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Purpose To retrospectively validate a first-pass analysis (FPA) technique that combines computed tomographic (CT) angiography and dynamic CT perfusion measurement into one low-dose examination. Materials and Methods The study was approved by the animal care committee. The FPA technique was retrospectively validated in six swine (mean weight, 37.3 kg ± 7.5 [standard deviation]) between April 2015 and October 2016. Four to five intermediate-severity stenoses were generated in the left anterior descending artery (LAD), and 20 contrast material-enhanced volume scans were acquired per stenosis. All volume scans were used for maximum slope model (MSM) perfusion measurement, but only two volume scans were used for FPA perfusion measurement. Perfusion measurements in the LAD, left circumflex artery (LCx), right coronary artery, and all three coronary arteries combined were compared with microsphere perfusion measurements by using regression, root-mean-square error, root-mean-square deviation, Lin concordance correlation, and diagnostic outcomes analysis. The CT dose index and size-specific dose estimate per two-volume FPA perfusion measurement were also determined. Results FPA and MSM perfusion measurements (PFPA and PMSM) in all three coronary arteries combined were related to reference standard microsphere perfusion measurements (PMICRO), as follows: PFPA_COMBINED = 1.02 PMICRO_COMBINED + 0.11 (r = 0.96) and PMSM_COMBINED = 0.28 PMICRO_COMBINED + 0.23 (r = 0.89). The CT dose index and size-specific dose estimate per two-volume FPA perfusion measurement were 10.8 and 17.8 mGy, respectively. Conclusion The FPA technique was retrospectively validated in a swine model and has the potential to be used for accurate, low-dose vessel-specific morphologic and physiologic assessment of coronary artery disease. © RSNA, 2017.

ObjectiveThis study's objective is to develop and validate a fast automated 3-D segmentation method for cardiac magnetic resonance imaging (MRI). The segmentation algorithm automatically reconstructs cardiac MRI DICOM data into a 3-D model (i.e., direct volumetric segmentation), without relying on prior statistical knowledge.MethodsA novel 3-D active contour method was employed to detect the left ventricular cavity in 33 subjects with heterogeneous heart diseases from the York University database. Papillary muscles were identified and added to the chamber using a convex hull of the left ventricle and interpolation. The myocardium was then segmented using a similar 3-D segmentation method according to anatomic information. A multistage approach was taken to determine the method's efficacy.ResultsOur method demonstrated a significant improvement in segmentation performance when compared to manual segmentation and other automated methods.Conclusion and significanceA true 3-D reconstruction technique without the need for training datasets or any user-driven segmentation has been developed. In this method, a novel combination of internal and external energy terms for active contour was utilized that exploits histogram matching for improving the segmentation performance. This method takes advantage of full volumetric imaging, does not rely on prior statistical knowledge, and employs a convex-hull interpolation to include the papillary muscles.

Computed tomographic (CT) angiography is an important tool for the evaluation of coronary artery disease but often correlates poorly with myocardial ischemia. Current dynamic CT perfusion techniques can assess ischemia but have limited accuracy and deliver high radiation dose. Therefore, an accurate, low-dose, dynamic CT perfusion technique is needed. A total of 20 contrast-enhanced CT volume scans were acquired in 5 swine (40±10 kg) to generate CT angiography and perfusion images. Varying degrees of stenosis were induced using a balloon catheter in the proximal left anterior descending coronary artery, and a pressure wire was used for reference fractional flow reserve (FFR) measurement. Perfusion measurements were made with only 2 volume scans using a new first-pass analysis (FPA) technique and with 20 volume scans using an existing maximum slope model (MSM) technique. Perfusion (P) and FFR measurements were related by PFPA=1.01 FFR-0.03 (R2=0.85) and PMSM=1.03 FFR-0.03 (R2=0.80) for FPA and MSM techniques, respectively. Additionally, the effective radiation doses were calculated to be 2.64 and 26.4 mSv for FPA and MSM techniques, respectively. A new FPA-based dynamic CT perfusion technique was validated in a swine animal model. The results indicate that the FPA technique can potentially be used for improved anatomical and functional assessment of coronary artery disease at a relatively low radiation dose.

BackgroundWe assessed in-hospital mortality and utilization of invasive cardiac procedures following Acute Coronary Syndrome (ACS) admissions on the weekend versus weekdays over the past decade in the United States.MethodsWe used data from the Nationwide Inpatient Survey (2001-2011) to examine differences in all-cause in-hospital mortality between patients with a principal diagnosis of ACS admitted on a weekend versus a weekday. Adjusted and hierarchical logistic regression model analysis was then used to identify if weekend admission was associated with a decreased utilization of procedural interventions and increased subsequent complications as well.Results13,988,772 ACS admissions were identified. Adjusted mortality was higher for weekend admissions for Non-ST-Elevation Acute Coronary Syndromes [OR: 1.15, 95% CI, 1.14-1.16] and only somewhat higher for ST-Elevation Myocardial Infarction [OR: 1.03; 95% CI, 1.01-1.04]. Additionally, patients were significantly less likely to receive coronary revascularization intervention/therapy on their first day of admission [OR: 0.97, 95% CI: 0.96-0.98 and OR: 0.75, 95% CI: 0.75-0.75 for STEMI and NSTE-ACS respectively]. For ACS patients admitted during the weekend who underwent procedural interventions, in-hospital mortality and complications were higher as compared to patients undergoing the same procedures on weekdays.ConclusionFor ACS patients, weekend admission is associated with higher mortality and lower utilization of invasive cardiac procedures, and those who did undergo these interventions had higher rates of mortality and complications than their weekday counterparts. This data leads to the possible conclusion that access to diagnostic/interventional procedures may be contingent upon the day of admission, which may impact mortality.

In this final portion of an extensive review of heart valve engineering, we focus on the computational methods and experimental studies related to heart valves. The discussion begins with a thorough review of computational modeling and the governing equations of fluid and structural interaction. We then move onto multiscale and disease specific modeling. Finally, advanced methods related to in vitro testing of the heart valves are reviewed. This section of the review series is intended to illustrate application of computational methods and experimental studies and their interrelation for studying heart valves.

AimsTranscatheter aortic valve implantation (TAVI) is an emerging field with technological challenges. One major challenge is to minimise delivery catheter size to reduce vascular trauma, while maintaining features such as repositionability and retrievability. This study was designed as proof of concept of FOLDAVALVE, using a short-term ovine model.Methods and resultsFOLDAVALVE is a fully repositionable and retrievable transcatheter aortic valve with a 14 Fr delivery system whose leaflets are excluded from the stent during crimping. A short-term ovine model (n=3) was used for transfemoral implantations at the Institut Mutualiste Montsouris in Paris. There was a smooth transition of the valve over the aortic arch followed by seamless delivery into the native ovine aortic position. Implantation was followed by repositioning, resheathing and retrieval, then implantation of a fresh prosthesis in the same animal. Transoesophageal echocardiography and fluoroscopy were used to monitor the delivery and implantation processes and to demonstrate valve functionality. Animal sacrifice and direct visualisation after explant confirmed excellent final position.ConclusionsFOLDAVALVE was successfully implanted in the aortic position of an ovine model. FOLDAVALVE is a promising technology which has been shown to be feasible in this preclinical TAVI study.

In this portion of an extensive review of heart valve engineering, we focus on the current and emerging technologies and techniques to repair or replace the mitral valve. We begin with a discussion of the currently available mechanical and bioprosthetic mitral valves followed by the rationale and limitations of current surgical mitral annuloplasty methods; a discussion of the technique of neo-chordae fabrication and implantation; a review the procedures and clinical results for catheter-based mitral leaflet repair; a highlight of the motivation for and limitations of catheter-based annular reduction therapies; and introduce the early generation devices for catheter-based mitral valve replacement.

The engineering of technologies for heart valve replacement (i.e., heart valve engineering) is an exciting and evolving field. Since the first valve replacement, technology has progressed by leaps and bounds. Innovations emerge frequently and supply patients and physicians with new, increasingly efficacious and less invasive treatment options. As much as any other field in medicine the treatment of heart valve disease has experienced a renaissance in the last 10 years. Here we review the currently available technologies and future options in the surgical and transcatheter treatment of aortic valve disease. Different valves from major manufacturers are described in details with their applications.

As the first section of a multi-part review series, this section provides an overview of the ongoing research and development aimed at fabricating novel heart valve replacements beyond what is currently available for patients. Here we discuss heart valve replacement options that involve a biological component or process for creation, either in vitro or in vivo (tissue-engineered heart valves), and heart valves that are fabricated from polymeric material that are considered permanent inert materials that may suffice for adults where growth is not required. Polymeric materials provide opportunities for cost-effective heart valves that can be more easily manufactured and can be easily integrated with artificial heart and ventricular assist device technologies. Tissue engineered heart valves show promise as a regenerative patient specific model that could be the future of all valve replacement. Because tissue-engineered heart valves depend on cells for their creation, understanding how cells sense and respond to chemical and physical stimuli in their microenvironment is critical and therefore, is also reviewed.

Transcatheter aortic valve implantation is a novel treatment for severe aortic valve stenosis. Due to the recent use of this technology and the procedural variability, there is very little data that quantify the hemodynamic consequences of variations in valve placement. Changes in aortic wall stresses and fluid retention in the sinuses of Valsalva can have a significant effect on the clinical response a patient has to the procedure. By comprehensively characterizing complex flow in the sinuses of Valsalva using digital particle image velocimetry and an advanced heart-flow simulator, various positions of a deployed transcatheter valve with respect to a bioprosthetic aortic valve (valve-in-valve) were tested in vitro. Displacements of the transcatheter valve were axial and directed below the simulated native valve annulus. It was determined that for both blood residence time and aortic Reynolds stresses, it is optimal to have the annulus of the transcatheter valve deployed as close to the aortic valve annulus as possible.

Epicardial adipose tissue (EAT) has been shown to have important effects on the development of coronary artery disease (CAD) through local paracrine influences on the vascular bed. We compared a cohort of asymptomatic patients with type II diabetes mellitus (DM) without known CAD to an age- and gender-matched group of asymptomatic patients without DM from the CTRAD (Cardiac CT's Role in Asymptomatic Patients with DM-II) study in which patients underwent a cardiac computed tomography angiogram, for early detection of CAD. Mean EAT volumes of 118.6 ± 43.0 and 70.0 ± 44.0 cm(3) were found in the DM and non-DM groups, respectively. When stratified by the presence and severity of CAD, it was found that in the DM (p = 0.003) and non-DM groups (p 120 cm(3) of EAT was found to be highly correlated with the presence of significant CAD (adjusted odds ratio 4.47, 95% confidence interval 1.35 to 14.82). We found that not only is EAT volume an independent predictor of CAD but that an increasing volume of EAT predicted increasing severity of CAD even after adjustment for CAC score.

BackgroundTranscatheter aortic valve replacement has emerged as a promising therapy for treatment of severe aortic stenosis. Although it has been shown that these valves can be safely delivered and implanted, studies of valve longevity are lacking because of the infancy of the technology. Particularly, the effects of stent crimping on the valve's leaflets have not yet been sufficiently investigated. In this study, we have characterized the effects of crimping on pericardial leaflets in time and through the depth of the tissue.MethodsTo test the structural changes at the surface and deep layers of bovine pericardial leaflets, scanning electron microscopy and second-harmonic generation microscopy were used. An uncrimped tissue sample was imaged, followed by imaging a segment of tissue after crimping in a stented transcatheter valve, immediately after, at 20 minutes, and 60 minutes after crimping. The crimping experiment was performed for multiple crimping sizes (ie, 14F, 16F, and 18F). We defined a damage index that quantifies the level of leaflet structural changes as a result of crimping.ResultsBased on the calculated damage indices and analyses of the raw images, it was determined that crimping does measurable damage to the leaflet tissue that persists with time.ConclusionsSignificant tissue damage was observed at the surface layers of the leaflets. In the deeper tissue layers, damage was substantial for 14F crimping; however, it became less significant but still visible for larger collapse profiles. Crimping may induce substantial structural damage to pericardial leaflets that does not improve with time.

Type II diabetes and metabolic syndrome are 2 intertwined conditions that are critical to the healthcare landscape in the United States and abroad. Patients with either diabetes or metabolic syndrome can have a dramatically increased risk of developing cardiovascular disease. Numerous treatment options have existed for some time, which include nonpharmacologic and pharmacologic therapies. In addition, within the last decade, a multiple of novel treatment options have emerged for the management of hyperglycemia in particular. By targeting novel pathways beyond the secretion and supply of insulin, these new therapeutics provide a valuable adjunct to the currently available therapies for diabetes and metabolic syndrome. Here we discuss the current guideline-driven usage of standard therapies with some novel indications. In addition, we discuss the novel therapies for the treatment of hyperglycemia, their mechanisms of action, and appropriate therapeutic indications.

Importance. Constrictive pericarditis is a rare clinical entity that frequently necessitates surgical intervention. Here we present a case of biventricular failure due to stress cardiomyopathy after pericardiectomy. This is an extremely rare complication that is not well described and does not have a definitive mechanism. Observations. A 40-year-old Ecuadorian woman who was found to have constrictive pericarditis due to Mycobacterium tuberculosis infection was referred to our institution. The presence of constrictive pericarditis was confirmed by echocardiography, computed tomography, magnetic resonance imaging, and cardiac catheterization. Following pericardiectomy, the patient developed biventricular failure consistent with stress cardiomyopathy (Takotsubo cardiomyopathy), based on the echocardiographic assessment of the ventricles, which demonstrated an akinetic apex and hyperactive base in both ventricles, the absence of significant epicardial coronary atherosclerosis, and prompt normalization of the cardiac function after intensive medical therapy. Conclusions and Relevance. Biventricular failure in the form of stress cardiomyopathy after pericardiectomy in the manner presented here has not been previously described in the literature. While postulations as to the cause of single ventricle dysfunction have been described, the exact mechanism is unclear and current theories do not explain the clinical features in this case of stress cardiomyopathy after pericardiectomy.

Objective: In the United States, racial minorities are underrepresented among patients receiving transcatheter aortic valve replacement (TAVR) and data regarding their outcomes is limited. Global longitudinal strain (GLS) is a measure left ventricular function and has independently predicted outcomes after TAVR. The aim of this study is to assess changes in GLS after TAVR according to race and factors predicting these changes., Methods: Electronic medical records of patients undergoing TAVR at the University of Illinois, Chicago and Jesse Brown Veteran's Administration Medical Center (Chicago, Illinois) from January 2017-February 2020 were reviewed retrospectively. The most recent transthoracic echocardiogram (TTE) prior to TAVR and the TTE 1-month post-procedure were used to determine GLS. Patients were included if both a pre- and post-procedure study were present and TTE images were of sufficient quality to process strain imaging., Results: A total of 103 patients (average age 76 ± 12 years, 80% male, 42% white) were included. At 1-month post-TAVR, GLS improved for all races: white (-2.7 ± 3.5%, P<0.001), African-American (-2.8 ± 3.3%, P<0.001), and Hispanic (-2.0 ± 2.1%, P<0.001). There were no differences in the degree of improvement among races (P=0.62). Baseline GLS was negatively correlated with changes in GLS overall (r=-0.44, P<0.001). Baseline aortic valve area (cm 2 ) was positively correlated with changes in GLS (r=0.2, P=0.036)., Conclusions: This study demonstrated that GLS improved after TAVR independent of race with similar degrees of change across races. Baseline GLS and aortic valve area predicted strain improvement after TAVR, which suggests that those with more impaired LV function may benefit most from the procedure., Competing Interests: None., (AJCD Copyright © 2021.)

Objective: The purpose of this study was to evaluate the effect of cardiac gating on the quality of images of the thoracic aorta at various levels during contrast-enhanced MR angiography compared with MR angiography without cardiac gating., Materials and Methods: Fifty patients underwent high-resolution contrast-enhanced MR angiography on a 1.5-T whole-body system. The 50 patients were composed of two groups of 25 consecutive patients; one group underwent MR angiography with ECG gating and the other group underwent MR angiography without ECG gating. A sagittal (3D) gradient-echo fast low-angle shot (FLASH) sequence (TR/TE, 2.8/1.4; flip angle, 25 degrees; readout, 512; voxel size, 1.4 x 0.8 x 1.3 mm) with an asymmetric k-space scanning scheme in all three gradient axes was used, and 0.2 mmol/kg of gadopentetate dimeglumine was injected at 2 mL/s. Sharpness of the thoracic aorta was evaluated at three levels by generating a signal intensity profile across the aortic vessel wall and calculating the distance between two points along a line representing the slope of the signal intensity profile. Both sides of the intensity profile were analyzed and averaged and then used to calculate sharpness. An additional group of six patients was included who had undergone both a gated and an ungated sequence; results of this group were analyzed independently., Results: Quantitative analysis of the sharpness of the ascending thoracic aorta showed a significant increase in sharpness in both the 50-patient and six-patient groups (p < 0.005) with the addition of cardiac gating., Conclusion: Cardiac gating significantly improves the sharpness of the ascending aorta, a portion of the aorta that is subject to a great deal of blurring caused by cardiac motion. High-resolution contrast-enhanced MR angiography with cardiac gating can produce high quality images of the thoracic vasculature, thus enabling accurate diagnosis of vessel disease.