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Eur J Cardiothorac Surg 2006;29:633
© 2006 Elsevier Science NL

Letter to the Editor

Reply to Takagi et al.

^a Division of Cardiothoracic Surgery, Beth Israel Deaconess Medical Center, Harvard University, Boston, MA, USA
^b Division of Cardiac Surgery and Department of Epidemiology, University of Ottawa, Ottawa, Ont., Canada

Received 5 January 2006; accepted 9 January 2006.

^_* Corresponding author. Address: University of Ottawa Heart Institute, Room H-3401, 40 Ruskin Street, Ottawa, Ont., Canada K1Y 4W7. Tel.: +1 613 761 4720; fax: +1 613 761 4713. (Email: mruel{at}ottawaheart.ca).

Key Words: Coronary artery bypass surgery • Percutaneous coronary interventions • Left internal thoracic artery • Stents • Meta-analysis

In response to our meta-analysis [1] comparing surgical versus percutaneous treatment of isolated LAD disease, Takagi et al. [2] present, in the form of a letter to the editor of the European Journal of Cardio-thoracic Surgery, the results of a ‘sub-meta-analysis’ of a subset of randomized trials where only minimally invasive bypass techniques were utilized for surgical revascularization. The authors justify the need for this ‘sub-meta-analysis’ by stating that there was a significant heterogeneity in the method of surgical revascularization used between the studies included in our meta-analysis. Furthermore, they state that because the type of surgical revascularization was predictive of between-study heterogeneity, it is appropriate to explore the subset of studies where only minimally invasive surgical revascularization (MIDCAB) was employed. The authors identified and included five randomized trials (four of which were included in our study) and report that the pooled estimate favors MIDCAB with regards to major adverse cardiac events (MACE) (risk ratio of 0.41 [0.27, 0.60]).

The authors have succinctly presented the results of a pooled analysis of five studies, but it is worth asking the question whether this sub-meta-analysis adds any new information to that already presented. Although we had a priori identified various sources of between-study heterogeneity and chosen a random-effects model for analysis, we found that all tests for heterogeneity were non-significant (P = 0.44 for mid-term MACE in the randomized trials); this is similar to the findings of Takagi et al. [2] (P = 0.89). Secondly, although we found that the type of surgical treatment was a univariate predictor of between-study heterogeneity, other univariate predictors were also significant, including the type of percutaneous treatment, duration of follow-up, and start year of the study. During meta-regression, only the start year of the study remained a significant multivariate predictor of study heterogeneity. In this regard, the start year of the study likely captures many key aspects of a study including the types of surgical and percutaneous treatments used as well as length of follow-up. This suggests, on statistical grounds, that a ‘sub-meta-analysis’ is not justified because statistically there does not appear to be significant heterogeneity to warrant considering this subset of trials separately. Not surprisingly, the findings presented by Takagi et al. [2] are similar to those previously presented by us.

Finally, the focus of our meta-analysis was the difference in the combined rates of mortality and myocardial infarction, because these, in our opinion, represent the most clinically meaningful endpoints that may change clinical practice. Differences in MACE, which are driven primarily by target vessel revascularization, are potentially less meaningful as many patients and their physicians may accept the possibility of repeated percutaneous interventions over surgery, provided that the risk of myocardial infarction or mortality is not higher. Furthermore, differences in MACE favoring surgery have been repeatedly demonstrated in adequately powered randomized trials. We are therefore of the opinion that future studies comparing CABG to PCI should focus on the clinically meaningful endpoints of mortality and myocardial infarction and be adequately powered to detect such differences.

References

1. Boodhwani M, Rubens FD, Sellke FW, Mesana TG, Ruel M. Mortality and myocardial infarction following surgical versus percutaneous revascularization of isolated left anterior descending artery disease: a meta-analysis. Eur J Cardiothorac Surg 2006;29:65-70.[Abstract/Free Full Text]
2. Takagi H, Kato T, Matsuno Y, Umemoto T. Letter to the Editor: Minimally invasive direct coronary artery bypass versus stenting. Eur J Cardiothorac Surg 2006;26:632.

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Alert me to new issues of the journal Add to Personal Folders Download to citation manager Author home page(s): Munir Boodhwani Marc Ruel Permission Requests Citing Articles Citing Articles via Google Scholar Google Scholar Articles by Boodhwani, M. Articles by Ruel, M. Search for Related Content PubMed Articles by Boodhwani, M. Articles by Ruel, M. Related Collections Coronary disease