Dalton S. McLean

Epicardial adipose tissue and coronary artery plaque characteristics

OBJECTIVE Epicardial adipose tissue (EAT) has been implicated in the pathogenesis of coronary atherosclerosis. The association of EAT volume with type of coronary artery plaque on computed tomography angiography (CTA) is not known. METHODS Coronary artery calcium (CAC) scoring and EAT volume measurement were performed on 214 consecutive patients (mean age 54+/-14 years) referred for coronary CTA. CAC was performed on non-contrast images, while EAT volume, the severity of luminal stenoses, and plaque characterization were assessed using contrast-enhanced CTA images. EAT volume was also indexed to body surface area (EAT-i). RESULTS EAT volume correlated with age, height, body mass index (BMI), and CAC score. EAT volume increased significantly with the severity of luminal stenosis (p<0.001), and in patients with no plaques, calcified, mixed, and non-calcified plaques (62+/-33mL, 63+/-22mL, 98+/-47mL, and 99+/-36mL, respectively, p<0.001). The EAT volume was significantly larger in patients with mixed or non-calcified plaques compared to patients with calcified plaques or no plaques (all p<0.01 or smaller). The trend remained significant after adjustment for traditional risk factors for coronary artery disease. In adjusted models EAT was an independent predictor of CAC [exp(B)=3.916, p<0.05], atherosclerotic plaques of any type [exp(B)=4.532, p<0.01], non-calcified plaques [exp(B)=3.849, p<0.01], and obstructive CAD [exp(B)=3.824, p<0.05]. The above results were unchanged after replacing EAT with EAT-i. CONCLUSION EAT volume was larger in the presence of obstructive CAD and non-calcified plaques. These data suggest that EAT is associated with the development of coronary atherosclerosis and potentially the most dangerous types of plaques.

Prognostic value of adenosine stress cardiovascular magnetic resonance in patients with low-risk chest pain

BackgroundApproximately 5% of patients with an acute coronary syndrome are discharged from the emergency room with an erroneous diagnosis of non-cardiac chest pain. Highly accurate non-invasive stress imaging is valuable for assessment of low-risk chest pain patients to prevent these errors. Adenosine stress cardiovascular magnetic resonance (AS-CMR) is an imaging modality with increasing application. The goal of this study was to evaluate the negative prognostic value of AS-CMR among low-risk acute chest pain patients.MethodsWe studied 103 patients, mean 56.7 ± 12.3 years of age, with chest pain and no electrocardiographic evidence of ischemia and negative cardiac biomarkers of necrosis, who were admitted to the Cardiac Decision Unit of our institution. All patients underwent AS-CMR. A negative AS-CMR was defined as absence of all the following: regional wall motion abnormalities at rest; perfusion defects during stress (adenosine) and rest; and myocardial scar on late gadolinium enhancement images. The patients were followed for a mean of 277 (range 161-462) days. The primary end point was defined as the combination of cardiac death, nonfatal acute myocardial infarction, re-hospitalization for chest pain, obstructive coronary artery disease (>50% coronary stenosis on invasive angiography) and coronary revascularization.ResultsIn 14 patients (13.6%), AS-CMR was positive. The remaining 89 patients (86.4%), who had negative AS-CMR, were discharged. No patient with negative AS-CMR reached the primary end-point during follow-up. The negative predictive value of AS-CMR was 100%.ConclusionAS-CMR holds promise as a useful tool to rule out significant coronary artery disease in patients with low-risk chest pain. Patients with negative AS-CMR have an excellent short and mid-term prognosis.

Effect of statin dose on incidence of atrial fibrillation: Data from the Pravastatin or Atorvastatin Evaluation and Infection Therapy–Thrombolysis in Myocardial Infarction 22 (PROVE IT–TIMI 22) and Aggrastat to Zocor (A to Z) trials

BACKGROUND Inflammation has been suggested as a factor in the initiation and maintenance of atrial fibrillation (AF). Several observational studies have suggested that statins, presumably through their anti-inflammatory properties, decrease the risk of AF. METHODS We analyzed 2 large, randomized trials, PROVE IT-TIMI 22 and phase Z of the A to Z trial, which compared lower- versus higher-intensity statin therapy to evaluate whether higher-intensity statin therapy lowered the risk of AF onset during the 2 years of follow-up. We hypothesized that higher-intensity statin therapy would decrease the risk of AF when compared to lower-intensity statin therapy. From each trial, patients experiencing the onset of AF during follow-up were identified from the adverse event reports. RESULTS Neither study showed a decreased AF risk with higher-dose statin. In PROVE IT-TIMI 22, 2.9% versus 3.3% in the high- versus standard-dose statin therapy, respectively, experienced the onset of AF over 2 years (OR 0.86, 95% CI 0.61-1.23, P = .41). In A to Z, rates were 1.6% versus 0.99%, respectively (OR 1.58, 95% CI 0.92-2.70, P = .096). In both trials, C-reactive protein levels (plasma or serum) tended to be higher among patients experiencing the onset of AF. CONCLUSION Our randomized comparison among 8659 patients found that higher-dose statin therapy did not reduce the short term incidence of AF among patients after acute coronary syndromes when compared with standard dose statin treatment.

Point-of-care platelet function testing predicts bleeding in patients exposed to clopidogrel undergoing coronary artery bypass grafting: Verify pre-op TIMI 45--a pilot study.

Guidelines recommend delaying coronary artery bypass grafting (CABG) for 5 days after discontinuing clopidogrel. However, platelet function may recover quicker in certain individuals.

Role of Echocardiography in the Assessment of Myocardial Viability Symbol

In the assessment of chronic myocardial infarction, echocardiography plays a vital role through the recognition of hibernating yet potentially viable myocardium that could benefit from revascularization. Echocardiography provides information through basic evaluation of cardiac structure and through evaluation of the functional response to dobutamine stress. In addition, a number of newer modalities such as myocardial contrast echocardiography, tissue Doppler imaging, and strain imaging provide further diagnostic capability. This review assesses the role of echocardiography in the identification of patients with chronic myocardial infarction who could benefit from revascularization.

Epicardial adipose tissue as a cardiovascular risk marker

Abstract Regional fat distribution appears to play a significant role in cardiovascular risk. Epicardial adipose tissue (EAT) is a type of visceral fat that is located adjacent to the heart in the thoracic cavity. Cytokines generated in EAT are postulated to diffuse directly to the vascular intima from the perivascular fat, leading to the initiation of inflammation, atherosclerosis development and plaque instability. Current research links increased EAT to an elevated risk of coronary artery disease. EAT has been correlated with both coronary artery calcification and angiographic coronary disease in most, but not all, studies. Further work is needed before EAT is included among the current battery of tests that are available for coronary artery disease risk stratification.

Adenosine stress magnetic resonance imaging in women with low risk chest pain: the Emory University experience.

Objectives:The purpose of this study was to evaluate the accuracy of adenosine stress magnetic resonance imaging (ASMRI) for the evaluation of women with low-risk chest pain (CP). Background:Coronary artery disease (CAD) can present differently among women than among men. There is increased interest in the use of ASMRI for lower risk patients in the emergency department to rule out CAD, and it would be valuable to assess its performance specifically in women. Methods:This study included 82 women with low-risk CP who presented to the emergency department during a 2-year period at our institution and were evaluated by ASMRI. Clinical events were followed by review of medical records. Results:The specificity of ASMRI for ischemia detection in this small cohort of patients was 100%. Sensitivity was 94.9%, negative predictive value 100%, and positive predictive value 42.9%. Conclusions:ASMRI may be used as the initial imaging modality for ruling out CAD in women with low-risk CP because of its very high sensitivity, specificity, and negative predictive value for the detection of ischemia. Further randomized controlled trials comparing ASMRI with established noninvasive nuclear and echocardiographic stress modalities are needed.

A Right Atrial Mass, Patent Foramen Ovale, and Indwelling Central Venous Catheter in a Patient With a Malignancy: A Diagnostic and Therapeutic Dilemma

A 33-year-old woman with a history of gestational trophoblastic disease presented for investigation of a right atrial mass. She had been receiving chemotherapy administered via a Port-a-Cath system for 2 months prior to presentation. On transesophageal echocardiography and magnetic resonance imaging, she was found to have a mass attached to the right atrial free wall, with a segment projecting across a patent foramen ovale. Because of the risk for an embolic event, the mass was surgically removed and the patent foramen ovale repaired. Pathology showed an organized thrombus. This case emphasizes the need for high suspicion for thrombus when a right atrial mass is found in a patient with a hypercoagulable state due to underlying malignancy who has a central venous catheter.

A Rare Coincidence of Two Coronary Anomalies in an Adult

Anomalous right-sided left main coronary arteries and dual type IV left anterior descending arteries are rare coronary anomalies. In this case report, we present a 59 year old man with atypical chest pain and a combination of the above coronary anomalies as identified by selective coronary angiography and computed tomography angiography. To the best of our knowledge, the coincidence of these coronary anomalies has not been previously described.

EPICARDIAL ADIPOSE TISSUE VOLUME AND CORONARY ARTERY CALCIUM TO PREDICT MYOCARDIAL ISCHEMIA ON POSITRON EMISSION TOMOGRAPHY-COMPUTED TOMOGRAPHY STUDIES

Background There appears to be an association of epicardial adipose tissue (EAT) with coronary artery disease (CAD) and its risk factors. EAT is assumed to influence CAD development by altering vasomotor tone and via toxic paracrine effects. The relationship of EAT to myocardial perfusion has not been studied.