Health Services and Outcomes Research

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

Edward L. Hannan, Chuntao Wu, Craig R. Smith, Robert S.D. Higgins, Russell E. Carlson, Alfred T. Culliford, Jeffrey P. Gold, Robert H. Jones
https://doi.org/10.1161/CIRCULATIONAHA.106.675595
Circulation. 2007;116:1145-1152
Originally published September 3, 2007

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Abstract

Background— Off-pump coronary artery bypass graft surgery (OPCAB) has been performed for many years, but its use is increasing in frequency, and it remains an open question whether OPCAB is associated with better outcomes than on-pump coronary artery bypass graft (CABG) surgery.

Methods and Results— New York State patients who underwent either OPCAB with median sternotomy (13 889 patients) or on-pump CABG surgery (35 941 patients) between 2001 and 2004 were followed up via New York databases. Short- and long-term outcomes were compared after adjustment for patient risk factors and after patients were matched on the basis of significant predictors of type of CABG surgery. OPCAB had a significantly lower inpatient/30-day mortality rate (adjusted OR 0.81, 95% confidence interval [CI] 0.68 to 0.97), lower rates for 2 perioperative complications (stroke: adjusted OR 0.70, 95% CI 0.57 to 0.86; respiratory failure: adjusted OR 0.80, 95% CI 0.68 to 0.93), and a higher rate of unplanned operation in the same admission (adjusted OR 1.47, 95% CI 1.01 to 2.15). In the matched samples, no difference existed in 3-year mortality (hazard ratio 1.08, 95% CI 0.96 to 1.22), but OPCAB patients had higher rates of subsequent revascularization (hazard ratio 1.55, 95% CI 1.33 to 1.80). The 3-year OPCAB and on-pump survival rates for matched patients were 89.4% and 90.1%, respectively (P=0.20). For freedom from subsequent revascularization, the respective rates were 89.9% and 93.6% (P<0.0001).

Conclusions— OPCAB is associated with lower in-hospital mortality and complication rates than on-pump CABG, but long-term outcomes are comparable, except for freedom from revascularization, which favors on-pump CABG.

Received December 12, 2006; accepted June 15, 2007.

One of the current controversies/open questions in coronary artery bypass graft (CABG) surgery is the advisability and relative effectiveness of performing the procedure on a beating heart without the use of a heart/lung machine. This method, referred to as off-pump CABG or OPCAB, gained in popularity considerably between 1997 and 2000, but its use has seemingly leveled off, accounting for 27.9% of all isolated CABG cases in New York between 2001 and 2004 (reported later in the present study).

Editorial p 1108

Clinical Perspective p 1152

Numerous studies in the literature have compared OPCAB with on-pump CABG surgery with respect to complications of CABG surgery, costs, and short-term mortality, and many of these studies have found that OPCAB has superior outcomes, particularly with regard to short-term mortality and complication rates.1–29 Other studies found no differences,30–33 and some studies found lower graft patency rates for OPCAB patients34,35 and higher mortality/revascularization rates for OPCAB.36,37 In general, potential disadvantages of OPCAB are lower graft patency rates and more incomplete revascularization, either of which could lead to the need for more subsequent revascularization.

The purpose of the present study is to contrast short-term mortality and complications, as well as long-term (3-year) mortality and subsequent revascularization, for patients undergoing OPCAB and on-pump CABG surgery in New York State from 2001 to 2004. To minimize selection bias in this observational study, most of the analyses involve a comparison of pairs of patients who were matched exactly with regard to significant predictors of type of surgery.

Methods

Database

The source of most of the data for the study was New York State’s Cardiac Surgery Reporting System (CSRS), a statewide registry in existence since 1989 that contains information on demographics; patient risk factors and complications; dates of admission, surgery, and discharge; discharge disposition (including in-patient mortality); and provider and patient identifiers for all patients undergoing cardiac surgery in the nonfederal hospitals in the state certified to perform open heart surgery. It also includes information on whether the patient underwent OPCAB and whether the patient’s procedure was converted from OPCAB to on-pump surgery.

Because we were also interested in longer-term mortality and in the need for subsequent revascularization, 2 other databases were required. New York’s vital statistics data were matched to CSRS data to determine whether patients died any time between the date of discharge and December 31, 2004. Also, to identify subsequent revascularizations, all patients in the study were matched to subsequent admissions in CSRS and in New York’s Percutaneous Coronary Interventions Reporting System, the companion registry for patients undergoing percutaneous coronary interventions in the state. If the patient did not have any revascularization after the initial procedure and did not experience an adverse outcome (death and/or subsequent revascularization) during the course of the study, the time between surgery and December 31, 2004, was noted as a censored time for that outcome.

Patients

Patients in the study included all patients undergoing CABG surgery between January 1, 2001, and December 31, 2004, except non–New York residents (2395 patients) and patients who underwent CABG surgery without sternotomy (1058 patients). This left a total of 49 830 patients, 13 889 of whom underwent OPCAB and 35 941 of whom underwent on-pump surgery. Patients were classified on the basis of intention-to-treat (patients whose procedures were converted from OPCAB to on-pump CABG were treated as OPCAB patients). The study was limited to New York residents so that deaths that occurred after discharge could be captured with New York’s vital statistics data.

Data Analysis

Frequencies were tabulated for each patient risk factor for each of the 2 procedures, and differences in prevalence were identified with χ2 tests after continuous variables were broken into categories. The difference in unadjusted inpatient/30-day mortality was examined with the χ2 test. To test for a significant difference in risk-adjusted inpatient/30-day mortality, a generalized estimating equation version of a stepwise logistic regression model was developed with inpatient/30-day mortality as the dependent binary variable.38 Type of procedure (OPCAB or on-pump) and all available patient risk factors were used as candidate independent variables. A generalized estimating equation was used to account for clustering. The coefficient of the binary variable of procedure type was exponentiated to obtain the OR for mortality of OPCAB versus on-pump surgery, and the confidence interval (CI) for the OR was used to assess the significance of type of surgery on mortality. The same method was used to determine whether differences existed in risk-adjusted complication rates between the 2 procedures for 9 different complications.

Risk-adjusted long-term mortality and subsequent revascularization for OPCAB and on-pump surgery were compared by the creation of stepwise Cox proportional hazards models (with P<0.05) with a robust covariance matrix that accounted for correlation of survival times for individuals within a hospital or operator cluster.39–41 All of the available patient risk factors were used as candidate independent variables. Also, OPCAB was forced into the model as an independent variable for purposes of obtaining the hazard ratio (HR) and its 95% CI for OPCAB.

To test for selection bias, we conducted a propensity analysis.42,43 First, a stepwise logistic regression model was used to predict type of procedure used. Candidate independent variables in this propensity model were the candidate independent variables in the Cox models described above. Cases were then subdivided into quartiles on the basis of predicted probability of OPCAB, and then, for each adverse outcome, HRs of OPCAB/on-pump surgery were compared across quartiles.

Selection bias was also tested by matching pairs of OPCAB and on-pump patients exactly with respect to important predictors of type of surgery. The significant predictors of surgery type were used to match each OPCAB patient to an on-pump patient with exactly the same set of predictors. When an OPCAB patient could be matched to more than 1 on-pump patient, the patient with the nearest and earliest procedure date was chosen. A total of 23 530 of the 49 830 patients were matched. Patients who could not be matched exactly were not considered in the subsequent analyses. Next, the matched data were restricted to high-volume surgeons (upper quartile) who primarily (>50% of the time) used OPCAB and surgeons who primarily used on-pump CABG surgery.

All differences were tested at the 0.05 level. SAS 9.1 (SAS Institute, Cary, NC) was used to conduct the statistical analyses.

The authors had full access to and take full responsibility for the integrity of the data. All authors have read and agree to the manuscript as written.

Results

Table 1⇓ presents differences between OPCAB and on-pump CABG in the prevalence of various risk factors for adverse outcomes of CABG surgery. As indicated, OPCAB patients were more likely to be older, and more women underwent OPCAB than on-pump CABG (29.3% versus 27.4%, P<0.0001). In addition, OPCAB patients appeared sicker in that they had worse ejection fractions (eg, 2.4% versus 1.8% for ejection fraction <20%, P<0.001) and greater prevalences of cerebrovascular disease (21.0% versus 19.0%, P<0.0001), peripheral vascular disease (12.2% versus 10.7%, P<0.0001), congestive heart failure (14.1% versus 12.4% at admission, P<0.0001), extensively calcified ascending aorta (9.0% versus 4.2%, P<0.0001), and renal failure (2.2% versus 1.6% for patients on dialysis, P<0.0001).

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TABLE 1. Baseline Characteristics of Patients Undergoing Off-Pump and On-Pump CABG Surgery in New York State, 2001–2004

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TABLE 1. Continued

On the other hand, on-pump patients appeared sicker with regard to having had 1 or more previous open heart procedures (3.6% versus 2.6%, P<0.0001) and with regard to having hemodynamic instability (1.3% versus 1.1% for unstable hemodynamic state, 0.4% versus 0.2% for shock, P=0.0017), diabetes mellitus (35.0% versus 33.6%, P=0.0041), emergency transfer to the operating room after catheterization (1.9% versus 1.4%, P<0.0001), stent thrombosis (0.2% versus 0.1%, P=0.041), and a greater number of diseased vessels (58.8% versus 51.2% for 3-vessel disease, P<0.0001). On-pump patients had a significantly lower CSRS-CABG risk score44 (3.83 versus 4.20, P<0.0001) and more anastomoses (3.42 versus 2.96, P<0.0001).

A total of 226 patients (1.63%) were converted from OPCAB to on-pump CABG, and their in-hospital/30-day mortality rate was 9.73%. The unadjusted (observed) inpatient/30-day mortality rates were not significantly different (P=0.31), but the risk-adjusted rates favored OPCAB (adjusted OR 0.81, 95% CI 0.68 to 0.97, P=0.0022).

Table 2 demonstrates that OPCAB patients had significantly lower risk-adjusted rates for 2 perioperative complications: stroke (adjusted OR 0.70, 95% CI 0.57 to 0.86) and respiratory failure (adjusted OR 0.80, 95% CI 0.68 to 0.93). OPCAB patients had a significantly higher rate of unplanned operations in the same admission (adjusted OR 1.47, 95% CI 1.01 to 2.15).

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TABLE 2. Intraoperative and Postoperative Complication Rates (%) and Adjusted ORs (Off-Pump/On-Pump Surgery) and 95% CIs for Complications

Among unmatched patients, the total number of deaths was 1398 (10.07%) for OPCAB patients and 3013 (8.38%) for on-pump patients. The total number of subsequent CABG procedures was 49 (0.35%) for OPCAB patients and 63 (0.18%) for on-pump patients; the total number of repeat percutaneous coronary interventions was 945 (6.80%) for OPCAB patients and 1705 (4.74%) for on-pump patients.

The variables used for matching were age, gender, race, ejection fraction, previous myocardial infarction, 1 or more previous open heart operations, hemodynamic state, extensively calcified ascending aorta, diabetes mellitus, renal failure, emergency transfer to the operating room after catheterization, previous PCI, stent thrombosis as a risk factor, left main disease, and number of coronary vessels diseased. It is also notable that only 1 unmatched risk factor with a significant difference in prevalence between the 2 types of procedures was present (cerebrovascular disease), and that the difference (19.7% OPCAB, 18.6% on-pump, P=0.033) does not appear to be of practical significance.

Table 3 demonstrates that although the unadjusted HR for mortality suggested higher mortality for OPCAB patients, no significant difference was present after adjustment. Also, in the matched samples, no significant difference was present with regard to mortality (HR 1.08, 95% CI 0.96 to 1.22). However, OPCAB patients had significantly higher rates of subsequent revascularization after risk adjustment of the entire sample (adjusted HR 1.50, 95% CI 1.32 to 1.70) and after patients were matched exactly on patient characteristics that were significant predictors of surgery type (HR 1.55, 95% CI 1.33 to 1.80). It is remarkable how similar these estimates are.

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TABLE 3. HRs (Off-Pump Surgery/On-Pump Surgery) and 95% CIs for Outcomes

Figures 1 and 2⇓ present Kaplan-Meier curves for OPCAB and on-pump CABG surgery that use the matched data. The 3-year OPCAB versus on-pump survival rates were 89.4% versus 90.1%, respectively (log-rank test, P=0.20). For subsequent revascularization, the respective rates were 89.9% versus 93.6% (P<0.0001).

Figure1

Figure 1. Three-year Kaplan-Meier curves for survival for off-pump and on-pump bypass surgery (matched cases). Numbers in the Figure are survival rates and 95% CIs. Numbers of patients at risk were 8867, 6027, and 3188 for OPCAB at 1, 2, and 3 years, respectively, and 8893, 6063, and 3155 for on-pump CABG.

Figure2

Figure 2. Three-year Kaplan-Meier curves for freedom from subsequent revascularization for off-pump and on-pump bypass surgery (matched cases). Numbers in the Figure are rates of freedom from subsequent revascularization and 95% CIs. Numbers of patients at risk were 8465, 5599, and 2880 for OPCAB at 1, 2, and 3 years, respectively, and 8624, 5742, and 2938 for on-pump CABG.

Table 4 presents HRs for mortality and subsequent revascularization for OPCAB relative to on-pump CABG surgery for subgroups of matched patients (patients 80 years of age and older, and patients with stroke, congestive heart failure, extensively calcified ascending aorta, renal failure, and left circumflex disease [stenosis ≥70%]) undergoing CABG surgery who were matched exactly with respect to patient characteristics that predicted type of surgery. As indicated, no mortality differences existed for any of the subgroups. However, 4 subgroups of patients demonstrated significantly higher rates of 3-year risk-adjusted subsequent revascularization for OPCAB patients, with the HRs ranging from 1.58 for patients with left circumflex disease to 2.64 for patients with renal failure. All of these HRs were higher than the HR of 1.55 for all matched patients presented in Table 3.

View this table:

TABLE 4. HRs (Off-Pump Surgery/On-Pump Surgery) and 95% CIs for Subgroups of Matched Patients

When we restricted the matched patient population to 3074 OPCAB cases performed by high-volume surgeons (upper quartile) who had used OPCAB for >50% of their surgical cases and 3074 on-pump cases performed by high-volume surgeons who had used on-pump CABG for >50% of their surgical cases, the HR was 1.12 (95% CI 0.88 to 1.43, P=0.34) for mortality and 1.56 (95% CI 1.16 to 2.10, P=0.004) for subsequent revascularization. Note that 77.6% of OPCAB cases were performed by surgeons who performed at least 50% of their cases off-pump.

The propensity analyses demonstrated that the HRs for 3-year mortality and repeat revascularization rates were not substantially different for any of the propensity-identified quartiles for each of the 2 outcome measures, nor was there an increasing or decreasing trend in HRs across quartiles. For mortality, which had an overall HR of 1.01, the quartile HRs ranged from 0.96 to 1.08, and for repeat revascularization, which had an overall HR of 1.50, the quartile HRs ranged from 1.31 to 1.67.

Discussion

Numerous studies in the literature have compared outcomes for OPCAB relative to on-pump CABG surgery.1–37 These outcomes include short-term mortality, long-term mortality, need for subsequent revascularization, cognitive function, renal function, and cost.1–18 However, most of these studies were either relatively small randomized, controlled trials (RCTs) or large observational studies without access to long-term outcomes. Also, many of the studies are dated, and because OPCAB has a longer learning curve than on-pump surgery, it is conceivable that the relative outcomes for the 2 types of procedures have changed over time as more surgeons have gained experience with OPCAB.

The intents of the present study were to identify differences in patient characteristics, short-term outcomes, and long-term outcomes among on-pump and OPCAB patients, as well as to document the extent to which OPCAB has penetrated the market in New York and the extent to which utilization and outcomes relative to on-pump surgery have changed since the last study conducted in New York.36

With respect to utilization and changes in utilization, an earlier (1997–2000) New York study documented that the number of isolated CABG surgery patients undergoing off-pump surgery with sternotomy rose from 3.0% of all cases in 1997 to 27.0% of all cases in 2000.36 The present study shows that the percentage of cases done on an off-pump basis has leveled off, with 27.9% of all isolated CABG cases performed off-pump between 2001 and 2004. We also found that OPCAB patients in the present study were similar to OPCAB patients in our previous study36 with regard to patient characteristics and with regard to having lower complication rates (risk-adjusted stroke and respiratory failure).

OPCAB patients also had significantly lower in-hospital/30-day mortality rates than on-pump patients (adjusted OR 0.81, 95% CI 0.68 to 0.97). This differed from the findings of our previous study, which found no significant difference in risk-adjusted in-hospital mortality.36

With respect to longer-term outcomes, we found no difference in 3-year mortality, whereas our previous study36 found that OPCAB patients did have a significantly higher mortality rate than on-pump patients. In both time periods, OPCAB patients had significantly higher rates of subsequent revascularization.

Our findings in the present study with respect to short-term outcomes are similar to those of several recent studies. Meta-analyses have identified lower complication rates, particularly with regard to stroke,21,22,28 atrial fibrillation,21,22 and short-term mortality.21,28 Also, 2 of 3 large observational studies found that OPCAB patients had lower risk-adjusted in-hospital mortality and complication rates,24,27 whereas the other study found no differences in risk-adjusted in-hospital mortality or complication rates.32

Less information is available from other studies on comparative long-term outcomes, but evidence exists of higher repeat revascularization rates and lower graft patency rates among OPCAB patients. For example, Wijeysundera et al,28 in a meta-analysis of randomized and observational studies, found higher long-term (1 to 2 years) repeat revascularization in both RCTs and observational studies.

The present study, which is much larger than the RCTs and which is the first large observational study to report longer-term outcomes, reinforces these findings. OPCAB patients had significantly higher rates of subsequent revascularization after risk adjustment of the entire sample (adjusted HR 1.50, 95% CI 1.32 to 1.70) and after patients were matched exactly on patient characteristics that were significant predictors of surgery type (HR 1.55, 95% CI 1.33 to 1.80).

We were unable to determine the extent to which the higher repeat revascularization rate was related to lower graft patency versus a higher incomplete revascularization rate during the index procedure. This is important because the latter may be more easily remedied by changing practice patterns.

Furthermore, when we restricted the matched patient population to 3074 OPCAB cases performed by high-volume surgeons (upper quartile) who had performed >50% of their CABG cases off-pump and 3074 on-pump cases performed by high-volume surgeons who had chosen on-pump CABG for >50% of their cases, the HR was 1.12 (95% CI 0.88 to 1.43, P=0.34) for mortality and 1.56 (95% CI 1.16 to 2.10, P=0.004) for subsequent revascularization. Thus, the results were consistent with the results for all patients.

As noted above, the present study is an observational study and not an RCT. An advantage of this is that it provides insight as to what is done in practice and how practice has changed. Also, observational studies tend to be larger and consequently have more statistical power for identifying significant differences. Moreover, observational studies tend to include more high-risk patients and are therefore able to detect whether 1 of the alternatives is associated with better outcomes for high-risk patients. Another advantage is that unlike many observational studies, we were able to capture intention-to-treat data, so that OPCAB cases that were converted to on-pump procedures were regarded as OPCAB cases in the results.

An obvious disadvantage of an observational study is the risk of selection bias because patients have not been chosen randomly. We attempted to minimize this bias by matching patients exactly on the basis of patient-related factors in our database that were significant predictors of type of procedure in multivariable analyses, in addition to the typical risk-adjusted outcome comparisons for the 2 procedures, followed by propensity analyses that did not demonstrate any selection bias. Nevertheless, a caveat of the study is that selection biases can still be present because of factors related to choice of procedure and to adverse outcomes that were not present in the database used in the present study. Examples of some of these factors are target-vessel size, intramyocardial location, and extent of disease in the target vessel.

We also note that because we did not adjust for multiple end points in the study, potential for inflated type I errors exists. This should not be a major caveat, because all of the outcome differences identified were highly significant (P<0.01), except for the difference in the rate of unplanned operation (Table 2).

Thus, in summary, we found that OPCAB patients had a small but statistically significantly lower rate of 2 perioperative complications, tempered by a substantially higher rate of subsequent revascularization. In conjunction with the recent results from the Octopus trial, which showed no difference in cognitive or cardiac outcomes between OPCAB and on-pump surgery in low-risk patients, it would appear that the benefits of OPCAB found in small RCTs may not be translatable to large geographic regions.33

We look forward to future efforts to chronicle comparative outcomes of OPCAB and on-pump CABG surgery and to identify which patients are best served by each procedure. Clearly, this should involve acting on recommendations to launch large RCTs of OPCAB and on-pump CABG surgery.45 However, unlike trials of devices for which the results are unaffected by surgical skill, it will also be important to account for the expertise of surgeons and its interaction with choice of procedure.

Acknowledgments

The authors would like to thank Kenneth Shine, MD, the chair of New York State’s Cardiac Advisory Committee, and the remainder of the Cardiac Advisory Committee for their encouragement and support of this study; and Paula Waselauskas, Kimberly Cozzens, Rosemary Lombardo, and the cardiac surgery departments and cardiac catheterization laboratories of the participating hospitals for their tireless efforts to ensure the timeliness, completeness, and accuracy of the registry data.

Disclosures

Dr Higgins reports having served on an expert panel on immunosuppression for AstraZeneca and having served as an expert witness for malpractice cases. Dr Culliford reports having served as an expert witness for malpractice case. The remaining authors report no conflicts.

References

  1. ↵
    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.
    OpenUrlCrossRefPubMed
  2. ↵
    Benetti FJ, Naselli G, Wood M, Geffner L. Direct myocardial revascularization without extracorporeal circulation: experience in 700 patients. Chest. 1991; 100: 312–316.
    OpenUrlCrossRefPubMed
  3. ↵
    Van Dijk D, Nierich AP, Jansen EW, Nathoe HM, Suyker WJ, Diephuis JC, van Boven WJ, Borst C, Buskens E, Grobbee DE, Robles De Medina EO, de Jaegere PP; Octopus Study Group. Early outcome after off-pump versus on-pump coronary bypass surgery: results from a randomized study. Circulation. 2001; 104: 1761–1766.
    OpenUrlAbstract/FREE Full Text
  4. ↵
    Van Dijk D, Jansen EW, Hijman R, Nierich AP, Diephuis JC, Moons KG, Lahpor JR, Borst C, Keizer AM, Nathoe HM, Grobbee DE, De Jaegere PP, Kalkman CJ; Octopus Study Group. Cognitive outcome after off-pump and on-pump coronary artery bypass graft surgery: a randomized trial. JAMA. 2002; 287: 1405–1412.
    OpenUrlCrossRefPubMed
  5. ↵
    Ascione R, Lloyd CT, Underwood MJ, Gomes WJ, Angelini GD. On-pump versus off-pump coronary revascularization: evaluation of renal function. Ann Thorac Surg. 1999; 68: 493–498.
    OpenUrlCrossRefPubMed
  6. ↵
    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.
    OpenUrlCrossRefPubMed
  7. ↵
    Ascione R, Lloyd CT, Underwood MJ, Lotto AA, Pitsis AA, Angelini GD. Inflammatory response after coronary revascularization with or without cardiopulmonary bypass. Ann Thorac Surg. 2000; 69: 1198–1204.
    OpenUrlCrossRefPubMed
  8. ↵
    Ascione R, Caputo M, Calori G, Lloyd CT, Underwood MJ, Angelini GD. Predictors of atrial fibrillation after conventional and beating heart coronary surgery: a prospective, randomized study. Circulation. 2000; 102: 1530–1535.
    OpenUrlAbstract/FREE Full Text
  9. ↵
    Mack MJ. Perspectives on minimally invasive coronary artery surgery: current assessment and future directions. Int J Cardiol. 1997; 62: S73–S79.
    OpenUrlCrossRefPubMed
  10. ↵
    Hernandez F, Cohn WE, Baribeau YR, Tryzelaar JF, Charlesworth DC, Clough RA, Klemperer JD, Morton JR, Westbrook BM, Olmstead EM, O’Connor GT; Northern New England Cardiovascular Disease Study Group. In-hospital outcomes of off-pump versus on-pump coronary artery bypass procedures: a multicenter experience. Ann Thorac Surg. 2001; 72: 1528–1533.
    OpenUrlCrossRefPubMed
  11. ↵
    Borst C, Santamore WP, Smedira NG, Bredee JJ. Minimally invasive coronary artery bypass grafting: on the beating heart and via limited access. Ann Thorac Surg. 1997; 63: S1–S5.
    OpenUrlCrossRefPubMed
  12. ↵
    Subramanian VA. Less invasive arterial CABG on a beating heart. Ann Thorac Surg. 1997; 63: S68–S71.
    OpenUrlCrossRefPubMed
  13. ↵
    Diegeler A, Hirsch R, Schneider F, Schilling LO, Falk V, Rauch T, Mohr FW. Neuromonitoring and neurocognitive outcome in off-pump versus conventional coronary bypass operation. Ann Thorac Surg. 2000; 69: 1162–1166.
    OpenUrlCrossRefPubMed
  14. ↵
    Jansen EW, Grundeman PF, Borst C, Eefting F, Diephuis J, Nierich A, Lahpor JR, Bredee JJ. Less invasive off-pump CABG using a suction device for immobilization: the “Octopus” method. Eur J Cardiothorac Surg. 1997; 12: 406–412.
    OpenUrlAbstract/FREE Full Text
  15. ↵
    Jansen EW, Borst C, Lahpor JR, Grundeman PF, Eefting FD, Nierich A, Robles de Medina EO, Bredee JJ. Coronary artery bypass grafting without cardiopulmonary bypass using the Octopus method: results in the first one hundred patients. J Thorac Cardiovasc Surg. 1998; 116: 60–67.
    OpenUrlCrossRefPubMed
  16. ↵
    Borst C, Jansen EW, Tulleken CA, Grundeman PF, Mansvelt Beck HJ, van Dongen JW, Hodde KC, Bredee JJ. Coronary artery bypass grafting without cardiopulmonary bypass and without interruption of native coronary flow using a novel anastomosis site restraining device (“Octopus”). J Am Coll Cardiol. 1996; 27: 1356–1364.
    OpenUrlCrossRefPubMed
  17. ↵
    Hart JC, Spooner TH, Pym J, Flavin TF, Edgerton JR, Mack MJ, Jansen EW. A review of 1,582 consecutive Octopus off-pump coronary bypass patients. Ann Thorac Surg. 2000; 70: 1017–1020.
    OpenUrlCrossRefPubMed
  18. ↵
    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. Eur J Cardiothorac Surg. 1999; 15: 685–690.
    OpenUrlAbstract/FREE Full Text
  19. ↵
    Kilger E, Pichler B, Weis F, Goetz A, Lamm P, Schutz A, Muehlbayer D, Frey L. Markers of myocardial ischemia after minimally invasive and conventional coronary operation. Ann Thorac Surg. 2000; 70: 2023–2028.
    OpenUrlCrossRefPubMed
  20. ↵
    Moshkovitz Y, Lusky A, Mohr R. Coronary artery bypass without cardiopulmonary bypass: analysis of short-term and mid-term outcome in 220 patients. J Thorac Cardiovasc Surg. 1995; 110: 979–987.
    OpenUrlCrossRefPubMed
  21. ↵
    Panesar SS, Athanasiou T, Nair S, Rao C, Jones C, Nicolaou M, Darzi A. Early outcomes in the elderly: a meta-analysis of 4921 patients undergoing coronary artery bypass grafting: a comparison between off-pump and on-pump techniques. Heart. 2006; 92: 1808–1816.
    OpenUrlAbstract/FREE Full Text
  22. ↵
    Sedrakyan A, Wu AW, Parashar A, Bass EB, Treasure T. Off-pump surgery is associated with reduced occurrence of stroke and other morbidity as compared with traditional coronary artery bypass grafting: a meta-analysis of systematically reviewed trials. Stroke. 2006; 37: 2759–2769.
    OpenUrlFREE Full Text
  23. ↵
    Calafiore AM, Di Mauro M, Contini M, Di Giammarco G, Pano M, Vitolla G, Bivona A, Carella R, D’Alessandro S. Myocardial revascularization with and without cardiopulmonary bypass in multivessel disease: impact of the strategy on early outcome. Ann Thorac Surg. 2001; 72: 456–462.
    OpenUrlCrossRefPubMed
  24. ↵
    Puskas JD, Williams WH, Mahoney EM, Huber PR, Block PC, Duke PG, Staples JR, Glas KE, Marshall JJ, Leimbach ME, McCall SA, Peterson RJ, Bailey DE, Weintraub WS, Guyton RA. 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.
    OpenUrlCrossRefPubMed
  25. ↵
    Legare JF, Buth KJ, King S, Wood J, Sullivan JA, Hancocok Friesen C, Lee J, Stewart K, Hirsch GM. Coronary bypass surgery performed off pump does not result in lower in-hospital morbidity than coronary artery bypass grafting performed on pump. Circulation. 2004; 109: 887–892.
    OpenUrlAbstract/FREE Full Text
  26. ↵
    Cleveland JC Jr, Shroyer AL, Chen AY, Peterson E, Grover FL. Off-pump coronary artery bypass grafting decreases risk-adjusted mortality and morbidity. Ann Thorac Surg. 2001; 72: 1282–1288.
    OpenUrlCrossRefPubMed
  27. ↵
    Plomondon ME, Cleveland JC, Ludwig ST, Grunwald GK, Kiefe CI, Grover FL, Shroyer AL. Off-pump coronary artery bypass is associated with improved risk-adjusted outcomes. Ann Thorac Surg. 2001; 72: 114–119.
    OpenUrlCrossRefPubMed
  28. ↵
    Wijeysundera DN, Beattie WS, Djaiani G, Rao V, Borger MA, Karkouti K, Cusimano RJ. Off-pump coronary artery surgery for reducing mortality and morbidity: meta-analysis of randomized and observational studies. J Am Coll Cardiol. 2005; 46: 872–882.
    OpenUrlCrossRefPubMed
  29. ↵
    Cheng DC, Bainbridge D, Martin JE, Novick RJ; Evidence-Based Perioperative Clinical Outcomes Research Group. 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.
    OpenUrlCrossRefPubMed
  30. ↵
    Straka Z, Widimsky P, Jirasek K, Stros P, Votava J, Vanek T, Brucek P, Kolesar M, Spacek R. Off-pump versus on-pump coronary surgery: final results from a prospective randomized study PRAGUE-4. Ann Thorac Surg. 2004; 77: 789–793.
    OpenUrlCrossRefPubMed
  31. ↵
    Nathoe HM, van Dijk D, Jansen EW, Suyker WJ, Diephuis JC, van Boven WJ, de la Riviere AB, Borst C, Kalkman CJ, Grobbee DE, Buskens E, de Jaegere PP; Octopus Study Group. A comparison of on-pump and off-pump coronary bypass surgery in low-risk patients. N Engl J Med. 2003; 348: 394–402.
    OpenUrlCrossRefPubMed
  32. ↵
    Hernandez F, Cohn WE, Baribeau YR, Tryzelaar JF, Charlesworth DC, Clough RA, Klemperer JD, Morton JR, Westbrook BM, Olmstead EM, O’Connor GT; Northern New England Cardiovascular Disease Study Group. In-hospital outcomes of off-pump versus on-pump coronary artery bypass procedures: a multicenter experience. Ann Thorac Surg. 2001; 72: 1528–1533.
    OpenUrlCrossRefPubMed
  33. ↵
    van Dijk D, Spoor M, Hijman R, Nathoe HM, Borst C, Jansen EW, Grobbee DE, de Jaegere PP, Calkman CJ; Octopus Study Group. Cognitive and cardiac outcomes 5 years after off-pump vs. on-pump coronary artery bypass graft surgery. JAMA. 2007; 297: 701–708.
    OpenUrlCrossRefPubMed
  34. ↵
    Parolari A, Alamanni F, Polvani G, Agrifoglio M, Chen YB, Kassem S, Veglia F, Tremoli E, Biglioli P. Meta-analysis of randomized trials comparing off-pump with on-pump coronary artery bypass graft patency. Ann Thorac Surg. 2005; 80: 2121–2125.
    OpenUrlCrossRefPubMed
  35. ↵
    Khan NE, De Souza A, Mister R, Flather M, Clague J, Davies S, Collins P, Wang D, Sigwart U, Pepper J. A randomized comparison of off-pump and on-pump multivessel coronary-artery bypass surgery. N Engl J Med. 2004; 350: 21–28.
    OpenUrlCrossRefPubMed
  36. ↵
    Racz MJ, Hannan EL, Isom OW, Subramanian VA, Jones RH, Gold JP, Ryan TJ, Hartman A, Culliford AT, Bennett E, Lancey RA, Rose EA. A comparison of short- and long-term outcomes after off-pump and on-pump coronary artery bypass graft surgery with sternotomy. J Am Coll Cardiol. 2004; 43: 557–564.
    OpenUrlCrossRefPubMed
  37. ↵
    Williams ML, Muhlbaier LH, Schroder JN, Hata JA, Peterson ED, Smith PK, Landolfo KP, Messier RH, Davis RD, Milano CA. Risk-adjusted short- and long-term outcomes for on-pump versus off-pump coronary artery bypass surgery. Circulation. 2005; 112 (suppl I): I-366–I-370.
    OpenUrlCrossRefPubMed
  38. ↵
    Zeger SL, Liang K-Y, Albert PS. Models for longitudinal data: a generalized estimating equation approach. Biometrics. 1988; 42: 1049–1060.
    OpenUrl
  39. ↵
    Lin DY, Wei LJ. The robust inference for the proportional hazards model. J Am Stat Assoc. 1989; 84: 1074–1078.
    OpenUrlCrossRef
  40. ↵
    Reid N, Crèpeau H. Influence functions for proportional hazards regression. Biometrika. 1985; 72: 1–9.
    OpenUrlAbstract/FREE Full Text
  41. ↵
    Binder DA. Fitting Cox’s proportional hazards models from survey data. Biometrika. 1992; 79: 139–147.
    OpenUrlAbstract/FREE Full Text
  42. ↵
    Rosenbaum PR, Rubin DR. Reducing bias in observational studies using subclassification on the propensity score. J Am Stat Assoc. 1984; 79: 516–524.
    OpenUrlCrossRef
  43. ↵
    Rosenbaum PR, Rubin DB. The central role of the propensity score in observational studies for causal effects. Biometrika. 1983; 70: 41–55.
    OpenUrlAbstract/FREE Full Text
  44. ↵
    Hannan EL, Wu C, Bennett EV, Carlson RE, Culliford AT, Gold JP, Higgins RS, Isom OW, Smith CR, Jones RH. Risk stratification of in-hospital mortality for coronary artery bypass graft surgery. J Am Coll Cardiol. 2006; 47: 661–668.
    OpenUrlCrossRefPubMed
  45. ↵
    Peterson ED, Mark DB. Off-pump bypass surgery: ready for the big dance? JAMA. 2004; 291: 1897–1899.
    OpenUrlCrossRefPubMed

CLINICAL PERSPECTIVE

Off-pump coronary artery bypass graft surgery (OPCAB) has been performed for many years, but its use is increasing in frequency, and it remains an open question whether OPCAB is associated with better outcomes than on-pump coronary artery bypass graft (CABG) surgery. This study examined data for New York State patients who underwent either OPCAB with median sternotomy (13 889 patients) or on-pump CABG surgery (35 941 patients) between 2001 and 2004. Short- and long-term outcomes were compared after adjustment for patient risk factors and after patients were matched on the basis of significant predictors of type of CABG surgery. Findings were that OPCAB had a significantly lower inpatient/30-day mortality rate (adjusted OR 0.81, 95% confidence interval [CI] 0.68 to 0.97), lower rates for 2 perioperative complications (stroke: adjusted OR 0.70, 95% CI 0.57 to 0.86; respiratory failure: adjusted OR 0.80, 95% CI 0.68 to 0.93), and a higher rate of unplanned operation in the same admission (adjusted OR 1.47, 95% CI 1.01 to 2.15). No difference existed in 3-year mortality (hazard ratio 1.08, 95% CI 0.96 to 1.22), but OPCAB patients had significantly higher rates of subsequent revascularization (hazard ratio 1.55, 95% CI 1.33 to 1.80). The 3-year OPCAB and on-pump survival rates for matched patients were 89.4% versus 90.1%, respectively (P=0.20). For freedom from subsequent revascularization, the respective rates were 89.9% versus 93.6% (P<0.0001). In conclusion, OPCAB is associated with lower in-hospital mortality and complication rates than on-pump CABG, but long-term outcomes are comparable except for freedom from revascularization, which favors on-pump CABG.

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Circulation
September 4, 2007, Volume 116, Issue 10

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  • Off-Pump Versus On-Pump Coronary Artery Bypass Graft Surgery
    Edward L. Hannan, Chuntao Wu, Craig R. Smith, Robert S.D. Higgins, Russell E. Carlson, Alfred T. Culliford, Jeffrey P. Gold and Robert H. Jones
    Circulation. 2007;116:1145-1152, originally published September 3, 2007
    https://doi.org/10.1161/CIRCULATIONAHA.106.675595
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