Chronic total occlusion heralds poor prognosis in diabetic STEMI patients
MedWire News: A study of diabetic patients with acute myocardial infarction has found that the presence of chronic total occlusion (CTO) in a non-infarct-related artery is a strong and independent predictor for 5-year mortality.
José Henriques (Academic Medical Center, Amsterdam, The Netherlands) and co-workers investigated the prevalence and impact of CTO in a non-infarct-related artery in patients with diabetes mellitus and ST-segment elevation myocardial infarction (STEMI).
From a hospital database they retrospectively identified 4506 patients admitted with acute STEMI between 1997 and 2007, 539 (12%) of whom had diabetes mellitus.
Based on angiography performed before percutaneous coronary intervention, the patients were classified as having single vessel disease (SVD), MVD only, or MVD with a CTO in a non-infarct-related-artery.
In patients without diabetes, SVD, MVD, and CTO were present in 67%, 21%, and 12%, respectively. For patients with diabetes, the respectively prevalences were 49%, 30%, and 21%.
Thus, diabetic patients were significantly more likely than non-diabetics to have a CTO in a non-infarct-related-artery, say the authors.
In terms of mortality, cumulative 5-year mortality was 18% in non-diabetics versus 28% in diabetics.
In non-diabetics, 5-year mortality increased with the increasing severity of coronary artery disease; by contrast, in diabetics, mortality was similar between SVD and MVD (25% vs 21%) and significantly higher, at 47%, in diabetic patients with a CTO.
Finally, in multivariate analysis, a CTO in a non-infarct-related artery was an independent predictor for 5-year mortality, with an adjusted hazard ratio of 2.2 versus SVD and 2.6 versus MVD alone.
Writing in Heart, Henriques and co-authors say that several factors may account for the increased mortality and morbidity after STEMI in diabetic patients, including greater severity of coronary disease, impaired myocardial tissue reperfusion, and longstanding metabolic and lipid abnormalities.
They conclude: "These results suggest that, particularly in the high-risk subgroup of patients with STEMI and diabetes mellitus, MVD has prognostic implications only if a concurrent CTO is present."
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By Joanna Lyford