Reproducibility of 4D cardiac computed tomography feature tracking myocardial strain and comparison against speckle-tracking echocardiography in patients with severe aortic stenosis.

BACKGROUND Myocardial strain is an established parameter for the assessment of cardiac function and routinely derived from speckle tracking echocardiography (STE). Novel post-processing tools allow deformation imaging also by 4D cardiac computed tomography angiography (CCT). This retrospective study aims to analyze the reproducibility of CCT strain and compare it to that of STE. METHODS Left (LV) and right ventricular (RV), and left atrial (LA) ejection fraction (EF), dimensions, global longitudinal (GLS), circumferential (GCS) and radial strain (GRS) were determined by STE and CCT feature tracking in consecutive patients with severe aortic stenosis evaluated for transcatheter aortic valve implantation. RESULTS 106 patients (mean age 79.9 ​± ​7.8, 44.3% females) underwent CCT at a median of 3 days (IQR 0-28 days) after STE. In CCT, strain measures showed good to excellent reproducibility (intra- and inter-reader intraclass correlation coefficient ≥0.75) consistently in the LV, RV and LA. In STE, only LV GLS and LA GLS yielded good reproducibility, whereas LV GCS and LV GRS showed moderate, and RV GLS and free wall longitudinal strain (FWLS) poor reproducibility. Agreement between CCT and STE was strong for LV GLS only, while other strain features displayed moderate (LV GCS, LA GLS) or weak (LV GRS, RV GLS and FWLS) inter-modality correlation. CONCLUSION LV, RV and LA CCT strain assessments were highly reproducible. While a strong agreement to STE was found for LV GLS, inter-modality correlation was moderate or weak for LV GCS, LV GRS, and RV and LA longitudinal strain, possibly related to poor reproducibility of STE measurements

Analysis of bi-atrial function using CMR feature tracking and long-axis shortening approaches in patients with diastolic dysfunction and atrial fibrillation.

OBJECTIVES Atrial function can be assessed using advancing cardiovascular magnetic resonance (CMR) post-processing methods: atrial feature tracking (FT) strain analysis or a long-axis shortening (LAS) technique. This study aimed to first compare the two FT and LAS techniques in healthy individuals and cardiovascular patients and then investigated how left (LA) and right atrial (RA) measurements are related to the severity of diastolic dysfunction or atrial fibrillation. METHODS Sixty healthy controls and 90 cardiovascular disease patients with coronary artery disease, heart failure, or atrial fibrillation, underwent CMR. LA and RA were analyzed for standard volumetry as well as for myocardial deformation using FT and LAS for the different functional phases (reservoir, conduit, booster). Additionally, ventricular shortening and valve excursion measurements were assessed with the LAS module. RESULTS The measurements for each of the LA and RA phases were correlated (p < 0.05) between the two approaches, with the highest correlation coefficients occurring in the reservoir phase (LA: r = 0.83, p < 0.01, RA: r = 0.66, p < 0.01). Both methods demonstrated reduced LA (FT: 26 ± 13% vs 48 ± 12%, LAS: 25 ± 11% vs 42 ± 8%, p < 0.01) and RA reservoir function (FT: 28 ± 15% vs 42 ± 15%, LAS: 27 ± 12% vs 42 ± 10%, p < 0.01) in patients compared to controls. Atrial LAS and FT decreased with diastolic dysfunction and atrial fibrillation. This mirrored ventricular dysfunction measurements. CONCLUSION Similar results were generated for bi-atrial function measurements between two CMR post-processing approaches of FT and LAS. Moreover, these methods allowed for the assessment of incremental deterioration of LA and RA function with increasing left ventricular diastolic dysfunction and atrial fibrillation. A CMR-based analysis of bi-atrial strain or shortening discriminates patients with early-stage diastolic dysfunction prior to the presence of compromised atrial and ventricular ejection fractions that occur with late-stage diastolic dysfunction and atrial fibrillation. KEY POINTS • Assessing right and left atrial function with CMR feature tracking or long-axis shortening techniques yields similar measurements and could potentially be used interchangeably based on the software capabilities of individual sites. • Atrial deformation and/or long-axis shortening allow for early detection of subtle atrial myopathy in diastolic dysfunction, even when atrial enlargement is not yet apparent. • Using a CMR-based analysis to understand the individual atrial-ventricular interaction in addition to tissue characteristics allows for a comprehensive interrogation of all four heart chambers. In patients, this could add clinically meaningful information and potentially allow for optimal therapies to be chosen to better target the dysfunction

Prevention of contrast-induced acute kidney injury by furosemide with matched hydration in patients undergoing interventional procedures. A systematic review and meta-anlysis of randomized trials

Objectives The objective of this meta-analysis of randomized trials was to evaluate if the administration of furosemide with matched hydration using the RenalGuard System reduces contrast-induced acute kidney injury (CI-AKI) in patients undergoing interventional procedures. Background CI-AKI is a serious complication following angiographic procedures and a powerful predictor of unfavorable early and long-term outcomes. Methods Online databases were searched up to October 1, 2016, for randomized controlled trials. The primary outcome was the incidence of CI-AKI, and the secondary outcomes were need for renal replacement therapy, mortality, stroke, and adverse events. Results A total of four trials (n = 698) published between 2011 and 2016 were included in the analysis and included patients undergoing percutaneous coronary procedures and transcatheter aortic valve replacement. RenalGuard therapy was associated with a lower incidence of CI-AKI compared with control treatment (27 of 348 [7.76%] patients vs. 75 of 350 [21.43%] patients; odds ratio [OR]: 0.31; 95% confidence interval [CI]: 0.19 to 0.50; I2 = 4%; p < 0.00001) and with a lower need for renal replacement therapy (2 of 346 [0.58%] patients vs. 12 of 348 [3.45%] patients; OR: 0.19; 95% CI: 0.05 to 0.76; I2 = 0%; p = 0.02). No major adverse events occurred in patients undergoing RenalGuard therapy. Conclusions The main finding of this meta-analysis is that furosemide with matched hydration by the RenalGuard System may reduce the incidence of CI-AKI in high-risk patients undergoing percutaneous coronary intervention or transcatheter aortic valve replacement. However, further independent high-quality randomized trials should elucidate the effectiveness and safety of this prophylactic intervention in interventional cardiology

Passive Leg Raise Stress Echocardiography in Severe Paradoxical Low-Flow, Low-Gradient Aortic Stenosis.

BACKGROUND Dobutamine stress echocardiography is used to increase transvalvular flow in patients with low-flow, low-gradient aortic stenosis (AS). Dobutamine fails to increase the stroke volume index (SVI) in one third of patients. The aim of this study was to test whether passive leg raise (PLR) added to dobutamine could increase SVI and transvalvular flow in patients with severe paradoxical low-flow, low-gradient AS. METHODS Forty-five patients with apparent severe low-flow, low-gradient AS on the basis of traditional measurements were included. Twenty-five were categorized as belonging to the paradox group (left ventricular ejection fraction [EF] ≥ 50%) and 20 to the low EF group (left ventricular EF < 50% or "classical" low-flow, low-gradient AS) for comparison. A four-step stress echocardiographic examination was performed: resting conditions (rest), PLR alone (PLR), maximal dobutamine infusion rate (Dmax), and a combination of Dmax and PLR (Dmax+PLR). Aortic valve area, SVI, and mean transvalvular flow were calculated using both the velocity-time integral (VTI) of left ventricular outflow tract and the Simpson method. Changes compared with rest and between the stress maneuvers were analyzed. RESULTS In the paradox group, compared with rest, left ventricular end-diastolic volume was significantly decreased with Dmax but was completely restored with Dmax+PLR (rest vs Dmax vs Dmax+PLR: 61 ± 15 vs 49 ± 18 mL [P 20% compared with rest was highest with Dmax+PLR in both groups. CONCLUSIONS Dobutamine decreases preload in paradoxical low-flow, low-gradient AS. Adding PLR counteracts this effect, resulting in increased SVI and flow (in one method). The combined stress maneuver allowed reclassification of some patients from severe to moderate AS and may therefore be useful in selected cases in this population in which severity is uncertain

Mechanical Characterization of the Male Lower Urinary Tract: Comparison among Soft Tissues from the Same Human Case Study

Background: Nowadays, a challenging task concerns the biomechanical study of the human lower urinary tract (LUT) due to the variety of its tissues and the low availability of samples. Methods: This work attempted to further extend the knowledge through a comprehensive mechanical characterization of the male LUT by considering numerous tissues harvested from the same cadaver, including some never studied before. Samples of the bladder, urethra, prostate, Buck’s fascia and tunica albuginea related to corpora cavernosa were considered and distinguished according to testing direction, specimen conformation and anatomical region. Uniaxial tensile and indentation tests were performed and ad hoc protocols were developed. Results: The tissues showed a non-linear and viscoelastic response but different mechanical properties due to their specific functionality and microstructural configuration. Tunica albuginea longitudinally displayed the highest stiffness (12.77 MPa), while the prostate transversally had the lowest one (0.66 MPa). The minimum stress relaxation degree (65.74%) was reached by the tunica albuginea and the maximum (88.55%) by the bladder. The prostate elastic modulus was shown to vary according to the presence of pathological changes at the microstructure. Conclusions: This is the first experimental work that considers the mechanical evaluation of the LUT tissues in relation to the same subject, setting the basis for future developments by expanding the sample population and for the development of effective in silico models to improve the solutions for most LUT pathologies

Impact of tafamidis on myocardial function and CMR tissue characteristics in transthyretin amyloid cardiomyopathy.

AIMS Tafamidis improves clinical outcomes in transthyretin amyloid cardiomyopathy (ATTR-CM), yet how tafamidis affects cardiac structure and function remains poorly described. This study prospectively analysed the effect of tafamidis on 12-month longitudinal changes in cardiac structure and function by cardiac magnetic resonance (CMR) compared with the natural course of disease in an untreated historic control cohort. METHODS AND RESULTS ATTR-CM patients underwent CMR at tafamidis initiation and at 12 months. Untreated patients with serial CMRs served as reference to compare biventricular function, global longitudinal strain (GLS), LV mass and extracellular volume fraction (ECV). Thirty-six tafamidis-treated (n = 35; 97.1% male) and 15 untreated patients (n = 14; 93.3% male) with a mean age of 78.3 ± 6.5 and 76.9 ± 6.5, respectively, and comparable baseline characteristics were included. Tafamidis was associated with preserving biventricular function (LVEF (%): 50.5 ± 12 to 50.7 ± 11.5, P = 0.87; RVEF (%): 48.2 ± 10.4 to 48.2 ± 9.4, P = 0.99) and LV-GLS (-9.6 ± 3.2 to -9.9 ± 2.4%; P = 0.595) at 12 months, while a significantly reduced RV-function (50.8 ± 7.3 to 44.2 ± 11.6%, P = 0.028; P (change over time between groups) = 0.032) and numerically worsening LVGLS (-10.9 ± 3.3 to -9.1 ± 2.9%, P = 0.097; P (change over time between groups) = 0.048) was observed without treatment. LV mass significantly declined with tafamidis (184.7 ± 47.7 to 176.5 ± 44.3 g; P = 0.011), yet remained unchanged in untreated patients (163.8 ± 47.5 to 171.2 ± 39.7 g P = 0.356, P (change over time between groups) = 0.027). Irrespective of tafamidis, ECV and native T1-mapping did not change significantly from baseline to 12-month follow-up (P > 0.05). CONCLUSIONS Compared with untreated ATTR-CM patients, initiation of tafamidis preserved CMR-measured biventricular function and reduced LV mass at 12 months. ECV and native T1-mapping did not change significantly comparable to baseline in both groups