Reply to the Letter to the Editor Reply to VonOppell

We appreciate the comments of Drs von Oppell and Rammohan on our article. The definition in our paper relates specifically to deep sternal wound infections and we appreciate that perhaps this is not made abundantly clear in the methodology. Superficial wound infections were defined as those that do not penetrate the subcutaneous tissue layer. The wound may exhibit erythema and a small amount of drainage that contains bacteria. In our series of 4228 patients undergoing isolated coronary artery bypass grafting (CABG) the incidence of deep sternal wound infection was 0.7% (95% CI 0.4–1.0) and that for superficial wound infection was 1.9% (95% CI 1.5–2.4). The authors are correct in assuming that all internal mammary (IMA) harvest used the pedicle technique. Our analysis revealed that bilateral internal mammary harvest was an independent predictor for all sternal wound infections (superficial and deep) with an odds ratio (OR) of 3.2 (95% CI 1.8–5.9). However, when split into superficial and deep groups bilateral IMA use was only a significant risk factor in the superficial group (OR 3.8, 95% CI 2.0–7.2). It is important to note that this finding was due to sample size with only 28 deep sternal wound infections in our series. Single IMA harvest was not a predictor of wound complications. The authors’ quoted experience of 786 consecutive patients includes both single and bilateral IMA usage in both isolated coronary bypass graft (CABG) patients as well as those having combined valve and CABG operations. We congratulate them on the low incidence of deep sternal wound infections and the apparent difference (not significant) between the skeletonised and pedicled harvesting techniques. However, the small patient numbers and the multiple variables do not lend themselves to any definite conclusion. We do appreciate, however, that there is evidence to suggest that the skeletonised technique of IMA harvest carries less risk of wound infection and therefore agree with them that modifying the IMA harvesting technique may reduce the risk of wound infections in those patients who are having bilateral IMA harvest especially if they are diabetic, obese or have significant peripheral vascular disease.