Diabetes and incomplete revascularisation in ST elevation myocardial infarction

Background: Incomplete revascularisation is common and prognostically important. The degree to which incomplete revascularisation (IR) is associated with adverse cardiac outcomes in patients with diabetes and ST-elevation myocardial infarction (STEMI) is unknown. Methods: Late outcomes (3.6 years) were evaluated in 589 consecutive STEMI patients treated with percutaneous coronary intervention in this observational study. Associations between incomplete revascularisation, and diabetes were assessed. A residual SYNergy Between Percutaneous Coronary Intervention With TAXus and Cardiac Surgery (SYNTAX) Score (rSS) >8 defined IR. The primary endpoint studied was cardiac death, myocardial infarction or cerebrovascular accident. Results: Incomplete revascularisation occurred in 36% of patients with diabetes (46/127) and 32% of patients without diabetes (147/462); p=0.329. The primary endpoint occurred in 27% of patients with diabetes compared to 18% of patients without diabetes (p=0.042); and in 28% with a rSS>8 compared to 16% of patients with a rSS≤8 (p<0.001). The primary endpoint occurred in 35% of patients with both diabetes and a rSS>8, 27% without diabetes with a rSS>8, 22% with diabetes and a rSS≤8, and 14% of with patients neither factor (p<0.001), with cardiac death rates respectively of 22%, 9%, 6%, 2% (p<0.001). Patients with both IR and diabetes accounted for only 8% of STEMI patients but 30% of all cardiac deaths. On multivariable analyses diabetes and IR were independently associated with cardiac death, myocardial infarction and cerebrovascular accident; both p<0.05. Conclusions: Diabetes and IR contribute independently to late outcomes in STEMI patients. The prognostic impact of diabetes was not due to IR alone. Diabetes acts synergistically with incomplete revascularisation to worsen prognosis.