Showing papers in "Circulation-cardiovascular Imaging in 2013"

(99m)Tc-pyrophosphate scintigraphy for differentiating light-chain cardiac amyloidosis from the transthyretin-related familial and senile cardiac amyloidoses.

Abstract: Background— Differentiating immunoglobulin light-chain (AL) from transthyretin-related cardiac amyloidoses (ATTR) is imperative given implications for prognosis, therapy, and genetic counseling. We validated the discriminatory ability of 99mTc-pyrophosphate (99mTc-PYP) scintigraphy in AL versus ATTR. Methods and Results— Forty-five subjects (12 AL, 16 ATTR wild type, and 17 ATTR mutants) underwent 99mTc-PYP planar and single-photon positive emission computed tomography cardiac imaging. Scans were performed by experienced nuclear cardiologists blinded to the subjects’ cohort assignment. Cardiac retention was assessed with both a semiquantitative visual score (range, 0; no uptake to 3, diffuse uptake) and by quantitative analysis by drawing a region of interest over the heart corrected for contralateral counts and calculating a heart-to-contralateral ratio. Subjects with ATTR cardiac amyloid had a significantly higher semiquantitative cardiac visual score than the AL cohort (2.9±0.06 versus 0.8±0.27; P 1.5 consistent with intensely diffuse myocardial tracer retention had a 97% sensitivity and 100% specificity with area under the curve 0.992, P <0.0001 for identifying ATTR cardiac amyloidosis. Conclusions— 99mTc-PYP cardiac imaging distinguishes AL from ATTR cardiac amyloidosis and may be a simple, widely available method for identifying subjects with ATTR cardiac amyloidosis, which should be studied in a larger prospective manner.

Identification and assessment of Anderson-Fabry disease by cardiovascular magnetic resonance noncontrast myocardial T1 mapping.

Abstract: Background— Anderson-Fabry disease (AFD) is a rare but underdiagnosed intracellular lipid disorder that can cause left ventricular hypertrophy (LVH). Lipid is known to shorten the magnetic resonance imaging parameter T1. We hypothesized that noncontrast T1 mapping by cardiovascular magnetic resonance would provide a novel and useful measure in this disease with potential to detect early cardiac involvement and distinguish AFD LVH from other causes. Methods and Results— Two hundred twenty-seven subjects were studied: patients with AFD (n=44; 55% with LVH), healthy volunteers (n=67; 0% with LVH), patients with hypertension (n=41; 24% with LVH), patients with hypertrophic cardiomyopathy (n=34; 100% with LVH), those with severe aortic stenosis (n=21; 81% with LVH), and patients with definite amyloid light-chain (AL) cardiac amyloidosis (n=20; 100% with LVH). T1 mapping was performed using the shortened modified Look-Locker inversion sequence on a 1.5-T magnet before gadolinium administration with primary results derived from the basal and midseptum. Compared with health volunteers, septal T1 was lower in AFD and higher in other diseases (AFD versus healthy volunteers versus other patients, 882±47, 968±32, 1018±74 milliseconds; P <0.0001). In patients with LVH (n=105), T1 discriminated completely between AFD and other diseases with no overlap. In AFD, T1 correlated inversely with wall thickness ( r =−0.51; P =0.0004) and was abnormal in 40% of subjects who did not have LVH. Segmentally, AFD showed pseudonormalization or elevation of T1 in the left ventricular inferolateral wall, correlating with the presence or absence of late gadolinium enhancement (1001±82 versus 891±38 milliseconds; P <0.0001). Conclusions— Noncontrast T1 mapping shows potential as a unique and powerful measurement in the imaging assessment of LVH and AFD.

Outcome prediction by quantitative right ventricular function assessment in 575 subjects evaluated for pulmonary hypertension.

Abstract: Background— Although right ventricular (RV) dysfunction is a major determinant of outcome in patients with pulmonary hypertension (PH), the optimal measure of RV function is poorly defined. We hypothesized that RV strain measured by speckle-tracking echocardiography predicts outcome in PH over a broad range of pulmonary pressures. Methods and Results— Prospective peak RV longitudinal systolic strain measurement was performed on 575 patients (mean age, 56±18 years; 63% women) referred for echocardiography for known or suspected PH. Survival status was assessed over a median of 16.5 (interquartile range, 7.6–20.0) months. There were 406 patients with PH (71%) (74% group 1, 14% group 3, and 12% group 4) and 169 patients without evidence of PH (29%). Among patients with PH, 46% were World Health Organization functional class III–IV. The mean RV strain was −21.2±6.7% for all patients. RV strain declined with worse functional class, shorter 6-minute walk distances, higher N-terminal pro-B-type natriuretic peptide levels, and the presence of right heart failure. RV strain predicted outcome across pulmonary pressures and groups of PH. Eighteen-month survival was 92%, 88%, 85%, and 71% according to RV strain quartile ( P <0.001), with a 1.46 higher risk of death (95% confidence interval, 1.05–2.12) per 6.7% decline in RV strain. RV strain predicted survival when adjusted for pulmonary pressure, pulmonary vascular resistance, and right atrial pressure and provided incremental prognostic value over conventional clinical and echocardiographic variables. Conclusions— Quantitative assessment of RV free-wall systolic strain is feasible and is a powerful predictor of the clinical outcome of patients with known or suspected PH.

Comprehensive validation of cardiovascular magnetic resonance techniques for the assessment of myocardial extracellular volume.

Abstract: Background— Extracellular matrix expansion is a key element of ventricular remodeling and a potential therapeutic target. Cardiovascular magnetic resonance (CMR) T1-mapping techniques are increasingly used to evaluate myocardial extracellular volume (ECV); however, the most widely applied methods are without histological validation. Our aim was to perform comprehensive validation of (1) dynamic-equilibrium CMR (DynEq-CMR), where ECV is quantified using hematocrit-adjusted myocardial and blood T1 values measured before and after gadolinium bolus; and (2) isolated measurement of myocardial T1, used as an ECV surrogate. Methods and Results— Whole-heart histological validation was performed using 96 tissue samples, analyzed for picrosirius red collagen volume fraction, obtained from each of 16 segments of the explanted hearts of 6 patients undergoing heart transplantation who had prospectively undergone CMR before transplantation (median interval between CMR and transplantation, 29 days). DynEq-CMR–derived ECV was calculated from T1 measurements made using a modified Look-Locker inversion recovery sequence before and 10 and 15 minutes post contrast. In addition, ECV was measured 2 to 20 minutes post contrast in 30 healthy volunteers. There was a strong linear relationship between DynEq-CMR–derived ECV and histological collagen volume fraction ( P <0.001; within-subject: r =0.745; P <0.001; r 2=0.555 and between-subject: r =0.945; P <0.01; r 2=0.893; for ECV calculated using 15-minute postcontrast T1). Correlation was maintained throughout the entire heart. Isolated postcontrast T1 measurement showed significant within-subject correlation with histological collagen volume fraction ( r =−0.741; P <0.001; r 2=0.550 for 15-minute postcontrast T1), but between-subject correlations were not significant. DynEq-CMR–derived ECV varied significantly according to contrast dose, myocardial region, and sex. Conclusions— DynEq-CMR–derived ECV shows a good correlation with histological collagen volume fraction throughout the whole heart. Isolated postcontrast T1 measurement is insufficient for ECV assessment.

Aortic dilation in bicuspid aortic valve disease: Flow pattern is a major contributor and differs with valve fusion type

Abstract: Background—Ascending aortic dilation is important in bicuspid aortic valve (BAV) disease, with increased risk of aortic dissection. We used cardiovascular MR to understand the pathophysiology better by examining the links between 3-dimensional flow abnormalities, aortic function, and aortic dilation. Methods and Results—A total of 142 subjects underwent cardiovascular MR (mean age, 40 years; 95 with BAV, 47 healthy volunteers). Patients with BAV had predominantly abnormal right-handed helical flow in the ascending aorta, larger ascending aortas (18.3±3.3 versus 15.2±2.2 mm/m 2 ; P<0.001), and higher rotational (helical) flow (31.7±15.8 versus 2.9±3.9 mm 2 /s; P<0.001), systolic flow angle (23.1°±12.5° versus 7.0°±4.6°; P<0.001), and systolic wall shear stress (0.85±0.28 versus 0.59±0.17 N/m 2 ; P<0.001) compared with healthy volunteers. BAV with right-handed flow and right- non coronary cusp fusion (n=31) showed more severe flow abnormalities (rotational flow, 38.5±16.5 versus 27.8±12.4 mm 2 /s; P<0.001; systolic flow angle, 29.4°±10.9° versus 19.4°±11.4°; P<0.001; in-plane wall shear stress, 0.64±0.23 versus 0.47±0.22 N/m 2 ; P<0.001) and larger aortas (19.5±3.4 versus 17.5±3.1 mm/m 2 ; P<0.05) than right-left cusp fusion (n=55). Patients with BAV with normal flow patterns had similar aortic dimensions and wall shear stress to healthy volunteers and younger patients with BAV showed abnormal flow patterns but no aortic dilation, both further supporting the importance of flow pattern in the pathogenesis of aortic dilation. Aortic function measures (distensibility, aortic strain, and pulse wave velocity) were similar across all groups. Conclusions—Flow abnormalities may be a major contributor to aortic dilation in BAV. Fusion type affects the severity of flow abnormalities and may allow better risk prediction and selection of patients for earlier surgical intervention. (Circ Cardiovasc Imaging. 2013;6:499-507.)

Detection of left atrial appendage thrombus by cardiac computed tomography in patients with atrial fibrillation: a meta-analysis.

Abstract: Background— Transesophageal echocardiogram (TEE) is considered the gold standard modality in detecting left atrial/LA appendage (LA/LAA) thrombi. However, this is a semi-invasive procedure with rare but potential life-threatening complications. Cardiac computed tomography has been proposed as an alternative method. The purpose of this meta-analysis was to evaluate the diagnostic accuracy of cardiac computed tomography assessing LA/LAA thrombi in comparison with TEE. Methods and Results— A systematic review of Medline, Cochrane, and Embase to look for clinical trials assessing detection of LA/LAA thrombi by cardiac computed tomography when compared with TEE in patients with a history of atrial fibrillation before electric cardioversion/pulmonary vein isolation or after cardioembolic cerebrovascular accident was performed using standard approach and bivariate analysis. Nineteen studies with 2955 patients (men, 71%; mean age, 61±4 years) fulfilled the inclusion criteria. Most studies (85%, 16 studies) used 64-slide multidetector computed tomography and 15 studies (79%) were electrocardiographic-gated. The incidence of LA/LAA thrombi was 8.9% (SD, ±7). The mean sensitivity and specificity were 96% and 92%, whereas the positive predictive value and negative predictive value were 41% and 99%, respectively. The diagnostic accuracy was 94%. In a subanalysis of studies in which delayed imaging was performed, the diagnostic accuracy significantly improved to a mean weighted sensitivity and specificity of 100% and 99%, respectively, whereas the positive predictive value and negative predictive value increased to 92% and 100%, respectively. The accuracy for this technique was 99%. Conclusions— Cardiac computed tomography, particularly when delayed imaging is performed, is a reliable alternative to TEE for the detection of LA/LAA thrombi/clot, avoiding the discomfort and risks associated with TEE.

Quantification of myocardial extracellular volume fraction in systemic AL amyloidosis: an equilibrium contrast cardiovascular magnetic resonance study.

Abstract: Background— Cardiac involvement predicts outcome in systemic AL amyloidosis and influences therapeutic options. Current methods of cardiac assessment do not quantify myocardial amyloid burden. We used equilibrium contrast cardiovascular magnetic resonance (EQ-CMR) to quantify the cardiac interstitial compartment, measured as myocardial extracellular volume (ECV) fraction, hypothesizing it would reflect amyloid burden. Methods and Results— Sixty patients with systemic AL amyloidosis (65% men, median age 65 years) underwent conventional clinical cardiovascular magnetic resonance, including late enhancement, equilibrium contrast cardiovascular magnetic resonance, and clinical cardiac evaluation, including ECG, echocardiography, assays of N-terminal pro-brain natriuretic peptide and Troponin T, and functional assessment comprising the 6-minute walk test in ambulant individuals. Cardiac involvement in the amyloidosis patients was categorized as definite, probable, or none, suspected by conventional criteria. Findings were compared with 82 healthy controls. Mean ECV was significantly greater in patients than healthy controls (0.25 versus 0.40, P <0.001) and correlated with conventional criteria for characterizing the presence of cardiac involvement, the categories of none, probable, definite corresponding to ECV of 0.276 versus 0.342 versus 0.488, respectively ( P <0.001). ECV was correlated with cardiac parameters by echocardiography (eg, Tissue Doppler Imaging [TDI] S-wave R=0.52, P<0.001) and conventional cardiovascular magnetic resonance (eg, indexed left ventricular mass R =0.56, P <0.001). There were also significant correlations with N-terminal pro-brain natriuretic peptide ( R =0.69, P <0.001) and Troponin T ( R =0.53, P =0.006). ECV was associated with smaller QRS voltages ( R =0.57, P <0.001) and correlated with poorer performance in the 6-minute walk test ( R =0.36, P =0.03). Conclusions— Myocardial ECV measurement has potential to become the first noninvasive test to quantify cardiac amyloid burden.

Cardiac MRI: a new gold standard for ventricular volume quantification during high-intensity exercise.

Abstract: Background— Accurate measures are critical when attempting to distinguish normal from pathological changes in cardiac function during exercise, yet imaging modalities have seldom been assessed against invasive exercise standards. We sought to validate a novel method of biventricular volume quantification by cardiac MRI (CMR) during maximal exercise. Methods and Results— CMR was performed on 34 subjects during exercise and free-breathing with the use of an ungated real-time (RT-ungated) CMR sequence. ECG and respiratory movements were retrospectively synchronized, enabling compensation for cardiac cycle and respiratory phase. Feasibility of RT-ungated imaging was compared with standard exercise CMR imaging with ECG gating (gated); accuracy of RT-ungated CMR was assessed against an invasive standard (direct Fick); and reproducibility was determined after a second bout of maximal exercise. Ventricular volumes were analyzed more frequently during high-intensity exercise with RT-ungated compared with gated CMR (100% versus 47%; P <0.0001) and with better interobserver variability for RT-ungated (coefficient of variation=1.9% and 2.0% for left and right ventricular stroke volumes, respectively) than gated (coefficient of variation=15.2% and 13.6%; P <0.01). Cardiac output determined by RT-ungated CMR proved accurate against the direct Fick method with excellent agreement (intraclass correlation coefficient, R =0.96), which was highly reproducible during a second bout of maximal exercise ( R =0.98). Conclusions— When RT-ungated CMR is combined with post hoc analysis incorporating compensation for respiratory motion, highly reproducible and accurate biventricular volumes can be measured during maximal exercise.

Noninvasive fractional flow reserve derived from computed tomography angiography for coronary lesions of intermediate stenosis severity: results from the DeFACTO study.

Abstract: Background— Fractional flow reserve derived from computed tomography angiography (FFRCT) is a noninvasive method for diagnosis of ischemic coronary lesions. To date, the diagnostic performance of FFRCT for lesions of intermediate stenosis severity remains unexamined. Methods and Results— Among 407 vessels from 252 patients at 17 centers who underwent CT, FFRCT, invasive coronary angiography, and invasive FFR, we identified 150 vessels of intermediate stenosis by CT, defined as 30% to 69% stenosis. FFRCT, FFR, and CT were interpreted in blinded fashion by independent core laboratories. FFRCT and FFR ≤0.80 were considered hemodynamically significant, whereas CT stenosis ≥50% was considered obstructive. Diagnostic performance of FFRCT versus CT was assessed for accuracy, sensitivity, specificity, positive predictive values, and negative predictive values. Area under the receiver operating characteristic curve and net reclassification improvement were evaluated. For lesions of intermediate stenosis severity, accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of FFRCT were 71%, 74%, 67%, 41%, and 90%, whereas accuracy, sensitivity, specificity, positive predictive value, and negative predictive value of CT stenosis were 63%, 34%, 72%, 27%, and 78%. FFRCT demonstrated superior discrimination compared with CT stenosis on per-patient (area under the receiver operating characteristic curve, 0.81 versus 0.50; P =0.0001) and per-vessel basis (area under the receiver operating characteristic curve, 0.79 versus 0.53; P <0.0001). FFRCT demonstrated significant reclassification of CT stenosis for lesion-specific ischemia (net reclassification improvement, 0.45; 95% confidence interval, 0.25–0.65; P =0.01). Conclusions— FFRCT possesses high diagnostic performance for diagnosis of ischemic for lesions of intermediate stenosis severity. Notably, the high sensitivity and negative predictive value suggest the ability of FFRCT to effectively rule out intermediate lesions that cause ischemia.

Sex differences in aortic valve calcification measured by multidetector computed tomography in aortic stenosis.

Abstract: Background— Aortic valve calcification (AVC) is the intrinsic mechanism of valvular obstruction leading to aortic stenosis (AS) and is measurable by multidetector computed tomography. The link between sex and AS is controversial and that with AVC is unknown. Methods and Results— We prospectively performed multidetector computed tomography in 665 patients with AS (aortic valve area, 1.05±0.35 cm2; mean gradient, 39±19 mm Hg) to measure AVC and to assess the impact of sex on the AVC–AS severity link in men and women. AS severity was comparable between women and men (peak aortic jet velocity: 4.05±0.99 versus 3.93±0.91 m/s, P =0.11; aortic valve area index: 0.55±0.20 versus 0.56±0.18 cm2/m2; P =0.46). Conversely, AVC load was lower in women versus men (1703±1321 versus 2694±1628 arbitrary units; P 0.67; P <0.0001), for any level of AS severity measured by peak aortic jet velocity or aortic valve area index, AVC load, absolute or indexed, was higher in men versus women (all P ≤0.01). Conclusions— In this large AS population, women incurred similar AS severity than men for lower AVC loads, even after indexing for their smaller body size. Hence, the relationship between valvular calcification process and AS severity differs in women and men, warranting further pathophysiological inquiry. For AS severity diagnostic purposes, interpretation of AVC load should be different in men and in women.

T1 Measurements Identify Extracellular Volume Expansion in Hypertrophic Cardiomyopathy Sarcomere Mutation Carriers With and Without Left Ventricular Hypertrophy

Abstract: Background— Myocardial fibrosis is a hallmark of hypertrophic cardiomyopathy (HCM) and a potential substrate for arrhythmias and heart failure. Sarcomere mutations seem to induce profibrotic changes before left ventricular hypertrophy (LVH) develops. To further evaluate these processes, we used cardiac magnetic resonance with T1 measurements on a genotyped HCM population to quantify myocardial extracellular volume (ECV). Methods and Results— Sarcomere mutation carriers with LVH (G+/LVH+, n=37) and without LVH (G+/LVH−, n=29), patients with HCM without mutations (sarcomere-negative HCM, n=11), and healthy controls (n=11) underwent contrast cardiac magnetic resonance, measuring T1 times pre- and postgadolinium infusion. Concurrent echocardiography and serum biomarkers of collagen synthesis, hemodynamic stress, and myocardial injury were also available in a subset. Compared with controls, ECV was increased in patients with overt HCM, as well as G+/LVH− mutation carriers (ECV=0.36±0.01, 0.33±0.01, 0.27±0.01 in G+/LVH+, G+/LVH−, controls, respectively; P ≤0.001 for all comparisons). ECV correlated with N-terminal probrain natriuretic peptide levels (r=0.58; P 60% of overt patients with HCM but absent from G+/LVH− subjects. Both ECV and late gadolinium enhancement were more extensive in sarcomeric HCM than sarcomere-negative HCM. Conclusions— Myocardial ECV is increased in HCM sarcomere mutation carriers even in the absence of LVH. These data provide additional support that fibrotic remodeling is triggered early in disease pathogenesis. Quantifying ECV may help characterize the development of myocardial fibrosis in HCM and ultimately assist in developing novel disease-modifying therapy, targeting interstitial fibrosis.

Prospective comparison of valve regurgitation quantitation by cardiac magnetic resonance imaging and transthoracic echocardiography.

Abstract: Background— Both transthoracic echocardiography (TTE) and cardiac magnetic resonance (CMR) imaging allow quantification of chronic aortic regurgitation (AR) and mitral regurgitation (MR) We hypothesized that CMR measurement of regurgitant volume (RVol) is more reproducible than TTE Methods and Results— TTE and CMR performed on the same day in 57 prospectively enrolled adults (31 with AR, 26 with MR) were measured by 2 independent physicians TTE RVolAR was calculated as Doppler left ventricular outflow minus inflow stroke volume RVolMR was calculated by both the proximal isovelocity surface area method and Doppler volume flow at 2 sites CMR RVolAR was calculated by phase-contrast velocity mapping at the aortic sinuses and RVolMR as total left ventricular minus forward stroke volume Intraobserver and interobserver variabilities were similar For AR, the Bland–Altman mean interobserver difference in RVol was −07 mL (95% confidence interval [CI], −5 to 4) for CMR and −9 mL (95% CI, −53 to −36) for TTE The Pearson correlation was higher ( P =0001) between CMR (099) than TTE readers (089) For MR, the Bland–Altman mean difference in RVol between observers was −4 mL (95% CI, −21 to 13) for CMR compared with 07 mL (95% CI, −30 to 32) for the proximal isovelocity surface area and −10 mL (95% CI, −76 to 56) for TTE volume flow at 2 sites Correlation was similar for CMR (094) versus TTE readers (090 for the proximal isovelocity surface area) Conclusions— Compared with TTE, CMR has lower intraobserver and interobserver variabilities for RVolAR, suggesting CMR may be superior for serial measurements Although RVolMR is similar by TTE and CMR, variability in measured RVol by both approaches suggests that caution is needed in clinical practice

Native Myocardial T1 Mapping by Cardiovascular Magnetic Resonance Imaging in Subclinical Cardiomyopathy in Patients With Systemic Lupus Erythematosus

Abstract: Background— Increased systemic inflammation has been linked to myocardial dysfunction and heart failure in patients with systemic lupus erythematosus (SLE). Accurate detection of early myocardial changes may be able to guide preventive intervention. We investigated whether multiparametric imaging by cardiovascular magnetic resonance can detect differences between controls and asymptomatic SLE patients. Methods and Results— A total of 33 SLE predominantly female patients (mean age, 40±9 years) underwent cardiovascular magnetic resonance for routine assessment of myocardial perfusion, function, and late gadolinium enhancement. T1 mapping was performed in single short-axis slice before and after 15 minutes of gadolinium administration. Twenty-one subjects with a low pretest probability and normal cardiovascular magnetic resonance served as a control group. Both groups had similar left ventricular volumes and mass and normal global systolic function. SLE patients had significantly reduced longitudinal strain (controls versus SLE, −20±2% versus −17±3%; P <0.01) and showed intramyocardial and pericardial late gadolinium enhancement. SLE patients had significantly increased native myocardial T1 (1056±27 versus 1152±46 milliseconds; P <0.001) and extracellular volume fraction (26±5% versus 30±6%; P =0.007) and reduced postcontrast myocardial T1 (454±53 versus 411±62 milliseconds; P =0.01). T1-derived indices were associated with longitudinal strain ( r =0.37–0.47) but not with the presence of late gadolinium enhancement. Native myocardial T1 values showed the greatest concordance with the presence of clinical diagnosis of SLE. Conclusions— In patients with SLE and free of cardiac symptoms, there is evidence of subclinical perimyocardial impairment. We further demonstrate that T1 mapping may have potential to detect subclinical myocardial involvement in patients with SLE.

Age-, Body Size-, and Sex-Specific Reference Values for Right Ventricular Volumes and Ejection Fraction by Three-Dimensional Echocardiography A Multicenter Echocardiographic Study in 507 Healthy Volunteers

Abstract: Background— Right ventricular (RV) volumes and ejection fraction (EF) vary significantly with demographic and anthropometric factors and are associated with poor prognosis in several cardiovascular diseases. This multicenter study was designed to (1) establish the reference values for RV volumes and EF using transthoracic three-dimensional (3D) echocardiography; (2) investigate the influence of age, sex, and body size on RV anatomy; (3) develop normative equations. Methods and Results— RV volumes (end-diastolic volume and end-systolic volume), stroke volume, and EF were measured by 3D echocardiography in 540 healthy adult volunteers, prospectively enrolled, evenly distributed across age and sex. The relation of age, sex, and body size parameters was investigated using bivariate and multiple linear regression. Analysis was feasible in 507 (94%) subjects (260 women; age, 45±16 years; range, 18–90). Age, sex, height, and weight significantly influenced RV volumes and EF. Sex effect was significant ( P <0.01), with RV volumes larger and EF smaller in men than in women. Older age was associated with lower volumes (end-diastolic volume, −5 mLdecade; end-systolic volume, −3 mL/decade; EF, −2 mL/decade) and higher EF (+1% per decade). Inclusion of body size parameters in the statistical models resulted in improved overall explained variance for volumes (end-diastolic volume, R 2=0.43; end-systolic volume, R 2=0.35; stroke volume, R 2=0.30), while EF was unaffected. Ratiometric and allometric indexing for age, sex, and body size resulted in no significant residual correlation between RV measures and height or weight. Conclusions— The presented normative ranges and equations could help standardize the 3D echocardiography assessment of RV volumes and function in clinical practice, considering the effects of age, sex, and body size.

T1 Mapping With Cardiovascular MRI Is Highly Sensitive for Fabry Disease Independent of Hypertrophy and Sex

Abstract: Background— Fabry disease (FD) is an X-linked disorder of lysosomal metabolism affecting multiple organs with cardiac disease being the leading cause of death. Current imaging evaluations of the heart are suboptimal. The goals of the current study are to evaluate the potential of quantitative T1 mapping with cardiovascular MRI as a disease-specific imaging biomarker. Methods and Results— A total of 31 patients with FD, 23 healthy controls, and 21 subjects with concentric remodeling or hypertrophy underwent cardiovascular MRI to measure left ventricular (LV) morphology, function, delayed enhancement, as well as myocardial T1 values, and derived parameters (extracellular volume). All subjects had LV ejection fraction >50% and similar volumes. FD and concentric remodeling or hypertrophy had similarly increased mass, wall thickness, and mass/volume as compared with controls. A total of 16 of 31 FD subjects and 10 of 21 concentric remodeling or hypertrophy subjects had LV hypertrophy. Noncontrast myocardial T1 values were substantially lower in FD as compared with controls and concentric remodeling or hypertrophy (1070±50, 1177±27, and 1207±33 ms, respectively; P <0.001), but extracellular volume was similar in all groups (21.7±2.4%, 22.2±3.1%, and 21.8±3.9%, respectively). Single-voxel NMR spectroscopy in 4 FD and 4 healthy control subjects showed a significant negative linear relationship between lipid content and noncontrast T1 values ( r =−0.9; P =0.002). Female subjects had lower LV mass and wall thickness, longer myocardial T1 values and larger extracellular volume suggesting a key sex difference in cardiac remodeling. Conclusions— Reduced noncontrast myocardial T1 values are the most sensitive and specific cardiovascular MRI parameter in patients with FD irrespective of sex and LV morphology and function.

Cardiac Remodeling in Obesity

Abstract: Obesity has generated much interest within the cardiovascular community within the past 2 decades.1 It is now recognized that obesity is an important contributor to cardiac and all-cause mortality,1,2 independent of its association with other cardiovascular risk factors and increases the risk for cardiovascular morbidity, including heart failure (Figure 1).2–4 The malefic consequences of obesity are due both to the associated structural and functional cardiac alterations as well as the high prevalence of coexisting conditions, such as coronary artery disease, hypertension, sleep–disordered breathing (SDB), and diabetes mellitus.1–7 To better understand the relationship between obesity and heart failure, we will review what is known about cardiac structural remodeling in obesity as well as the evidence for preclinical abnormalities in left-ventricular (LV) systolic and diastolic functions. We will place particular emphasis on newer concepts and findings suggested by contemporary imaging methods. Figure 1. The population attributable risk of heart failure because of overweight is 14% in women and 8.8% in men. In obesity, the corresponding population attributable risks in women and men are 13.9 and 10.9%, respectively. From Kenchaiah et al,4 used with permission. By National Institutes of Health criteria, obesity is defined as a body mass index (BMI) ≥30 kg/m2 and severe obesity as a BMI≥40 kg/m2.8 Obesity involves the growth of both lean body mass and adipose tissue and is characterized by a disproportionate growth of adipose tissue in relationship to lean body mass.9 It is now recognized that adipose tissue is not a homogeneous organ, but is differentiated in relation to its metabolic activity. Whereas fat accumulating in the subcutaneous region does not require substantial blood supply,10 fat surrounding organs (abdominal, epicardial) is metabolically active, requires energy, and produces a number of compounds …

Cardiac magnetic resonance postcontrast T1 time is associated with outcome in patients with heart failure and preserved ejection fraction.

Abstract: Background— The underlying pathophysiology of heart failure with preserved ejection fraction (HFPEF) is incompletely understood, but myocardial extracellular matrix accumulation is thought to play a major role. Our aims were to estimate myocardial extracellular matrix using cardiac magnetic resonance T1 mapping and to assess the relationship between pathobiology/pathophysiology and prognosis. Methods and Results— Patients with suspected HFPEF (n=100) were enrolled in this prospective, observational study. Confirmatory diagnostic tests, cardiac magnetic resonance imaging including T1 mapping, and invasive hemodynamic assessments were performed at baseline. Sixty-one patients with confirmed HFPEF entered a longitudinal outcome-monitoring phase (mean, 22.9±5.0 months), during which 16 had a cardiac event. Cardiac magnetic resonance T1 time (hazard ratio, 0.99; 95% confidence interval, 0.98–0.99; P =0.046), left atrial area (hazard ratio, 1.08; 95% confidence interval, 1.03–1.13; P <0.01), and pulmonary vascular resistance (hazard ratio, 1.01; 95% confidence interval, 1.00–1.01; P =0.03) were significantly associated with cardiac events. Patients with T1 times below the median (<388.3 ms) were at greater risk of cardiac events than the rest of the group ( P <0.01). Extracellular matrix of left ventricular biopsies (n=9), quantified by TissueFAXS technology correlated with T1 time ( R =0.98; P <0.01). T1 time also correlated with right ventricular–pulmonary arterial coupling (pulmonary vascular resistance: R =−0.36; P <0.01; right ventricular ejection fraction: R =0.28; P =0.01). Conclusions— In the present preliminary study, cardiac magnetic resonance postcontrast T1 time is associated with prognosis in HFPEF, suggesting postcontrast T1 as possible biomarker for HFPEF.

Focal arterial inflammation precedes subsequent calcification in the same location: a longitudinal FDG-PET/CT study

Abstract: Background— Arterial calcium (Ca) deposition has been identified as an active inflammatory process. We sought to test the hypothesis that local vascular inflammation predisposes to subsequent arterial calcium deposition in humans. Methods and Results— From a hospital database, we identified 137 patients (age, 61±13 years; 48.1% men) who underwent serial positron-emission tomography/computed tomography (1–5 years apart). Focal arterial inflammation was prospectively determined by measuring 18F-flourodeoxyglucose uptake (using baseline positron-emission tomography) within predetermined locations of the thoracic aortic wall and was reported as a standardized uptake value. A separate, blinded investigator evaluated calcium deposition (on the baseline and follow-up computed tomographic scans) along the same standardized sections of the aorta. New calcification was prospectively defined using square root–transformed difference of calcium volume score, with a cutoff value of 2.5. Accordingly, vascular segment was classified as either with or without subsequent calcification. Overall, 67 (9%) of aortic segments demonstrated subsequent calcification. Baseline median (interquartile range) standardized uptake value was higher in segments with versus without subsequent calcification (2.09 [1.84–2.44] versus 1.92 [1.72–2.20], P =0.002). This was also true in the subset of segments with Ca present at baseline (2.08 [1.81–2.40] versus 1.86 [1.66–2.09], P =0.02), as well as those without (2.17 [1.87–2.51] versus 1.93 [1.73–2.20], P =0.04). Furthermore, across all patients, subsequent Ca deposition was associated with the underlying 18F-flourodeoxyglucose uptake (inflammatory signal), measured as standardized uptake value (odds ratio [95% confidence interval]=2.94 [1.27–6.89], P =0.01) or target-to-background ratio (2.59 [1.18–5.70], P =0.02), after adjusting for traditional cardiovascular risk factors. Conclusions— Here, we provide first-in-man evidence that arterial inflammation precedes subsequent Ca deposition, a marker of plaque progression, within the underlying location in the artery wall.

Effect of Combined Systolic and Diastolic Functional Parameter Assessment for Differentiation of Cardiac Amyloidosis From Other Causes of Concentric Left Ventricular Hypertrophy

Abstract: Background— Differentiation of cardiac amyloidosis (CA) from other causes of concentric left ventricular hypertrophy remains a clinical challenge, especially in patients with preserved ejection fraction at the early disease stages. Methods and Results— Consecutive hypertrophic patients with CA, isolated arterial hypertension, Fabry disease, and Friedreich ataxia (n=25 per group) were investigated; 25 healthy volunteers served as a control group. Standard echocardiography was performed, and segmental longitudinal peak systolic strain (LSsys) in the septum was assessed by 2-dimensional speckle tracking imaging. Indices of left ventricular hypertrophy and ejection fraction were similar among all patient groups. Deceleration time of early filling was significantly lower in patients with CA (147±46 milliseconds) compared with those with isolated arterial hypertension, Fabry disease, or control subjects (all P 0.05). A data-driven cutoff value for the ratio of septal apical to basal LSsys ratio >2.1 differentiated CA from other causes of left ventricular hypertrophy (sensitivity, 88%; specificity, 85%; positive predictive value, 67%; negative predictive value, 96%). The prevalence of septal apical to basal LSsys ratio >2.1 plus deceleration time of early filling <200 milliseconds was 88% in CA but 0% in all other groups. Conclusions— A systolic septal longitudinal base-to-apex strain gradient (septal apical to basal LSsys ratio >2.1), combined with a shortened diastolic deceleration time of early filling (deceleration time of early filling <200 milliseconds), aids in differentiating CA from other causes of concentric left ventricular hypertrophy.

Cardiac MRI in the Assessment of Cardiac Injury and Toxicity From Cancer Chemotherapy: A Systematic Review

Abstract: During the past 30 years, there has been a significant decrease in cancer mortality rates, predominantly attributable to improvements in treatment options.1 However, survivors are at increased risk of premature cardiac disease,2 both because of the overlap in risk factors for cancer and cardiovascular disease3 and the cardiotoxic effects of cancer chemotherapy. Two chemotherapeutic agent classes that are commonly associated with cardiotoxicity are the anthracyclines and tyrosine kinase inhibitors, both of which can cause left ventricular (LV) dysfunction and heart failure (HF).4,5 Mechanisms of cardiac injury from cancer therapy have been summarized elsewhere.4,6 Briefly, anthracycline cardiotoxicity has been attributed to reactive oxygen species formation, transcriptional changes in intracellular adenosine triphosphate production in cardiac myocytes, and, more recently, through interaction with cardiac topoisomerase IIβ.4,6 Trastuzumab cardiotoxicity seems to be because of inhibition of cardiomyocyte human epidermal growth factor receptor 2, resulting in ATP depletion and contractile dysfunction.4 Other proposed mechanisms include immune-mediated destruction of cardiomyocytes.4,6 At the tissue level, early anthracycline toxicity has been associated with myocardial inflammation,7–9 vacuolization,9–12 and cell swelling/edema.11,13 These changes seem to occur before myocardial functional abnormalities.11,13 Later stages of toxicity are associated with myocardial fibrosis.14,15 Unfortunately, the use of myocardial biopsy is not feasible for diagnostic purposes in this setting. However, once HF manifests, the 2-year mortality can be as high as 60%.16 This emphasizes the importance of early recognition of cardiac injury and institution of cardioprotective therapy in an effort to prevent development of HF and allow uninterrupted completion of cancer therapy.17 Thus, the diagnosis is dependent on either direct evidence of myocardial damage or functional disturbance. Either signal may be identified …

Identification of Therapeutic Benefit from Revascularization in Patients With Left Ventricular Systolic Dysfunction Inducible Ischemia Versus Hibernating Myocardium

Abstract: Background— Although the recent surgical treatment of ischemic heart failure substudy reported that revascularization of viable myocardium did not improve survival, these results were limited by the viability imaging technique used and the lack of inducible ischemia information. We examined the relative impact of stress-rest rubidium-82/F-18 fluorodeoxyglucose positron emission tomography identified ischemia, scar, and hibernating myocardium on the survival benefit associated with revascularization in patients with systolic dysfunction. Methods and Results— The extent of perfusion defects and metabolism-perfusion mismatch was measured with an automated quantitative method in 648 consecutive patients (age, 65±12 years; 23% women; mean left ventricular ejection fraction, 31±12%) undergoing positron emission tomography. Follow-up time began at 92 days (to avoid waiting-time bias); deaths before 92 days were excluded from the analysis. During a mean follow-up of 2.8±1.2 years, 165 deaths (27.5%) occurred. Cox proportional hazards modeling was used to adjust for potential confounders, including a propensity score to adjust for nonrandomized treatment allocation. Early revascularization was performed within 92 days of positron emission tomography in 199 patients (33%). Hibernating myocardium, ischemic myocardium, and scarred myocardium were associated with all-cause death ( P =0.0015, 0.0038, and 0.0010, respectively). An interaction between treatment and hibernating myocardium was present such that early revascularization in the setting of significant hibernating myocardium was associated with improved survival compared with medical therapy, especially when the extent of viability exceeded 10% of the myocardium. Conclusions— Among patients with ischemic cardiomyopathy, hibernating, but not ischemic, myocardium identifies which patients may accrue a survival benefit with revascularization versus medical therapy.

Relation of regional fat distribution to left ventricular structure and function

Abstract: Background— The relation of body fat distribution to left ventricular (LV) structure and function is poorly defined. Methods and Results— A total of 2710 participants without heart failure or LV dysfunction in the Dallas Heart Study underwent dual energy x-ray absorptiometry and MRI assessment of fat distribution, LV morphology, and hemodynamics. Cross-sectional associations of fat distribution with LV structure and function were examined after adjustment for age, sex, race, comorbidities, and lean mass. Mean age was 44 years with 55% women; 48% blacks; and 44% obese. After multivariable adjustment, visceral adipose tissue was associated with concentric remodeling characterized by lower LV end-diastolic volume (β=−0.21), higher concentricity (β=0.20), and wall thickness (β=0.09; P <0.0001 for all). In contrast, lower body subcutaneous fat was associated with higher LV end-diastolic volume (β=0.48), reduced concentricity (β=−0.50), and wall thickness (β=−0.28, P <0.0001 for all). Visceral adipose tissue was also associated with lower cardiac output (β=−0.10, P <0.05) and higher systemic vascular resistance (β=0.08, P <0.05), whereas lower body subcutaneous fat associated with higher cardiac output (β=0.20, P <0.0001) and lower systemic vascular resistance (β=−0.18, P <0.0001). Abdominal subcutaneous fat showed weaker associations with concentric remodeling and was not associated with hemodynamics. Among the subset of obese participants, visceral adipose tissue, but not abdominal subcutaneous fat, was significantly associated with concentric remodeling. Conclusions— Visceral adipose tissue, a marker of central adiposity, was independently associated with concentric LV remodeling and adverse hemodynamics. In contrast, lower body subcutaneous fat was associated with eccentric remodeling. The impact of body fat distribution on heart failure risk requires prospective study.

Cardiac Magnetic Resonance Assessment of Myocarditis

Abstract: Symptoms consistent with myocarditis are a frequent cause of medical visits, especially in young and middleaged patients. Moreover, myocarditis was found to be the most frequent disease in patients with acute coronary syndrome yet normal coronary arteries. 1 Although many causes have been identified, acute cases are mostly because of myocardial involvement in systemic viral disease. 2,3 During the first days of viral myocarditis, there is direct cardiomyocyte injury, accompanied by edema, necrosis, and, depending on its spatial extent, regional, or even global contractile dysfunction. The tissue is typically cleared from the virus within 5 days; yet, reactive inflammation (clean-up) may last for several weeks. In uncomplicated disease, there is full tissue and functional recovery within 3 to 4 weeks, whereas more severe disease necrosis results in myocardial scarring. Prolonged autoimmune response or virus persistence may lead to chronic inflammation and is considered a frequent cause of dilated cardiomyopathy. 3 Symptoms are not specific; patients may present with chest pain, fatigue, dyspnea, or arrhythmia. ECG findings may include AV block, ventricular or supraventricular arrhythmia, and ST changes, including severe elevation mimicking acute myocardial infarction. Except for more severe cases, echocardiography typically shows normal systolic wall motion or just mild regional dysfunction. Serological markers for cardiomyocyte injury, such as troponin, may be normal. Because of the nonspecificity of its symptoms, signs and test findings, myocarditis is often diagnosed by exclusion of other cardiac diseases. The specific identification of an active nonischemic inflammatory process, therefore, is a clinical challenge, especially in patients presenting with acute chest pain and heart failure. Invasive endomyocardial biopsy is only recommended in patients with evidence for heart failure in combination with acute disease (<2 weeks, class I) or left ventricular dilatation (<3 months, class I) or specific other cases of heart failure (class IIa). 4 While nuclear imaging methods have not been proven useful, echocardiography and contrast-enhanced cardiovascular magnetic resonance (CMR) are standard imaging tools in patients with suspected myocarditis. Figures 1 to 3 present results of a 31-year-old male patient presenting with acute chest pain and a normal physical examination. Although ECG, coronary angiography, and echocardiography were either normal or nonspecific, CMR provided strong evidence for myocardial edema, hyperemia, and necrosis and thus allowed for establishing the diagnosis of acute myocarditis.

Prognostic Significance of Exercise-induced Right Ventricular Dysfunction in Asymptomatic Degenerative Mitral Regurgitation

Abstract: Background—The role of exercise-induced pulmonary hypertension in decision making regarding surgical timing for asymptomatic chronic mitral regurgitation is controversial. We reasoned that the exercise-induced pulmonary hypertension response could not be interpreted without knowledge of right ventricular (RV) function. The aim of this study was to assess the role of RV measures at rest and during exercise as predictors of prognosis in asymptomatic mitral regurgitation. Methods and Results—Comprehensive resting and exercise echocardiography was performed in 196 consecutive patients (56±13 years; 64% male) with isolated moderate to severe mitral regurgitation (effective regurgitant orifice area, 38±18 mm 2 ) and preserved left ventricular function in whom initial management was expectant. Left ventricular and RV longitudinal strain were analyzed at rest using velocity vector imaging. Tricuspid annular plane systolic excursion and systolic pulmonary arterial pressure were measured at rest and during exercise. Valve surgery was performed in 88 patients (45%) over 27±15 months. After adjustment for age and sex in a Cox proportional-hazards model, exercise tricuspid annular plane systolic excursion (hazard ratio, 0.26; P<0.001), was associated with valve surgery-free survival, independent of resting left ventricular strain (hazard ratio, 1.09; P=0.027), exercise systolic pulmonary arterial pressure (hazard ratio, 1.03; P<0.001), and resting RV strain (hazard ratio, 1.10; P=0.004). In sequential Cox models, a model based on clinical data and left ventricular strain (χ 2 , 15.9) was improved by RV strain and RV chamber size (χ 2 , 28.8; P=0.003) and exercise systolic pulmonary arterial pressure (χ 2 , 40.1; P=0.002) and further increased by exercise tricuspid annular plane systolic excursion (χ 2 , 52.2; P=0.002). Conclusions—Exercise-induced RV dysfunction provides important incremental prognostic value in the management of asymptomatic mitral regurgitation. (Circ Cardiovasc Imaging. 2013;6:167-176.)

Validation and prognosis of coronary artery calcium scoring in nontriggered thoracic computed tomography: systematic review and meta-analysis.

Abstract: Background— Coronary calcium score (CS), traditionally based on electrocardiography-triggered computed tomography (CT), predicts cardiovascular risk. Currently, nontriggered thoracic CT is extensively used, such as in lung cancer screening. The purpose of the study was to determine the correlation in CS between nontriggered and electrocardiography-triggered CT, and to evaluate the prognostic performance of the CS derived from nontriggered CT. Methods and Results— PubMed, Embase, and Web of Knowledge were searched until November 2012. Two reviewers independently screened 2120 records to identify studies reporting the CS in nontriggered CT and extracted information. Study quality was evaluated by standardized assessment tools. Cohen κ was extracted for agreement of CS categories between nontriggered and electrocardiography-triggered CT (validation). Hazard ratio (HR) was extracted for prognostic performance. Five studies about validation comprising 1316 individuals were included. Five studies about prognosis comprising 34 028 cardiac asymptomatic individuals, mainly from lung cancer screening trials, were included. All studies were of high quality. Meta-analysis could only be performed for validation studies because studies on prognostic performance were highly heterogeneous. Pooled Cohen κ for agreement between the 2 techniques was 0.89 (95% confidence interval, 0.83–0.95) for increasing CS categories. Increasing CS categories were associated with increasing risk of cardiovascular death or events. Nontriggered CT yielded false-negative CS in 8.8% of individuals and underestimated high CS in 19.1% of individuals. Conclusions— Our analysis shows the prognostic value and potential role of nontriggered assessment of coronary calcium, but it does not suggest that electrocardiography-triggered CT should be replaced by nontriggered examinations.

Myocardial Fibrosis as a Key Determinant of Left Ventricular Remodeling in Idiopathic Dilated Cardiomyopathy A Contrast-Enhanced Cardiovascular Magnetic Study

Abstract: Background—In idiopathic dilated cardiomyopathy, there are scarce data on the influence of late gadolinium enhancement (LGE) assessed by cardiovascular magnetic resonance on left ventricular (LV) remodeling. Methods and Results—Fifty-eight consecutive patients with idiopathic dilated cardiomyopathy underwent baseline clinical, biohumoral, and instrumental workup. Medical therapy was optimized after study enrollment. Cardiovascular magnetic resonance was used to assess ventricular volumes, function, and LGE extent at baseline and 24-month follow-up. LV reverse remodeling (RR) was defined as an increase in LV ejection fraction ≥ 10 U, combined with a decrease in LV end-diastolic volume ≥10% at follow-up. ΔLGE extent was the difference in LGE extent between follow-up and baseline. LV-RR was observed in 22 patients (38%). Multivariate regression analysis showed that the absence of LGE at baseline cardiovascular magnetic resonance was a strong predictor of LV-RR (odds ratio, 10.857 [95% confidence interval, 1.844–63.911]; P =0.008) after correction for age, heart rate, New York Heart Association class, LV volumes, and LV and right ventricular ejection fractions. All patients with baseline LGE (n=26; 45%) demonstrated LGE at follow-up, and no patient without baseline LGE developed LGE at follow-up. In LGE-positive patients, there was an increase in LGE extent over time (P=0.034), which was inversely related to LV ejection fraction variation (Spearman ρ, −0.440; P=0.041). Five patients showed an increase in LGE extent >75th percentile of ΔLGE extent, and among these none experienced LV-RR and 4 had a decrease in LV ejection fraction ≥10 U at follow-up. Conclusions—In patients with idiopathic dilated cardiomyopathy, the absence of LGE at baseline is a strong independent predictor of LV-RR at 2-year follow-up, irrespective of the initial clinical status and the severity of ventricular dilatation and dysfunction. The increase in LGE extent during follow-up was associated with progressive LV dysfunction. (Circ Cardiovasc Imaging. 2013;6:790-799.)

Interpretation of Left Ventricular Diastolic Dysfunction in Children with Cardiomyopathy by Echocardiography: Problems and Limitations

Abstract: Background—Left ventricular diastolic dysfunction (DD) is a key determinant of outcomes in pediatric cardiomyopathy (CM), but remains very challenging to diagnose and classify. Adult paradigms and ...

Quantification of chronic functional mitral regurgitation by automated 3-dimensional peak and integrated proximal isovelocity surface area and stroke volume techniques using real-time 3-dimensional volume color Doppler echocardiography: in vitro and clinical validation.

Abstract: Background— The aim of this study was to test the accuracy of an automated 3-dimensional (3D) proximal isovelocity surface area (PISA) (in vitro and patients) and stroke volume technique (patients) to assess mitral regurgitation (MR) severity using real-time volume color flow Doppler transthoracic echocardiography. Methods and Results— Using an in vitro model of MR, the effective regurgitant orifice area and regurgitant volume (RVol) were measured by the PISA technique using 2-dimensional (2D) and 3D (automated true 3D PISA) transthoracic echocardiography. The mean anatomic regurgitant orifice area (0.35±0.10 cm2) was underestimated to a greater degree by the 2D (0.12±0.05 cm2) than the 3D method (0.25±0.10 cm2; P 0.05 for both). In patients (n=30, functional MR), 3D effective regurgitant orifice area correlated well with cardiac magnetic resonance imaging RVol r =0.84 and regurgitant fraction r =0.80. Compared with cardiac magnetic resonance imaging RVol (33±22 mL), the integrated PISA RVol (34±26 mL; P =0.42) was not significantly different; however, the peak PISA RVol was higher (48±27 mL; P <0.001). In addition, RVol calculated as the difference in automated mitral and aortic stroke volumes by real-time 3D volume color flow Doppler echocardiography was not significantly different from cardiac magnetic resonance imaging (34±21 versus 33±22 mL; P =0.33). Conclusions— Automated real-time 3D volume color flow Doppler based 3D PISA is more accurate than the 2D PISA method to quantify MR. In patients with functional MR, the 3D RVol by integrated PISA is more accurate than a peak PISA technique. Automated 3D stroke volume measurement can also be used as an adjunctive method to quantify MR severity.

Atherosclerotic Plaque Composition and Classification Identified by Coronary Computed Tomography: Assessment of Computed Tomography-Generated Plaque Maps Compared With Virtual Histology Intravascular Ultrasound and Histology

Abstract: Background— Computed tomography (CT) is used routinely for coronary angiography, and higher-risk features of plaques can also be identified. However, the ability of CT to discriminate individual plaque components and classify plaques according to accepted histological definitions is unknown. Methods and Results— We first determined CT attenuation ranges for individual plaque components using combined in vivo CT coregistered with virtual histology intravascular ultrasound (VH-IVUS) in 108 plaques from 57 patients. Comparison with contrast attenuation created plaque/contrast attenuation ratios that were significantly different for each component. In a separate validation cohort of 47 patients, these Plaque Maps correlated significantly with VH-IVUS–determined plaque component volumes (necrotic core: r =0.41, P =0.002; fibrous plaque: r =0.54, P <0.001; calcified plaque: r =0.59, P <0.001; total plaque: r =0.62, P <0.001). We also assessed VH-IVUS and CT Plaque Maps against coregistered histology in 72 (VH-IVUS) and 87 (CT) segments from 8 postmortem coronary arteries. The diagnostic accuracy of CT to detect calcified plaque (83% versus 92%), necrotic core (80% versus 65%), and fibroatheroma (80% versus 79%) was comparable with VH-IVUS. However, although VH-IVUS could identify thin-cap fibroatheromas (TCFA) with a diagnostic accuracy of between 74% and 82% (depending on the TCFA definition used), the spatial resolution of CT prevented direct identification of TCFA. Conclusions— CT-derived Plaque Maps based on contrast-adjusted attenuation ranges can define individual plaque components with a similar accuracy to VH-IVUS ex vivo. However, coronary CT Plaque Maps could not reliably classify plaques and identify TCFA, such that high-risk plaques may be misclassified or overlooked.

Prognostic significance of cardiac magnetic resonance imaging in children with pulmonary hypertension.

Abstract: Background— There are very few validated prognostic markers in pediatric pulmonary hypertension. Cardiac MRI is a useful, noninvasive method for determining prognosis in adults. The present study is the first to assess its prognostic value in children. Methods and Results— A total of 100 children with pulmonary hypertension (median, 10.4 years; range, 0.5–17.6 years) were evaluated (idiopathic, n=60; repaired congenital heart disease, n=22; miscellaneous, n=18). In all patients, ventricular volumes and great vessel flow were measured. Volumetric data were obtained using retrospectively gated cine imaging (n=37) or real-time imaging (n=63), depending on the patient’s ability to hold his or her breath. During a median follow-up of 1.9 years, 11 patients died and 3 received lung transplantation. Of the cardiac MR parameters measured, right ventricular ejection fraction and left ventricular stroke volume index were most strongly predictive of survival on univariate analysis (2.6- and 2.5-fold increase in mortality for every 1-SD decrease, respectively; P <0.05). These results were reflected in good separation of tertile-based Kaplan-Meier survival curves for these variables. Conclusions— Cardiac MR measures correlate with clinical status and prognosis in children with pulmonary hypertension. Cardiac MR is feasible and may be useful in clinical decision making in pediatric pulmonary hypertension.