Benefits of OPCAB are not for everybody. Costs are.

Abstract

In the present issue of the Journal, Haynes and Trachiotis comment on recent literature regarding on-pump coronary artery bypass versus off-pump coronary artery bypass (OPCAB) surgery, including the data on graft patency from the Danish On-pump Versus Off-pump Randomization Study (DOORS). It is correct when the authors claim that the angiographic follow-up data from the DOORS were not complete because only 56% of the surviving patients consented to have the examination performed.1Houlind K. Fenger-Grøn M. Holme S.J. Kjeldsen B.J. Madsen S.N. Rasmussen B.S. et al.DOORS Study GroupGraft patency after off-pump coronary artery bypass surgery is inferior even with identical heparinization protocols: results from the Danish On-pump Versus Off-pump Randomization Study (DOORS).J Thorac Cardiovasc Surg. 2014; 148: 1812-1819Abstract Full Text Full Text PDF PubMed Scopus (65) Google Scholar However, as pointed out in the accompanying editorial by Smith,2Smith C. #SLOPCAB: is the party over?.J Thorac Cardiovasc Surg. 2014; 148: 1788-1789Abstract Full Text Full Text PDF PubMed Scopus (9) Google Scholar an extensive statistical analysis was performed to ensure the balance of both perioperative and patient-related risk factors of graft occlusion. Therefore, we consider the observations to be valid. We confirmed the findings of a number of earlier investigators who found graft patency to be inferior.3Shroyer A.L. Grover F.L. Hattler B. Collins J.F. McDonald G.O. Kozora E. et al.On-pump versus off-pump coronary-artery bypass surgery.N Engl J Med. 2009; 361: 1827-1837Crossref PubMed Scopus (887) Google Scholar, 4Khan N.E. De Souza A. Mister R. Flather M. Clague J. Davies S. et al.A randomized comparison of off-pump and on-pump multivessel coronary-artery bypass surgery.N Engl J Med. 2004; 350: 21-28Crossref PubMed Scopus (486) Google Scholar Even in smaller series performed by excellent OPCAB enthusiasts,5Puskas J.D. Williams W.H. Mahoney E.M. Huber P.R. Block P.C. Duke P.G. et al.Off-pump versus conventional coronary artery bypass grafting: early and 1 year graft patency, cost, and quality-of-life outcomes. A randomized trial.JAMA. 2004; 291: 1841-1849Crossref PubMed Scopus (484) Google Scholar there was a trend toward inferior graft patency after OPCAB, although the statistical power to conclude was not present. The number of grafts received by patients undergoing OPCAB is consistently lower than the number of grafts received by patients undergoing conventional coronary artery bypass grafting (cCABG) in most trials. It is probably safe to assume that the majority of cardiac surgeons consider their own skills to be above average. Nevertheless, when performing an anastomosis, a bloodless, immobile field is an advantage in the hands of everyone, and even the surgeon who performs well without cardiopulmonary bypass is likely to perform even better when using it. It seems that with the current knowledge, the question that remains is not whether the grafts are better when performed with the use of cardiopulmonary bypass and cardioplegic arrest, but rather to which extent the advantage is clinically relevant and outweighs the risks. In the DOORS, after 6 months follow-up, we found no significant difference between the OPCAB and cCABG groups with regard to survival or self-assessed, health-related quality of life.6Houlind K. Kjeldsen B.J. Madsen S.N. Rasmussen B.S. Holme S.J. Nielsen P.H. et al.DOORS Study GroupOn-pump versus off-pump coronary artery bypass surgery in elderly patients: results from the Danish on-pump versus off-pump randomization study.Circulation. 2012; 125: 2431-2439Crossref PubMed Scopus (125) Google Scholar In addition, the number and duration of secondary admissions to hospital within this period tended to be lower among OPCAB cases.7Houlind K. Kjeldsen B.J. Madsen S.N. Rasmussen B.S. Holme S.J. Pallesen P.A. et al.DOORS Study GroupOPCAB surgery is cost-effective for elderly patients.Scand Cardiovasc J. 2013; 47: 185-192Crossref PubMed Scopus (12) Google Scholar These findings seem to suggest that even if the graft patency indeed was poorer and the number of grafts was lower, this did not have any clinically relevant effect on the patients. However, results from other studies point in the opposite direction. In the CABG Off or On Pump Revascularization Study (CORONARY)8Lamy A. Deveraux P.J. Prabhakaran D. Taggart D.P. Hu S. Paolasso E. et al.Effects of off-pump and on-pump coronary-artery bypass grafting at 1 year.N Engl J Med. 2013; 368: 1179-1188Crossref PubMed Scopus (330) Google Scholar and German Off Pump Coronary Artery Bypass in Elderly (GOPCABE)9Diegeler A. Börgermann J. Kappert U. Breuer M. Böning A. Ursulescu A. et al.Off-pump versus on-pump coronary-artery bypass grafting in elderly patients.N Engl J Med. 2013; 368: 1189-1198Crossref PubMed Scopus (354) Google Scholar trials, the risk of need for reintervention was increased after OPCAB, and, most disturbing, in the Randomized On/Off Bypass (ROOBY) trial even cardiac mortality was higher after 1 year.3Shroyer A.L. Grover F.L. Hattler B. Collins J.F. McDonald G.O. Kozora E. et al.On-pump versus off-pump coronary-artery bypass surgery.N Engl J Med. 2009; 361: 1827-1837Crossref PubMed Scopus (887) Google Scholar Long-term mortality also seemed to be higher in the recent meta-analysis by Tagaki and Umemoto,10Tagaki H. Umemoto T. Worse survival after off-pump than on-pump coronary artery bypass grafting.J Thorac Cardiovasc Surg. 2014; 148: 1820-1829Abstract Full Text Full Text PDF PubMed Scopus (71) Google Scholar although this conclusion was not based on randomized, controlled trials. So, when the efficacy of OPCAB is inferior to that of cCABG in terms of completeness of revascularization, need for reintervention, and risk of cardiac death, the argument to pursue this strategy should be that the risk of complications is lower with OPCAB than with cCABG. The use of OPCAB originally was promoted on the basis of the belief that cardiopulmonary bypass led to a very high incidence of postoperative cognitive dysfunction, a syndrome known colloquially as “pump head.” In a few early randomized trials with a short follow-up (7 days to 10 weeks), patients undergoing cCABG scored significantly worse postoperatively compared with patients undergoing OPCAB when subjected to neurocognitive tests.11Diegeler A. Hirsch R. Schneider F. Schilling L.O. Falk V. Rauch T. et al.Neuromonitoring and neurocognitive outcome in off-pump versus conventional coronary bypass operation.Ann Thorac Surg. 2000; 69: 1162-1166Abstract Full Text Full Text PDF PubMed Scopus (352) Google Scholar, 12Zamvar V. Williams D. Hall J. Payne N. Cann C. Young K. et al.Assessment of neurocognitive impairment after off-pump and on-pump techniques for coronary artery bypass graft surgery: prospective randomised controlled trial.BMJ. 2002; 325: 1268-1273Crossref PubMed Google Scholar In the Octopus trial,13van Dijk D. Spoor M. Hijman R. Nathoe H.M. Borst C. Jansen E.W. et al.Cognitive and cardiac outcomes 5 years after off-pump versus on-pump coronary artery bypass graft surgery.JAMA. 2007; 297: 701-708Crossref PubMed Scopus (239) Google Scholar a significant difference in favor of OPCAB was found after 3 months, but not after 1 year or after 5 years of follow-up. At the 5-year follow-up, a more than 50% decline in scores at neurocognitive testing was found in both groups. The ROOBY trial showed small, statistically but probably not clinically significant differences at 1-year follow-up.3Shroyer A.L. Grover F.L. Hattler B. Collins J.F. McDonald G.O. Kozora E. et al.On-pump versus off-pump coronary-artery bypass surgery.N Engl J Med. 2009; 361: 1827-1837Crossref PubMed Scopus (887) Google Scholar Cognitive decline is also common after noncardiac surgery, especially in elderly patients.14Moller J.T. Cluitmans P. Rasmussen L.S. Houx P. Rasmussen H. Canet J. et al.Long-term postoperative dysfunction in the elderly: ISPOCD1 study.Lancet. 1988; 351: 857-861Abstract Full Text Full Text PDF Scopus (1806) Google Scholar In addition, patients in need of cCABG have a high prevalence of risk factors, such as diabetes mellitus and hypertension, which also predispose them to neurocognitive decline. In fact, a similar rate of neurocognitive decline has been found in nonsurgical controls and in patients who underwent cCABG after the 3-year follow-up,15Selnes O.A. Grega M.A. Borowicz Jr., L.M. Barry S. Zeger S. Baumgartner W.A. et al.Cognitive outcomes 3 years after coronary artery bypass surgery: a comparison of on-pump coronary artery bypass graft surgery and nonsurgical controls.Ann Thorac Surg. 2005; 79: 1201-1209Abstract Full Text Full Text PDF PubMed Scopus (84) Google Scholar and in a randomized study of elderly patients, the postoperative neurocognitive decline tended to be more severe in OPCAB than in cCABG cases.16Jensen B.Ø. Rasmussen L.S. Steinbrüchel D.A. Cognitive outcomes in elderly high-risk patients 1 year after off-pump versus on-pump coronary artery bypass grafting. A randomized trial.Eur J Cardiothorac Surg. 2008; 34: 1016-1021Crossref PubMed Scopus (58) Google Scholar Generally, it seems that the “pump head” argument is less valid than originally anticipated. A large number of other differences in minor or surrogate outcomes carry less weight.17Houlind K. On-pump versus off-pump coronary artery bypass surgery: what is the status after ROOBY, DOORS, CORONARY and GOPCABE?.Future Cardiol. 2013; 9: 569-579Crossref PubMed Scopus (8) Google Scholar However, one important argument in favor of OPCAB does remain: Less manipulation of the ascending aorta potentially diminishes the risk of periprocedural stroke. In 2012, Afilalo and co-workers18Afilalo J. Rasti M. Ohayon S.M. Shimoni A. Eisenberg M.J. Off-pump vs. on-pump coronary artery bypass surgery: an updated meta-analysis and meta-regression of randomised trials.Eur Heart J. 2012; 33: 1257-1267Crossref PubMed Scopus (134) Google Scholar performed a meta-regression analysis. Including all the major randomized controlled trials from which data were available at this time. Their analysis comprised 30-day follow-up data from 8961 patients in 59 trials. They found a significant 30% reduction in stroke rate with OPCAB compared with cCABG. In the DOORS, we did not have the statistical strength to document a significant difference in stroke rate between groups according to the principle of intention to treat, but most of the strokes in the OPCAB group were related to conversion to the on-pump technique or the use of a side-biting clamp when making the proximal anastomosis. Because the periprocedural risk of stroke is very low in younger patients, it seems that this argument for accepting the lower efficacy of OPCAB is valid only in elderly patients with increased risk. As pointed out by Sabik19Sabik III, J.F. On-pump coronary revascularization should be our preferred surgical revascularization strategy.J Thorac Cardiovasc Surg. 2014; 148: 2472-2474Abstract Full Text Full Text PDF PubMed Scopus (8) Google Scholar in his recent editorial, the implication of the evidence is that “…we routinely cannot do as good a surgical revascularization off pump as we can do on pump.” This means that we should probably reserve off-pump operations for patients who are at an increased risk of stroke, and in these cases, the use of the off-pump technique should be accompanied by the principle of no-touch aorta for the patients to experience the benefit. The state of off-pump coronary artery bypass in 2015The Journal of Thoracic and Cardiovascular SurgeryVol. 149Issue 4PreviewOver the past few years, dedicated investigators have continued to deliver compelling data on the outcomes of off-pump coronary artery bypass grafting (OPCAB) compared with conventional on-pump grafting (cCABG). The trial known as DOORS (Danish On-Pump vs Off-Pump Randomization Study)1 reported a concerning decrease in 6-month graft patency with OPCAB, whereas the results of the CORONARY trial (Coronary Artery Bypass Grafting Surgery Off or On Pump Revascularization Study)2 showed an increase in perioperative acute kidney injury with cCABG while confirming no difference in survival and kidney function at 1 year. Full-Text PDF Open Archive