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Coronary artery bypass surgery can offer excellent results when performed with cardiopulmonary bypass (on pump) or without cardiopulmonary bypass (off pump). The debate as to which technique is superior remains unanswered. Intra-operative conversion from off- to on-pump coronary surgery is a relatively unexplored phenomenon, which cannot be assessed within randomised controlled trial design. We aimed to assess the effect of off-pump conversion on patient mortality. Medline, Embase, Cochrane and Google Scholar databases were systematically reviewed for studies published between 1980 and 2010 that compared the incidence of mortality between converted and non-converted off-pump patients. Publication bias and heterogeneity were assessed and data were extracted independently by multiple observers. We undertook a meta-analysis of these studies using random effects modelling. A total of 17 studies fulfilled our inclusion criteria, containing data for 18,870 off-pump coronary artery bypass operations spanning a decade (1998-2008), involving 920 cases of conversion. Overall, conversion increased mortality by an odds ratio of 6.18 (95% confidence interval 4.65-8.20), whereas emergency conversion further raised the odds ratio of mortality to 6.99 (95% confidence interval 5.18-9.45). The conversion from off- to on-pump cardiac surgery may significantly increase the chance of an adverse outcome, whereas emergency conversion confers a significant rise in mortality. The risk of conversion should be discussed when obtaining the patient's informed consent and its prevention warrants serious consideration by cardiac surgeons and cardiac surgical training programmes.

Graft and patient survival were good in both countries. These results are better than those published in the literature over the previous 20 years. Although phenotypic differences in monozygotic twins can exist, immunosuppression may be unnecessary in all these patients. Ideally, all identical twins who are currently on immunosuppression should undergo zygosity testing to establish whether they should continue the immunosuppression unless they need it for another reason.

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We suggest further prospective randomized studies to examine the effect of saphenous system vein grafting, and choice of low molecular weight heparin prophylaxis on the incidence of post-CABG PE.

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A best evidence topic was written according to a structured protocol. The question addressed was 'is the saphenous vein graft or right gastroepiploic artery a better conduit for revascularization of the right coronary artery?' One hundred and five articles were found using a designated search, of which 10 articles were found to represent the best available evidence to answer the clinical question. Of these 10 articles, two were reports of a randomized controlled trial and represented the highest level of evidence, whereas eight articles were retrospective observational studies. All were published between 2002 and 2012. Outcome measures varied considerably, but mostly included graft patency at varying periods of follow-up. The randomized evidence suggested that the saphenous vein had better early (6-month) and mid-term (3-year) graft patency than the right gastroepiploic artery when used for right coronary artery revascularization. The use of the saphenous vein was also found to be predictive of superior graft function using multivariate regression; however, a more recent propensity score analysis identified gastroepiploic-right coronary grafts to yield superior very long-term (>10 years) clinical outcomes. Overall, based on the best quality evidence and in view of technical limitations and flow characteristics of the right gastroepiploic artery, it appears that saphenous vein grafts may offer superior outcomes for revascularization of the right coronary artery in most cases, and should be preferentially used.

A best evidence topic was written according to a structured protocol. The question addressed was whether the right internal thoracic artery (RITA) provides a superior outcome for revascularization of the right coronary artery (RCA) compared with the saphenous vein graft (SVG). Using a designated search strategy, 226 articles were found, of which five represented the best available evidence. The authors, journal, date, country of publication, study type, patient group studied, relevant outcomes and results were tabulated. Of these five studies, one offered level I evidence (data from a randomized trial) and four were level II studies (reports of observational data). The outcome measures varied considerably, but most included graft patency at varying levels of the follow-up. The randomized data showed strong evidence favouring the SVG, mainly in terms of mid-term patency. With the exception of a large cohort study that demonstrated the superior patency of the RITA compared with the SVG in the right coronary territory, the observational studies showed better results for SVG in graft patency, reintervention and cardiovascular complication rate. Overall, and in view of the methodological limitations and the different weight of evidence among studies, it appears that the SVG may offer a superior outcome for revascularization of the RCA when compared with the RITA.