Evaluation of graft patency by computed tomographic angiography in symptom-free post-coronary artery bypass surgery patients.

BACKGROUND: Accelerated atherosclerosis occurs in aortocoronary saphenous vein grafts, contributing to increased morbidity and mortality rates. We estimated the prevalence of asymptomatic graft failure in patients 5 years or more after coronary artery bypass grafting (CABG) using electron-beam computed tomographic angiography (EBA). METHODS AND RESULTS: EBA was performed in 45 symptom-free patients (mean age, 66 +/- 9 years; 87% male; mean time interval after CABG, 8 +/- 5 years). A total of 102 vein grafts and 37 internal mammary artery grafts were evaluated. Patients with graft stenosis or occlusion on EBA underwent myocardial perfusion scintigraphy and invasive angiography. Six grafts were unevaluable by EBA. Twenty patients had evidence of graft stenosis or occlusion on EBA. Of 20 asymptomatic patients with graft disease, 17 (85%) had abnormal myocardial perfusion, with moderate to severe reversible ischemia occurring in one third of subjects. Fourteen occluded and eleven stenosed vein grafts were correctly diagnosed by EBA. There were 2 false-positive EBA diagnoses of graft stenosis, resulting in a 100% positive predictive accuracy for detecting graft occlusion and 85% positive predictive accuracy for detecting graft stenosis. All occluded internal mammary artery grafts (n = 3) were accurately diagnosed. CONCLUSION: Computed tomographic coronary angiography permits reliable identification of bypass graft stenoses and occlusions in symptom-free patients more than 5 years after CABG. Future studies are needed to assess the prognostic benefit of early detection of graft disease and intervention in asymptomatic patients.

Incidental finding of giant pericardial lipoma.

We describe a patient with an incidental finding of a large mass adjacent to the heart detected on a screening CT scan. The differential diagnosis included primary and secondary tumours of the heart. Subsequent investigation with trans-thoracic echocardiogram and cardiac MRI confirmed a diagnosis of a giant pericardial lipoma, one of the common benign primary cardiac tumours.

A rare case of primary cardiac lymphoma.

A 71-year-old man presented with shortness of breath and tachycardia along with systemic symptoms of weight loss and lethargy. A pulmonary embolus was the initial suspected diagnosis but through extensive investigations a rarer cause of his symptoms was identified. This case demonstrates the importance of cardiac imaging in the assessment and non-invasive tissue characterisation of a suspected cardiac tumour; in our case, this was subsequently confirmed by careful histological/immunocytochemical evaluation of the pericardial effusion as a primary cardiac B-cell non-Hodgkin's lymphoma, thus enabling appropriate management leading to an excellent clinical outcome.

Increased volume of epicardial fat is an independent risk factor for accelerated progression of sub-clinical coronary atherosclerosis.

BACKGROUND: Epicardial adipose tissue (EAT), a metabolically active visceral fat depot surrounding the heart, has been implicated in the pathogenesis of coronary artery disease (CAD) through possible paracrine interaction with the coronary arteries. We examined the association of EAT with metabolic syndrome and the prevalence and progression of coronary artery calcium (CAC) burden. METHODS: CAC scan was performed in 333 asymptomatic diabetic patients without prior history of CAD (median age 54 years, 62% males), followed by a repeat scan after 2.7±0.3 years. CAC progression was defined as >2.5mm(3) increase in square root transformed volumetric CAC scores. EAT and intra-thoracic fat volumes were quantified using a dedicated software (QFAT), and were examined in relation to the metabolic syndrome, baseline CAC scores and CAC progression. RESULTS: Both epicardial and intra-thoracic fat were associated with metabolic syndrome after adjustment for conventional cardiovascular risk factors, but the association was attenuated after additional adjustment for body mass index. EAT, but not intra-thoracic fat, showed significant association with baseline CAC scores (odds ratio [OR] 1.13, 95% confidence interval [CI] 1.04-1.22, p=0.04) and CAC progression (OR 1.12, 95% CI 1.05-1.19, p<0.001) after adjustment for conventional measures of obesity and risk factors. CONCLUSION: EAT volume measured on non-contrast CT is an independent marker for the presence and severity of coronary calcium burden and also identifies individuals at increased risk of CAC progression. EAT quantification may thus add to the prognostic value of CAC imaging.

Determinants of progression of coronary artery calcification in type 2 diabetes role of glycemic control and inflammatory/vascular calcification markers.

OBJECTIVES: This study prospectively evaluated the relationship between cardiovascular risk factors, selected biomarkers (high-sensitivity C-reactive protein [hs-CRP], interleukin [IL]-6, and osteoprotegerin [OPG]), and the progression of coronary artery calcification (CAC) in type 2 diabetic subjects. BACKGROUND: Coronary artery calcification is pathognomonic of coronary atherosclerosis. Osteoprotegerin is a signaling molecule involved in bone remodeling that has been implicated in the regulation of vascular calcification and atherogenesis. METHODS: Three hundred ninety-eight type 2 diabetic subjects without prior coronary disease or symptoms (age 52 +/- 8 years, 61% male, glycated hemoglobin [HbA(1)c] 8 +/- 1.5) were evaluated serially by CAC imaging (mean follow-up 2.5 +/- 0.4 years). Progression/regression of CAC was defined as a change > or =2.5 between the square root transformed values of baseline and follow-up volumetric CAC scores. Demographic data, risk factors, glycemic control, medication use, serum hs-CRP, IL-6, and plasma OPG levels were measured at baseline and follow-up. RESULTS: Two hundred eleven patients (53%) had CAC at baseline. One hundred eighteen patients (29.6%) had CAC progression, whereas 3 patients (0.8%) had regression. Age, male gender, hypertension, baseline CAC, HbA(1)c >7, waist-hip ratio, IL-6, OPG, use of beta-blockers, calcium channel antagonists, angiotensin-converting enzyme (ACE) inhibitors, statins, and Framingham/UKPDS (United Kingdom Prospective Diabetes Study) risk scores were univariable predictors of CAC progression. In the multivariate model, baseline CAC (odds ratio [OR] for CAC >400 = 6.38, 95% confidence interval [CI] 2.63 to 15.5, p < 0.001), HbA(1)c >7 (OR 1.95, CI 1.08 to 3.52, p = 0.03), and statin use (OR 2.27, CI 1.38 to 3.73, p = 0.001) were independent predictors of CAC progression. CONCLUSIONS: Baseline CAC severity and suboptimal glycemic control are strong risk factors for CAC progression in type 2 diabetic subjects.

The role of non-invasive imaging in the risk stratification of asymptomatic diabetic subjects.

AIMS: Coronary artery disease (CAD) is the leading cause of death in patients with diabetes. Patients often present with advanced and asymptomatic disease. Proposed strategies that may favourably affect CAD risk and outcomes in this patient population include identifying diabetic patients with subclinical disease at high risk of future cardiac events. The purpose of this article was to review the role of both atherosclerosis imaging tests (coronary calcium imaging and high-resolution ultrasound assessment of carotid intima-media thickness) and functional imaging techniques [stress echocardiography and radionuclide myocardial perfusion imaging (MPI)] in the diagnostic and prognostic evaluation of asymptomatic diabetic subjects. METHODS AND RESULTS: We identified studies using MEDLINE searches (1966 to April 2005) and by reviewing reference lists. A comprehensive list of search terms was applied. All stress echocardiography and MPI studies evaluating the prevalence and/or prognostic value of myocardial ischaemia (n = 19) and coronary calcium imaging studies (n = 2) evaluating the prognostic value of subclinical atherosclerosis in diabetic patients were included. CONCLUSION: Asymptomatic myocardial ischaemia can be detected in a significant proportion of diabetic subjects by non-invasive imaging tests such as MPI and stress echocardiography. The results of ongoing and future studies may be helpful in guiding the selection of asymptomatic diabetic subjects to undergo non-invasive imaging, establishing the cost-effectiveness of various testing strategies and their impact on prognosis.

The relationship between plasma osteoprotegerin levels and coronary artery calcification in uncomplicated type 2 diabetic subjects.

OBJECTIVES: This study sought to prospectively evaluate the relationship between plasma osteoprotegerin (OPG), inflammatory biomarkers (high-sensitivity C-reactive protein [hs-CRP], interleukin-6 [IL-6], coronary artery calcification (CAC), and cardiovascular events in patients with type 2 diabetes. BACKGROUND: Arterial calcification is a prominent feature of atherosclerosis and is associated with an increased risk of cardiovascular events. Osteoprotegerin is a cytokine that has recently been implicated in the regulation of vascular calcification. METHODS: A total of 510 type 2 diabetic patients (53 +/- 8 years; 61% male) free of symptoms of cardiovascular disease were evaluated by CAC imaging. Risk factors, hs-CRP, IL-6, and OPG levels were measured. Patients were followed up for cardiovascular events (cardiac death, myocardial infarction, acute coronary syndrome, late revascularization, and nonhemorrhagic stroke). RESULTS: Significant CAC (>10 Agatston units) was seen in 236 patients (46.3%); OPG was significantly elevated in patients with increased CAC. In multivariable analyses, OPG retained a strong association with elevated CAC scores after adjustment for age, gender, and other risk factors (odds ratio = 2.84, 95% confidence interval 2.2 to 3.67; p < 0.01). Sixteen cardiovascular events occurred during a mean follow-up of 18 +/- 5 months. The waist-to-hip ratio, United Kingdom Prospective Diabetes Study (UKPDS) risk score, OPG level, and CAC score were significant predictors of time to cardiovascular events in a univariate Cox proportional hazards model. In the multivariate model, the CAC score was the only independent predictor of adverse events. Levels of hs-CRP and IL-6 were related to neither the extent of CAC nor short-term events. CONCLUSIONS: A high proportion of asymptomatic diabetic patients have significant subclinical atherosclerosis. Of the biomarkers studied, only OPG predicted both subclinical disease and near-term cardiovascular events. Therefore, measurement of OPG merits further investigation as a simple test for identifying high-risk type 2 diabetic patients.

Risk stratification in uncomplicated type 2 diabetes: prospective evaluation of the combined use of coronary artery calcium imaging and selective myocardial perfusion scintigraphy.

AIMS: To determine the prevalence and clinical predictors of subclinical atherosclerosis and myocardial ischaemia in uncomplicated type 2 diabetes and assess their relationship to short-term outcome. METHODS AND RESULTS: Established risk factors and coronary artery calcium (CAC) scores were prospectively measured in 510 asymptomatic type 2 diabetic subjects (mean age 53+/-8 years, 61% males) without prior cardiovascular disease. Myocardial perfusion scintigraphy (MPS) was performed in all subjects with CAC > 100 Agatston units (AU) (n=127), and a random sample of the remaining patients with CAC < or = 100 AU (n=53). Significant CAC (> 10 AU) was found in 46.3%. Twenty events occurred (two coronary deaths, nine non-fatal myocardial infarctions, three acute coronary syndromes, three non-haemorrhagic strokes, and three late revascularisations) during a median follow-up of 2.2 years (25th-75th percentile = 1.9-2.5 years). The age, systolic blood pressure, the duration of diabetes, United Kingdom Prospective Diabetes Study risk score, CAC score, and extent of myocardial perfusion abnormality were significant predictors of time to cardiovascular events in a univariable Cox proportional hazard model. No cardiac events or perfusion abnormalities occurred in subjects with CAC < or = 10 AU up until 2 years of follow-up. CAC and MPS findings were synergistic for the prediction of short-term cardiovascular events. CONCLUSION: Subclinical atherosclerosis, measured by CAC imaging, is superior to the established cardiovascular risk factors for predicting silent myocardial ischaemia and short-term outcome. Further studies evaluating the impact of CAC imaging on clinical outcomes and its cost effectiveness are warranted.