BACKGROUND AND OBJECTIVE:The MitraClip is the most widely used percutaneous treatment for mitral regurgitation, typically performed under the real-time guidance of 3D transesophageal echocardiography (TEE). However, artifacts and low image contrast in echocardiography hinder accurate clip visualization. This study presents a proof-of-concept of an automated pipeline for clip detection from 3D TEE images acquired in a controlled in vitro simulation environment. METHODS:An Attention UNet was employed to segment the device, while a DenseNet classifier predicted its configuration among ten possible states, ranging from fully closed to fully open. Based on the predicted configuration, a template model derived from computer-aided design (CAD) was automatically registered to refine the segmentation and enable quantitative characterization of the device. The pipeline was trained and validated on 196 3D TEE images acquired using a heart simulator, with ground-truth annotations refined through CAD-based templates. RESULTS:The Attention UNet achieved an average surface distance of 0.76 mm and a 95% Hausdorff distance of 2.44 mm for segmentation, while the DenseNet achieved an average weighted F1-score of 0.80 for classification. Post-refinement, segmentation accuracy improved, with average surface distance and 95% Hausdorff distance reduced to 0.69 mm and 1.83 mm, respectively. CONCLUSION:This pipeline enhanced clip visualization, providing fast and accurate detection with quantitative feedback, potentially improving procedural efficiency and reducing adverse outcomes.

INTRODUCTION:Endovascular techniques and materials have significantly expanded their application in the treatment of abdominal and thoraco-abdominal aortic lesions, allowing for the management of increasingly complex pathologies that may require cannulation of target vessels. The treatment of such diseases deserves a particular approach and dedicated materials, for which correct procedural planning is mandatory. In the last decades, the use of 3D printing technology as an assisting tool for preoperative rehearsal of complex cases has progressively widespread. AREAS COVERED:A review was performed about the use of 3D printing technology for the planning of endovascular repair of complex abdominal and thoraco-abdominal aortic lesions. Also, our experience of planning and simulation of an elective challenging endovascular procedure for a Crawford's type II thoraco-abdominal aortic aneurysm using a Cook Zenith® T-BranchTM endograft, leveraging a 3D-printed model of the patient-specific anatomy from the aortic arch to the common femoral artery, is herein described. EXPERT OPINION:The benefits of using 3D printing technologies as an assistive tool in planning complex endovascular repairs of abdominal and thoraco-abdominal aortic lesions have been well-documented in the literature, including their application in urgent cases. However, further research and development are necessary to overcome the current limitations of this potentially highly valuable technology.

Cardiovascular magnetic resonance (CMR) is the gold-standard to estimate right ventricular (RV) volumes, which are key for clinical management of patients with repaired tetralogy of Fallot (rTOF). Semi-automated threshold-based methods (SAT) have been proposed for CMR post-processing as alternatives to fully manual standard tracing. We investigated the impact of SAT on RV analysis using different thresholds in rTOF patients. RV volumes and mass were estimated using SAT and standard fully manual tracing methods in rTOF patients. Two threshold levels were set for SAT, i.e., default 50 (SAT-50) and 30 (SAT-30). RV stroke volumes (SV) were compared to main pulmonary artery forward flow (MPA-FF). Post-processing time, intra- and interobserver variabilities were compared across methods. Sixty-two CMRs of rTOF patients were analyzed. Compared to the standard fully manual tracing, no significant differences in RV mass, volumes and ejection fraction were observed using SAT-30, whereas SAT-50 significantly underestimated RV end-diastolic-volume index (EDVi) by 10.4

BACKGROUND:The GCA is a well performing device in terms of efficacy despite complex anatomies (aortic rim <5 mm and ASD diameter >17 mm) with a good safety profile. AIMS:To evaluate atrial septal defect (ASD) features impacting on right disc device thrombosis in patients who underwent Gore Cardioform ASD Occluder (GCA) implantation. METHODS:A total of 44 consecutive patients undergoing percutaneous ASD with GCA device from January 2020 to September 2022 at our tertiary care Center were evaluated. The minimum follow-up was 6 months. RESULTS:The patients were stratified in two groups according to a cut-off value of ASD diameter equal to 20 mm at sizing balloon, derived from ROC analysis (AUC = 0.894; p = 0.024). Baseline characteristics were comparable between groups in terms of age, sex, weight, height, and interatrial septum dimensions. Patients with ASD > 20 mm (n = 9) had a higher ASD/device dimension ratio, both at echocardiography (p = 0.009) and at sizing balloon (p = 0.001), longer fluoroscopic time (p = 0.022), and higher incidence of device thrombosis (0.006). Right disc thrombosis was observed in three patients of the ASD > 20 mm group, always in the inferior portion of the right disc. On univariate analysis, ASD diameter at sizing balloon (OR 1.360; p = 0.036) was the only positive predictor of device thrombosis. CONCLUSIONS:Right disc thrombosis of the GCA device may be under-recognized at follow-up, hence deserving clinical attention, especially in those patients with larger ASD diameters.

AbstractIn transcatheter aortic valve implantation (TAVI), final device position may be affected by device interaction with the whole aortic landing zone (LZ) extending to ascending aorta. We investigated the impact of aortic LZ curvature and angulation on TAVI implantation depth, comparing short-frame balloon-expanding (BE) and long-frame self-expanding (SE) devices. Patients (n = 202) treated with BE or SE devices were matched based on one-to-one propensity score. Primary endpoint was the mismatch between the intended (HPre) and the final (HPost) implantation depth. LZ curvature and angulation were calculated based on the aortic centerline trajectory available from pre-TAVI computed tomography. Total LZ curvature ($${k}_{LZ,tot}$$ k L Z , t o t ) and LZ angulation distal to aortic annulus ($${\alpha }_{LZ,Distal}$$ α L Z , D i s t a l ) were greater in the SE compared to the BE group (P < 0.001 for both). In the BE group, HPost was significantly higher than HPre at both cusps (P < 0.001). In the SE group, HPost was significantly deeper than HPre only at the left coronary cusp (P = 0.013). At multivariate analysis, $${\alpha }_{LZ,Distal}$$ α L Z , D i s t a l was the only independent predictor (OR = 1.11, P = 0.002) of deeper final implantation depth with a cut-off value of 17.8°. Aortic LZ curvature and angulation significantly affected final TAVI implantation depth, especially in high stent-frame SE devices reporting, upon complete release, deeper implantation depth with respect to the intended one.

Diastolic vortex ring (VR) plays a key role in the blood-pumping function exerted by the left ventricle (LV), with altered VR structures being associated with LV dysfunction. Herein, we sought to characterize the VR diastolic alterations in ischemic cardiomyopathy (ICM) patients with systo-diastolic LV dysfunction, as compared to healthy controls, in order to provide a more comprehensive understanding of LV diastolic function. 4D Flow MRI data were acquired in ICM patients (n = 15) and healthy controls (n = 15). The λ2 method was used to extract VRs during early and late diastolic filling. Geometrical VR features, e.g., circularity index (CI), orientation (α), and inclination with respect to the LV outflow tract (ß), were extracted. Kinetic energy (KE), rate of viscous energy loss ( ĖL̇ ), vorticity (W), and volume (V) were computed for each VR; the ratios with the respective quantities computed for the entire LV were derived. At peak E-wave, the VR was less circular (p = 0.032), formed a smaller α with the LV long-axis (p = 0.003) and a greater ß (p = 0.002) in ICM patients as compared to controls. At peak A-wave, CI was significantly increased (p = 0.034), while α was significantly smaller (p = 0.016) and β was significantly increased (p = 0.036) in ICM as compared to controls. At both peak E-wave and peak A-wave, ĖL̇_VR/ĖL̇_LV , WVR/WLV, and VVR/VLV significantly decreased in ICM patients vs. healthy controls. KEVR/VVR showed a significant decrease in ICM patients with respect to controls at peak E-wave, while VVR remained comparable between normal and pathologic conditions. In the analyzed ICM patients, the diastolic VRs showed alterations in terms of geometry and energetics. These derangements might be attributed to both structural and functional alterations affecting the infarcted wall region and the remote myocardium.

Journal Article Biomechanical imbalance of neochordal forces: the dark side of mitral valve prolapse repair Get access Francesco Sturla, Francesco Sturla 3D and Computer Simulation Laboratory, IRCCS Policlinico San Donato, San Donato Milanese, ItalyDepartment of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy Corresponding author. 3D and Computer Simulation Laboratory, IRCCS Policlinico San Donato, Via Rodolfo Morandi 30, San Donato Milanese, Italy. Tel: +39-02-5277-4353; e-mail: francesco.sturla@grupposandonato.it (F. Sturla). https://orcid.org/0000-0001-7317-304X Search for other works by this author on: Oxford Academic PubMed Google Scholar Emiliano Votta Emiliano Votta 3D and Computer Simulation Laboratory, IRCCS Policlinico San Donato, San Donato Milanese, ItalyDepartment of Electronics, Information and Bioengineering, Politecnico di Milano, Milano, Italy https://orcid.org/0000-0001-7115-0151 Search for other works by this author on: Oxford Academic PubMed Google Scholar European Journal of Cardio-Thoracic Surgery, Volume 65, Issue 3, March 2024, ezae073, https://doi.org/10.1093/ejcts/ezae073 Published: 04 March 2024 Article history Published: 04 March 2024 Corrected and typeset: 13 March 2024

Although survival has significantly improved in the last four decades, the diagnosis of Ebstein’s anomaly is still associated with a 20-fold increased risk of mortality, which generally drops after neonatal period and increases subtly thereafter. With increasing age of presentation, appropriate timing of intervention is challenged by a wide spectrum of disease and paucity of data on patient-tailored interventional strategies. The present review sought to shed light on the wide grey zone of post-neonatal Ebstein’s manifestations, highlighting current gaps and achievements in knowledge for adequate risk assessment and appropriate therapeutic strategy. A ‘wait-and-see’ approach has been adopted in many circumstances, though its efficacy is now questioned by the awareness that Ebstein’s anomaly is not a benign disease, even when asymptomatic. Moreover, older age at intervention showed a negative impact on post-surgical outcome. In order to tackle the extreme heterogeneity of Ebstein’s anomaly, this review displays the multimodality imaging assessment necessary for a proper anatomical classification and the multidisciplinary approach needed for a comprehensive risk stratification and monitoring strategy. Currently available predictors of clinical outcome are summarised for both operated and unoperated patients, with the aim of supporting the decisional process on the choice of appropriate therapy and optimal timing for intervention.

BACKGROUND AND OBJECTIVE:Dysfunction of the right ventricular outflow tract (RVOT) is a common long-term complication following surgical repair in patients with congenital heart disease. Transcatheter pulmonary valve implantation (TPVI) offers a viable alternative to surgical pulmonary valve replacement (SPVR) for treating pulmonary regurgitation but not all RVOT anatomies are suitable for TPVI. To identify a suitable landing zone (LZ) for TPVI, three-dimensional multiphase (4D) computed tomography (CT) is used to evaluate the size, shape, and dynamic behavior of the RVOT throughout the cardiac cycle. However, manually extracting measurements from multiplanar CT reformats is operator-dependent and time-consuming. Leveraging an optical-flow (OF) algorithm, we proposed a novel semi-automated pipeline for dynamic and comprehensive geometrical analysis of the RVOT anatomy. METHODS:Upon 4D-CT availability, at a pre-defined reference time-point, the patient-specific anatomy is semi-automatically segmented to generate the corresponding three-dimensional surface, which is navigated through a graphical user interface to define the mid-section of the potential LZ. Based on the axial length of the intended device, the proximal and distal LZ cross-sections are automatically identified. An OF-based algorithm is used to track the three LZ cross-sections frame by frame throughout the cardiac cycle, taking RVOT out-of-plane motion into account to update RVOT contours on each cross-section and to elaborate LZ geometrical changes. Finally, LZ time-dependent geometrical features are quantified and extracted. RESULTS:The pipeline was successfully applied to a retrospective cohort of patients, with OF-based tracking reporting excellent agreement (r2 = 0.99) compared to manual processing, with a bias < 1% for both LZ area and perimeter, while also significantly improving time efficiency. CT-derived measurements extracted from LZ mid-section were the most influential covariates affecting the likelihood of TPVI feasibility. Among these, the minimum perimeter outperformed all other geometric LZ parameters in classifying patients as suitable for either TPVI or SPVR and achieved the highest area under the curve of 0.99, with accuracy and precision of 0.93 and 0.92, respectively. CONCLUSIONS:Dynamic OF-based quantification of key RVOT geometric parameters can enhance and expedite the selection process for TPVI candidates and guide optimal valve sizing during TPVI planning.

We describe a rare and extremely challenging case of transcatheter pulmonary valve implantation in repaired tetralogy of Fallot and anomalous origin of the left main coronary artery from the right coronary sinus. Procedural planning based on advanced multimodality imaging and 3-dimensional technology proved to be the key to procedural success.

Dataset from Castelvecchio S, Frigelli M, Sturla F, Milani V, Pappalardo OA, Citarella M, Menicanti L, Votta E. Elucidating the mechanisms underlying left ventricular function recovery in patients with ischemic heart failure undergoing surgical remodeling: A 3-dimensional ultrasound analysis. J Thorac Cardiovasc Surg. 2021 Feb 26:S0022-5223(21)00381-0. doi: 10.1016/j.jtcvs.2021.02.067. Epub ahead of print. PMID: 33781593. Abstract Objective: The study objective was to elucidate the mechanisms of left ventricle functional recovery in terms of endocardial contractility and synchronicity after surgical ventricular reconstruction. Methods: Real-time 3-dimensional transthoracic echocardiography was performed on 20 patients with anterior left ventricle remodeling and ischemic heart failure before surgical ventricular reconstruction and at 6-month follow-up, and on 15 healthy controls matched by age and body surface area. Real-time 3-dimensional transthoracic echocardiography datasets were analyzed through TomTec software (4D LV-Analysis; TomTec Imaging Systems GmbH, Unterschleissheim, Germany): Left ventricle volumes, ejection fraction, and global longitudinal strain were computed; the time-dependent endocardial surface yielded by 3-dimensional speckle-tracking echocardiography was postprocessed through in-house software to quantify local systolic minimum principal strain as a measure of fiber shortening and mechanical dispersion as a measure of fiber synchronicity. Results: Compared with controls, patients with heart failure before surgical ventricular reconstruction showed lower ejection fraction (P < .0001) and significantly impaired mechanical dispersion (P < .0001) and minimum principal strain (P < .0001); the latter worsened progressively from left ventricle base to apex. After surgical ventricular reconstruction, global longitudinal strain improved from -6.7% to -11.3% (P < .0001); mechanical dispersion decreased in every left ventricle region (P ≤ .017) and mostly in the basal region, where computed mechanical dispersion values were comparable to physiologic values (P ≥ .046); minimum principal strain improved mostly in the basal region, changing from -16.6% to -22.3% (P = .0027). Conclusions: At 6-month follow-up, surgical ventricular reconstruction was associated with significant recovery in global left ventricle function, improved mechanical dispersion indicating a more synchronous left ventricle contraction, and improved left ventricle fiber shortening mostly in the basal region, suggesting the major role of the remote myocardium in enhancing left ventricle functional recovery.

Cappelletti S, Caimi A, Caldiroli A, Baroni I, Votta E, Riboldi SA, Marrocco-Trischitta MM, Redaelli A, Sturla F. Non-invasive estimation of vascular compliance and distensibility in the arm vessels: a novel ultrasound-based protocol. Quant Imaging Med Surg. 2022 Jul;12(7):3515-3527. doi: 10.21037/qims-21-987. PMID: 35782271; PMCID: PMC9246759. Abstract Background: Performance and durability of arterio-venous grafts depend on their ability to mimic the mechanical behavior of the anastomized blood vessels. To select the most suitable synthetic graft, in vivo evaluation of the radial deformability of peripheral arteries and veins could be crucial; however, a standardized non-invasive strategy is still missing. Herein, we sought to define a novel and user-friendly clinical protocol for in vivo assessment of the arm vessel deformability. Methods: A dedicated protocol, applied on 30 volunteers, was specifically designed to estimate both compliance and distensibility of the brachial and radial arteries, and of the basilic and cephalic veins. Bi-dimensional ultrasound imaging was used to acquire cross-sectional areas (CSAs) of arteries in clinostatic configuration, and CSAs of veins combining clinostatic and orthostatic configurations. Arterial pulse pressure was measured with a digital sphygmomanometer, while venous hydrostatic pressure was derived from the arm length in orthostatic configuration. Results: For each participant, all CSAs were successfully extracted from ultrasound images. The basilic vein and the radial artery exhibited the largest (21.5±8.9 mm2) and the smallest (3.4±1.0 mm2) CSAs, respectively; CSA measurements were highly repeatable (Bland-Altman bias <10% and Pearson correlation ≥0.90, for both arteries and veins). In veins, compliance and distensibility were higher than in arteries; compliance was significantly higher (P<0.0001) in the brachial than in the radial artery (3.52×10-4 vs. 1.3×10-4 cm2/mmHg); it was three times larger in basilic veins than in cephalic veins (17.4×10-4 vs. 5.6×10-4 cm2/mmHg, P<0.0001). Conclusions: The proposed non-invasive protocol proved feasible, effective and adequate for daily clinical practice, allowing for the estimation of patient-specific compliance and distensibility of peripheral arteries and veins. If further extended, it may contribute to the fabrication of biohybrid arterio-venous grafts, paving the way towards patient-tailored solutions for vascular access.

Post-ischemic left ventricular (LV) remodeling is a biologically complex process involving myocardial structure, LV shape, and function, beginning early after myocardial infarction (MI) and lasting until 1 year. Adverse remodeling is a post-MI maladaptive process that has been associated with long-term poor clinical outcomes. Cardiac Magnetic Resonance (CMR) is the best tool to define adverse remodeling because of its ability to accurately measure LV end-diastolic and end-systolic volumes and their variation over time and to characterize the underlying myocardial changes. Therefore, CMR is the gold standard method to assess in vivo myocardial infarction extension and to detect the presence of microvascular obstruction and intramyocardial hemorrhage, both associated with adverse remodeling. In recent times, new CMR quantitative biomarkers emerged as predictive of post-ischemic adverse remodeling, such as T1 mapping, myocardial strain, and 4D flow. Additionally, CMR T1 mapping imaging may depict infarcted tissue and assess diffuse myocardial fibrosis by using surrogate markers such as extracellular volume fraction, which may predict functional recovery or risk stratification of remodeling. Finally, there is emerging evidence supporting the utility of intracavitary blood flow kinetic energy and hemodynamic features assessed by the 4D flow CMR technique as early predictors of remodeling.

Abstract Funding Acknowledgements Type of funding sources: None. Background Failure of the systemic right ventricle (SRV) is based on morphological differences between right and left ventricles (RVs and LVs). RV adaptation to systemic afterload includes increased circumferential (GCS) over longitudinal global myocardial strain (GLS) with an unknown impact on intracavitary blood flow distribution. This study aimed to explore the SRV pattern of hemodynamic forces (HFs). Methods 4D-Flow cardiovascular magnetic resonance data were acquired using a prototype sequence on a 1.5-T MAGNETOM Aera. The ratio between transverse (inferior-anterior, HFIA and septal-lateral, HFSL) and longitudinal (basal-apical, HFBA) HFs (RRMS) was calculated as in Figure 1, for systole and diastole. Results We enrolled 12 adults with SRV (6 D-transposition of great arteries after atrial switch operation and 6 L-transpositions) and 12 age-matched healthy subjects (41±12 vs 42±13,p = 0.89). SRVs reported comparable end-diastolic volumes (83±18 ml/m2), ejection fraction (60±8%) and GLS (−20.2±3.8%) to control RVs (75±13 ml/m2,p = 0.18; 64±5%,p = 0.25; −23±5.6%,p = 0.21). Differently, SRV mass (55±24 g/m2) and GCS (−18.9±7.8%) were greater than RVs (20±3 g/m2,p<0.001 and −12.4±4,p = 0.016) and comparable to control LVs (57±11 g/m2,p = 0.7 and −20.2±3.8%,p = 0.3). The 4D-Flow analysis showed that SRV systolic RRMS (0.98±0.31) was similar to LVs (0.94±0.27,p = 0.78) but lower than RVs (1.32±0.45,p = 0.04). This reflected a significantly increased HFBA with respect to RVs (0.338±0.150 vs. 0.162±0.097, p = 0.0025) and similar to LVs (0.462 ± 0.186, p = 0.087). Concomitantly, a moderate correlation was demonstrated between SRV systolic HFBA magnitude and GCS (r2=0.47,p = 0.013). During diastole, SRVs showed lower HFBA (0.173±0.086) than LVs (0.304±0.104,p = 0.0028), revealing a diastolic RRMS (0.74 ± 0.14) comparable to RVs (0.73 ± 0.17,p = 0.95) and significantly different from LVs (0.50 ± 0.19,p = 0.003). Conclusions In SRVs, RRMS is similar to LVs during systole, possibly as a result of increased GCS. Inversely, the SRV filling appears to be closely related to ventricular morphology as suggested by RRMS comparable to RVs during diastole.

Abstract Funding Acknowledgements Type of funding sources: Private hospital(s). Main funding source(s): This work was supported by IRCCS Policlinico San Donato, a Clinical Research Hospital partially funded by the Italian Ministry of Health. Introduction Blood flowing into the left ventricle (LV) forms a 3D vortex ring starting from the free margin of mitral valve leaflets and encompassing the inflow jet. Vortex ring formation is presumed to store part of the kinetic energy of the entering jet and help directing blood flow towards the aorta [1]. Changes in vortex formation are associated to altered endocardial wall motion and LV chamber remodeling, as in case of ischemic cardiomyopathy (ICM). 4D Flow MRI is currently the unique volumetric imaging technique to assess in vivo changes of diastolic vortex ring. Purpose To characterize changes in LV diastolic vortex ring and associated energetics in a cohort of ICM patients (n = 12) vs. controls (n = 12) with comparable age. Methods 4D Flow MRI data were acquired for ICM patients presenting with anterior myocardial infarction and in healthy controls. The diastolic vortex ring was assessed at peak E-wave and at peak A-wave through the λ2 method [2]. Geometrical features of the vortex ring, e.g., circularity index (CI) and vortex orientation (α), were extracted (Figure 1). Kinetic energy (KE), rate of viscous energy loss (EL), vorticity and volume were computed for each vortex ring core; the ratios with the respective quantities computed for the entire LV were derived. Results At peak E-wave, the vortex ring was less circular (p = 0.017) and formed a smaller α with the mitral valve plane (p = 0.024) in ICM patients as compared to controls. At peak A-wave, the vortex ring core remained less circular (p = 0.027) in ICM patients, while vortex orientation remained comparable between the two groups. KE ratio, EL ratio, vorticity ratio and volume ratio significantly decreased for ICM patients at both E-peak and A-peak (Table 1). Conclusions Though ICM is primarily addressed and investigated as a systolic dysfunction, diastolic function can be deranged too, as highlighted by altered diastolic vortex ring shape and energetics.

An 8-year-old girl, diagnosed with mid-aortic syndrome (MAS) at the age of 2 months and under antihypertensive therapy, presented with severe systemic hypertension (>200/120 mmHg). Computed tomography (CT) examination revealed aortic aneurysm between severe stenoses at pre- and infra-renal segments, and occlusion of principal splanchnic arteries with peripheral collateral revascularization. Based on CT imaging, preoperative three-dimensional (3D) anatomy was reconstructed to assess aortic dimensions and a dedicated in vitro planning platform was designed to investigate the feasibility of a stenting procedure under fluoroscopic guidance. The in vitro system was designed to incorporate a translucent flexible 3D-printed patient-specific model filled with saline. A covered 8-zig 45-mm-long Cheatham-Platinum (CP) stent and a bare 8-zig, 34-mm-long CP stent were implanted with partial overlap to treat the stenoses (global peak-to-peak pressure gradient > 60 mmHg), excluding the aneurysm and avoiding risk of renal arteries occlusion. Percutaneous procedure was successfully performed with no residual pressure gradient and exactly replicating the strategy tested in vitro. Also, as investigated on the 3D-printed model, additional angioplasty was feasible across the frames of the stent to improve bilateral renal flow. Postoperative systemic pressure significantly reduced (130/70 mmHg) as well as dosage of antihypertensive therapy. This is the first report demonstrating the use of a 3D-printed model to effectively plan percutaneous intervention in a complex pediatric MAS case: taking full advantage of the combined use of a patient-specific 3D model and a dedicated in vitro platform, feasibility of the stenting procedure was successfully tested during pre-procedural assessment. Hence, use of patient-specific 3D-printed models and in vitro dedicated platforms is encouraged to assist pre-procedural planning and personalize treatment, thus enhancing intervention success.

The total kinetic energy (KE) of blood can be decomposed into mean KE (MKE) and turbulent KE (TKE), which are associated with the phase-averaged fluid velocity field and the instantaneous velocity fluctuations, respectively. The aim of this study was to explore the effects of pharmacologically induced stress on MKE and TKE in the left ventricle (LV) in a cohort of healthy volunteers. 4D Flow MRI data were acquired in eleven subjects at rest and after dobutamine infusion, at a heart rate that was ∼60% higher than the one in rest conditions. MKE and TKE were computed as volume integrals over the whole LV and as data mapped to functional LV flow components, i.e., direct flow, retained inflow, delayed ejection flow and residual volume. Diastolic MKE and TKE increased under stress, in particular at peak early filling and peak atrial contraction. Augmented LV inotropy and cardiac frequency also caused an increase in direct flow and retained inflow MKE and TKE. However, the TKE/KE ratio remained comparable between rest and stress conditions, suggesting that LV intracavitary fluid dynamics can adapt to stress conditions without altering the TKE to KE balance of the normal left ventricle at rest.

EDITORIAL article Front. Med. Technol., 23 June 2023Sec. Cardiovascular Medtech Volume 5 - 2023 | https://doi.org/10.3389/fmedt.2023.1222837

Accurate planning of transcatheter aortic implantation (TAVI) is important to minimize complications, and it requires anatomic evaluation of the aortic root (AR), commonly done through 3D computed tomography (CT) image analysis. Currently, there is no standard automated solution for this process. Two convolutional neural networks (CNNs) with 3D U-Net architectures (model 1 and model 2) were trained on 310 CT scans for AR analysis. Model 1 performed AR segmentation and model 2 identified the aortic annulus and sinotubular junction (STJ) contours. Results were validated against manual measurements of 178 TAVI candidates. After training, the two models were integrated into a fully automated pipeline for geometric analysis of the AR. The trained CNNs effectively segmented the AR, annulus and STJ, resulting in mean Dice scores of 0.93 for the AR, and mean surface distances of 1.16 mm and 1.30 mm for the annulus and STJ, respectively. Automatic measurements were in good agreement with manual annotations, yielding annulus diameters that differed by 0.52 [-2.96, 4.00] mm (bias and 95% limits of agreement for manual minus algorithm). Evaluating the area-derived diameter, bias and limits of agreement were 0.07 [-0.25, 0.39] mm. STJ and sinuses diameters computed by the automatic method yielded differences of 0.16 [-2.03, 2.34] and 0.1 [-2.93, 3.13] mm, respectively. The proposed tool is a fully automatic solution to quantify morphological biomarkers for pre-TAVI planning. The method was validated against manual annotation from clinical experts and showed to be quick and effective in assessing AR anatomy, with potential for time and cost savings.