Elzbieta Chamera

Accuracy of Doppler Echocardiography in the Hemodynamic Assessment of Pulmonary Hypertension

RATIONALE Transthoracic Doppler echocardiography is recommended for screening for the presence of pulmonary hypertension (PH). However, some recent studies have suggested that Doppler echocardiographic pulmonary artery pressure estimates may frequently be inaccurate. OBJECTIVES Evaluate the accuracy of Doppler echocardiography for estimating pulmonary artery pressure and cardiac output. METHODS We conducted a prospective study on patients with various forms of PH who underwent comprehensive Doppler echocardiography within 1 hour of a clinically indicated right-heart catheterization to compare noninvasive hemodynamic estimates with invasively measured values. MEASUREMENTS AND MAIN RESULTS A total of 65 patients completed the study protocol. Using Bland-Altman analytic methods, the bias for the echocardiographic estimates of the pulmonary artery systolic pressure was -0.6 mm Hg with 95% limits of agreement ranging from +38.8 to -40.0 mm Hg. Doppler echocardiography was inaccurate (defined as being greater than +/-10 mm Hg of the invasive measurement) in 48% of cases. Overestimation and underestimation of pulmonary artery systolic pressure by Doppler echocardiography occurred with a similar frequency (16 vs. 15 instances, respectively). The magnitude of pressure underestimation was greater than overestimation (-30 +/- 16 vs. +19 +/- 11 mm Hg; P = 0.03); underestimates by Doppler also led more often to misclassification of the severity of the PH. For cardiac output measurement, the bias was -0.1 L/min with 95% limits of agreement ranging from +2.2 to -2.4 L/min. CONCLUSIONS Doppler echocardiography may frequently be inaccurate in estimating pulmonary artery pressure and cardiac output in patients being evaluated for PH.

Reproducibility of functional aortic analysis using magnetic resonance imaging: the MESA

AIMS To assess the test-retest, intra- and inter-reader reliability of thoracic aorta measurements by magnetic resonance imaging (MRI). METHODS AND RESULTS Twenty-five participants underwent aortic MRI twice over 13 ± 7 days. All aortic variables from baseline and repeat MR were analysed using a semi-automated method by the ARTFUN software. To assess the inter-study reproducibility of aortic variables, we calculated intraclass correlation coefficient (ICC) for individual aortic measurements. Intra- and inter-observer variability was also assessed using the baseline MR data. Mean ascending aortic strain had moderate inter-study reproducibility (11.53 ± 6.44 vs. 10.55 ± 6.64, P = 0.443, ICC = 0.53, P < 0.01). Mean descending aortic strain and arch pulse wave velocity (PWV) had good inter-study reproducibility (descending aortic strain: 8.65 ± 5.30 vs. 8.35 ± 5.26, P = 0.706, ICC = 0.74, P < 0.001; PWV: 9.92 ± 4.18 vs. 9.94 ± 4.55, P = 0.968, ICC = 0.77, P < 0.001, respectively). All aortic variables had excellent intra- and inter-observer reproducibility (intra-: ICC range, 0.87-0.99, inter-: ICC range, 0.56-0.99, respectively). CONCLUSION Inter-study reproducibility of all aortic variables was acceptable. Intra- and inter-observer reproducibility of all aortic variables was excellent. MRI can provide a repeatable method of measuring aortic structural and functional parameters.

Association of Cardiovascular Risk Factors and Myocardial Fibrosis With Early Cardiac Dysfunction in Type 1 Diabetes: The Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications Study

OBJECTIVE We investigated the association of cardiovascular risk factors and myocardial fibrosis with early cardiac dysfunction in type 1 diabetes. RESEARCH DESIGN AND METHODS Participants with type 1 diabetes aged 13–39 years without a known history of cardiovascular disease (CVD) (n = 1,441) were recruited into the Diabetes Control and Complications Trial (1983–1993) and subsequently followed in the Epidemiology of Diabetes Interventions and Complications study (1994 to present). Seven hundred fourteen participants underwent cardiac magnetic resonance (CMR) imaging (2007–2009) with late gadolinium enhancement sequences to assess ischemic and nonischemic scars and tagging sequences to evaluate circumferential strain. CMR-derived T1 mapping also was used to assess interstitial fibrosis. The influence of cardiovascular risk factors and myocardial scar on circumferential strain was assessed using linear regression. RESULTS Circumferential dysfunction was consistently associated with older age, male sex, smoking history, obesity, higher blood pressure, lower HDL cholesterol, and higher mean HbA1c. Participants with nonischemic scars (n = 16) had the worst circumferential function compared with those without scars (β ± SE 1.32 ± 0.60; P = 0.03). In sex-adjusted models, the correlation between T1 times and circumferential strain was not significant. In the fully adjusted models, a trend toward circumferential dysfunction in participants with nonischemic scars was found. Left ventricular ejection fraction was not associated with risk factors but was significantly lower if a myocardial scar was present. CONCLUSIONS Traditional CVD risk factors and elevated HbA1c levels are major factors related to early cardiac dysfunction in type 1 diabetes. Nonischemic myocardial scar, possibly as a marker of chronic exposure to known risk factors, may predict early cardiac dysfunction mediated by diffuse myocardial fibrosis as seen in diabetic cardiomyopathy.

Lipid modifying therapy and aortic wall thickness regression by Magnetic Resonance Imaging (MRI): the plaque follow up study by the National Institute of Aging (NIA)

Methods 114 participants age >65 years were enrolled in a double blinded randomized trial as part of the NIA Plaque study. Participants were randomly assigned to two treatment groups; one receiving simvastatin and niacin and other receiving simvastatin and placebo. Baseline MRI was performed on all participants using a 1.5-Tesla scanner. Follow-up MRI exams were done every 6 months for 18 months. Axial images of 3 segments of the thoracic aorta (ascending, arch and descending) were obtained using a double inversion recovery black blood fast spin-echo sequence with ECG-gating. 0.1 mmol/kg of gadodiamide contrast was given intravenously. Post contrast T1weighted images were used to evaluate the changes in vessel wall thickness and lumen diameter over the course of lipid therapy. Paired t test and multivariable regression were used for data analyses.

The association of left atrial volume with age, ethnicity and cardiovascular risk factors in men and women: the Multi-Ethnic Study of Atherosclerosis (MESA)

Methods LA volume indexed to body surface area (LAVi) was measured by CMR using steady-state free precession cine long and short axis images in 2576 participants of the MultiEthnic Study of Atherosclerosis (68.7 years, 53.0% women). We used gender stratified regression models to evaluate the association of LAVi as the dependent variable with demographic and cardiovascular risk factors, left ventricular (LV) parameters and diagnosis of coronary heart disease as independent variables. LAVi between ethnicities were compared using analysis of variance (ANOVA) with Tukey’s post-hoc analysis. To determine normal LA dimensions we also selected a group of participants with normal body mass index (≥18.5 and < 25 kg/m), without hypertension, diabetes, coronary heart disease, congestive heart failure, LV systolic dysfunction (defined as ejection fraction less than 50%), LV hypertrophy or atrial fibrillation (n = 285, 65.6 years, 61.8% women). Results The unadjusted mean LA volume index in the whole cohort was 36.5 ± 11.4 ml/m and was 9% smaller in men (35.9 ± 11.1 vs. 37.0 ± 11.6 ml/m, p < 0.05). LAVi was greater with age in men (b = 0.2 ml/m/yr, p < 0.0001) and women (b = 0.3 ml/m/yr, p < 0.0001). Both Chinese American men and women had significantly (p < 0.05) smaller LAVi compared to other ethnicities (Figure 2). History of coronary disease was associated with 10% larger LAVi in women (b=3.7 ml/m, p < 0.05), but not in men (p = ns). In the normal reference cohort free of cardiovascular disease there were no differences in LAVi by gender (men 34.5 ± 9.9 ml/m, women 36.0 ± 10.2 ml/m, p = 0.30).

Reproducibility of cuff-induced hyperemic popliteal artery flow analysis using phase-contrast MRI: Patients With Intermittent Claudication Injected With ALDH Bright Cells (PACE) trial

Background Peripheral artery disease (PAD) is a major consequence of atherosclerosis. Recently, quantitative evaluation of hyperemic arterial flow reserve measured using cuff occlusion has been identified as a method of measuring arterial stiffness. Phase-contrast MRI (PCMRI) is an extensively used and accurate technique to quantify vessel flow. The aim of this study was to assess the interobserver, intra-observer and test-retest reproducibility of hyperemic popliteal arterial flow measurements using PCMRI in a protocol developed for the Cardiovascular Cell Therapy Research Network (CCTRN).

Reproducibility of functional aortic analysis using MRI: the multi-ethnic study of atherosclerosis

Methods Twenty-five participants underwent aortic MRI twice over 13 ± 7 days. All aortic variables (ascending aortic area, descending aortic area, ascending and descending aortic strain [maximum area minus minimum area divided by minimum area], aortic arch transit time and pulse wave velocity [PWV]) from baseline and repeat MR were analyzed using a semi-automated method by the ARTFUN software. Phase contrast (PC) cine at the level of the pulmonary artery bifurcation was used for assessment of aortic area, aortic strain, and PWV. Steady State Free Precession (SSFP) sagittal images were used to measure aortic arch transit distance. To assess the inter-study reproducibility of aortic variables, we calculated intraclass correlation coefficient (ICC) for individual aortic measurements. Intraand inter-observer variability was also assessed using the baseline MR data.

Quantification of the relationship between two cardiac magnetic resonance techniques: fast gradient echo and steady-state free precession for determination of left atrial volumes

Background Steady-state free precession (SSFP) results in larger volumes and lower ejection fraction for the left ventricle compared to fast gradient echo (fGRE) imaging. Similar comparisons for the left atrium (LA) are not available and may be relevant for 3T imaging and historical comparison to prior imaging datasets. As opposed to LV imaging, volumes in the LA are more commonly derived using biplane area measurements.

Comparison of strain measurement from multimodality tissue tracking with strain-encoding MRI and harmonic ophase MRI in Pulmonary Hypertension

article i nfo Background:Pixel-basedmultimodality tissuetracking (MTT) isa newnoninvasivemethodfor thequantification of cardiac deformation from cine image of MRI. The aim of this study is to validate bi-ventricular strain measure- ment by MTT compared to strain-encoding (SENC) MRI and harmonic phase (HARP) MRI in pulmonary hyper- tension (PH) patients. Methods:In 45 subjects (30 PH patients and 15 normal subjects), RV and LV peak global longitudinal strains (Ell) were measured from long axis 4 chamber view using MTT. LV peak global circumferential strains (Ecc) by MTT were measured from short axis. For validation, RV and LV Ell by MTT were compared to measures by SENC- MRI from short axis, and LV Ecc by MTT was compared to measures by short axis tagged MRI analysis (HARP). Reproducibility of MTT was also determined. Results: MTT quantified RV Ell correlated closelyto those of SENC (r = 0.72, p b 0.001), with good limits of agree- ment.LVEllquantifiedbyMTTshowedmoderatecorrelationwithSENC(r=0.57,p=0.001),andLVEccbyMTT

Left atrial structure and functional quantitation using cardiac magnetic resonance: comparison of manual delineation vs. multimodality tissue tracking based semi-automated methods

Background Left atrium (LA) volume and function are important markers of cardiovascular disease. LA volume can be assessed by several different methods. In clinical practice, the Simpson’s method is well accepted as a reference standard, although there is no standardization for LA volume calculations. We aimed to compare the estimations of LA volume by the Simpson’s method and the modified biplane Simpson’s method; and to introduce Multimodality Tissue Tracking (MTT, Japan, Toshiba) as a new semi-automated method for quantifying LA function based on tissue feature tracking. Methods Thirty subjects (mean age: 71.3 ± 8.7, 87% male) including twenty subjects with cardiovascular events (4 atrial fibrillation, 18 myocardial scar from late gadolinium enhancement, 2 heart failure) and ten healthy subjects, with CMR imaging were evaluated in the Multi-Ethnic Study of Atherosclerosis (MESA). LA volumes were measured using the modified biplane Simpson’ sm ethod from 2- and 4-chamber projections and the original Simpson’s method using short-axis slices. For the manual methods, LA endo- and epicardial boundaries were delineated at left-ventricular end-diastole (Vmin), end-systole (Vmax) and just before the pre-atrial contraction (VpreA). Using MTT, LA endocardial and epicardial borders were manually delineated at end-systole and the boundaries were propagated automatically throughout the cardiac