Epicardial adipose tissue volume as a marker of coronary artery disease severity in patients with diabetes independent of coronary artery calcium: findings from the CTRAD study

AIMS

The association between epicardial adipose tissue (EAT) volume and coronary artery disease (CAD) severity was evaluated, independent of traditional risk factors and coronary artery calcium (CAC) scores, in patients with diabetes type 2 (DM-2) using cardiac computed tomography angiography (CTA).

METHODS

A multivariate analysis was utilized to assess for an independent association after calculating EAT volume, CAD severity, and calcium scores in 92 patients with DM-II from the CTRAD study. We graded CAD severity as none (normal coronaries), mild-moderate (<70% stenosis), and severe (70% or greater stenosis).

RESULTS

A total of 39 (42.3%) asymptomatic patients with diabetes did not have CAD; 30.4% had mild/moderate CAD; and 27.1% had severe CAD. Mean EAT volume was highest in patients with severe CAD (143.14 cm(3)) as compared to mild/moderate CAD (112.7 cm(3)), and no CAD (107.5 cm(3)) (p = 0.003). After adjustment of clinical risk factors, notably, CAC score, multivariate regression analysis showed EAT volume was an independent predictor of CAD severity in this sample (odds ratio 11.2, 95% confidence interval 1.7-73.8, p = 0.01).

CONCLUSIONS

Increasing EAT volume in asymptomatic patients with DM-II is associated with presence of severe CAD, independent of BMI and CAC, as well as traditional risk factors.

Comparison of epicardial adipose tissue volume and coronary artery disease severity in asymptomatic adults with versus without diabetes mellitus

Epicardial adipose tissue (EAT) has been shown to have important effects on the development of coronary artery disease (CAD) through local paracrine influences on the vascular bed. We compared a cohort of asymptomatic patients with type II diabetes mellitus (DM) without known CAD to an age- and gender-matched group of asymptomatic patients without DM from the CTRAD (Cardiac CT's Role in Asymptomatic Patients with DM-II) study in which patients underwent a cardiac computed tomography angiogram, for early detection of CAD. Mean EAT volumes of 118.6 ± 43.0 and 70.0 ± 44.0 cm(3) were found in the DM and non-DM groups, respectively. When stratified by the presence and severity of CAD, it was found that in the DM (p = 0.003) and non-DM groups (p <0.001), there was a statistically significant increase in EAT volume as the patients were found to have increasingly severe CAD. After adjusting for age, race, gender, DM, hypertension, insulin use, body mass index, and coronary artery calcium (CAC) score, the presence of >120 cm(3) of EAT was found to be highly correlated with the presence of significant CAD (adjusted odds ratio 4.47, 95% confidence interval 1.35 to 14.82). We found that not only is EAT volume an independent predictor of CAD but that an increasing volume of EAT predicted increasing severity of CAD even after adjustment for CAC score.

Role of echocardiography in the treatment of cardiac tamponade

Accumulation of fluid within the pericardial sac results in elevation of intrapericardial pressure with consequent cardiac compression or tamponade. Cardiac tamponade is a life-threatening condition which requires urgent evacuation of pericardial effusion (PE). Current pericardial evacuation techniques and approaches are varied. Echocardiography provides valuable insights into identifying patients who are suitable candidates and further facilitates pericardiocentesis by improving guidance techniques. Several previous publications have provided excellent reviews of the pathophysiology of cardiac tamponade. We review the clinical presentation and role of echocardiography for diagnosis of tamponade. We focus on medical and surgical approaches for the removal of PE. Moreover, as the clinical and hemodynamic consequences of PE depend on the volume and the rate of accumulation of PE, we review the various scenarios of "small" PE resulting in cardiac tamponade.

Unique morphological variations of transient midventricular syndrome: a case series-review

Older individuals (especially women) enduring an inciting emotional or physical event are prone to developing left ventricular ballooning syndrome. Ballooning of apical distribution is the most common type. However, a midventricular variant is increasingly reported. As this variant becomes further delineated, we describe a case series in which various morphological patterns of midleft ventricular segments are seen. Each case involves a female patient with a presumptive diagnosis of acute coronary syndrome, who upon further cardiac workup demonstrated normal epicardial coronary blood flow. Subsequent cardiac imaging, including transthoracic echocardiography, revealed unique midventricular dilation and akinesis, with preserved or hypercontractility of the basal and apical segments. However, more unique to this, was the fact that the left ventricular regional wall motion abnormalities were of either "symmetric" ballooning morphology, involving all mid segments of the left ventricle; or more dramatically, "asymmetric" ballooning morphology, which involves abnormal regional motion of only a focal left ventricular wall. Furthermore, we review current literature on midventricular ballooning and propose likely mechanisms and optimal treatment strategies in the face of potential complications of midventricular ballooning syndrome.

Evaluation of non-ST segment elevation acute chest pain syndromes with a novel low-profile continuous imaging ultrasound transducer

BACKGROUND

This investigation was designed to test the hypothesis that continuous cardiac imaging using an ultrasound transducer developed in our laboratory (ContiScan) is superior to electrocardiogram (ECG) monitoring in the diagnosis of coronary artery disease (CAD) in patients with acute non-ST segment elevation chest pain syndromes.

METHODS

Seventy patients with intermediate to high probability of CAD who presented with typical anginal chest pain and no evidence of ST segment elevation on the ECG were studied. The 2.5-MHz transducer is spherical in its distal part mounted in an external housing to permit steering in 360 degrees. The transducer was placed at the left sternal border to image the left ventricular short-axis view and recorded on video tape at baseline, during and after episodes of chest pain. Two ECG leads were continuously monitored. The presence of CAD was confirmed by coronary arteriography or nuclear or echocardiographic stress testing.

RESULTS

Twenty-four patients had regional wall motion abnormalities (RWMA) on their initial echo which were unchanged during the period of monitoring. All had evidence of CAD. Twenty-eight patients had transient RWMA. All had evidence of CAD. Eighteen patients had normal wall motion throughout the monitoring period, 14 of these had no evidence of CAD, and four had evidence of CAD. These four patients did not have chest pain during monitoring. The sensitivity, specificity, and accuracy of echocardiographic monitoring for diagnosing non-ST elevation myocardial infarction was 88%, 100%, and 91% respectively. The sensitivity, specificity, and accuracy of the ECG for diagnosis of CAD were 31%, 100%, and 52%, respectively. Echocardiography was superior to ECG (P < 0.001).

CONCLUSIONS

The data indicate that continuous cardiac imaging is superior to ECG monitoring for the diagnosis of CAD in patients presenting with acute non-ST segment elevation chest pain syndromes. This technique could be a useful adjunct to ECG monitoring for myocardial ischemia in the acute care setting.

Implications of acute left ventricular remodeling during squatting stress echocardiography

BACKGROUND

We previously demonstrated that squatting induces left ventricular (LV) wall motion abnormalities (WMA) in areas subtended by stenotic coronary arteries. In addition, it was observed that some subjects developed acute changes in LV shape (acute left ventricular remodeling [ALVRM]) during squatting.

OBJECTIVE

This study tested the hypothesis that patients with ALVRM during squatting echocardiography have higher incidences of severe coronary artery disease (CAD).

METHODS

Echocardiography was performed in all standard views during standing and squatting. End-systolic frames in the apical four-chamber view were analyzed.

RESULTS

The subjects were divided into three groups. Group 1 consisted of 12 subjects who developed squatting-induced ALVRM with apical and distal posterior septal akinesis, dilation of the apex and marked LV shape change at end-systole. Group 2 consisted of 20 subjects with distal posterior septal and apical akinesis without ALVRM, during squatting. Group 3 consisted of 64 subjects who developed WMA in areas other than the apex (n = 49), or normal wall motion (n = 15) during squatting. Coronary angiography in group 1 revealed that 6 subjects had left main coronary artery stenosis (LMCAS ≥ 50%), two had severe three vessel disease (≥ 90% stenosis), and one had 100% left anterior descending coronary artery occlusion. Severe CAD was defined for purpose of this study as the presence of LMCAS, or severe three vessel disease (≥ 90% stenosis). Six subjects in group 2 had LMCAS and none had severe three vessel disease (P < 0.05 vs. group 1 for LMCAS and/or three vessel disease). In group 3, eight had LMCAS and none had severe three vessel disease (P < 0.0001 vs. group 1).

CONCLUSION

Patients with ALVRM have severe CAD. Therefore, patients who develop ALVRM during squatting require urgent evaluation for revascularization therapy.

Detection of wall motion abnormalities during ambulatory echocardiography using a novel ultrasound transducer

BACKGROUND

This investigation was designed to determine whether transient wall motion abnormalities due to myocardial ischemia induced by walking could be detected by ambulatory echocardiography.

METHODS

Two groups were studied. Group 1 consisted of 10 males (mean age 34 years) who had no symptoms of angina. Group 2 consisted of eight selected patients (mean 61 years) with angina and angiographic evidence of coronary artery disease. The 2.5 MHz transducer is spherical in its distal part and mounted in an external housing to permit steering in 360°. The external housing was attached to the chest wall using an adhesive patch. The transducer was placed in the 3rd or 4th intercostal space at the left sternal border to permit imaging of the left ventricle (LV) in its short axis and attached to the chest wall. The transducer was interfaced with an Acuson Cypress echocardiography system which was placed on a mobile cart. To permit portability, the echocardiography system was powered by a capacitor (UPS device). The subjects were asked to walk along the corridor as fast as possible for 10 minutes or until the onset of symptoms while pushing the cart. The short axis of the LV was displayed on a monitor and recorded on optical disks.

RESULTS

The heart rate, systolic blood pressure (SBP), and double product of Group 1 at rest were 77 ± 3 beats/min, 119 ± 13 mmHg, and 9,150 ± 868, respectively, and increased to 106 ± 8 beats/min, 129 ± 15 mmHg, and 1,3793 ± 2,176 with walking. The baseline heart rate, SBP, and double product were 71 ± 12 beats/min, 130 ± 14 mmHg, and 8,555 ± 1,928 in Group 2 and increased to 94 ± 14 beats/min, 135 ± 20 mmHg, and 12,480 ± 3,830 with walking. All patients in Group 1 had normal wall motion at rest and during walking. Patients in Group 2 had normal wall motion during rest and new wall motion abnormalities were noted in all subjects during walking (anterior septum and/or anterolateral wall in seven, posterolateral wall in one). The wall motion abnormalities resolved shortly after discontinuation of walking.

CONCLUSION

Ambulatory echocardiography permitted the detection of transient wall motion abnormalities in patients with coronary artery disease (CAD). This technique could be potentially useful in evaluating selected patients for myocardial ischemia.

The Sirtuin System: The Holy Grail of Resveratrol?

The oxidative stress theory has been associated with atherosclerosis and has prompted a multitude of studies to evaluate the effects of antioxidants on cardiovascular disease prevention. Resveratrol, a relatively new antioxidant has gained considerable curiosity. This polyphenol stilbene identified in grape skin, is believed to be the main component contributing to the anti-atherosclerotic benefits linked to red wine consumption. It has demonstrated the ability to protect endothelial cells from lipid damage, promote vasodilation via modulation of nitric oxide synthesis, and inhibit platelet aggregation and smooth muscle proliferation. Although the complete mechanism of Resveratrol has yet to be fully elucidated, the Sirtuin system, consisting of 7 highly conserved families of regulator genes, are thought to be instrumental in establishing the various health benefits. In this article we assess the current applications, mechanism, pharmacokinetics, bioavailability, and safety profile of the novel antioxidant Resveratrol and provide an in-depth review of the influence of the Sirtuin system on the Resveratrol mechanism of action. We resolve that while early data on Resveratrol are promising, the anti-oxidative and ultimately, anti-atherosclerotic potential depends on further clarification of the intricate and complex relationship between Resveratrol and the Sirtruin system.

Atherosclerosis in chronic kidney disease: lessons learned from glycation in diabetes

In diabetes, glycation is a nonenzymatic posttranslational modification resulting from the bonding of a sugar molecule with a protein or lipid followed by oxidation, resulting in the development of advanced glycation end products (AGE). Like glycation, carbamylation is a posttranslational protein modification that is associated with AGE formation. Glycation of extracellular matrix proteins and low-density lipoprotein with subsequent deposition in the vessel wall could contribute to inflammatory response and atheroma formation. It is logical to extrapolate that carbamylation may result in modification of vessel wall proteins similar to glycation, and predispose to atherosclerosis.