Outcomes and survival following thoracic endovascular repair in patients with aortic aneurysms limited to the descending thoracic aorta.

BACKGROUND: Thoracic endovascular aortic repair (TEVAR) is a well-established therapy for descending aortic aneurysms (DTA). There is a paucity of large series reporting the mid- and long-term outcomes from this era. The main aim of this study was to evaluate the outcomes of TEVAR with regards to the effect of aortic morphology and procedure-related variables on survival, reintervention and freedom from endoleaks. METHODS: In this retrospective single center study, we evaluated the clinical outcomes among 158 consecutive patients with DTA than underwent TEVAR between 2006 and 2019 at our center. The cohort included 51% patients with device landing zones proximal to the subclavian artery and 25.9% patients undergoing an emergent or urgent TEVAR. The primary outcome was survival, and secondary outcomes were reintervention and occurrence of endoleaks. RESULTS: Median follow-up was 33 months [IQR 12 to 70] while 50 patients (30.6%) had longer than 5-year follow-up. With a median patient age of 74 years, post-operative Kaplan Meyer survival estimates were 94.3% (95%CI 90.8-98.0, SE 0.018%) at 30 days, 76.4% (95%CI 70.0-83.3, SE 0.034%) at one year and, 52.9% (95%CI 45.0-62.2, SE 0.043%) at five years. Freedom from reintervention at 30 days, one year, and five years was 92.9% (95%CI 89.0-97.1, SE 0.021%), 80.0% (95%CI 72.6-88.1, SE 0.039%), and 52.8% (95%CI 41.4-67.4, SE 0.065%), respectively. On cox regression analysis greater aneurysm diameter, and the use of device landing zones in aortic regions 0-1 were associated with an increased probability of all-cause mortality, and with reintervention during follow-up. Independent of aneurysm size undergoing urgent or emergent TEVAR was associated with higher mortality risk for the first three years post-operative but not on long-term follow-up. CONCLUSIONS: Larger aneurysms and those requiring stent-graft landing in aortic zones 0 or 1, are associated with higher risk for mortality and reintervention. There remains a need to optimize clinical management and device design for larger proximal aneurysms.

Pre-Glenn aorto-pulmonary collaterals in single-ventricle patients.

BACKGROUND: In single-ventricle patients undergoing staged-bidirectional Glenn, 36-59% have aorto-pulmonary collateral flow, but risk factors and clinical outcomes are unknown. We hypothesise that shunt type and catheter haemodynamics may predict pre-bidirectional Glenn aorto-pulmonary collateral burden, which may predict death/transplantation, pulmonary artery or aorto-pulmonary collateral intervention. METHODS: Retrospective cohort study of patients undergoing a Norwood procedure for single-ventricle anatomy. Covariates included clinical and haemodynamic characteristics up to/including pre-bidirectional Glenn catheterisation and aorto-pulmonary collateral burden at pre-bidirectional Glenn catheterisation. Multivariable models used to evaluate relationships between risk factors and outcomes. RESULTS: From January 2011 to March 2016, 104 patients underwent Norwood intervention. Male sex (odds ratio 3.36, 95% confidence interval 1.17-11.4), age at pre-bidirectional Glenn assessment (2.12, 1.33-3.39 per month), and pulmonary to systemic flow ratio (1.23, 1.08-1.41 per 0.1 unit) were associated with aorto-pulmonary collateral burden. Aorto-pulmonary collateral burden was not associated with death/transplantation (hazard ratio 1.19, 95% confidence interval 0.37-3.85), pulmonary artery (sub-hazard ratio 1.38, 0.32-2.61), or aorto-pulmonary collateral interventions (sub-hazard ratio 1.11, 0.21-5.76). Longer post-Norwood length of stay was associated with greater risk of death/transplantation (hazard ratio 1.22 per week, 95% confidence interval 1.08-1.38), but lower risk of aorto-pulmonary collateral intervention (sub-hazard ratio 0.86 per week, 95% confidence interval 0.75-0.98). Time to pre-bidirectional Glenn catheterisation was associated with lower risk of pulmonary artery (sub-hazard ratio 0.80 per month, 95% confidence interval 0.65-0.98) and aorto-pulmonary collateral intervention (sub-hazard ratio 0.79, 0.63-0.99). Probability of moderate/severe aorto-pulmonary collateral burden increased with left-to-right shunt (22.5% at <1.0, 57.6% at >1.4) and the age at pre-bidirectional Glenn catheterisation (10.6% at <2 months, 56.9% at >5 months). CONCLUSIONS: Aorto-pulmonary collateral burden is common after Norwood procedure and increases as age at bidirectional Glenn increases. As expected, higher pulmonary to systemic flow ratio is a marker for greater aorto-pulmonary collateral burden pre-bi-directional Glenn; aorto-pulmonary collateral burden does not confer risk of death/transplantation or pulmonary artery intervention.

Aortic remodelling and late outcomes following thoracic endovascular repair with a bare-metal stent distal extension among patients with complicated type-B aortic dissection.

OBJECTIVES: The goal of this study was to describe the factors affecting mid and late aortic remodelling following thoracic endovascular aortic repair with the PETTICOAT (Provisional Extension To Induce Complete Attachment) technique among patients with complicated acute or subacute type B aortic dissection. METHODS: A retrospective single-centre study that evaluates clinical and morphological outcomes among 65 consecutive patients. The area and diameter of the true and false lumen, overall aortic diameter and false lumen perfusion were evaluated. RESULTS: Concomitant direct visceral artery stenting was successfully conducted in 32 (49%) patients. There was one (1.5%) postoperative stroke; three (4.6%) patients developed spinal cord ischaemia; two (3%) patients suffered retrograde type A dissection; and two (3%) patients had mesenteric ischaemia, despite successful reperfusion, that required a bowel resection. Median postoperative follow-up was 63.1 (interquartile range, 32.1- 91.8) months. The probability of survival was 96.9% [95% confidence interval (CI) 88.3%-99.2%] at 30 days, 93.9% (95% CI 84.4%-97.6%) at 1 year, 78.0 (95% CI 64.2%-87.0%) at 5 years and 72.8% (95% CI at 57.9%-83.2%) at 10 years postoperatively. There was a statistically significant postoperative increase in true-lumen area, diameter and true-lumen index in all five aortic levels measured. Complete false lumen (FL) thrombosis at the coeliac trunk, renal arteries and aortic bifurcation levels was observed in 47%, 15% and 24% of patients at midterm (6-15 months) and in 29%, 21% and 29% on late (later than 21 months) computed tomography angiograms (CTA). Persistent false lumen (FL) perfusion at the coeliac level on midterm CTA was associated with a larger extent of late aortic growth (P = 0.042) and was, in the majority of cases, caused by iliac re-entries either alone (28.57) or in combination with visceral and lumbar (28.57%) or distal aortic (10.71%) re-entries. A larger abdominal aortic diameter at midterm was associated with an increased probability of distal aortic reinterventions (hazard ratio 7.26, 95% CI 2.41-21.9, P < 0.001). CONCLUSIONS: Persistent FL perfusion of the distal aorta at midterm following TEVAR with the PETTICOAT technique among patients with acute and subacute type B dissection is caused mainly by iliac, visceral, lumber and distal aorta re-entries. Patients with persistent FL perfusion have an increased risk of aortic aneurysmal growth at late follow-up.

Tricuspid valve repair concomitant with the Norwood operation among babies with hypoplastic left heart syndrome.

OBJECTIVES: Among patients with hypoplastic left heart syndrome (HLHS), tricuspid valve regurgitation (TR) portends a poor prognosis. Our goal was to describe the outcomes of tricuspid valve reconstruction (TVR) concomitant with the Norwood operation and using two-dimensional echocardiography and evaluate the structural factors associated with successful functional correction. METHODS: We performed a retrospective, single-centre study of patients with HLHS undergoing TVR at the time of the Norwood operation. Structural echocardiographic parameters were compared between patients with successful correction (≤ mild TR) and those with ≥ moderate regurgitation at discharge. Preoperative dimensions of matched HLHS controls with ≤ trivial TR were used as a reference. RESULTS: Of 205 patients with HLHS undergoing the Norwood operation, 18 patients had a concomitant TVR. Ten (56%) patients had an improved TR grade postoperatively, 8 (44%) of whom had ≤ mild TR at discharge. Improvement in TR grade (P = 0.001) and having ≤ mild TR at discharge (P = 0.011) were associated with an improved reintervention and TR-free survival. Patients with successful functional correction had smaller preoperative tricuspid annulus lateral dimensions (P = 0.023), tricuspid valve area (P = 0.007) and right ventricle mid-width (P = 0.064). Preoperatively, the successful TVR cases tended to have had higher anterior leaflet excursion (80 ± 20 vs 55 ± 11, P = 0.010), and a higher proportion of anterior leaflet prolapse (63% vs 10%, P = 0.043) compared to cases where TVR was not successful. CONCLUSIONS: Patients with HLHS with significant tricuspid regurgitation undergoing the stage 1 operation were more likely to have successful concomitant tricuspid valve repair if they had less tricuspid annular dilation, less-severe RV enlargement and predominantly anterior leaflet prolapse. Successful tricuspid valve repair was associated with improved mid- and long-term outcomes.

Cascaded neural network-based CT image processing for aortic root analysis.

PURPOSE: Careful assessment of the aortic root is paramount to select an appropriate prosthesis for transcatheter aortic valve implantation (TAVI). Relevant information about the aortic root anatomy, such as the aortic annulus diameter, can be extracted from pre-interventional CT. In this work, we investigate a neural network-based approach for segmenting the aortic root as a basis for obtaining these parameters. METHODS: To support valve prosthesis selection, geometric measures of the aortic root are extracted from the patient's CT scan using a cascade of convolutional neural networks (CNNs). First, the image is reduced to the aortic root, valve, and left ventricular outflow tract (LVOT); within that subimage, the aortic valve and ascending aorta are segmented; and finally, the region around the aortic annulus. From the segmented annulus region, we infer the annulus orientation using principal component analysis (PCA). The area-derived diameter of the annulus is approximated based on the segmentation of the aortic root and LVOT and the plane orientation resulting from the PCA. RESULTS: The cascade of CNNs was trained using 90 expert-annotated contrast-enhanced CT scans routinely acquired for TAVI planning. Segmentation of the aorta and valve within the region of interest achieved an F1 score of 0.94 on the test set of 36 patients. The area-derived diameter within the annulus region was determined with a mean error below 2 mm between the automatic measurement and the diameter derived from annotations. The calculated diameters and resulting errors are comparable to published results of alternative approaches. CONCLUSIONS: The cascaded neural network approach enabled the assessment of the aortic root with a relatively small training set. The processing time amounts to 30 s per patient, facilitating time-efficient, reproducible measurements. An extended training data set, including different levels of calcification or special cases (e.g., pre-implanted valves), could further improve this method's applicability and robustness.

The feasibility of mitral valve device foldoplasty: an in vivo study to evaluate durable retention.

OBJECTIVES: We have previously shown in experimental settings that a leaflet foldoplasty device reduces redundant leaflet area to re-establish mitral valve (MV) coaptation. The current study investigates the in vivo device retention and functional durability following foldoplasty. METHODS: The prototype is of superelastic nitinol formed into a 3-dimensional shape. It is unfolded to engage a specified area of leaflet tissue and then folded to exclude this tissue from the coaptation surface. Design modifications were made and tested in benchtop studies to determine the optimal design for durable retention within the leaflet. To evaluate in vivo performance, posterior leaflet chordae were severed in Yorkshire pigs to produce complete posterior leaflet prolapse and severe mitral regurgitation. Design modifications were then used for MV repair. Five animals that underwent repair using the optimal design were observed for 2 weeks postoperative to evaluate the functional result and implant retention. RESULTS: Device position and orientation were maintained at 2 weeks while preserving the functional MV repair in all 5 animals. Coaptation height was 5.5 ± 1.5 mm, which was not significantly different from a baseline of 4.9 ± 0.8 mm. The degree of leaflet excursion was 41.0 ± 16.0 compared to a baseline of 58.7 ± 27.5. CONCLUSIONS: Device foldoplasty is a new concept for MV repair based on the reduction of redundant leaflet tissue area. This study demonstrates the feasibility of safe maintenance of this repair without early dislodgement or embolization.

Importance of Preserved Tricuspid Valve Function for Effective Soft Robotic Augmentation of the Right Ventricle in Cases of Elevated Pulmonary Artery Pressure.

PURPOSE: In clinical practice, many patients with right heart failure (RHF) have elevated pulmonary artery pressures and increased afterload on the right ventricle (RV). In this study, we evaluated the feasibility of RV augmentation using a soft robotic right ventricular assist device (SRVAD), in cases of increased RV afterload. METHODS: In nine Yorkshire swine of 65-80 kg, a pulmonary artery band was placed to cause RHF and maintained in place to simulate an ongoing elevated afterload on the RV. The SRVAD was actuated in synchrony with the ventricle to augment native RV output for up to one hour. Hemodynamic parameters during SRVAD actuation were compared to baseline and RHF levels. RESULTS: Median RV cardiac index (CI) was 1.43 (IQR, 1.37-1.80) L/min/m2 and 1.26 (IQR 1.05-1.57) L/min/m2 at first and second baseline. Upon PA banding RV CI fell to a median of 0.79 (IQR 0.63-1.04) L/min/m2. Device actuation improved RV CI to a median of 0.87 (IQR 0.78-1.01), 0.85 (IQR 0.64-1.59) and 1.11 (IQR 0.67-1.48) L/min/m2 at 5 min (p = 0.114), 30 min (p = 0.013) and 60 (p = 0.033) minutes respectively. Statistical GEE analysis showed that lower grade of tricuspid regurgitation at time of RHF (p = 0.046), a lower diastolic pressure at RHF (p = 0.019) and lower mean arterial pressure at RHF (p = 0.024) were significantly associated with higher SRVAD effectiveness. CONCLUSIONS: Short-term augmentation of RV function using SRVAD is feasible even in cases of elevated RV afterload. Moderate or severe tricuspid regurgitation were associated with reduced device effectiveness.

Infrastructure Availability for the Care of Congenital Heart Disease Patients and Its Influence on Case Volume, Complexity and Access Among Healthcare Institutions in 17 Middle-Income Countries.

The care for patients with congenital heart disease (CHD) is multi-disciplinary and resource intensive. There is limited information about the infrastructure available among programs that care for CHD patients in low and middle-income countries (LMIC). A survey covering the entire care-pathway for CHD, from initial assessment to inpatient care and outpatient follow-up, was administered to institutions participating in the International Quality Improvement Collaborative for Congenital Heart Disease (IQIC). Surgical case complexity-mix was collected from the IQIC registry and estimated surgical capacity requirement was based on population data. The statistical association of selected infrastructure with case volume, case-complexity and percentage of estimated case-burden actually treated, was analyzed. Thirty-seven healthcare institutions in seventeen countries with median annual surgical volume of 361 (41-3503) operations completed the survey. There was a median of two (1-16) operating room/s (OR), nine (2-80) intensive care unit (ICU) beds, three (1-20) cardiac surgeons, five (3-30) OR nurses, four (2-35) anesthesiologists, four (1-25) perfusionists, 28 (5-194) ICU nurses, six (0-30) cardiologists and three (1-15) interventional cardiologists. Higher surgical volume was associated with higher OR availability (p = 0.007), number of surgeons (p = 0.002), OR nurses (0.008), anesthesiologists (p = 0.04), perfusionists (p = 0.001), ICU nurses (p < 0.001), years of experience of the most senior surgeon (p = 0.03) or cardiologist (p = 0.05), and ICU bed capacity (p = 0.001). Location in an upper-middle income country (P = 0.04), OR availability (p = 0.02), and number of cardiologists (p = 0.004) were associated with performing a higher percentage of complex cases. This study demonstrates an overall deficit in the infrastructure available for the care of CHD patients among the participating institutions. While there is considerable variation across institutions surveyed, deficits in infrastructure that requires long-term investment like operating rooms, intensive care capacity, and availability of trained staff, are associated with reduced surgical capacity and access to CHD care.

Real-time intraoperative co-registration of transesophageal echocardiography with fluoroscopy facilitates transcatheter mitral valve-in-valve implantation in cases of invisible degenerated bioprosthetic valves.

OBJECTIVES: Transcatheter mitral valve-in-valve (TMViV) implantation is an alternative treatment to surgery for high-risk patients with degenerated bioprosthetic mitral valves. Some types of bioprostheses are fluoroscopically translucent, resulting in an 'invisible' target deployment area. In this study, we describe the feasibility and outcomes of this procedure using intraoperative fusion of transoesophageal echocardiography (TEE) and live fluoroscopy to facilitate valve deployment in cases of invisible bioprosthetic valves. METHODS: We reviewed all TMViV implantations at our centre from July 2014 to July 2019. Patient, procedure and outcome details were compared between those with a visible bioprosthesis (N = 22) to those with an invisible one (N = 12). Intra-operative TEE and live Fluoroscopy co-registration were used for real-time guidance for all invisible targets. RESULTS: All valve implantations were completed successfully in both groups without cardiovascular injury, valve migration or left ventricular outflow-tract obstruction. Technical success was 100% in both groups. One-year survival was 83% [95% confidence interval (CI) 70-96] for the entire cohort, with 79% (95% CI 63-100) survival for the visible group and 92% (95% CI 77-100) for the invisible group. Probability of 1-year survival free from mitral valve reintervention, significant valve dysfunction, stroke or myocardial infraction was 78% (95% CI 63-93) for all patients whereby the probability was 72% (95% CI 54-97) in the visible group and 80% (95% CI 59-100) for the invisible group. CONCLUSIONS: The use of intraoperative TEE and live fluoroscopy image fusion facilitates accurate TMViV among patients with a fluoroscopically invisible target-landing zone.

Interactive editing of virtual chordae tendineae for the simulation of the mitral valve in a decision support system.

PURPOSE: Decision support systems for mitral valve disease are an important step toward personalized surgery planning. A simulation of the mitral valve apparatus is required for decision support. Building a model of the chordae tendineae is an essential component of a mitral valve simulation. Due to image quality and artifacts, the chordae tendineae cannot be reliably detected in medical imaging. METHODS: Using the position-based dynamics framework, we are able to realistically simulate the opening and closing of the mitral valve. Here, we present a heuristic method for building an initial chordae model needed for a successful simulation. In addition to the heuristic, we present an interactive editor to refine the chordae model and to further improve pathology reproduction as well as geometric approximation of the closed valve. RESULTS: For evaluation, five mitral valves were reconstructed based on image sequences of patients scheduled for mitral valve surgery. We evaluated the approximation of the closed valves using either just the heuristic chordae model or a manually refined model. Using the manually refined models, prolapse was correctly reproduced in four of the five cases compared to two of the five cases when using the heuristic. In addition, using the editor improved the approximation in four cases. CONCLUSIONS: Our approach is suitable to create realistically parameterized mitral valve apparatus reconstructions for the simulation of normally and abnormally closing valves in a decision support system.

Dynamic Augmentation of Left Ventricle and Mitral Valve Function With an Implantable Soft Robotic Device.

Left ventricular failure is strongly associated with secondary mitral valve regurgitation. Implantable soft robotic devices are an emerging technology that enables augmentation of a native function of a target tissue. We demonstrate the ability of a novel soft robotic ventricular assist device to dynamically augment left ventricular contraction, provide native pulsatile flow, simultaneously reshape the mitral valve apparatus, and eliminate the associated regurgitation in an Short-term large animal model of acute left ventricular systolic dysfunction.

Combining position-based dynamics and gradient vector flow for 4D mitral valve segmentation in TEE sequences.

PURPOSE: For planning and guidance of minimally invasive mitral valve repair procedures, 3D+t transesophageal echocardiography (TEE) sequences are acquired before and after the intervention. The valve is then visually and quantitatively assessed in selected phases. To enable a quantitative assessment of valve geometry and pathological properties in all heart phases, as well as the changes achieved through surgery, we aim to provide a new 4D segmentation method. METHODS: We propose a tracking-based approach combining gradient vector flow (GVF) and position-based dynamics (PBD). An open-state surface model of the valve is propagated through time to the closed state, attracted by the GVF field of the leaflet area. The PBD method ensures topological consistency during deformation. For evaluation, one expert in cardiac surgery annotated the closed-state leaflets in 10 TEE sequences of patients with normal and abnormal mitral valves, and defined the corresponding open-state models. RESULTS: The average point-to-surface distance between the manual annotations and the final tracked model was [Formula: see text]. Qualitatively, four cases were satisfactory, five passable and one unsatisfactory. Each sequence could be segmented in 2-6 min. CONCLUSION: Our approach enables to segment the mitral valve in 4D TEE image data with normal and pathological valve closing behavior. With this method, in addition to the quantification of the remaining orifice area, shape and dimensions of the coaptation zone can be analyzed and considered for planning and surgical result assessment.

Endovascular treatment of acute type A aortic dissection in a nonagenarian: stabilization of a short covered stent using a bare-metal stent.

Endovascular treatment is a viable alternative therapy in high-risk patients with acute type A aortic dissection. However, the optimal endovascular treatment strategy is still evolving. Herein, we present a case of a 91-year-old man who successfully underwent repair of an ascending aortic dissection using a stent-in-stent technique. At 1-year follow-up, the stent demonstrated repair durability.

Simulation of a Right Anterior Thoracotomy Access for Aortic Valve Replacement Using a 3D Printed Model.

OBJECTIVE: The right anterior lateral thoracotomy (RALT) approach for aortic valve replacement provides excellent outcomes in expert hands while avoiding sternal disruption. It, however, remains a technically demanding niche operation. Instrument trajectories via this access are influenced by patient anatomy, the intercostal space chosen, and surgical retraction maneuvers. METHODS: To simulate the typical surgical maneuvers, on an anatomically accurate model, and to measure the instrument trajectories, we generated a 3-dimensional (3D) printed model of the heart and chest cavity. A simulated approach to the base of the right coronary sinus via the medial-second intercostal, the lateral-second intercostal, or third intercostal space was made. Keeping the instrument in place, 3D scans of the models and geometrical measurements of the instrument trajectories were performed. RESULTS: The 3D scans of the 3D printed model showed a high fidelity when compared to the original computed tomographic scan image geometry (mean deviation of 1.26 ± 1.27mm). The instrument intrathoracic distance was 75 mm via the medial-second, 115 mm via the lateral-second, and 80 mm via the third intercostal space. The 3D angulation of the instrument to the incision was 33.77o, 55.93o, and 38.4o respectively. The distance of the instrument to the lateral margin was 12, 26, and 5 mm respectively. The cranial margin of the incision was always a limiting margin for the instrument. CONCLUSIONS: Three-dimensional printing and 3D scanning facilitated a realistic simulation of the instrument trajectory during RALT approach. The lateral-second intercostal approach showed the most favorable approach angle and distance from the lateral margin, although it also had the longest intrathoracic distance.

User-dependent variability in mitral valve segmentation and its impact on CFD-computed hemodynamic parameters.

PURPOSE: While novel tools for segmentation of the mitral valve are often based on automatic image processing, they mostly require manual interaction by a proficient user. Those segmentations are essential for numerical support of mitral valve treatment using computational fluid dynamics, where the reconstructed geometry is incorporated into a simulation domain. To quantify the uncertainty and reliability of hemodynamic simulations, it is crucial to examine the influence of user-dependent variability in valve segmentation. METHODS: Previously, the inter-user variability of landmarks in mitral valve segmentation was investigated. Here, the inter-user variability of geometric parameters of the mitral valve, projected orifice area (OA) and projected annulus area (AA), is investigated for 10 mitral valve geometries, each segmented by three users. Furthermore, the propagation of those variations into numerically calculated hemodynamics, i.e., the blood flow velocity, was investigated. RESULTS: Among the three geometric valve parameters, AA was least user-dependent. Almost all deviations to the mean were below 10%. Larger variations were observed for OA. Variations observed for the numerically calculated hemodynamics were in the same order of magnitude as those of geometric parameters. No correlation between variation of geometric parameters and variation of calculated hemodynamic parameters was found. CONCLUSION: Errors introduced due to the user-dependency were of the same size as the variations of calculated hemodynamics. The variation was thereby of the same scale as deviations in clinical measurements of blood flow velocity using Doppler echocardiography. Since no correlation between geometric and hemodynamic uncertainty was found, further investigation of the complex relationship between anatomy, leaflet shape and flow is necessary.

A Novel Technique for Transcatheter Aortic Valve Replacement in Pure Aortic Regurgitation.

Transcatheter aortic valve replacement (TAVR) in pure aortic regurgitation (AR) is challenging, because of the subsequent difficulty in anchoring the transcatheter valve in a noncalcified device landing zone (DLZ). Prestenting can help to prepare a stable DLZ for TAVR in pure AR and prevent valve migration. Here we report the first-in-human implantation of an uncovered stent into a noncalcified aortic valve as a prestenting strategy to prepare an easy DLZ for TAVR in pure AR. We consider this technique a useful novel tool to improve device success, at least as long as specific TAVR devices for pure AR are lacking.

Extraction of open-state mitral valve geometry from CT volumes.

PURPOSE: The importance of mitral valve therapies is rising due to an aging population. Visualization and quantification of the valve anatomy from image acquisitions is an essential component of surgical and interventional planning. The segmentation of the mitral valve from computed tomography (CT) acquisitions is challenging due to high variation in appearance and visibility across subjects. We present a novel semi-automatic approach to segment the open-state valve in 3D CT volumes that combines user-defined landmarks to an initial valve model which is automatically adapted to the image information, even if the image data provide only partial visibility of the valve. METHODS: Context information and automatic view initialization are derived from segmentation of the left heart lumina, which incorporates topological, shape and regional information. The valve model is initialized with user-defined landmarks in views generated from the context segmentation and then adapted to the image data in an active surface approach guided by landmarks derived from sheetness analysis. The resulting model is refined by user landmarks. RESULTS: For evaluation, three clinicians segmented the open valve in 10 CT volumes of patients with mitral valve insufficiency. Despite notable differences in landmark definition, the resulting valve meshes were overall similar in appearance, with a mean surface distance of [Formula: see text] mm. Each volume could be segmented in 5-22 min. CONCLUSIONS: Our approach enables an expert user to easily segment the open mitral valve in CT data, even when image noise or low contrast limits the visibility of the valve.

Towards Alternative Approaches for Coupling of a Soft Robotic Sleeve to the Heart.

Efficient coupling of soft robotic cardiac assist devices to the external surface of the heart is crucial to augment cardiac function and represents a hurdle to translation of this technology. In this work, we compare various fixation strategies for local and global coupling of a direct cardiac compression sleeve to the heart. For basal fixation, we find that a sutured Velcro band adheres the strongest to the epicardium. Next, we demonstrate that a mesh-based sleeve coupled to the myocardium improves function in an acute porcine heart failure model. Then, we analyze the biological integration of global interface material candidates (medical mesh and silicone) in a healthy and infarcted murine model and show that a mesh interface yields superior mechanical coupling via pull-off force, histology, and microcomputed tomography. These results can inform the design of a therapeutic approach where a mesh-based soft robotic DCC is implanted, allowed to biologically integrate with the epicardium, and actuated for active assistance at a later timepoint. This strategy may result in more efficient coupling of extracardiac sleeves to heart tissue, and lead to increased augmentation of heart function in end-stage heart failure patients.

A leaflet plication clip is an effective surgical template for mitral valve foldoplasty.

OBJECTIVES: During mitral valve repair using the foldoplasty technique, correct judgement of the necessary dimensions and orientation of the leaflet fold is a critical but challenging step that can affect the chances of successful repair. In this study, we investigated whether a leaflet plication clip can be used to guide suture foldoplasty for posterior leaflet prolapse of the mitral valve. METHODS: Complete posterior leaflet prolapse was created in both in vivo and ex vivo pig hearts by severing the chordae supporting the middle scallop. A plication clip was applied to perform leaflet foldoplasty. Sutures were then placed using the clip as a template and the clip was removed. Leaflet width after flail creation, clip application and suture placement was determined in an ex vivo test. In vivo repair and evaluation was then performed in 7 pigs to determine the repair efficacy under normal physiological loading, at 1 and 6 h after recovery from cardiopulmonary bypass. RESULTS: Leaflet width after suture placement was comparable to the clip alone (7.0 ± 1.4 vs 9.0 ± 1.6) and both were significantly less than the flail width 15.7± 2.5 mm. In vivo, average coaptation height following repair was restored to 4.7 ± 1.4 mm and 4.2 ± 1.3 mm at 1 and 6 h, respectively, after recovery compared with the baseline height of 5.5 ± 0.9 mm. Mitral regurgitation was reduced from moderate-severe to mild or less, and addition of a De-Vega annuloplasty in the last 3 animals abolished residual leaks to trivial or none. CONCLUSIONS: Application of the adjustable leaflet plication clip facilitated accurate determination of the correct position, width, height and orientation of the foldoplasty. Any necessary clip repositioning was made prior to the placement of sutures avoiding the need to redo the sutures. This approach could potentially help improve the ease and reproducibility of the foldoplasty repair.