SciELO - Scientific Electronic Library Online

 
vol.98 número1Índice tornozelo-braquial e hipertrofia ventricular na hipertensão arterialImpacto da insuficiência renal crônica na eficácia de stents farmacológicos índice de autoresíndice de assuntospesquisa de artigos
Home Pagelista alfabética de periódicos  

Serviços Personalizados

Journal

Artigo

Indicadores

Links relacionados

Compartilhar


Arquivos Brasileiros de Cardiologia

versão impressa ISSN 0066-782X

Arq. Bras. Cardiol. vol.98 no.1 São Paulo jan. 2012

http://dx.doi.org/10.1590/S0066-782X2012000100014 

REVIEW ARTICLE

 

On-pump versus off-pump coronary-artery bypass surgery: a meta-analysis

 

 

Ana Sofia GodinhoI; Ana Sofia AlvesI; Alexandre José PereiraI; Telmo Santos PereiraII

IEscola Superior de Saúde Dr. Lopes Dias, Castelo Branco
IIEscola Superior de Tecnologia da Saúde de Coimbra, Coimbra, Portugal

Mailing Address

 

 


ABSTRACT

There are controversies about the possible benefits of off-pump coronary artery bypass grafting (OPCABG) compared to on-pump coronary artery bypass grafting (ONCABG). For a better perspective on this important issue, we performed a meta-analysis of randomized controlled trials, comparing the two techniques.
The objective of this study was to verify which technique applied in Coronary Artery Bypass Surgery, OPCABG or ONCABG, provides better results through a meta-analysis of published randomized trials comparing the two techniques.
We carried out a computer-based literature search in PubMed, Embase, B-on and Science Direct from March 2009 to January 2010. The studies covered were recovered according to predetermined criteria. A systematic review of randomized clinical trials was performed in order to evaluate the differences between the two revascularization techniques (OPCABG versus ONCABG) regarding mortality and morbidity. Selected studies did not include patients at high risk and long-term longitudinal evaluations.
The meta-analysis focused on nine randomized clinical trials, corresponding to a total of 75,086 patients, and compared OPCABG to ONCABG. Regarding mortality, a reduction of 18% in the risk of cardiovascular mortality (OR: 0.82, 95%CI: 0.70 to 0.98, p = 0.03) and 27% in the risk of stroke postoperatively (OR: 0.73, 95%CI: 0.63 to 0.85, p = 0.0001) were observed, both in favor of OPCABG. Concerning the occurrence of complications associated with the procedure, no significant differences were found between the two surgical techniques, particularly with regard to the occurrence of kidney complications (OR: 0.97, 95%CI: 0.84-1.14, p = 0, 74) and sepsis (OR 0.98, 95%CI: 0.64-1.51, p = 0.93, respectively).
Off-pump CABG significantly reduces the occurrence of major cardiovascular events (mortality and CVA) compared to on-pump CABG surgery.

Keywords: Coronary artery bypass; off pump; myocardial revascularization; intraoperative complications; meta-analysis.


 

 

Introduction

Cardiopulmonary bypass (CPB) as a support method in cardiac surgery is, from the historical point of view, relatively new. Among the several procedures of myocardial revascularization surgery (CABG), only the method of Vineberg1 showed promising results, and it was performed without knowledge of the anatomy of coronary arteries1. Later, Rene Favaloro was the pioneer of the CABG surgery using the saphenous vein, using CPB and cardiac arrest2. The familiarity of surgeons with the CPB circuit and the development of strategies for myocardial protection has led to the carrying out of CABG procedures using this technique3.

One of the most important trends of the 90s was the search for methods that would allow a reduction of the trauma that accompanies the CABG procedures with CPB. The first such initiative was the rediscovery of the CABG procedures without CPB, initially described by Kolesov4-6 in 1967, but made popular only in the second to last decade by Benetti4,7 in Argentina and Buffolo in Brazil4,8.

Currently, off-pump (OPCABG) CABG has acquired its own identity; however, despite evidence of the feasibility and safety of this technique, conventional on-pump CABG (ONCABG) is still used by most surgeons4.

Cardiovascular diseases are the ninth leading cause of mortality9, and coronary heart disease (CHD) the fourth leading cause of years of life lost, making it an important public health problem10.

Today, several therapeutic options are available in the context of ischemic heart disease. Regarding surgical options, several techniques have been developed, but controversies remain regarding the benefits of the different available types11.

ONCABG surgery remains a reference in this context; however, important limitations are acknowledged in this technique. In the last two decades, in spite of a dramatic increase in patient risk factors, morbidity and postoperative complications have decreased significantly. These improvements are attributed to systematic advances in surgical techniques, anesthetic techniques and myocardial protection strategies11,12. Nevertheless, neurologic complications remain a risk for patients undergoing CPB. Currently, the use of this method is still recognized as a leading cause of complex organic systemic inflammatory response (OSIR), which greatly contributes to several adverse effects in the postoperative period, namely, kidney, pulmonary or neurological complications and bleeding episodes, among other13,14.

Over the last ten years there has been an increasing interest in performing CABG without CPB, or off-pump CABG (OPCABG), stimulated by the recognition of the harmful effects of CPB12-18. In this sense, the OPCABG has gained some acceptance and has become a widely performed procedure in an attempt to reduce morbidity and neurological injury related to ONCABG from12,19-25.

In contrast, according to some authors, the OPCABG involves risk of intraoperative hemodynamic instability and incomplete revascularization, thereby increasing mortality and morbidity in the long term26-31. However, the real clinical impact of this alternative surgical technique remains limited by the scarcity of studies comparing the two methods26-31. According to Gerola et al32, there are no statistically significant differences in mortality and morbidity rates in low-risk patients.

On the other hand, some studies have documented important effects of OPCABG, although the available evidence is not sufficient to define the possible relevance of this technique in clinical practice; thereby, the controversy remains on the real benefits of its use23-37.

Thus, we carried out a meta-analysis of randomized controlled trials comparing the ONCABG to OPCABG, to assess the relative benefits in terms of mortality, morbidity and complications inherent in the procedures.

 

Methods

Research

We carried out a literature search using the search engines PubMed, Embase, B-on and Science Direct, looking for articles that contained the combinations of the words: coronary artery bypass grafting, on-pump versus off-pump, Complications, morbidity, mortality, cardiopulmonary bypass, myocardial revascularization, CPB versus off-pump, complications, morbidity, mortality, cardiopulmonary bypass. The research began in March 2009 and ended in January 2010.

Inclusion Criteria

We analyzed the titles and abstracts of the articles and included in the review all those that reported CABG in the context of on-pump and off-pump surgeries. We only considered studies with adult patients undergoing CABG with and without CPB. Research with animals were excluded from this review, as well as studies written in other languages rather than English, Spanish or Portuguese.

Data extraction

The selection criteria of the methods described were applied to 94 studies identified in literature search in the aforementioned search engines. Based on a review by two independent observers, which concealed the identity of the authors, the articles were accepted or not.

In a first phase, the titles and abstracts of 94 studies were analyzed to determine potential eligibility for further evaluation. Thus, all studies that met the following criteria were selected: prospective randomized study comparing on-pump and off-pump CABG. In this first phase, it was observed that 32 studies were duplicates, 6 had combined procedures, 11 studies were not randomized, 6 had no OPCABG group and did not conta n ONCABG group, leaving only 34 studies.

In a second phase, the 34 selected studies were evaluated in more details, showing that 19 contained insufficient data, 4 did not meet the inclusion criteria, and two were still ongoing. Thus, nine studies remained, which showed characteristics potentially suitable for inclusion in the meta-analysis. The following endpoints were obtained from these articles: mortality, cerebrovascular accident (CVA), kidney complications and septicemia.

Statistical Analysis

The data were analyzed using the Statistical Review Manager Version 5.0 (Copenhagen, The Nordic Cochrane Centre, The Cochrane Collaboration, 2008) using fixed effect and random effect models. Heterogeneity was assessed by Q test and complemented with I2, which indicates the proportion of variability between studies, providing a measure of heterogeneity38-40.

The results were assessed as dichotomous variables, for which the odds ratio (OR) and 95% confidence intervals (95%CI) were calculated41. The criterion for statistical significance was a p value < 0.05 for a confidence interval of 95%.

 

Results

Selected studies

The inclusion criteria were applied to the 94 studies assessed, but only nine articles were selected and evaluated in details. These were all published studies, of which clinical characteristics are shown in Table 142-50.

 

Meta-analysis

Mortality

Mortality was reported in seven studies (23,163 patients, Figure 1)42,44-48,50 and according to the analysis, it was significantly lower in off-pump group (OR = 0.82, 95%CI: 0.70 - 0.98, p = 0.03), with heterogeneity regarding the overall effect in the sample (Chi2 = 24.51, p = 0.0004). The OR represents a 18% reduction in the mortality risk in favor of the OPCABG surgical technique and must be considered with care in the context of the heterogeneity among the studies mentioned above.

Cerebral-vascular Accident (CVA)

The incidence of CVA was reported in five studies (64,713 patients, Figure 2)42,43,45,47,48. The analysis showed that this incidence was significantly lower in the OPCABG group and that there was no heterogeneity, i.e., the studies were homogeneous with respect to the overall effect in the sample (Chi2 = 3.86, p = 0.43). The meta-analysis showed a significant difference in CVA risk, with an OR of 0.73 (95%CI: 0.63 to 0.85, p = 0.0001), indicating a 27% reduction in risk of postoperative CVA in favor of OPCABG.

Kidney Complications

Kidney complications were reported in five studies (59,410 patients, Figure 3)43-45,47,50 and the analysis showed there was heterogeneity regarding the overall effect in the sample (Chi2 = 10.01, p = 0.04). The meta-analysis showed no significant difference in kidney complications, indicating an OR of 0.97 (95%CI: 0.84 - 1.14, p = 0.74).

Septicemia

Septicemia was reported in three studies (58,457 patients, Figure 4)43,44,47, which, according to the analysis, were homogeneous with respect to the overall effect in the sample (Chi2 = 3.09, p = 0.21). The meta-analysis showed no significant difference in septicemia (OR = 0.98, 95%CI: 0.64 -1.51, p = 0.93).

 

Discussion

The OPCABG is an important surgical technique in the present context, although its use and dissemination in clinical practice still lack scientific support, regardless of any improvements made over the past years in order to reduce mortality and morbidity in the postoperative period attributable to the surgery51-54. However, due to difficulties in conducting prospective randomized trials in this area and therefore the small number of recorded patients, the statistical power of available studies is relatively low. Moreover, one must consider the low incidence of mortality and morbidity in patients undergoing myocardial revascularization55.

In recent years, several studies have been published, but the number of available randomized clinical trials is also limited56-58. Thus, with regard to key endpoints (death and CVA), only randomized studies with large samples can conclusively demonstrate differences in outcomes between treatment groups of low-risk patients54. On the other hand, the studies series tend to exclude higher-risk patients, perhaps the most likely to benefit from the OPCABG technique, and therefore, doubts remain about the safety of this technique in this context51,56-58.

Moreover, one must consider the existence of studies that effectively show a reduction in mortality and morbidity in the operative and post-operative period of OPCABG when compared to ONCABG. However, the generalization of results can be questioned due to the subtle external validity of the studies26,51,57,58. In addition to the existing controversy, some studies also advocate that patients undergoing OPCABG have increased risk of postoperatively bypass occlusion. Thus, one discusses the durability of revascularization supported by this technique, although it has been recognized that the risk of obstruction in the first year is low and the two procedures can overlap58,59.

Aiming to contribute to the clarification of key issues that have polarized the discussion of this topic, several meta-analysis have been carried out, using data available in the scientific literature, with the main objective of providing additional statistical support to clarify the status of OPCABG54-57 compared to ONCABG. The present study is an attempt to provide further clarification. In this sense, the results indicate a clinical advantage toward OPCABG, indicating an 18% reduction in the mortality risk (OR 0.82, 95%CI: 0.70 - 0.98, p = 0.03) and a 27% reduction the risk of postoperative CVA (OR 0.73, 95%CI: 0.63 - 0.85, p = 0.0001). Regarding the occurrence of postoperative complications, namely, sepsis and kidney complications, no statistically significant differences were found, although most of the included studies suggested a greater impact of ONCABG on the kidney. This aspect is expressed in the results obtained in the meta-analysis (OR 0.97, 95%CI: 0.84 - 1.14, p = 0.74), outlining a trend suggestive of lower risk of complications associated with OPCABG29,57,60-62.

Other evidence relevant to this problem, previously addressed in other studies, concern the need for transfusion, length of hospital stay and cost of surgery. In this sense, the currently available evidence indicates that OPCABG is characterized by reduced need for blood transfusion, shortest length of stay and therefore, lower hospital costs45,46,48-50,55-57,63.

These aspects have been supported by a recent meta-analysis54, which has shown that the OPCABG is less expensive compared to ONCABG. Moreover, another study64 showed that the costs of patients submitted to OPCABG were significantly lower when compared to ONCABG (OPCABG 6,515 ± 926 € vs. ONCABG 9,872 ± 1,299 €, p <0.0001). This difference is mainly due to decreased postoperative complications and reduced stay in intensive care unit. However, one should consider that patients submitted to OPCABG requiring transition to ONCABG, have a higher risk of postoperative mortality and multiple organ failure, compared to patients submitted initially to ONCABG surgery43,65. This reinforces the need to select the right patients for the surgical technique that best suits the individual clinical profile.

 

Limitations

The studies included in this meta-analysis were published between 2002 and 2007 and therefore may not reflect practical realities that are non-representative of more current surgical and anesthetic practices. While they overall favor the OPCABG, the results should be interpreted with some caution, as four of the nine studies did not contain information concerning the clinical characteristics of patients included in the study.

Although this meta-analysis outlines the current situation, it also serves to highlight some of the questions that remain to be clarified. The most notable is the lack of long-term clinical research, as well as the lack of research in high-risk patients, which makes it difficult to place the OPCABG technique in terms of clinical significance in patients at high surgical risk57.

 

Conclusion

The ONCABG, of the two surgical techniques studied, is the oldest and most widely used in current clinical practice; technological and surgical advances have allowed this procedure to present very low mortality and morbidity, with excellent results. On the other hand, the OPCABG, which is a newer technique, has comparative advantages, as it has excellent results, but with potentially smaller rates of mortality, morbidity and complications as well as lower costs.

These aspects have been well illustrated in this meta-analysis of randomized trials, showing that the OPCABG technique is associated with lower mortality rates and lower risk of CVA. However, this apparent clinical superiority of OPCABG compared to ONCABG surgery still needs to be demonstrated in particular clinical contexts. Both techniques are evolving and have advantages and disadvantages in certain subgroups of patients65, and risks and benefits of both approaches need to be considered, so that the choice of strategy for the patient will maximize the long-term benefit and minimize short-term risk55,58.

Potential Conflict of Interest

No potential conflict of interest relevant to this article was reported.

Sources of Funding

There were no external funding sources for this study.

Study Association

This article is part of a full professor's thesis on Ana Sofia Gomes Godinho from the Escola Superior de Saúde Dr. Lopes Dias.

 

References

1. Vineberg AM. Development of an anastomosis between the coronary vessels and a transplanted internal mammary artery. Can Med Assoc J. 1946;55(2):117-9.         [ Links ]

2. Favaloro RG. Saphenous vein autograft replacement of severe segmental coronary artery occlusion: operative technique. Ann Thorac Surg. 1968;5(4):334-9.         [ Links ]

3. Taggart DP, Westaby S. Neurological and cognitive disorders after coronary artery bypass grafting. Curr Opin Cardiol. 2001;16(5):271-6.         [ Links ]

4. Souza MH, Elias DO. Fundamentos da circulação extracorpórea. 2ª ed. Rio de Janeiro: Centro Editorial Alfa; 2006.         [ Links ]

5. McGoldrick JP. Cardiac surgery without cardiopulmonary bypass. In: Kay PH, Munsch CM. Techniques in extracorporeal circulation. 4th ed. London: Arnold Hill; 2004.         [ Links ]

6. Kolesov VI, Potashov LV. [Surgery of coronary arteries]. Eksp Khir Anesteziol. 1965;10(2):3-8.         [ Links ]

7. Benetti FJ, Naselli G, Wood M, Geffner L. Direct myocardial revascularization without extra-corporeal circulation: experience in 700 patients. Chest. 1991;100(2):312-6.         [ Links ]

8. 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(1):63-6.         [ Links ]

9. Portal da Saúde. Programas Nacionais Prioritários: Programa Nacional de Prevenção e Controle das Doenças Cardiovasculares. [Citado em 2009 dez 3]. Disponível em: http://www.min-saude.pt/portal/conteudo.         [ Links ]

10. Ministério da Saúde. Direção Geral da Saúde. Plano Nacional da Saúde. [Citado em 2009 dez 3]. Disponível em: http://www.dgsaude.min-saude.pt/pns/capa/html.         [ Links ]

11. Bergsland J, Fosse E, Svennevig JL. Coronary artery bypass grafting with or without cardiopulmonary bypass. Cardiac Surgery Today. 2008;4:10-7.         [ Links ]

12. Nimesh D, Desai ND, Pelletier MP, Mallidi HR, Christakis GT, Cohen GN, Fremes SE, et al. Why is off-pump coronary surgery uncommon in Canada? Results of a population-based survey of Canadian heart surgeons. Circulation. 2004;110(11 Suppl. 1):II7-12.         [ Links ]

13. Kaiser, Kron IL, Spray TL. Mastery of cardiothoracic surgery. Philadelphia: Lippincott Williams & Wilkins; 2007.         [ Links ]

14. Parolari A, Alamanni F, Cannata A, Naliato M, Bonati L, Rubini P, et al. Off-pump versus on-pump coronary artery bypass: meta-analysis of currently available randomized trials. Ann Thorac Surg. 2003;76(1):37-40.         [ Links ]

15. Kirklin JK. Prospects for understanding and eliminating the deleterious effects of cardiopulmonary bypass. Ann Thorac Surg. 1991;51(4):529-31.         [ Links ]

16. Brasil LA, Gomes WJ, Salomão R, Buffolo E. Inflammatory response after myocardial revascularization with or without cardiopulmonary bypass. Ann Thorac Surg. 1998;66(1):56-9.         [ Links ]

17. Srüber M, Cremer JT, Gohrbandt B, Hagl C, Jankowski M, Völker B, et al. Human cytokine responses to coronary artery bypass grafting with or without cardiopulmonary bypass. Ann Thorac Surg. 1999;68(4):1330-5.         [ Links ]

18. 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(4):1198-204.         [ Links ]

19. 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(1):63-6.         [ Links ]

20. Plomondon ME, Cleveland JC Jr, Ludwig ST, Grunwald GK, Kiefe CI, Grover FL, et al. Off-pump coronary artery bypass is associated with improved risk-adjusted outcomes. Ann Thorac Surg. 2001;72(1):114-9.         [ Links ]

21. 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(4):1282-8.         [ Links ]

22. Al-Ruzzeh S, Ambler G, Asimakopoulos G, Omar RZ, Hason R, Fabri B, et al. Comparative Analysis of Early Clinical Outcome. 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): II1-8.         [ Links ]

23. Sabik JF, Gillinov AM, Blackstone EH, Vacha C, Houghtaling PL, Navia J, et al. Does off-pump coronary surgery reduce morbidity and mortality? J Thorac Cardiovasc Surg. 2002;124(4):698-707.         [ Links ]

24. Mack M, Bachand D, Acuff T, Edgerton J, Prince S, Dewey T, et al. Improved outcomes in coronary artery bypass grafting with beating-heart techniques. J Thorac Cardiovasc Surg. 2002;124(3):598-607.         [ Links ]

25. Taggart DP, Westaby S. Neurological and cognitive disorders after coronary artery bypass grafting. Curr Opin Cardiol. 2001;16(5):271-6.         [ Links ]

26. Ascione R, Angelini GD. Off-pump coronary artery bypass surgery the implications of the evidence. J Thorac Cardiovasc Surg. 2003;125(4):779-81.         [ Links ]

27. Motallebzadeh R, Jahangiri M. Meta-analysis of randomized controlled trials of cognitive decline after on-pump versus off-pump coronary artery bypass graft surgery. J Thorac Cardiovasc Surg. 2008;135(6):1400-2.         [ Links ]

28. Bedi HS, Suri A, Kalkat MS, Sengar BS, Mahajan V, Chawla R, et al. Global myocardial revascularization without cardiopulmonary bypass using innovative techniques for myocardial stabilization and perfusion. Ann Thorac Surg. 2000;69(1):156-64.         [ Links ]

29. Jones EL, Weintraub WS. The importance of completeness of revascularization during long-term follow-up after coronary artery operations. J Thorac Cardiovasc Surg. 1996;112(2):227-37.         [ Links ]

30. Lytle BW. On-pump and off-pump coronary bypass surgery. Circulation. 2007;116(10):1108-9.         [ Links ]

31. Bonchek LI. Off-pump coronary bypass it for everyone? J Thorac Cardiovasc Surg. 2002;124(3):431-4.         [ Links ]

32. Gerola LR, Buffolo E, Jasbik W, Botelho B, Bosco J, Brasil LA, et al. 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(2):569-73.         [ Links ]

33. Ngaage DL. Off-pump coronary artery bypass grafting: the myth, the logic and the science. Eur J Cardiothorac Surg. 2003;24(4):557-70.         [ Links ]

34. Van Dijk D, Nierich AP, Jansen EW, Nathoe HM, Suyker WJ, Diephuis JC, et al. Early outcome after off-pump versus on pump coronary bypass surgery. Circulation. 2001;104(15):1761-6.         [ Links ]

35. Puskas JD, Williams WH, Duke PG, Staples JR, Glas KE, Marshall JJ, et al. 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(4):797-808.         [ Links ]

36. 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(9313):1194-9.         [ Links ]

37. Shroyer AL, Grover FL, Hattler B, Collins JF, McDonald GO, Kozora E, et al. On-pump versus off-pump coronary artery bypass surgery. N Engl J Med. 2009;361(19):1827-37.         [ Links ]

38. Green S, Higgins JPT, Alderson P, Clarke M, Mulrow CD, Oxman AD. Cochrane reviewers' handbook 4.2.1. Chichester: John Wiley & Sons Ltd; 2003.         [ Links ]

39. Higgins JP, Thompson SG, Deeks JJ, Altman DG. Measuring inconsistency in meta-analyses. BMJ. 2003;327(7414):557-60.         [ Links ]

40. Higgins JP, Thompson SG. Quantifying heterogeneity in a meta-analysis. Stat Med; 2002;21(11):1539-58.         [ Links ]

41. Paul SR, Donner A. Small sample performance of tests of homogeneity of odds ratios in K 2 x 2 tables. Stat Med. 1992;11(2):159-65.         [ Links ]

42. Brown JM, Poston RS, Gammie JS, Cardarelli MG, Schwartz K, Sikora JA, et al. Off-pump versus on-pump coronary artery bypass grafting in consecutive patients: decision-making algorithm and outcomes. Ann Thorac Surg. 2006;81(2):555-61.         [ Links ]

43. Hannan EL, Wu C, Smith CR, Higgins RS, Carlson RE, Culliford AT, et al. 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(10):1145-52.         [ Links ]

44. Mack MJ, Brown P, Houser F, Katz M, Kugelmass A, Simon A, et al. On-pump versus off-pump coronary artery bypass surgery in a matched sample of women: a comparison of outcomes. Circulation. 2004;110(11 Suppl. 1):II1-6.         [ Links ]

45. Mizutani S, Matsuura A, Miyahara K, Eda T, Kawamura A, Yoshioka T, et al. On-pump beating-heart coronary artery bypass: a propensity matched analysis. Ann Thorac Surg. 2007;83(4):1368-73.         [ Links ]

46. Muneretto C, Bisleri G, Negri A, Manfredi J, Metra M, Nodari S, et al. Off-pump coronary artery bypass surgery technique for total arterial myocardial revascularization: a prospective randomized study. Ann Thorac Surg. 2003;76(3):778-83.         [ Links ]

48. Palmer G, Herbert MA, Prince SL, Williams JL, Magee MJ, Brown P, et al. Coronary Artery Revascularization (CARE) Registry: an observational study of on-pump and off-pump coronary artery revascularization. Ann Thorac Surg. 2007;83(3):986-92.         [ Links ]

49. Puskas JD, Kilgo PD, Lattouf OM, Thourani VH, Cooper WA, Vassiliades TA, et al. Off-pump coronary bypass provides reduced mortality and morbidity and equivalent 10-year survival. Ann Thorac Surg. 2008;86(4):1139-46.         [ Links ]

50. Straka Z, Widimsky P, Jirasek K, Stros P, Votava J, Janek T, et al Off-pump versus on-pump coronary surgery: final results from a Prospective Randomized Study PRAGUE-4. Ann Thorac Surg. 2004;77(3):789-93.         [ Links ]

51. Yokoyama T, Baumgartner FJ, Gheissari A, Capouya ER, Parragiotides GP, Declusin RJ. Off-pump versus on-pump coronary bypass in high-risk subgroups. Ann Thorac Surg. 2000;70(5):1546-50.         [ Links ]

52. Reston JT, Tregear SJ, Turkelson CM. Meta-analysis of short-term and mid-term outcomes following off-pump coronary artery bypass grafting. Ann Thorac Surg. 2003;76(5):1510-5.         [ Links ]

53. Mack M, Bachand D, Acuff T, Edgerton J, Prince S, Dewey T, et al. Improved outcomes in coronary artery bypass grafting with beating-heart techniques. J Thorac Cardiovasc Surg. 2002;124(3):598-607.         [ Links ]

54. Patel NC, Grayson AD, Jackson M, Au J, Yonan N, Hasan R, et al. The effect off-pump coronary artery bypass surgery on in-hospital mortality and morbidity, Eur J Cardiothorac Surg. 2002;22(2):255-60.         [ Links ]

55. Puskas J, et al (2005). Off-Pump versus Conventional Coronary Artery Bypass Grafting: A Meta-Analysis and Consensus Statement From The 2004 ISMICS Consensus Conference. Innovations: Technology and Techniques in Cardiothoracic and Vascular Surgery: 1: 3-27.         [ Links ]

56. Reeves BC, Ascione R, Caputo M, Angelini GD. (). Morbidity and mortality following acute conversion from off-pump to on pump coronary, Eur J Cardiothorac Surg. 2006;29(6):941-7.         [ Links ]

57. Parolari A, Alamanni F, Cannata A, Maliato M, Bonati L, Rubini P, et al. On-pump versus off-pump coronary-artery bypass: meta-analysis of currently available randomized trials. Ann Thorac Surg. 2003;37(1):37-40.         [ Links ]

58. Geert JMG, van der Heyden GJ, Nathoe HM, Jansen EW, Grobbee DE. Meta-analysis on the effect of off-pump coronary bypass surgery. Eur J Cardiothorac Surg. 2004;26(1):81-4.         [ Links ]

59. Parolari A, Alamanni F, Polvani G, Agrifoglio M, Chen YB, Kassen S, et al. Meta-analysis of randomized trials comparing off-pump with on-pump coronary artery bypass graft patency. Ann Thorac Surg. 2005;80(6):2121-5.         [ Links ]

60. Cheng DC, Bainbridge D, Martin JE, Novick RJ. 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(1):188-203.         [ Links ]

61. Motwani JG, Topol EJ. Aortocoronary saphenous vein graft disease: pathogenesis, predisposition, and prevention. Circulation. 1998;97(9):916-31.         [ Links ]

62. Ascione R, Caputo M, Angelini GD. Off-pump coronary artery bypass grafting: not a flash in the pan. Ann Thorac Surg. 2003;75(1):306-13.         [ Links ]

63. Martin JE. Low dosage tricyclic antidepressants in depression: non superiority does not equal equivalence. BMJ. 2003;326(7387):499.         [ Links ]

64. Kastanioti C. Costs clinical outcomes, and health-related quality of life of off-pump vs. on-pump coronary bypass surgery. Eur J Cardiovasc Nurs. 2007;6(1):54-9.         [ Links ]

65. Sellke FW, DiMaio JM, Caplan LR, Ferguson TB, Gardner TJ, Hiratzka LF, et al. Comparing on-pump and off-pump coronary artery bypass grafting: numerous studies but few conclusions: a scientific statement from the American Heart Association council on cardiovascular surgery and anesthesia in collaboration with the interdisciplinary working group on quality of care and outcomes research. Circulation. 2005;111(21):2858-64.         [ Links ]

66. Shekar PS. Cardiology patient page: on-pump and off-pump coronary artery bypass grafting. Circulation. 2006;113(4):e51-2.         [ Links ]

 

 

Mailing Address:
Ana Godinho
Rua dos Valinhos, n.º20, Vales do Rio
6200-811 - Covilhã, Portugal
E-mail: asofia.godinho@gmail.com

Manuscript received May 25, 2011; revised manuscript received August 22, 2011; accepted September 05, 2011.

Creative Commons License Todo o conteúdo deste periódico, exceto onde está identificado, está licenciado sob uma Licença Creative Commons