W. Gregory Hundley

ACCF/ACR/AHA/NASCI/SCMR 2010 Expert Consensus Document on Cardiovascular Magnetic Resonance A Report of the American College of Cardiology Foundation Task Force on Expert Consensus Documents

Robert A. Harrington, MD, FACC, FAHA, Chair Jeffrey L. Anderson, MD, FACC, FAHA[††][1] Eric R. Bates, MD, FACC Charles R. Bridges, MD, MPH, FACC, FAHA Mark J. Eisenberg, MD, MPH, FACC, FAHA Victor A. Ferrari, MD, FACC, FAHA Cindy L. Grines, MD, FACC[††][1] Mark A. Hlatky, MD, FACC,

Cardiovascular Function in Multi-Ethnic Study of Atherosclerosis: Normal Values by Age, Sex, and Ethnicity

OBJECTIVE MRI provides accurate and high-resolution measurements of cardiac anatomy and function. The purpose of this study was to describe the imaging protocol and normal values of left ventricular (LV) function and mass in the Multi-Ethnic Study of Atherosclerosis (MESA). SUBJECTS AND METHODS Eight hundred participants (400 men, 400 women) in four age strata (45-54, 55-64, 65-74, 75-84 years) were chosen at random. Participants with the following known cardiovascular risk factors were excluded: current smoker, systolic blood pressure > 140 mm Hg, diastolic blood pressure > 90 mm Hg, fasting glucose > 110 mg/dL, total cholesterol > 240 mg/dL, and high-density lipoprotein (HDL) cholesterol < 40 mg/dL. Cardiac MR images were analyzed using MASS software (version 4.2). Mean values, SDs, and correlation coefficients in relationship to patient age were calculated. RESULTS There were significant differences in LV volumes and mass between men and women. LV volumes were inversely associated with age (p < 0.05) for both sexes except for the LV end-systolic volume index. For men, LV mass was inversely associated with age (slope = -0.72 g/year, p = 0.0021), but LV mass index was not associated with age (slope = -0.179 g/m2/year, p = 0.075). For women, LV mass (slope = -0.15 g/year, p = 0.30) and LV mass index (slope = 0.0044 g/m2/year, p = 0.95) were not associated with age. LV mass was the largest in the African-American group (men, 181.6 +/- 35.8 [SD] g; women, 128.8 +/- 28.1 g) and was smallest in the Asian-American group (men, 129.1 +/- 20.0 g; women, 89.4 +/- 13.3 g). CONCLUSION The normal LV differs in volume and mass between sexes and among certain ethnic groups. When indexed by body surface area, LV mass was independent of age for both sexes. Studies that assess cardiovascular risk factors in relationship to cardiac function and structure need to account for these normal variations in the population.

Utility of Fast Cine Magnetic Resonance Imaging and Display for the Detection of Myocardial Ischemia in Patients Not Well Suited for Second Harmonic Stress Echocardiography

BACKGROUND Some patients referred for pharmacological stress testing with transthoracic echocardiography (TTE) are unable to undergo testing owing to poor acoustic windows. Fast cine MRI can be used to assess left ventricular contraction, but its utility for detection of myocardial ischemia in patients poorly suited for echocardiography is unknown. METHODS AND RESULTS One hundred fifty-three patients (86 men and 67 women aged 30 to 88 years) with poor acoustic windows that prevented adequate second harmonic TTE imaging were consecutively referred for MRI to diagnose inducible myocardial ischemia during intravenous dobutamine and atropine. Diagnostic studies were completed in an average of 53 minutes. No patients experienced myocardial infarction, ventricular fibrillation, exacerbation of congestive heart failure, or death. In patients who underwent computer-assisted quantitative coronary angiography, the sensitivity and specificity for detecting a >50% luminal diameter narrowing were 83% and 83%, respectively. In the 103 patients with a negative MRI examination, the cardiovascular occurrence-free survival rate was 97%. CONCLUSIONS Fast cine cardiac MRI provides a mechanism to assess left ventricular contraction and diagnose inducible myocardial ischemia in patients not well suited for stress echocardiography.

Cardiac cycle-dependent changes in aortic area and distensibility are reduced in older patients with isolated diastolic heart failure and correlate with exercise intolerance.

OBJECTIVES The goal of this study was to determine if cardiac cycle-dependent changes in proximal thoracic aortic area and distensibility are associated with exercise intolerance in elderly patients with diastolic heart failure (DHF). BACKGROUND Aortic compliance declines substantially with age. We hypothesized that a reduction in cardiac cycle-dependent changes in thoracic aortic area and distensibility (above that which occurs with aging) could be associated with the exercise intolerance that is prominent in elderly diastolic heart failure patients. METHODS Thirty subjects (20 healthy individuals [10 < 30 years of age and 10 > 60 years of age] and 10 individuals > the age of 60 years with DHF) underwent a magnetic resonance imaging (MRI) study of the heart and proximal thoracic aorta followed within 48 h by maximal exercise ergometry with expired gas analysis. RESULTS The patients with DHF had higher resting brachial pulse and systolic blood pressure, left ventricular mass, aortic wall thickness and mean aortic flow velocity, and, compared with healthy older subjects, they had a significant reduction in MRI-assessed cardiac cycle-dependent change in aortic area and distensibility (p < 0.0001) that correlated with diminished peak exercise oxygen consumption (r = 0.79). After controlling for age and gender in a multivariate analysis, thoracic aortic distensibility was a significant predictor of peak exercise oxygen consumption (p < 0.04). CONCLUSIONS Older patients with isolated DHF have reduced cardiac cycle-dependent changes in proximal thoracic aortic area and distensibility (beyond that which occurs with normal aging), and this correlates with and may contribute to their severe exercise intolerance.

Magnetic Resonance Imaging Determination of Cardiac Prognosis

Background—Regional assessments of left ventricular (LV) wall motion obtained during MRI cardiac stress tests can be used to identify myocardial injury and ischemia, but the utility of MRI stress test results for the assessment of cardiac prognosis is not known. Methods and Results—Two hundred seventy-nine patients referred (because of poor LV endocardial visualization with echocardiography) for dobutamine/atropine MRI for the detection of inducible ischemia were followed for an average of 20 months. After MRI stress testing, the occurrence of myocardial infarction, cardiac death, death attributable to any cause, coronary arterial revascularization, and unstable angina or congestive heart failure requiring hospitalization was determined. In a multivariate analysis, the presence of inducible ischemia (hazard ratio 3.3, CI 1.1 to 9.7) or an LV ejection fraction <40% (hazard ratio 4.2, CI 1.3 to 13.9) was associated with future MI or cardiac death independent of the presence of risk factors for coronary arteriosclerosis. Conclusions—In patients with poor echocardiograms, the results of cardiac MRI stress tests can be used to forecast myocardial infarction or cardiac death.

Expert Consensus DocumentACCF/ACR/AHA/NASCI/SCMR 2010 Expert Consensus Document on Cardiovascular Magnetic Resonance: A Report of the American College of Cardiology Foundation Task Force on Expert Consensus Documents

American College of Cardiology Foundation Representative; †North merican Society for Cardiovascular Imaging Representative; ‡Society or Cardiovascular Magnetic Resonance Representative; §American cademy of Pediatrics; American College of Radiology Representaive; ¶ACCF Task Force Liaison; #American Heart Association epresentative. **The findings and conclusions in this expert consensus ocument reflect ACCF policy and do not necessarily represent the iews of the Uniformed Services University of the Health Sciences, the .S. Department of Defense, or the U.S. Government, by whom Dr.

Administration of an intravenous perfluorocarbon contrast agent improves echocardiographic determination of left ventricular volumes and ejection fraction: comparison with cine magnetic resonance imaging

OBJECTIVES The purpose of this study was to determine whether contrast-enhanced transthoracic echocardiography improves the evaluation of left ventricular (LV) volumes and ejection fraction (EF). BACKGROUND Echocardiographic assessment of LV volumes and EF is widely used but may be inaccurate when the endocardium is not completely visualized. Recently the intravenous (i.v.) administration of perfluorocarbon microbubbles has been shown to enhance opacification of the LV cavity, but the utility of these agents to improve the echocardiographic assessment of LV systolic function is unknown. METHODS In 40 subjects (29 men and 11 women, aged 24 to 81 years) an assessment of LV volumes and EF was performed with a magnetic resonance imaging examination, followed immediately by a transthoracic echocardiogram before and after the intravenous administration of 2% dodecafluoropentane emulsion (EchoGen; Sonus Pharmaceuticals, Bothell, Washington). RESULTS Contrast enhanced the echocardiographic assessment of LV end diastolic volume (p < 0.02), end systolic volume (p < 0.01) and LVEF (p < 0.03). The percentage of subjects in whom the correct echocardiographic classification EF was normal, mild to moderately depressed or severely reduced improved significantly after contrast enhancement (from 71% before contrast to 94% after, p < 0.03). These findings were most striking in the subjects with two or more adjacent endocardial segments not visualized at baseline. CONCLUSIONS Administration of an intravenous contrast agent improves the ability to accurately assess LV volumes and EF in humans. Contrast enhancement is most useful in subjects with two or more adjacent endocardial segments not seen at baseline.

Assessment of Coronary Arterial Flow and Flow Reserve in Humans With Magnetic Resonance Imaging

BACKGROUND The noninvasive measurement of absolute epicardial coronary arterial flow and flow reserve would be useful in the evaluation of patients with coronary circulatory disorders. Phase-contrast magnetic resonance imaging (PC-MRI) has been used to measure coronary arterial flow in animals, but its accuracy in humans is unknown. METHODS AND RESULTS Twelve subjects (7 men, 5 women: age 44 to 67 years) underwent PC-MRI measurements of flow in the left anterior descending coronary artery or one of its diagonal branches at rest and after administration of adenosine (140 microgram . kg(-1) . min (-1) IV). Immediately thereafter, intracoronary Doppler velocity (IDV) and flow measurements were made during cardiac catheterization at rest and after intravenous administration of adenosine. For the 12 patients, the correlation between MRI and invasive measurements of coronary arterial flow and coronary arterial flow reserve was excellent: coronary flow (MRI) (mL/min)= 0.85 x coronary flow (IDV) (mL/min)+17 (mL/min), r=.89, and coronary flow reserve (MRI) =0.79 x coronary velocity reserve (IDV) + 0.34, r=.89. For the range of coronary arterial flows (18 to 161 mL/min) measured by MRI, the limit of agreement between MRI and catheterization measurements of flow was -13+/-30 mL/min; for the range of coronary reserves (0.7 to 3.7) measured by MRI, the limit of agreement between the two techniques was 0.1+/-0.4. CONCLUSIONS Cine velocity-encoded PC-MRI can noninvasively measure absolute coronary arterial flow in the left anterior descending artery in humans. PC-MRI can detect pharmacologically induced changes in coronary arterial flow and can reliably distinguish between those subjects with normal and abnormal coronary artery flow reserve.

Low to Moderate Dose Anthracycline-Based Chemotherapy Is Associated With Early Noninvasive Imaging Evidence of Subclinical Cardiovascular Disease

OBJECTIVES The goal of this study was to determine if low to moderate doses of anthracycline-based chemotherapy (Anth-bC) are associated with subclinical cardiovascular (CV) injury. BACKGROUND Cancer survivors who receive Anth-bC experience premature CV events. It is unknown whether low to moderate doses of anthracyclines promote early subclinical CV disease manifested by deteriorations in left ventricular ejection fraction (LVEF) or increases in aortic stiffness, or if these doses are associated with changes in quality of life (QOL). METHODS In 53 men and women with breast cancer, leukemia, or lymphoma, we assessed left ventricular volumes, LVEF, circumferential strain, aortic pulse wave velocity, late gadolinium enhancement, serum B-type natriuretic peptide, troponin I, and the impact of treatment on QOL before and 1, 3, and 6 months after receipt of Anth-bC. RESULTS Participants averaged 50 ± 2 (range 19 to 80) years in age, 58% were women, 17% were black, and they each received a range of 50 to 375 mg/m(2) of doxorubicin-equivalent chemotherapy. Left ventricular end-systolic volume (48 ± 3 ml to 54 ± 3 ml; p = 0.02), left ventricular strain (-17.7 ± 0.4 to -15.1 ± 0.4; p = 0.0003), pulse wave velocity (6.7 ± 0.5 m/s to 10.1 ± 1 m/s; p = 0.0006), and QOL deterioration (15.4 ± 3.3 to 28.5 ± 3.9; p = 0.008) increased, whereas LVEF (58 ± 1% to 53 ± 1%; p = 0.0002) decreased within 6 months after low to moderate doses of Anth-bC. All findings persisted after accounting for age, gender, race (white/black), doxorubicin-equivalent dose, doxorubicin administration technique, comorbidities associated with CV events, and cancer diagnosis (p = 0.02 to 0.0001 for all). There were no new late gadolinium enhancement findings after 6 months. CONCLUSIONS In these study patients, low to moderate doses of Anth-bC were associated with the early development of subclinical abnormalities of cardiac and vascular function that in other populations are associated with the future occurrence of CV events.

Quantitation of cardiac output with velocity-encoded, phase-difference magnetic resonance imaging

Velocity-encoded, phase-difference magnetic resonance imaging (MRI) previously has been used to measure flow in the aorta, as well as in the pulmonary, carotid, and renal arteries, but these measurements have not been validated against currently accepted invasive techniques. To determine the accuracy of velocity-encoded, phase-difference MRI measurements of cardiac output, 23 subjects (11 men and 12 women, aged 15 to 72 years) underwent velocity-encoded, phase-difference MRI measurements of cardiac output in the proximal aorta, followed immediately by cardiac catheterization, with measurement of cardiac output by the Fick principle and by thermodilution. For MRI, Fick, and thermodilution measurements, stroke volume was calculated by dividing cardiac output by heart rate. The magnetic resonance images were acquired in 1 to 3 minutes. For all patients, the agreement between measurements of stroke volume was 3 +/- 9 ml for MRI and Fick, -3 +/- 11 ml for MRI and thermodilution, and 0 +/- 8 ml for MRI and the average of Fick and thermodilution. Compared with standard invasive measurements, velocity-encoded, phase-difference MRI can accurately and rapidly determine cardiac output.