of life. The patient with recurrent cardiac ischemia after previous CABG requires special consideration. If interventional procedures are applicable, they should probably be utilized first, realizing that a potential catheterization-laboratory crash is particularly dangerous in a redo situation.
When surgical revascularization is required, a patient-specific strategy must be used, i.e. which are the more important vessels, what incision is most appropriate for the particular patient, and should an integrated approach be utilized.
The detrimental effects of CPB in heart surgery have been clearly demonstrated. Mangano's report
[8] demonstrates a high incidence of adverse effects on the brain. Other reports
[9]
[10], using more sophisticated methods, have demonstrated very high incidence of CNS dysfunction.
Our own data, using clinical indicators of morbidity, as required by NYS shows 27.9% incidence of major complications in reoperative CABG when CPB is used. When CPB was avoided the complication rate was reduced to 8.6%. Allen's recent report demonstrated clear clinical benefits in a small series comparing minimally-invasive to conventional redo CABG
[11]. The major objection to the performance of CABG without CPB has always been the technical difficulty involved in such procedures. A number of the operations in this series was performed during the so-called `learning phase' of the non-CPB CABG surgery program. Also, we did not use mechanical stabilizing devices in most cases, since they were not available until recently. In spite of this, the perioperative infarction rate was much lower in the non-CPB group and demand for postoperative IABP was also much lower than in the patients undergoing CABG with CPB. With presently-available stabilizers and computerized transit-time flow measurements, malfunctioning grafts can be all but eliminated from beating-heart surgery. We do not yet have long-term follow-up on our patients as far as survival or ultimate relief of ischemia is concerned. Such studies are obviously of crucial importance and are presently being performed.
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Conclusion
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Reoperative CABG can be performed without CPB with identical or lower mortality than when CPB is utilized. Complications are significantly reduced and post-discharge data, although incomplete, are promising. We believe that reoperative CABG should be performed without the use of the heart–lung machine except in very unusual circumstances.
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Footnotes
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Presented at the 11th Annual Meeting of the European Association for Cardio-thoracic Surgery, Copenhagen, Denmark, September 28 – October 1, 1997. 
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Appendix A. Conference discussion
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Dr D. Taggart (Oxford, UK): I would agree with you in general terms it is worthwhile trying to avoid bypass for redo patients, and it's often possible to do so. I think, however, you made a number of opening comments that need to be addressed, because I think there is a lot of confusion about brain injury and cardiac surgery. The papers to which you referred demonstrate that brain injury occurs after cardiac surgery, but that is not the same as saying it's due to cardiopulmonary bypass. About 2% of patients will suffer obvious brain damage after cardiac surgery. In our data from Oxford comparing neuropsychological injury in patients operated with and without cardiopulmonary bypass there is no difference in cerebral injury. Much of what has been attributed to cardiopulmonary bypass over the last decade is in fact due to general anesthesia.
Dr Bergsland: I think that the neuropsychological testing has shown widely different results. If you look at Murkin's data from London, Ontario, he has totally different results than you.
Dr Taggart: No, I have to interrupt you there. Again, I think this illustrates the confusion. No one is disputing that you get neuropsychological injury after cardiac surgery. But what I'm saying is, it is not due simply to cardiopulmonary bypass. And Murkin has never done the study we've done, which is comparing two groups of patients undergoing coronary revascularization through a median sternotomy, same anesthetic technique, with and without cardiopulmonary bypass. He hasn't presented any data on that.
Dr Bergsland: Well, we have not done that study ourselves, so I shouldn't really comment too much on that. But what is obvious is that the more severe cerebrovascular complications are much more common if you put the patient on cardiopulmonary bypass than if you don't do that.
Dr Taggart: No, I agree with you. No, you didn't actually demonstrate that. But the incidence of cerebral injury that you're talking about is due to patient-created factors. These are patients with heavily diseased aortas. But that's a different type of injury from neuropsychological injury.
Dr Bergsland: That is not true. I didn't show you the data, but actually the patients done off-pump had much higher risk factors such as calcified aorta, peripheral vascular disease, and so forth. And in spite of that we saw essentially no stroke. So I think that stroke is the pump.
Dr Taggart: The stroke is, but not –
Dr Bergsland: The stroke is the pump.
Dr R.Replogle (Chicago, IL, USA): I think that argument is not going to be solved.
Dr Replogle: I have one comment and then a question myself. I have noticed in the audience a large number of colleagues who have had cardiopulmonary bypass, and I wonder if we could have a display of their neuropsychiatric difficulties. I've had some doubts about some of them from time to time, but they seem to be functioning pretty well. I have one question. And I preface it by saying I'm an average heart surgeon. There are not many of us, I represent a very small group of people. And so I look at a paper like this for some evidence that I should or should not get into this new technology. I noticed one area in your abstract which concerns me and that is, the patients were selected by surgeon preference. And that leads me to wonder, who and why and what was the surgeon's preference? I would study the mortality rate of the surgeons that preferred cardiopulmonary bypass in general, maybe he was like I am, an average surgeon; and maybe the people that did it without bypass were not average surgeons, which most of the people in this audience are. Could you answer that? Why did some surgeons prefer not to use bypass? Why did some prefer to use bypass?
Dr Bergsland: This is obviously a very good point. And if I'm going to answer it, I have to tell you that it was basically two of us, Dr. Salerno and myself, that did the cases off-pump and the other guys did the other cases. I think that if you look at mortality, it is relatively similar, so perhaps that can be an indicator that this is not mainly a surgeon factor. But I have to agree with you that before we had mechanical stabilization, and actually most of these cases were done before stabilization, it is technically more difficult to do it off-pump. But with stabilization, I don't think it's much more difficult than to do it on-pump. So that is basically the question, it's a question of choice.
Dr Bachet (Suresnes, France): If I understood well, you assess the quality of your bypasses with a flow study in the operating room. In our experience, flow studies are not very convincing because the result depends on many tiny things, like the exact position of the probe, the exact diameter of the probe on the graft, etc., etc. So don't you think that your demonstration in favor of your technique would be much more convincing if every single patient undergoing this technique had an angiogram before being discharged from the hospital?
Dr Bergsland: I agree that it would be a definite benefit, but it's difficult to organize. But the flow measurement basically can tell you if a graft is bad. It cannot tell you if it's good, but it can tell you if it's bad. And then you must revise it. That is the main benefit of the flow measurement.
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References
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- Hannan E.L., Kilburn H., Racz M., Shields E., Chassin M.R. Improving the outcomes of coronary artery bypass surgery in New York State. J Am Med Assoc 1994;271:761-766.[Abstract/Free Full Text]
- Hannan E.L., Kilburn H., O'Donnel J.F., Lukacik G., Shields E.P. Adult open heart surgery in New York State. An analysis of risk factors and hospital mortality rates. J Am Med Assoc 1990;264:2768-2774.[Abstract/Free Full Text]
- Calafiore A.M., Giammarco G.D., Teodori G., Bosco G., D'Annunzio E., Barsetti A., Maddestra N., Paloscia L., Vitolla G., Sciaara A., Fino C., Contini M. Left anterior descending coronary artery grafting via left anterior small thoracotomy without cardiopulmonary bypass. Ann Thorac Surg 1996;61:1658-1665.[Abstract/Free Full Text]
- Angelini G.D., Wilde P., Salerno T.A., Bosco G., Calafiore A.M. Integrated left small thoracotomy and angioplasty for multivessel coronary revascularization. Lancet 1996;347:757-758.[Medline]
- Teoh K.H.T., Panos A.L., Harmantas A.A., Lichtenstein S., Salerno T.A. Optimal visualization of artery anastomosis by gas jet. Ann Thorac Surg 1991;52:564.[Abstract]
- He G., Acuff T.E., Ryan W.H., He Y., Mack M.J. Determinants of mortality in reoperative coronary artery bypass grafting. J Thorac Cardiovasc Surg 1995;110:978-978.
- Weintraub WS, Jones EL, Craver JM, Grosswald R, Guyton RA. In hospital and long term outcome after reoperative coronary artery bypass graft surgery. Circulation 1995;92(Suppl 2):II:50–7.
- Roach G.W., Kanchuger M., Mangano C.M., Newman M., Nussmeier N., Wolman R., Aggarwal A., Marschall K., Graham S.N., Ley C., Ozanne G., Mangano D.T. Adverse cerebral outcome after coronary bypass surgery. N Eng J Med 1996;335:1857-1863.[Abstract/Free Full Text]
- Murkin J.M. The brain at risk during cardiopulmonary bypass. Cardiovasc Engineer 1997;2:104-112.
- Toner I., Taylor K.M., Newman S., Smith P.L.C. Cerebral functional changes following cardiac surgery: Neuropsychological and EEG assessment. Eur J Cardiothorac Surg 1998;13:13-20.[Abstract/Free Full Text]
- Allen K.B., Matheny R.G., Robison R.J., Heimansohn D.A., Shaar C.J. Minimally invasive versus conventional reoperative coronary artery bypass. Ann Thorac Surg 1997;64:616-622.[Abstract/Free Full Text]
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Top
Abstract
Introduction
