|
|
||||||||
Ann Thorac Surg 2001;72:456-462
© 2001 The Society of Thoracic Surgeons
a Department of Cardiology and Cardiac Surgery, "G. DAnnunzio" University, Chieti, Italy
Accepted for publication May 1, 2001.
Address reprint requests to Dr Calafiore, Division of Cardiac Surgery, "G. DAnnunzio" University, S. Camillo de Lellis Hospital, via C. Forlanini, 50, 66100 Chieti, Italy
e-mail: calafiore{at}unich.it
| Abstract |
|---|
|
|
|---|
Methods. From May 21, 1997 to November 30, 2000, 1,843 consecutive patients underwent isolated myocardial revascularization. From this total, 919 patients were done without CPB (group A, 49.9%) and 924 patients were done with CPB (group B, 50.1%). Patients that converted from without CPB to with CPB were included in group A. Thirty-three variables were evaluated with univariate and multivariate analysis to identify the independent variables predictive of higher incidence of early mortality, acute myocardial infarction, cerebrovascular accident, and early major events.
Results. Early mortality was 2.2% (group A, 1.4%; group B, 3.0%; p = 0.016), acute myocardial infarction incidence was 1.8% (group A, 1.1%; group B, 2.6%; p = 0.027), cerebrovascular accident incidence was 0.9% (group A, 0.8%; group B, 1.0%; p = not significant), and early major events incidence was 6.7% (group A, 5.3%; group B, 8.2%; p < 0.001). Stepwise logistic regression analysis showed that CPB was an independent risk factor for higher mortality (odds ratio, 2.2; p = 0.0217), higher incidence of acute myocardial infarction (odds ratio, 2.5; p = 0.0185), and higher incidence of early major events (odds ratio, 1.8, p = 0.0034).
Conclusions. When CPB was not used, patients experienced lower early mortality and incidences of acute myocardial infarction were less complicated, both at univariate analysis and stepwise logistic regression analysis.
| Introduction |
|---|
|
|
|---|
In order to evaluate the impact of myocardial revascularization without CPB in our division, with different surgeons working under similar guidelines, we reviewed all patients who had isolated myocardial revascularization for multivessel disease through median sternotomy during the recent past, when the techniques for coronary marginal grafting were well established.
| Material and methods |
|---|
|
|
|---|
Patient selection
Candidates for myocardial revascularization without CPB were patients: (1) with suitable anatomy (epicardial vessels with a size greater than or equal to 1.2 mm, not calcified, and (2) with high risk for perioperative or postoperative organ dysfunction (kidney, brain, liver, etc.). Ejection fraction, per se, was not a contraindication; however, dilated hearts, in our opinion, would not tolerate the verticalization in order to expose the lateral wall. Contraindications to the procedure were: (1) unfavorable anatomy (small vessel disease, intramyocardial vessels or vessels with diffuse calcifications), (2) marginal branches in redo operations (such as epicarditis and fibrosis) often do not allow correct opening of a lateral vessel along with CPB and cardiac arrest, and (3) electrical or mechanical instability, or both electrical and mechanical instability.
Surgical technique
Patients were anesthetized as usual. A pulmonary catheter was seldom used. In group A, without CPB, mechanical stabilization was obtained with the CTS stabilizers (initially OPCAB Midline Multi-Vessel System, CTS, Cupertino, CA), later Acces Ultima System, (Guidant Corp, Cupertino, CA). The heart was verticalized using different techniques. First only four slings were used [3]; later a single Lima stitch was added [7]. More recently, the verticalization of the heart was obtained with the Xpose (Guidant Corp, Cupertino, CA) (apical suction) and a single Lima stitch with a single additional sling. Hemodynamic stability was obtained with Trendelenburg position, adding volume, and with small boluses of a vasopressor when needed (metaraminol or diluted norepinephrine). In group B, with CPB, normothermic perfusion and intermittent warm blood cardioplegia was used in all of the patients (except 34 patients in which the aorta was not cross-clamped and the procedure was performed under circulatory assistance).
After each single procedure, flow in the grafts was measured using two different flow meters (Transonic, Ithaca, NY and Medi-Stim, Oslo, Norway).
Postoperative course
All the patients were admitted into the intensive care unit and subsequently, into the regular ward. A complete 30-day follow-up was available on all patients.
Methodology of the study
End points of this study were early mortality, incidences of cerebrovascular accidents, incidences of acute myocardial infarction, and incidences of early major events (EMEs). The period of the study was limited to the first 30 days after the operation. All these end points were analyzed using a variety of risk factors (see the Appendix), including CPB.
Definition of terms
Early mortality included death of any cause. Cerebrovascular accident (CVA) was defined as global or focal neurologic deficit, lasting less (transient ischemic attack) or more (stroke) than 24 hours, that could be evident after emergence from anesthesia or after first awakening without any neurologic deficits. Cerebrovascular accident was diagnosed by a neurologist and confirmed by a brain computed tomographic scan. Acute myocardial infarction (AMI) was defined as enzymatic elevation, electrocardiogram sign of necrosis, new akinetic segment(s) at echocardiogram, ventricular arrhythmias non K+ related. Early major events (EMEs) were defined as the sum of death of any cause, CVA, AMI, low output syndrome (defined as need of intraaortic balloon pump or inotropic drugs, or both, for more than 12 hours), need of mechanical ventilation for more than 24 hours in absence of low output syndrome, acute renal insufficiency (defined as blood creatinine level greater than or equal to 2.0 and 2 times the preoperative value), acute renal failure (need of ultrafiltration or hemodialysis), gastrointestinal complications with or without a related operation.
Statistical analysis
Results are expressed as mean value ± standard deviation unless otherwise indicated. Statistical analysis comparing two groups was performed with unpaired two-tailed t tests for the means or
2 test for categorical variables. Stepwise logistic regression analysis was used to select the independent variables that could predict the end points of this study and included all the univariate variables with a p value less than or equal to 0.2. In the final regression model, independent variables were expressed as an odds ratio with a 95% confidence limit; the related p value was also reported. The SPSS software (SPSS Inc, Chicago, IL) was used.
| Results |
|---|
|
|
|---|
|
|
|
The great majority of patients were discharged home (62.3% in group A and 64.6% in group B; p = not significant) and their mean postoperative length of stay was shorter in group A than in group B (4.4 ± 2.9 vs 4.9 ± 2.9; p = 0.003). The remaining patients were admitted in a rehabilitation center; their postoperative in-hospital length of stay was shorter in group A (3.8 ± 2.4 vs 4.7 ± 2.2; p < 0.001).
The incidence of redo cases was higher in group B (8.0% vs 1.7%; p < 0.001). Even though reoperations are usually associated with higher mortality and morbidity, in our experience the results were similar in patients who had first or second (or third) time myocardial revascularization. Thirty-day mortality was 2.2% in the redo cases and 2.2% in the remaining cases (p = not significant); the incidence of AMI was 3.3% and 1.8% (p = not significant); CVA incidence was 1.1% and 0.9% (p = not significant), and the incidence of EMEs was 11.1% and 6.6% (p = not significant). Because of these results, the variable redo was considered for the stepwise logistic regression only for EMEs (p = 0.115; whereas the p value for the other events was always higher than 0.2).
Table 4 shows the variables with a p value less than or equal to 0.2 that entered the multivariate analysis. Table 5 shows the results of the stepwise logistic regression for higher incidence of early mortality, CVA, AMI, and EMEs.
|
|
| Comment |
|---|
|
|
|---|
The incidence of coronary surgery without CPB in our division during the time frame considered in this study is 60.1%, considering all surgical approaches. This percentage falls to 49.9% if only patients who have myocardial revascularization for multivessel disease through median sternotomy are considered. This part of our experience is the object of this article.
Although myocardial revascularization without CPB was the beginning of coronary surgery [8, 9], the advent of a safe CPB and cardioplegic arrest limited the interest in a technique that was more technically demanding. In fact, even if some surgeons continued to perform such a procedure [1012], the surgical technique was far from being well established. Grafting the lateral wall was rarely done. Also, in a recent report [13], marginal branches were rarely grafted. In recent years a new way of performing the operation was developed. The introduction of stabilizers and the different techniques described in order to verticalize the heart [1, 36] were striking improvements that modified the feasibility of the procedure. The hemodynamic changes during the verticalization, when present [14], were not of such a magnitude to avoid a safe operation [15].
Although some studies showed that there was significant reduction of the inflammatory response in patients operated on without CPB [16], improvement in neurocognitive outcome [17] and no increase of extracellular brain water [18] in comparison with patients operated on with CPB, primary end points (mortality, CVA, and AMI incidence) were never reported to be lower, at multivariate analysis, if CPB was not used.
When patients operated on with and without CPB were compared, the 30-day mortality was similar [1925]. Although Koutlas and colleagues [26] reported a lower incidence of deaths in patients greater than or equal to 75 years of age when CPB was not used (no multivariate analysis was performed), Ricci and colleagues [27] did not confirm this observation in patients greater than or equal to 80 years of age. Also when high-risk patients were considered, mortality was similar [22, 28]. In our previous reports [7, 29, 30] we were not able to find any difference between the groups. The incidence of AMI was uniformly similar in all comparative studies that were recently published [19, 21, 23, 25, 29, 30].
Perioperative or postoperative CVA is a major complication that can strongly influence the outcome of coronary artery bypass grafting. Causes are multifactorial and are not influenced only by the use of CPB. Many authors [1926], including us, were not able to find any difference. Ricci and colleagues [27] found an incidence of 9.3% in patients greater than or equal to 80 years of age if CPB was used, whereas when CPB was not used the incidence was nil. However, no multivariate analysis was used to confirm this observation.
Reduction of postoperative morbidity is considered a positive effect of myocardial revascularization without CPB. Patients operated on without CPB had a reduced need of blood transfusions [1922, 25, 26, 29, 30], lower cardiomyolitic enzymatic release [19, 21, 23, 29, 30], better preserved renal function [31], lower incidence of low output syndrome [24] or need of postoperative intraaortic balloon pump [19, 28], lower incidence of inotropic agents [25], reduced ventilation time [20, 21, 24, 25], lower incidence of new atrial fibrillation [23, 24], shorter intensive care unit stay [24, 25, 29, 30], and shorter postoperative length of stay [23, 25, 26, 29, 30]. However, these data were inconstant, as the same quoted reports were not uniform in their results. Thus, patients operated on with and without CPB showed similar needs for blood transfusion [23, 27], similar cardiomyolitic enzymatic release [20], similar postoperative renal function [32], similar incidence of renal failure [20, 22, 2527], similar incidence of inotropic agents [19], similar ventilation time [22], similar incidence of new atrial fibrillation [1921, 26], similar intensive care unit stay [1923], and similar postoperative length of stay [1922, 27].
The real impact of myocardial revascularization without CPB in the daily practice of coronary bypass grafting operation is hard to document. Randomized studies are advocated to determine the benefit of the technique on the other one [20, 33]. We believe randomized studies are not needed for the following reasons: (1) the percentage of randomized patients is always too small to be a mirror of the reality, (2) the results are true only for the patients that are randomized, not necessarily for the others, and (3) randomization criteria reflecting the biases of the surgeon. Recently, the bypass angioplasty revascularization investigation (BARI) trial found that surgical revascularization in diabetic patients gave better results than percutaneous transluminal coronary angioplasty [34]. This finding was contradicted by other studies [35, 36]; among them, an observational study inside the bypass angioplasty revascularization investigation (BARI) trial, which included patients that refused randomization [36].
We prefer to consider all patients that were operated on in our division by all the surgeons. Surgical guidelines were similar. The patients were selected, which is always one of the most important steps when an operation is necessary. Of course, patient selection is the same as the goal of an operation, which is to perform the right operation on the right patient, not following preconceived beliefs. A multivariate analysis was applied to try to limit the biases of selection; for the same purpose, patients were grouped according to the intention to treat, not according to the final strategy used during the procedure.
Cardiopulmonary bypass was found to be an independent risk factor for higher mortality, higher incidence of AMI, and higher incidence of EMEs. Or, if a patient can have the same operation performed with or without CPB, the non-CPB strategy will allow him/her to have a globally lower risk (ie, in our hands, CPB has an intrinsic risk that can become evident when the number of patients treated is high). A better myocardial protection is reached if coronary operations are performed without CPB. In our experience, this is evident from the lower enzymatic release. Again, increased numbers of patients operated on correlate with higher incidences of AMI after CPB, and cardioplegic arrest can become significant. It is noteworthy that in previous reports we were not able to find any difference in 30-day mortality and AMI incidence between groups [7, 29, 30].
Postoperative CVA incidence was not influenced by the surgical strategy. This can be caused by the fact that 2 of 3 CVAs are delayed [37], not strictly related to what happens in the operating room. Other factors are involved, such as a hypo- and hypercoagulable state that are present in the postoperative period and are similar for patients operated on with or without CPB. Moreover, ascending aorta manipulation is avoided only if total arterial revascularization is performed [38].
The higher incidence of EMEs we found were not in contrast with other reports. However, the sum of many events is more likely to reach statistical significance than the single event itself.
Myocardial revascularization without CPB is a technique with indications and contraindications that give selected patients the possibility of grafting all vessels, including the lateral ones. The operation is reproducible and the early patency rate is satisfying [7, 24, 3941]. Moreover, even if cost containment is not a primary goal, and even if our healthcare system does not allow us to draw any conclusions, other experiences indicate evidence of reducing costs [24, 25].
In conclusion, when myocardial revascularization can be performed without CPB, two primary end points (30-day mortality and postoperative AMI) have statistically significant lower incidences. Globally, the EME rate is lower. Some secondary end points (such as the need for blood transfusions, intensive care unit length of stay, and postoperative in-hospital length of stay) are favorable if CPB is not used, and they contribute to increasing patient comfort.
| Appendix |
|---|
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
ACE = activated converting enzyme; CVA = cerebrovascular accident; iv = intravenous; PO2 = oxygen pressure.
| References |
|---|
|
|
|---|
Related Article
This article has been cited by other articles:
![]() |
D. Navia, M. Vrancic, G. Vaccarino, F. Piccinini, H. Raich, S. Florit, and J. Thierer Total arterial off-pump coronary revascularization using bilateral internal thoracic arteries in triple-vessel disease: surgical technique and clinical outcomes. Ann. Thorac. Surg., August 1, 2008; 86(2): 524 - 530. [Abstract] [Full Text] [PDF] |
||||
![]() |
U. K. Chowdhury, V. Malik, R. Yadav, S. Seth, L. Ramakrishnan, M. Kalaivani, S. M. Reddy, G. K. Subramaniam, R. Govindappa, and M. Kakani Myocardial injury in coronary artery bypass grafting: On-pump versus off-pump comparison by measuring high-sensitivity C-reactive protein, cardiac troponin I, heart-type fatty acid-binding protein, creatine kinase-MB, and myoglobin release. J. Thorac. Cardiovasc. Surg., May 1, 2008; 135(5): 1110 - 1119.e10. [Abstract] [Full Text] [PDF] |
||||
![]() |
V. Mazzei, G. Nasso, G. Salamone, F. Castorino, A. Tommasini, and A. Anselmi Prospective Randomized Comparison of Coronary Bypass Grafting With Minimal Extracorporeal Circulation System (MECC) Versus Off-Pump Coronary Surgery Circulation, October 16, 2007; 116(16): 1761 - 1767. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. L. Hannan, C. Wu, C. R. Smith, R. S.D. Higgins, R. E. Carlson, A. T. Culliford, J. P. Gold, and R. H. Jones Off-Pump Versus On-Pump Coronary Artery Bypass Graft Surgery: Differences in Short-Term Outcomes and in Long-Term Mortality and Need for Subsequent Revascularization Circulation, September 4, 2007; 116(10): 1145 - 1152. [Abstract] [Full Text] [PDF] |
||||
![]() |
Y.-N. Youn, Y.-L. Kwak, and K.-J. Yoo Can the EuroSCORE Predict the Early and Mid-Term Mortality After Off-Pump Coronary Artery Bypass Grafting? Ann. Thorac. Surg., June 1, 2007; 83(6): 2111 - 2117. [Abstract] [Full Text] [PDF] |
||||
![]() |
I. J. Ferreira-Gonzalez, A. Ribera, P. Cascant, G. Permanyer-Miralda, and for the ARCA study group Outcomes in off-pump vs. on-pump coronary artery bypass grafting stratified by pre-operative risk profile: an assessment using propensity score Eur. Heart J., October 2, 2006; 27(20): 2473 - 2480. [Abstract] [Full Text] [PDF] |
||||
![]() |
E Sharoni, H K Song, R J Peterson, R A Guyton, and J D Puskas Off pump coronary artery bypass surgery for significant left ventricular dysfunction: safety, feasibility, and trends in methodology over time--an early experience Heart, April 1, 2006; 92(4): 499 - 502. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. N. Wijeysundera, W. S. Beattie, G. Djaiani, V. Rao, M. A. Borger, K. Karkouti, and R. J. Cusimano Off-Pump Coronary Artery Surgery for Reducing Mortality and Morbidity: Meta-Analysis of Randomized and Observational Studies J. Am. Coll. Cardiol., September 6, 2005; 46(5): 872 - 882. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Zimarino, A. M. Calafiore, and R. De Caterina Complete myocardial revascularization: between myth and reality Eur. Heart J., September 2, 2005; 26(18): 1824 - 1830. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. M. Calafiore, G. Di Giammarco, G. Teodori, A. L. Iaco, M. Pano, M. Contini, G. Vitolla, and M. Di Mauro Bilateral internal thoracic artery grafting with and without cardiopulmonary bypass: Six-year clinical outcome J. Thorac. Cardiovasc. Surg., August 1, 2005; 130(2): 340 - 345. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Ohata, M. Kaneko, T. Kuratani, H. Ueda, and K. Shimamura Using the EuroSCORE to Assess Changes in the Risk Profiles of the Patients Undergoing Coronary Artery Bypass Grafting Before and After the Introduction of Less Invasive Coronary Surgery Ann. Thorac. Surg., July 1, 2005; 80(1): 131 - 135. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. D.L. Keenan, Y. Abu-Omar, and D. P. Taggart Bypassing the Pump: Changing Practices in Coronary Artery Surgery Chest, July 1, 2005; 128(1): 363 - 369. [Abstract] [Full Text] [PDF] |
||||
![]() |
J.-F. Legare, K. J. Buth, and G. M. Hirsch Conversion to on pump from OPCAB is associated with increased mortality: results from a randomized controlled trial Eur. J. Cardiothorac. Surg., February 1, 2005; 27(2): 296 - 301. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Di Mauro, A. L. Iaco, M. Contini, G. Teodori, G. Vitolla, M. Pano, G. Di Giammarco, and A. M. Calafiore Reoperative Coronary Artery Bypass Grafting: Analysis of Early and Late Outcomes Ann. Thorac. Surg., January 1, 2005; 79(1): 81 - 87. [Abstract] [Full Text] [PDF] |
||||
![]() |
R. Pandey, A. D. Grayson, D. M. Pullan, B. M. Fabri, and W. C. Dihmis Total arterial revascularisation: effect of avoiding cardiopulmonary bypass on in-hospital mortality and morbidity in a propensity-matched cohort Eur. J. Cardiothorac. Surg., January 1, 2005; 27(1): 94 - 98. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. M. Calafiore, G. Di Giammarco, G. Teodori, M. Di Mauro, A. L. Iaco, A. Bivona, M. Contini, and G. Vitolla Late results of first myocardial revascularization in multiple vessel disease: single versus bilateral internal mammary artery with or without saphenous vein grafts Eur. J. Cardiothorac. Surg., September 1, 2004; 26(3): 542 - 548. [Abstract] [Full Text] [PDF] |
||||
![]() |
H. K. Shinn, Y. J. Oh, S. H. Kim, J. H. Lee, C. S. Lee, and Y. L. Kwak Evaluation of serial haemodynamic changes during coronary artery anastomoses in patients undergoing off-pump coronary artery bypass graft surgery: initial experiences using two deep pericardial stay sutures and octopus tissue stabilizer Eur. J. Cardiothorac. Surg., June 1, 2004; 25(6): 978 - 984. [Abstract] [Full Text] [PDF] |
||||
![]() |
K. Alwan, P.-E. Falcoz, J. Alwan, W. Mouawad, G. Oujaimi, S. Chocron, and J.-P. Etievent Beating versus arrested heart coronary revascularization: evaluation by cardiac troponin I release Ann. Thorac. Surg., June 1, 2004; 77(6): 2051 - 2055. [Abstract] [Full Text] [PDF] |
||||
![]() |
T. Suzuki, M. Okabe, M. Handa, F. Yasuda, and Y. Miyake Usefulness of preoperative intraaortic balloon pump therapy during off-pump coronary artery bypass grafting in high-risk patients Ann. Thorac. Surg., June 1, 2004; 77(6): 2056 - 2059. [Abstract] [Full Text] [PDF] |
||||
![]() |
O. Reuthebuch, A. Kadner, M. Lachat, A. Kunzli, U. P. Schurr, and M. I. Turina Early bypass occlusion after deployment of Nitinol connector devices J. Thorac. Cardiovasc. Surg., May 1, 2004; 127(5): 1421 - 1426. [Abstract] [Full Text] [PDF] |
||||
![]() |
V. Casati, S. Benussi, L. Sandrelli, M. A. Grasso, S. Spagnolo, and A. D'Angelo Intraoperative Moderate Acute Normovolemic Hemodilution Associated with a Comprehensive Blood-Sparing Protocol in Off-Pump Coronary Surgery Anesth. Analg., May 1, 2004; 98(5): 1217 - 1223. [Abstract] [Full Text] [PDF] |
||||
![]() |
Z. Straka, P. Widimsky, K. Jirasek, P. Stros, J. Votava, T. Vanek, P. Brucek, M. Kolesar, and R. Spacek Off-pump versus on-pump coronary surgery: final results from a prospective randomized study Prague-4 Ann. Thorac. Surg., March 1, 2004; 77(3): 789 - 793. [Abstract] [Full Text] [PDF] |
||||
![]() |
J.-F. Legare, K. J. Buth, S. King, J. Wood, J. A. Sullivan, C. H. Friesen, J. Lee, K. Stewart, and G. M. Hirsch Coronary Bypass Surgery Performed off Pump Does Not Result in Lower In-Hospital Morbidity Than Coronary Artery Bypass Grafting Performed on Pump Circulation, February 24, 2004; 109(7): 887 - 892. [Abstract] [Full Text] [PDF] |
||||
![]() |
J. F. Sabik, E. H. B |