Skip Navigation


European Heart Journal Advance Access originally published online on March 16, 2008
European Heart Journal 2008 29(11):1346-1349; doi:10.1093/eurheartj/ehn128
This Article
Right arrow Abstract Freely available
Right arrow FREE Full Text (PDF) Freely available
Right arrow All Versions of this Article:
29/11/1346    most recent
ehn128v1
Right arrow E-letters: Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when E-letters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Right arrow Disclaimer
Google Scholar
Right arrow Articles by Briffa, N.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Briffa, N.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?

Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2008. For permissions please email: journals.permissions@oxfordjournals.org

Off pump coronary artery bypass: a passing fad or ready for prime time?

Norman Briffa1,2,*

1 South Yorkshire Cardiothoracic Centre, STH NHS Trust, Chesterman Wing, Northern General Hospital, Herries Road, Sheffield S5 7AU, UK
2 University of Sheffield, Sheffield, UK

Received 18 February 2008; accepted 29 February 2008; online publish-ahead-of-print 16 March 2008.

* Corresponding author. Tel: +44 1142266786, Fax: +44 1142610350, Email: norman.briffa{at}sth.nhs.uk


   Abstract
Top
 Abstract
Summary points
 References
 
Off pump coronary artery bypass (OPCAB) allows multivessel coronary disease to be bypassed surgically without the need for cardiopulmonary bypass, myocardial ischaemia, and in many cases ascending aortic manipulation. Many randomized controlled studies of OPCAB vs. on pump CABG (coronary artery bypass grafting) have been completed and published. Although non-inferior, OPCAB does not, in these trials, offer any clear benefits. As a consequence, surgeons and industry are losing interest in this undeniably harder technique. As the risk profile of patients being referred for coronary surgery is increasing, is it time for OPCAB to prove itself? A large, appropriately powered randomized controlled trial of OPCAB vs. on pump CABG in high-risk patients will determine whether it is now or never for OPCAB.

Key Words: Coronary disease • Surgery • Bypass • Cardiopulmonary bypass

When coronary artery bypass surgery was being investigated as a viable treatment of patients with coronary artery disease, the use of cardiopulmonary bypass was well-established in heart valve and congenital heart surgery. It is not surprising therefore that the use of the heart lung machine became the default in the coronary artery bypass grafting (CABG) operation.

During this operation, the patient is heparinized and attached to an extracorporeal circuit. His/her aorta is cannulated and clamped and the heart is rendered globally ischaemic.

It has become clear over the years that much of the morbidity associated with the CABG operation is directly attributable to the way the operation is performed.

The use of extracorporeal circulation is a potent stimulus of a generalized inflammatory state involving interleukins and complement1–9 affecting all organs in the body.

Occult atheromatous disease in the ascending aorta is a frequent cause of neurological injury10,11 because of debris that embolizes to the brain12 when the aorta is cannulated and clamped.

Although periods of global myocardial ischaemia that are required for accurate placement of the coronary grafts are usually well tolerated, there are many instances when it would be desirable to limit the time the myocardium is deprived of its blood supply—operating on patients with impaired left ventricular function or patients who have had a recent myocardial infarct would be good examples.

Thus, avoidance of cardiopulmonary bypass, aortic manipulation, and global myocardial ischaemia during a coronary artery bypass operation could potentially improve outcomes.

Although, as mentioned above, the use of cardiopulmonary bypass became standard in coronary surgery, during the early 1990s a number of surgeons published accounts of a series of CABG operations performed without the heart–lung machine.13–15 As industry became interested, new products became available to facilitate off pump coronary artery bypass (OPCAB)—these included mechanical stabilizers and intra-coronary shunts. It is now possible, in most cases, to achieve full surgical revascularization of the heart through a median sternotomy without cardio pulmonary bypass or myocardial ischaemia and if in situ conduits are used, e.g. Y graft of radial artery or RITA from LITA, the ascending aorta is not touched.

A number of randomized controlled studies comparing OPCAB to on pump CABG have been completed. Although outcomes have been largely comparable, the evidence of benefit of OPCAB from these trials has not been as convincing as was first anticipated.

One outcome that is clearly superior in patients undergoing OPCAB is bleeding and the need for transfusion. Seven randomized controlled studies have clearly shown that patients who undergo OPCAB bleed less and require fewer transfusions of red blood cells and clotting factors.16–21

Avoidance of cardiopulmonary bypass does not necessarily protect the kidney. In randomized controlled trials, there was no difference in the need for renal replacement treatment between patients undergoing OPCAB and those undergoing on pump CABG.17,20,22,23 One study from Angelini's24 group in Bristol, UK demonstrated a smaller drop of creatinine clearance after OPCAB. This was associated with the improved glomerular and tubular function in these patients. Another study using similar methods to assess renal function failed to demonstrate any benefit in these patients.25

In five randomized studies, there were smaller rises in cardiac enzymes (CKMB and/or troponin) in patients undergoing OPCAB.17,18,20,23,26 This difference did not translate into a clinical benefit apart from in one study which demonstrated that patients undergoing OPCAB were less likely to require postoperative inotropes or to suffer postoperative arrhythmias, including atrial fibrillation.27,28

Cardiac MRI has been used to quantify the amount of myocardial necrosis that inevitably occurs after coronary bypass surgery.29 In this study, although patients who underwent OPCAB had larger cardiac indices and smaller end-systolic volumes immediately after surgery when compared to those who were put on bypass, the amount of viable myocardium in the postoperative period was not different between the two groups.

In randomized controlled trials comparing the incidence of cerebral microemboli measured with high-intensity transient signals (HITS) using Doppler, investigators have found that avoiding bypass resulted in a dramatic decrease in the number of emboli.30–32 This did not translate into a smaller number of neurological events. Two imaging studies (one using magnetic resonance and the other, radionuclide scanning) have found a smaller number of postoperative defects in the brains of patients undergoing OPCAB.19,33 A third study using magnetic resonance imaging, 3 months after surgery,32 did not find a difference. There was a significantly greater deterioration in postoperative psychometric tests in three randomized controlled studies in patients undergoing on pump CABG when compared to those undergoing OPCAB.19,34,35 In one further study, there was no differences between the two groups.36

None of the randomized controlled studies showed a difference in mortality between patients undergoing OPCAB and those undergoing on pump CABG.17,18,20,22,23,37,38 Two studies showed a difference in length of stay in ITU22,39 and one a difference in in-hospital length of stay.39

One of the potential pitfalls and original concerns with OPCAB is that high graft patency rates would be sacrificed with this methodology. Causes of graft failure would include the greater difficulty of anastomosis and the pronounced procoagulant phase that seems to occur in patient undergoing OPCAB.40–42 Three randomized trials comparing OPCAB with on pump CABG have failed to show any difference in patency.20,39,43 One trial from the Brompton hospital in London, UK38 did show a difference with lower graft patency rates in the OPCAB patients. This trial was criticized for the fact that patient numbers were small (52) and that the patients from the ‘learning curve’ were included in the analysis. A retrospective study from New York State, published recently, suggested that patients undergoing OPCAB were more likely to require addition revascularization procedures in the medium term when compared to patients undergoing on pump CABG.44

The lack of evidence for unequivocal superiority of OPCAB over on pump CABG and a stressful steep learning curve has persuaded many established surgeons to give up the technique and dissuaded many trainee surgeons from investing in proper training opportunities. The rate for OPCAB in the UK peaked to around 19% of all CABGs and is now declining (Personal Communication, UK Central Cardiac Audit Database). Industry is losing heart and many companies are less inclined to invest in training than they did 5 years ago.

The lack of evidence does not mean, however, that there is no role for OPCAB and loss of interest in the technique is premature.

Mortality and morbidity rates after coronary artery bypass surgery in most patients are very low. In the UK, the chance of a patient dying after an elective CABG operation is 0.8% (Society of Cardiothoracic Surgery UK and Ireland, personal communication) and rates for major morbid events are less than 10% (STS database). For a randomized controlled trial to detect differences in outcomes whose incidence is low, they would have to be powered appropriately, i.e. to include thousands of patients. The biggest randomized controlled trial of OPCAB vs. on pump CABG only had 280 patients23 and patients recruited in most of the studies were of the low-risk elective type.

Coronary disease is now a disease of the elderly. The 75+ year old patient with calcific tight left main stem, RCA disease, and impaired left ventricular function who presents with an NSTEMI and pulmonary oedema and is found to have a porcelain aorta at surgery is becoming a dreaded phenotype many cardiac surgeons are becoming familiar with. Major databases for coronary surgery (STS, SCTS) on both sides of the Atlantic confirm that the risk profile for patients undergoing CABG has a steep incline. These high-risk patients are the ones who would ideally benefit from OPCAB techniques.

Information on the outcome of thousands (rather than hundreds) of patients undergoing OPCAB has been published in a number of retrospective studies in which outcomes of patients undergoing OPCAB are compared to those of propensity matched patients who have undergone on pump CABG. The patients are matched for variables known to influence outcome after cardiac surgery, e.g. age, left ventricular function, etc. To date, all these retrospective studies45,46 have demonstrated a significantly lower mortality and a lower incidence of serious morbid events such as CVA, renal failure, and major wound infection in patients undergoing OPCAB. This effect was more pronounced in high-risk patients. In a very large study of more than 100 000 US wide patients presented at the 2007 annual meeting of the Society of Thoracic Surgeons in San Diego, the beneficial effect of avoiding cardiopulmonary bypass in CABG was more pronounced in women.47 Thus, gender was a less of an independent risk factor for death in OPCAB when compared to on pump CABG. In a recent retrospective study of more than 50 000 patients undergoing OPCAB and on pump CABG in the New York State area, authors found that mortality and complication rates were indeed smaller in patients undergoing OPCAB.44 These were offset by the greater need for further revascularization in these patients.

Retrospective studies are always open to the charge of selection bias and a large randomized trial of OPCAB in high-risk patients is urgently required. Such a trial would have to involve many centres in different countries. Taggart et al.48 in Oxford have proven with the ART trial that it is possible to organize a multi centre international surgical study of thousands of patients.

An appropriately powered study should confirm or refute the dramatic results of the retrospective studies and determine whether it is the time for OPCAB to find its true role in the armamentarium of the cardiac surgeon.


   Summary points
Top
 Abstract
 Summary points
References
 
OPCAB allows surgical revascularization of diseased coronary arteries without the use of cardiopulmonary bypass and global myocardial ischaemia.

Randomized controlled studies have failed to demonstrate benefit of OPCAB over on pump CABG.

Retrospective studies of large number of patients suggest benefit of OPCAB in high-risk patients.

Adequately powered RCTs examining this technique in high-risk patients are required.

Conflict of interest: none declared.


   References
Top
 Abstract
 Summary points
 References
 

  1. Haslam PL, Townsend PJ, Branthwaite MA. Complement activation during cardiopulmonary bypass. Anaesthesia (1980) 35:22–26.[Web of Science][Medline]
  2. Chaitman BR, Fisher LD, Bourassa MG, Davis K, Rogers WJ, Maynard C, Tyras DH, Berger RL, Judkins MP, Ringqvist I, Mock MB, Killip T. Effect of coronary bypass surgery on survival patterns in subsets of patients with left main coronary artery disease. Report of the Collaborative Study in Coronary Artery Surgery (CASS). Am J Cardiol (1981) 48:765–777.[CrossRef][Web of Science][Medline]
  3. Chenoweth DE, Cooper SW, Hugli TE, Stewart RW, Blackstone EH, Kirklin JW. Complement activation during cardiopulmonary bypass: evidence for generation of C3a and C5a anaphylatoxins. N Engl J Med (1981) 304:497–503.[Abstract]
  4. White JV. Complement activation during cardiopulmonary bypass. N Engl J Med (1981) 305:51.[Web of Science][Medline]
  5. Jones HM, Matthews N, Vaughan RS, Stark JM. Cardiopulmonary bypass and complement activation. Involvement of classical and alternative pathways. Anaesthesia (1982) 37:629–633.[Web of Science][Medline]
  6. Wysocki H, Ponizynski A, Wierusz-Wysocka B, Brocki Z, Czarnecki R. Cardiopulmonary bypass-induced complement activation. Evidence for C5a participation. Int J Artif Organs (1982) 5:305–308.[Web of Science][Medline]
  7. Gandhi JG, Salm TV, Szymanski IO. Effect of cardiopulmonary bypass on plasma fibronectin, IgG, and C3. Transfusion (1983) 23:476–479.[CrossRef][Web of Science][Medline]
  8. Chiu RC, Samson R. Complement (C3, C4) consumption in cardiopulmonary bypass, cardioplegia, and protamine administration. Ann Thorac Surg (1984) 37:229–232.[Abstract]
  9. Meri S, Verkkala K, Miettinen A, Valtonen V, Linder E. Complement levels and C3 breakdown products in open-heart surgery: association of C3 conversion with the postpericardiotomy syndrome. Clin Exp Immunol (1985) 60:597–604.[Web of Science][Medline]
  10. Roach GW, Kanchuger M, Mangano CM, Newman M, Nussmeier N, Wolman R, Aggarwal A, Marschall K, Graham SH, Ley C. Adverse cerebral outcomes after coronary bypass surgery. Multicenter Study of Perioperative Ischemia Research Group and the Ischemia Research and Education Foundation Investigators. N Engl J Med (1996) 335:1857–1863.[Abstract/Free Full Text]
  11. Gilman S. Neurological complications of open heart surgery. Ann Neurol (1990) 28:475–476.[CrossRef][Web of Science][Medline]
  12. Schmitz C, Blackstone EH. International Council of Emboli Management (ICEM) Study Group results: risk adjusted outcomes in intraaortic filtration. Eur J Cardiothorac Surg (2001) 20:986–991.[Abstract/Free Full Text]
  13. Benetti FJ. Direct coronary surgery with saphenous vein bypass without either cardiopulmonary bypass or cardiac arrest. J Cardiovasc Surg (Torino) (1985) 26:217–222.[Medline]
  14. Buffolo E, de Andrade CS, Branco JN, Teles CA, Aguiar LF, Gomes WJ. Coronary artery bypass grafting without cardiopulmonary bypass. Ann Thorac Surg (1996) 61:63–66.[Abstract/Free Full Text]
  15. Buffolo E, Gerola LR. Coronary artery bypass grafting without cardiopulmonary bypass through sternotomy and minimally invasive procedure. Int J Cardiol (1997) 62(Suppl. 1):S89–S93.[CrossRef][Web of Science][Medline]
  16. Ascione R, Williams S, Lloyd CT, Sundaramoorthi T, Pitsis AA, Angelini GD. Reduced postoperative blood loss and transfusion requirement after beating-heart coronary operations: a prospective randomized study. J Thorac Cardiovasc Surg (2001) 121:689–696.[Abstract/Free Full Text]
  17. 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.[Abstract/Free Full Text]
  18. Gerola LR, Buffolo E, Jasbik W, Botelho B, Bosco J, Brasil LA, Branco JN. Off-pump versus on-pump myocardial revascularization in low-risk patients with one or two vessel disease: perioperative results in a multicenter randomized controlled trial. Ann Thorac Surg (2004) 77:569–573.[Abstract/Free Full Text]
  19. Lee JD, Lee SJ, Tsushima WT, Yamauchi H, Lau WT, Popper J, Stein A, Johnson D, Lee D, Petrovitch H, Dang CR. Benefits of off-pump bypass on neurologic and clinical morbidity: a prospective randomized trial. (Discussion 25-16). Ann Thorac Surg (2003) 76:18–25.[Abstract/Free Full Text]
  20. Puskas JD, Williams WH, Duke PG, Staples JR, Glas KE, Marshall JJ, Leimbach M, Huber P, Garas S, Sammons BH, McCall SA, Petersen RJ, Bailey DE, Chu H, Mahoney EM, Weintraub WS, Guyton RA. Off-pump coronary artery bypass grafting provides complete revascularization with reduced myocardial injury, transfusion requirements, and length of stay: a prospective randomized comparison of two hundred unselected patients undergoing off-pump versus conventional coronary artery bypass grafting. J Thorac Cardiovasc Surg (2003) 125:797–808.[Abstract/Free Full Text]
  21. van Dijk D, Diephuis JC, Nierich AP, Keizer AM, Kalkman CJ. Beating heart versus conventional cardiopulmonary bypass: the octopus experience: a randomized comparison of 281 patients undergoing coronary artery bypass surgery with or without cardiopulmonary bypass. Semin Cardiothorac Vasc Anesth (2006) 10:167–170.[Abstract/Free Full Text]
  22. 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.[CrossRef][Web of Science][Medline]
  23. 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. Early outcome after off-pump versus on-pump coronary bypass surgery: results from a randomized study. Circulation (2001) 104:1761–1766.[Abstract/Free Full Text]
  24. 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.[Abstract/Free Full Text]
  25. Tang AT, Knott J, Nanson J, Hsu J, Haw MP, Ohri SK. A prospective randomized study to evaluate the renoprotective action of beating heart coronary surgery in low risk patients. Eur J Cardiothorac Surg (2002) 22:118–123.[Abstract/Free Full Text]
  26. Penttila HJ, Lepojarvi MV, Kiviluoma KT, Kaukoranta PK, Hassinen IE, Peuhkurinen KJ. Myocardial preservation during coronary surgery with and without cardiopulmonary bypass. Ann Thorac Surg (2001) 71:565–571.[Abstract/Free Full Text]
  27. 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.[Abstract/Free Full Text]
  28. Ascione R, Reeves BC, Taylor FC, Seehra HK, Angelini GD. Beating heart against cardioplegic arrest studies (BHACAS 1 and 2): quality of life at mid-term follow-up in two randomised controlled trials. Eur Heart J (2004) 25:765–770.[Abstract/Free Full Text]
  29. Selvanayagam JB, Petersen SE, Francis JM, Robson MD, Kardos A, Neubauer S, Taggart DP. Effects of off-pump versus on-pump coronary surgery on reversible and irreversible myocardial injury: a randomized trial using cardiovascular magnetic resonance imaging and biochemical markers. Circulation (2004) 109:345–350.[Abstract/Free Full Text]
  30. Motallebzadeh R, Kanagasabay R, Bland M, Kaski JC, Jahangiri M. S100 protein and its relation to cerebral microemboli in on-pump and off-pump coronary artery bypass surgery. Eur J Cardiothorac Surg (2004) 25:409–414.[Abstract/Free Full Text]
  31. Abu-Omar Y, Cader S, Guerrieri Wolf L, Pigott D, Matthews PM, Taggart DP. Short-term changes in cerebral activity in on-pump and off-pump cardiac surgery defined by functional magnetic resonance imaging and their relationship to microembolization. J Thorac Cardiovasc Surg (2006) 132:1119–1125.[Abstract/Free Full Text]
  32. Lund C, Hol PK, Lundblad R, Fosse E, Sundet K, Tennoe B, Brucher R, Russell D. Comparison of cerebral embolization during off-pump and on-pump coronary artery bypass surgery. (Discussion 770). Ann Thorac Surg (2003) 76:765–770.[Abstract/Free Full Text]
  33. Abu-Omar Y, Cifelli A, Matthews PM, Taggart DP. The role of microembolisation in cerebral injury as defined by functional magnetic resonance imaging. Eur J Cardiothorac Surg (2004) 26:586–591.[Abstract/Free Full Text]
  34. 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. Cognitive outcome after off-pump and on-pump coronary artery bypass graft surgery: a randomized trial. JAMA (2002) 287:1405–1412.[Abstract/Free Full Text]
  35. Zamvar V, Williams D, Hall J, Payne N, Cann C, Young K, Karthikeyan S, Dunne J. 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.[Abstract/Free Full Text]
  36. Keizer AM, Hijman R, van Dijk D, Kalkman CJ, Kahn RS. Cognitive self-assessment one year after on-pump and off-pump coronary artery bypass grafting. (Discussion 838–839). Ann Thorac Surg (2003) 75:835–838.[Abstract/Free Full Text]
  37. Carrier M, Perrault LP, Jeanmart H, Martineau R, Cartier R, Page P. Randomized trial comparing off-pump to on-pump coronary artery bypass grafting in high-risk patients. Heart Surg Forum (2003) 6:E89–E92.[Web of Science][Medline]
  38. 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.[Abstract/Free Full Text]
  39. Al-Ruzzeh S, George S, Bustami M, Wray J, Ilsley C, Athanasiou T, Amrani M. Effect of off-pump coronary artery bypass surgery on clinical, angiographic, neurocognitive, and quality of life outcomes: randomised controlled trial. BMJ (2006) 332:1365.[Abstract/Free Full Text]
  40. Moller CH, Steinbruchel DA. Platelet function after coronary artery bypass grafting: is there a procoagulant activity after off-pump compared with on-pump surgery? Scand Cardiovasc J (2003) 37:149–153.[CrossRef][Web of Science][Medline]
  41. Mariani MA, Gu YJ, Boonstra PW, Grandjean JG, van Oeveren W, Ebels T. Procoagulant activity after off-pump coronary operation: is the current anticoagulation adequate? Ann Thorac Surg (1999) 67:1370–1375.[Abstract/Free Full Text]
  42. Englberger L, Immer FF, Eckstein FS, Berdat PA, Haeberli A, Carrel TP. Off-pump coronary artery bypass operation does not increase procoagulant and fibrinolytic activity: preliminary results. Ann Thorac Surg (2004) 77:1560–1566.[Abstract/Free Full Text]
  43. 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. A comparison of on-pump and off-pump coronary bypass surgery in low-risk patients. N Engl J Med (2003) 348:394–402.[Abstract/Free Full Text]
  44. Hannan EL, Wu C, Smith CR, Higgins RS, Carlson RE, Culliford AT, Gold JP, Jones RH. 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 (2007) 116:1145–1152.[Abstract/Free Full Text]
  45. Mack MJ, Pfister A, Bachand D, Emery R, Magee MJ, Connolly M, Subramanian V. Comparison of coronary bypass surgery with and without cardiopulmonary bypass in patients with multivessel disease. J Thorac Cardiovasc Surg (2004) 127:167–173.[Abstract/Free Full Text]
  46. Al-Ruzzeh S, Ambler G, Asimakopoulos G, Omar RZ, Hasan R, Fabri B, El-Gamel A, DeSouza A, Zamvar V, Griffin S, Keenan D, Trivedi U, Pullan M, Cale A, Cowen M, Taylor K, Amrani M. Off-Pump Coronary Artery Bypass (OPCAB) surgery reduces risk-stratified morbidity and mortality: a United Kingdom Multi-Center Comparative Analysis of Early Clinical Outcome. Circulation (2003) 108(Suppl. 1):II1–II8.[Medline]
  47. Puskas JD, Kilgo PD, Kutner M, Pusca SV, Lattouf O, Guyton RA. Off-pump techniques disproportionately benefit women and narrow the gender disparity in outcomes after coronary artery bypass surgery. Circulation (2007) 116(Suppl. 11):I192–I199.[Web of Science][Medline]
  48. Taggart DP, Lees B, Gray A, Altman DG, Flather M, Channon K. Protocol for the Arterial Revascularisation Trial (ART). A randomised trial to compare survival following bilateral versus single internal mammary grafting in coronary revascularisation [ISRCTN46552265]. Trials (2006) 7:7.[CrossRef][Medline]

Add to CiteULike CiteULike   Add to Connotea Connotea   Add to Del.icio.us Del.icio.us    What's this?


This article has been cited by other articles:


Home page
 Ann. Thorac. Surg.Home page
S. A.R. Doi
Modelling methodologic quality into meta-analyses and pitfalls of not doing this.
Ann. Thorac. Surg., March 1, 2009; 87(3): 985 - 986.
[Full Text] [PDF]

This Article
Right arrow Abstract Freely available
Right arrow FREE Full Text (PDF) Freely available
Right arrow All Versions of this Article:
29/11/1346    most recent
ehn128v1
Right arrow E-letters: Submit a response
Right arrow Alert me when this article is cited
Right arrow Alert me when E-letters are posted
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Similar articles in ISI Web of Science
Right arrow Similar articles in PubMed
Right arrow Alert me to new issues of the journal
Right arrow Add to My Personal Archive
Right arrow Download to citation manager
Right arrowRequest Permissions
Right arrow Disclaimer
Google Scholar
Right arrow Articles by Briffa, N.
Right arrow Search for Related Content
PubMed
Right arrow PubMed Citation
Right arrow Articles by Briffa, N.
Social Bookmarking
Add to CiteULike   Add to Connotea   Add to Del.icio.us  
What's this?