Assessment of Intramyocardial Fat Content Using Computed Tomography: Is There a Relationship With Obesity?

BACKGROUND: Fat deposition in the liver and the skeletal muscle are linked to cardiovascular risk factors. Fat content in tissues can be estimated by measuring attenuation on noncontrast computed tomography (CT). Quantifying intramyocardial fat content is of interest as it may be related to myocardial dysfunction or development of heart failure. We hypothesized that myocardial fat content would correlate with severity of obesity, liver fat, and components of the metabolic syndrome. METHODS: We measured attenuation values on 121 noncontrast CT scans from the spleen, liver, erector spinae muscle, and myocardial septum. A chart review was performed for patient demographics and clinical characteristics. We tested for correlations between attenuation values in each of the tissues and various clinical parameters. RESULTS: We studied 78 females and 43 males, with a mean age of 54.5±11.2 years. Weak, but significant inverse Spearman correlation between body mass index and attenuation values were found in the liver (ρ=-0.228, P=0.012), spleen (ρ=-0.225, P=0.017), and erector spinae muscle (ρ=-0.211, P=0.022) but not in the myocardial septum (ρ=0.012, P=0.897). Mean attenuation in the nonobese group versus obese group (body mass index >30 kg/m2) were 41.1±5.0 versus 42.3±6.9 (P=0.270) in myocardial septum, 56.1±8.7 versus 51.7±10.9 (P=0.016) in the liver, 43.9±8.9 versus 40.1±10.4 (P=0.043) in the spleen, and 41.7±8.3 versus 39.0±8.8 (P=0.087) in the erector spinae muscle. CONCLUSIONS: Although CT is a theoretically appealing modality to assess fat content of the myocardium, we did not find a relationship between myocardial CT attenuation and obesity, or other cardiovascular risk factors. These findings suggest that the degree of myocardial fat accumulation in obesity or metabolic syndrome is too small to be detected with this modality.

In-Hospital Cost Comparison of Triple-Rule-Out Computed Tomography Angiography Versus Standard of Care in Patients With Acute Chest Pain.

PURPOSE: The purpose of this study was to evaluate the utilization of invasive and noninvasive tests and compare cost in patients presenting with chest pain to the emergency department (ED) who underwent either triple-rule-out computed tomography angiography (TRO-CTA) or standard of care. MATERIALS AND METHODS: We performed a retrospective single-center analysis of 2156 ED patients who presented with acute chest pain with a negative initial troponin and electrocardiogram for myocardial injury. Patient cohorts matched by patient characteristics who had undergone TRO-CTA as a primary imaging test (n=1139) or standard of care without initial CTA imaging (n=1017) were included in the study. ED visits, utilization of tests, and costs during the initial episode of hospital care were compared. RESULTS: No significant differences in the diagnosis of coronary artery disease, pulmonary embolism, or aortic dissection were observed. Median ED waiting time (4.5 vs. 7.0 h, P<0.001), median total length of hospital stay (5.0 vs. 32.0 h, P<0.001), hospital admission rate (12.6% vs. 54.2%, P<0.001), and ED return rate to our hospital within 30 days (3.5% vs. 14.6%, P<0.001) were significantly lower in the TRO-CTA group. Moreover, reduced rates of additional testing and invasive coronary angiography (4.9% vs. 22.7%, P<0.001), and ultimately lower total cost per patient (11,783$ vs. 19,073$, P<0.001) were observed in the TRO-CTA group. CONCLUSIONS: TRO-CTA as an initial imaging test in ED patients presenting with acute chest pain was associated with shorter ED and hospital length of stay, fewer return visits within 30 days, and ultimately lower ED and hospitalization costs.

Assessment of Predictors of Left Atrial Volume Response to a Transcatheter InterAtrial Shunt Device (from the REDUCE LAP-HF Trial).

In patients with heart failure and preserved or mildly reduced ejection fractions (EF ≥40%), implantation of an interatrial shunt device (IASD) resulted in heterogenous changes of the left atrial (LA) volume. Baseline characteristics that correlate with a favorable decrease in LA volume are unknown. We hypothesized that a larger ratio of left to right atrial volume at baseline would correlate strongly with LA volume decongestion following IASD implantation. Reduce Elevated LA Pressure in Patients With Heart Failure was a multicenter study of the safety and feasibility of IASD implantation. Sixty-four patients with EF ≥40% underwent device implantation along with baseline conventional echocardiograms, speckle tracking echocardiography, and resting and exercise hemodynamics. Higher LA compliance (-4.2%, p = 0.048) and right atrial reservoir strain (-0.8%, p = 0.005) were independently associated with a percent decrease in the systolic LA volume index from baseline to 6-months. In conclusion, greater LA volume reduction following IASD implantation is associated with higher baseline compliance of the left atrium and higher reservoir strain of the right atrium.

Sex Differences in Demographics, Risk Factors, Presentation, and Noninvasive Testing in Stable Outpatients With Suspected Coronary Artery Disease: Insights From the PROMISE Trial.

OBJECTIVES: The aim of this study was to determine whether presentation, risk assessment, testing choices, and results differ by sex in stable symptomatic outpatients with suspected coronary artery disease (CAD). BACKGROUND: Although established CAD presentations differ by sex, little is known about stable, suspected CAD. METHODS: The characteristics of 10,003 men and women in the PROMISE (Prospective Multicenter Imaging Study for Evaluation of Chest Pain) trial were compared using chi-square and Wilcoxon rank-sum tests. Sex differences in test selection and predictors of test positivity were examined using logistic regression. RESULTS: Women were older (62.4 years of age vs. 59.0 years of age) and were more likely to be hypertensive (66.6% vs. 63.2%), dyslipidemic (68.9% vs. 66.3%), and to have a family history of premature CAD (34.6% vs. 29.3) (all p values <0.005). Women were less likely to smoke (45.6% vs. 57.0%; p < 0.001), although their prevalence of diabetes was similar to that in men (21.8% vs. 21.0%; p = 0.30). Chest pain was the primary symptom in 73.2% of women versus 72.3% of men (p = 0.30), and was characterized as "crushing/pressure/squeezing/tightness" in 52.5% of women versus 46.2% of men (p < 0.001). Compared with men, all risk scores characterized women as being at lower risk, and providers were more likely to characterize women as having a low (<30%) pre-test probability of CAD (40.7% vs. 34.1%; p < 0.001). Compared with men, women were more often referred to imaging tests (adjusted odds ratio: 1.21; 95% confidence interval: 1.01 to 1.44) than nonimaging tests. Women were less likely to have a positive test (9.7% vs. 15.1%; p < 0.001). Although univariate predictors of test positivity were similar, in multivariable models, age, body mass index, and Framingham risk score were predictive of a positive test in women, whereas Framingham and Diamond and Forrester risk scores were predictive in men. CONCLUSIONS: Patient sex influences the entire diagnostic pathway for possible CAD, from baseline risk factors and presentation to noninvasive test outcomes. These differences highlight the need for sex-specific approaches for the evaluation of CAD.

The expanding role of computed tomography in the assessment of coronary artery disease and cardiac anatomy.

There are increasing options for noninvasive tests to assess patients with chest pain syndromes or risk factors for atherosclerosis. Choosing the optimal test for an individual patient can be challenging. This review focuses on the expanding role of cardiac computed tomography (CT) and the rationale for its use in different patient groups. It also discusses which patients are best suited for cardiac CT and the necessary patient preparation.

Close coupling of systolic and diastolic function: combined assessment provides superior prediction of exercise capacity.

BACKGROUND: Isolated diastolic dysfunction is thought to account for approximately 50% of cases of heart failure. We tested the hypotheses that (1) the use of different methods for assessing systolic and diastolic function may contribute to the apparent frequency with which they are dissociated and (2) that combined assessment of systolic and diastolic function is superior to either one alone. METHODS AND RESULTS: A total of 110 patients underwent echocardiography with tissue Doppler imaging (TDI) of the mitral annulus before maximal exercise testing. The correlation between left ventricular (LV) ejection fraction (EF) and exercise capacity was weak (r = 0.199). Among patients with EF greater than 55%, those with normal exercise capacity (>7 METs) had a higher systolic velocity of the mitral annulus than those achieving less than 7 METs (9.6 +/- 0.3 versus 7.5 +/- 0.4 cm/s, P = .001). The mitral annular systolic (Sa) and early diastolic (Ea) velocities each correlated moderately with exercise tolerance (r = 0.40 and 0.49, respectively). Sa and Ea correlated highly with each other (r = 0.79, P < .001). The sum of isovolumic contraction and relaxation times measured from TDI correlated moderately with exercise duration (r = -0.59). A combined index of systolic and diastolic function that includes isovolumic contraction and relaxation times and ejection time had the best correlation with achieved METs (r = -0.73, P < .001). A TDI index of cardiac performance higher than 0.52 had excellent sensitivity (86%) and specificity (100%) for predicting reduced exercise tolerance lower than 7 METs. CONCLUSION: When assessed with the same technique, LV systolic and diastolic function are tightly linked. A TDI-derived combined index of myocardial performance is the best predictor of exercise capacity.