The impact of diabetes on the relationship of coronary artery disease and outcome: a study using multimodality imaging.

BACKGROUND: Patients with prediabetes or diabetes are at increased risk of developing cardiovascular disease and adverse outcomes. First-line coronary computed tomography angiography (CTA) followed by selective use of positron emission tomography (PET) myocardial perfusion imaging is a feasible strategy to diagnose and risk-stratify patients with suspected coronary artery disease (CAD). The aim of the present study was to study whether diabetes changes the relationship of CAD and long-term outcome. METHODS: We retrospectively identified consecutive symptomatic patients who underwent coronary CTA for suspected CAD. In patients with suspected obstructive CAD on CTA, myocardial ischemia was evaluated by 15O-water PET myocardial perfusion imaging. The relationship of the phenotype of CAD and long-term outcome in patients with no diabetes, prediabetes, or type 2 diabetes was investigated. A composite endpoint included all-cause mortality, myocardial infarction (MI), and unstable angina pectoris (UAP). RESULTS: A total of 1743 patients were included: 1214 (70%) non-diabetic, 259 (15%) prediabetic, and 270 (16%) type 2 diabetic patients. During 6.43 years of median follow-up, 164 adverse events occurred (106 deaths, 41 MIs, 17 UAPs). The prevalence of normal coronary arteries on CTA was highest in the non-diabetic patients (39%). The prevalence of hemodynamically significant CAD (abnormal perfusion) increased from 14% in non-diabetic patients to 20% in prediabetic and 27% in diabetic patients. The event rate was lowest in patients with normal coronary arteries and highest in patients with concomitant type 2 diabetes and hemodynamically significant CAD (annual event rate 0.2% vs. 4.7%). However, neither prediabetes nor diabetes were independent predictors of the composite adverse outcome after adjustment for the clinical risk factors and imaging findings. CONCLUSIONS: Coronary CTA followed by selective downstream use of PET myocardial perfusion imaging predicts long-term outcome similarly in non-diabetic and diabetic patients.

Global and segmental absolute stress myocardial blood flow in prediction of cardiac events: [15O] water positron emission tomography study.

PURPOSE: We evaluated the value of reduced global and segmental absolute stress myocardial blood flow (sMBF) quantified by [15O] water positron emission tomography (PET) for predicting cardiac events in patients with suspected obstructive coronary artery disease (CAD). METHODS: Global and segmental sMBF during adenosine stress were retrospectively quantified in 530 symptomatic patients who underwent [15O] water PET for evaluation of coronary stenosis detected by coronary computed tomography angiography. RESULTS: Cardiovascular death, myocardial infarction, or unstable angina occurred in 28 (5.3%) patients at a 4-year follow-up. Reduced global sMBF was associated with events (area under the receiver operating characteristic curve 0.622, 95% confidence interval (95% CI) 0.538-0.707, p = 0.006). Reduced global sMBF (< 2.2 ml/g/min) was found in 22.8%, preserved global sMBF despite segmentally reduced sMBF in 35.3%, and normal sMBF in 41.9% of patients. Compared with normal sMBF, reduced global sMBF was associated with the highest risk of events (adjusted hazard ratio (HR) 6.970, 95% CI 2.271-21.396, p = 0.001), whereas segmentally reduced sMBF combined with preserved global MBF predicted an intermediate risk (adjusted HR 3.251, 95% CI 1.030-10.257, p = 0.044). The addition of global or segmental reduction of sMBF to clinical risk factors improved risk prediction (net reclassification index 0.498, 95% CI 0.118-0.879, p = 0.010, and 0.583, 95% CI 0.203-0.963, p = 0.002, respectively). CONCLUSION: In symptomatic patients evaluated for suspected obstructive CAD, reduced global sMBF by [15O] water PET identifies those at the highest risk of adverse cardiac events, whereas segmental reduction of sMBF with preserved global sMBF is associated with an intermediate event risk.