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[en] Non-response cardiac resynchronization therapy (CRT) remains an issue, despite the refinement of selection criteria. The purpose of this study was to investigate the role of stress echocardiography along with dyssynchrony parameters for identification of CRT responders or late responders. 106 symptomatic heart failure patients were examined before, 6 months and 2–4 years after CRT implementation. Inotropic contractile reserve (ICR) and inferolateral (IL) wall viability were studied by stress echocardiography. Dyssynchrony was assessed by: (1) Septal to posterior wall motion delay (SPWMD) by m-mode. (2) Septal to lateral wall delay (SLD) by TDI. (3) Interventricular mechanical delay (IVMD) by pulsed wave Doppler for (4) difference in time to peak circumferential strain (TmaxCS) by speckle tracking. (5) Apical rocking (ApR) and septal flash (SF) by visual assessment. At 6 months there were 54 responders, with 12 additional late responders. TmaxCS had the greatest predictive value with an area under curve (AUC) of 0.835, followed by the presence of both ICR and viability of IL wall (AUC 0.799), m-mode (AUC = 0.775) and presence of either ApR or SF (AUC = 0.772). Predictive ability of ApR and of ICR is augmented if late responders are also included. Performance of dyssynchrony parameters is enhanced, in patients with both ICR and IL wall viability. Stress echocardiography and dyssynchrony parameters are simple and reliable predictors of 6-month and late CRT response. A stepwise approach with an initial assessment of ICR and viability and, if positive, further dyssynchrony analysis, could assist decision making.
[en] Coronary artery calcium (CAC) scoring is used in asymptomatic patients to improve their clinically predicted risk for future cardiovascular events. Current CT protocols seek to reduce radiation exposure without diminishing image quality. Reported radiation exposure remains widely variable (0.8–5 mSv) depending on the type of protocol. In this study, we report the radiation exposure of CAC scoring from the Society for Heart Attack Prevention and Eradication (SHAPE) early detection program cohort sites, which spanned multiple centers using 64-MDCT (multi-detector computed tomography) scanners. We reviewed radiation exposure in milliSieverts (mSv) for 82,214 participants from the SHAPE early detection program cohort who underwent CAC scoring. This occurred over a 2.5-year period (2012–2014) divided among 33 sites in 7 countries with four different types 64-MDCT scanners. The effective radiation dose was reported as mSv. Mean radiation dosing amongst all 82,214 participants was 1.03 mSv, a median dose of 0.94 mSv. The mean radiation dose ranged from 0.76 to 1.31 mSv across the 33 sites involved with the SHAPE program cohort. Subgroup analysis by age, gender or body mass index (BMI) less than 30 kg/m2 showed no variability. Radiation dose in patients with BMI > 30 kg/m2 were significantly greater than other subgroups (µ = 1.96 mSv, p < 0.001). The use of 64-MDCT scanners and protocols provide the effective radiation dose for CAC scoring, which is approximately 1 mSv. This is consistently lower than previously reported for CAC scanning, regardless of scanner type, age or gender. In contrast, a greater BMI influenced mean radiation doses.
[en] Little is known about the comparison of multiple-gated acquisition (MUGA) scanning with cardiovascular magnetic resonance (CMR) for serial monitoring of HER2+ breast cancer patients receiving trastuzumab. The association of cardiac biomarkers with CMR left ventricular (LV) function and volume is also not well studied. Our objectives were to compare CMR and MUGA for left ventricular ejection fraction (LVEF) assessment, and to examine the association between changes in brain natriuretic peptide (NT-BNP) and troponin-I and changes in CMR LV function and volume. This prospective longitudinal two-centre cohort study recruited HER2+ breast cancer patients between January 2010 and December 2013. MUGA, CMR, NT-BNP and troponin-I were performed at baseline, 6, 12, and 18 months after trastuzumab initiation. In total, 41 patients (age 51.7 ± 10.8 years) were enrolled. LVEF comparison between MUGA and CMR demonstrated weak agreement (Lin’s correlation coefficient r = 0.46, baseline; r = 0.29, 6 months; r = 0.42, 12 months; r = 0.39, 18 months; all p < 0.05). Bland–Altman plots demonstrated wide LVEF agreement limits (pooled agreement limits 3.0 ± 6.2). Both modalities demonstrated significant LVEF decline at 6 and 12 months from baseline, concomitant with increased LV volumes on CMR. Changes in NT-BNP correlated with changes in LV diastolic volume at 12 and 18 months (p < 0.05), and LV systolic volume at 18 months (p < 0.05). Changes in troponin-I did not correlate with changes in LV function or volume at any timepoint. In conclusion, CMR and MUGA LVEF are not interchangeable, warranting selection and utility of one modality for serial monitoring. CMR is useful due to less radiation exposure and accuracy of LV volume measurements. Changes in NT-BNP correlated with changes in LV volumes.
[en] Intraventricular velocity distribution reflects left ventricular (LV) diastolic function and can be measured non-invasively by flow mapping technologies. We designed our study to compare intraventricular velocities and gradients, obtained by vector flow mapping (VFM) technology during early diastole in consecutive patients diagnosed with mild and advanced diastolic dysfunction at echocardiography and a control group with a purpose to validate the hypothesis of relationship between new parameters and severity of diastolic dysfunction and conventional markers of elevated LV filling pressure. Two-dimensional streamline fields were obtained using VFM technology in 121 subjects (57 with normal diastolic function, 38 with mild diastolic dysfunction and 26 with advanced diastolic dysfunction). We measured several velocities and calculated a gradient along the selected streamline, which we compared between groups and correlated them with conventional echocardiographic parameters. Apical intraventricular velocity gradient (GrIV) was the lowest in control group, followed by mild and advanced diastolic dysfunction groups (5.3 ± 1.9 vs. 6.8 ± 2.5 vs. 13.6 ± 5.0/s, p < 0.001) and showed good correlation with E/e’ (r = 0.751, p < 000.1). GrIV/e’ ratio was the strongest single predictor of severity of diastolic dysfunction. Different degrees of diastolic dysfunction affect the Intraventricular velocity behavior during early diastole obtained by VFM. GrIV could discriminate between groups with different levels of diastolic dysfunction and was closely associated with classical echocardiographic indices of elevated LV filling pressure. GrIV/e’ ratio has a potential to become a single parameter needed to assess left ventricular diastolic function.
[en] Large animal ischemic cardiomyopathy models are widely used for preclinical testing of promising novel therapeutic approaches. Pressure volume (PV) loop analysis and cardiac magnetic resonance imaging (CMRI) allow functional and morphological phenotyping. In this study we performed a comparative analysis of both methods highlighting the strength of each and their synergistic potential. Myocardial infarction (MI) was created in German farm pigs (German Landrace) by 2 h LCX occlusion (n = 11) and subsequent reperfusion. Cardiac function was assessed by PV-loops and CMRI 56 and 112 days post-MI. Two hours occlusion of the LCX led to mid-size left ventricular (LV) MI represented by high-sensitive troponin T (hsTnT) 3 days post-MI, correlating well with cardiac CMRI late enhancement. CMRI determined end-diastolic and end-systolic volumes significantly increased post-MI, while ejection fraction was reduced in infarcted animals compared to the sham group (n = 6). PV-loop derived preload-insensitive parameters of systolic and diastolic function were diminished post-MI compared to sham animals while preload-dependent parameters only deteriorated in advanced HF. PV-loop analysis significantly correlates with CMRI analysis of cardiac function in pig post-MI ischemic cardiomyopathy. PV-Loop analysis accurately quantifies LV volumetry and function in post-MI HF, and thus eccentric LV morphology. PV-loop analysis correlates well to cardiac MRI. Preload–insensitive parameters show high sensitivity to quantify HF while preload–sensitive parameters are not able to quantify early-stages of LV HF.
[en] Magnetic resonance imaging (MRI) plays an increasingly important role in the non-invasive evaluation of the pulmonary vasculature. MR angiographic (MRA) techniques provide morphological information, while MR perfusion techniques provide functional information of the pulmonary vasculature. Contrast-enhanced MRA can be performed at high spatial resolution using 3D T1-weighted spoiled gradient echo sequence or at high temporal resolution using time-resolved techniques. Non-contrast MRA can be performed using 3D steady state free precession, double inversion fast spin echo, time of flight or phase contrast sequences. MR perfusion can be done using dynamic contrast-enhanced technique or using non-contrast techniques such as arterial spin labelling and time-resolved imaging of lungs during free breathing with Fourier decomposition analysis. MRI is used in the evaluation of acute and chronic pulmonary embolism, pulmonary hypertension and other vascular abnormalities, congenital anomalies and neoplasms. In this article, we review the different MR techniques used in the evaluation of pulmonary vasculature and its clinical applications.
[en] An accurate distinction between isolated post-capillary pulmonary hypertension (Ipc-PH) and combined post- and pre-capillary pulmonary hypertension (Cpc-PH) is integral to therapy and prognosis in heart failure (HF). This study aimed to compare the ability of four previously validated Doppler estimates of pulmonary vascular resistance (PVRDoppler) to distinguish Ipc-PH from Cpc-PH in a well-defined HF population. Consecutive subjects referred for HF assessment underwent standard echocardiography immediately followed by right heart catheterization (RHC). Subjects with atrial fibrillation, acute coronary syndrome, significant valvular disease or poor image quality were excluded. PVRDoppler estimates were correlated with invasive PVR and agreement was studied using Bland–Altman analysis. Receiver operating characteristics analyses were performed to determine the ability of PVRDoppler methods to identify PVR > 3WU. 55 HF subjects (58 ± 16 years, 55% Ipc-PH) were analyzed. PVRDoppler estimates demonstrated weak to modest associations with invasive PVR. The Doppler method proposed by Abbas et al. demonstrated relatively strong discriminatory ability to distinguish Ipc-PH from Cpc-PH (AUC = 0.79; 95% CI 0.63–0.96; p = 0.001). However, Bland–Altman analysis revealed wide limits of agreement (bias = 0; SD = 1.83WU) and greater variability at higher mean PVR. Conclusions: PVRDoppler estimates demonstrate reasonable ability to distinguish Ipc-PH from Cpc-PH but may not be reliable independent PH distinguishers in HF.