Mediastinitis after
coronary artery bypass grafting (CABG) gives a longstanding chronic
inflammation and has a detrimental negative effect on long-term survival. For this reason, we aimed to study the effect of
mediastinitis on graft patency after CABG. The epidemiologic design was of an exposed (
mediastinitis, n = 41) versus non-exposed (non-
mediastinitis, controls, n = 41) cohort with two endpoints: (i) obstruction of saphenous vein grafts (SVG) and (ii) obstruction of the internal mammary artery (IMA) grafts. The graft patency was evaluated with coronary CT-angiography examination at a median follow-up of 2·7 years. The number of occluded SVG in the
mediastinitis group was 18·9% versus 15·5% in the control group. Using generalized estimating equations model with exchangeable matrix, and confounding effect of ischaemic time and patients age, we found no significant association between presence of
mediastinitis and SVG obstruction [rate ratio (RR) = 0·96, 95% CI (0·52-2·67), P = 0·697]. The number of occluded IMA grafts was 10·5% in the
mediastinitis group and 2·4% in the control group. Using the Poisson regression model, we estimated RR = 5·48, 95% CI (1·43-21·0) and P = 0·013. There was a significant association between
mediastinitis and IMA graft obstruction, when controlling for the confounding effect of ischaemic time, body mass index, presence of
diabetes mellitus and the number of diseased vessels. Presence of
mediastinitis increases the risk of IMA graft obstruction. This may confirm the importance of
inflammation as a major contributor to the pathogenesis of
atherosclerosis and explain the negative effect of
mediastinitis on a long-term survival.