Effective orifice diameter: a new sizing parameter of surgical valve prostheses to inform valve selection.

Background: The labeled sizes of surgical valve prostheses and their discordance with the physical internal valve orifice sizes has long been a controversy in the cardiac surgery community, leading many to believe it to be a contributing factor in prosthesis-patient mismatch following valvular replacement surgery. In an attempt to address this issue, the International Organization for Standardization (ISO) 5840-2:2021 standard for surgical valve prostheses recommends that a new sizing parameter, namely, the effective orifice diameter, be provided in labeling by all manufacturers as an indicator of the true flow-passing capacity of a prosthetic valve. Methods: The ISO Cardiac Valves Working Group conducted a multi-laboratory round-robin study to investigate whether the effective orifice diameter of a prosthetic surgical valve could be derived repeatably and reproducibly through steady forward-flow testing. A total of seven valve models, each with multiple sizes, were tested, including a mechanical heart valve and multiple biological heart valves. Results: The round-robin study confirmed that the steady forward-flow test had good intra-laboratory repeatability and inter-laboratory reproducibility in deriving the effective orifice diameters of surgical valve prostheses. On average, among the participating laboratories, the experimentally derived effective orifice diameter of a prosthetic heart valve was 3-12 mm smaller than its labeled size. Conclusions: The effective orifice diameter provides better characterization of the hydrodynamic characteristics of a surgical valve prosthesis and can be derived using a validated steady forward-flow test method. This new sizing parameter will soon be adopted by surgical valve manufacturers and provided in device labeling to inform valve selection by surgeons.

3D Characterization of the Aortic Valve and Aortic Arch in Bicuspid Aortic Valve Patients.

Patients with bicuspid aortic valve (BAV) commonly have associated aortic stenosis and aortopathy. The geometry of the aortic arch and BAV is not well defined quantitatively, which makes clinical classifications subjective or reliant on limited 2D measurements. The goal of this study was to characterize the 3D geometry of the aortic arch and BAV using objective and quantitative techniques. Pre-TAVR computed tomography angiogram (CTA) in patients with BAV and aortic stenosis (AS) were analyzed (n = 59) by assessing valve commissural angle, presence of a fused region, percent of fusion, and calcium volume. The ascending aorta and aortic arch were reconstructed from patient-specific imaging segmentation to generate a centerline and calculate maximum curvature and maximum area change for the ascending aorta and the descending aorta. Aortic valve commissural angle signified a bimodal distribution suggesting tricuspid-like (≤ 150°, 52.5% of patients) and bicuspid-like (> 150°, 47.5%) morphologies. Tricuspid like was further classified by partial (10.2%) or full (42.4%) fusion, and bicuspid like was further classified into valves with fused region (27.1%) or no fused region (20.3%). Qualitatively, the aortic arch was found to have complex patient-specific variations in its 3D shape with some showing extreme diameter changes and kinks. Quantitatively, subgroups were established using maximum curvature threshold of 0.04 and maximum area change of 30% independently for the ascending and descending aorta. These findings provide insight into the geometric structure of the aortic valve and aortic arch in patients presenting with BAV and AS where 3D characterization allows for quantitative classification of these complex anatomic structures.

Hemodynamics of the VenusP Valve System™-an in vitro study.

This study aims to evaluate the fluid dynamic characteristics of the VenusP Valve System™ under varying cardiac outputs in vitro. A thorough hemodynamic study of the valve under physiological cardiac conditions was conducted and served as an independent assessment of the performance of the valve. Flow fields downstream of the valve near the pulmonary bifurcation were quantitatively studied by two-dimensional Particle Image Velocimetry (PIV). The obtained flow field was analyzed for potential regions of flow stasis and recirculation, and elevated shear stress and turbulence. High-speed en face imaging capturing the leaflet motion provided data for leaflet kinematic modeling. The experimental conditions for PIV studies were in accordance with ISO 5840-1:2021 standard, and two valves with different lengths and different orientations were studied. Results show good hemodynamics performance for the tested valves according to ISO 5840 standard without significant regions of flow stasis. Observed shear stress values are all well below established hemolysis limits.

Sensitivity of Post-TAVR Hemodynamics to the Distal Aortic Arch Anatomy: A High-Fidelity CFD Study.

PURPOSE: Patient-specific simulations of transcatheter aortic valve (TAV) using computational fluid dynamics (CFD) often rely on assumptions regarding proximal and distal anatomy due to the limited availability of high-resolution imaging away from the TAV site and the primary research focus being near the TAV. However, the influence of these anatomical assumptions on computational efficiency and resulting flow characteristics remains uncertain. This study aimed to investigate the impact of different distal aortic arch anatomies-some of them commonly used in literature-on flow and hemodynamics in the vicinity of the TAV using large eddy simulations (LES). METHODS: Three aortic root anatomical configurations with four representative distal aortic arch types were considered in this study. The arch types included a 90-degree bend, an idealized distal aortic arch anatomy, a clipped version of the idealized distal aortic arch, and an anatomy extruded along the normal of segmented anatomical boundary. Hemodynamic parameters both instantaneous and time-averaged such as Wall Shear Stress (WSS), and Oscillatory Shear Index (OSI) were derived and compared from high-fidelity CFD data. RESULTS: While there were minor differences in flow and hemodynamics across the configurations examined, they were generally not significant within our region of interest i.e., the aortic root. The choice of extension type had a modest impact on TAV hemodynamics, especially in the vicinity of the TAV with variations observed in local flow patterns and parameters near the TAV. However, these differences were not substantial enough to cause significant deviations in the overall flow and hemodynamic characteristics. CONCLUSIONS: The results suggest that under the given configuration and boundary conditions, the type of outflow extension had a modest impact on hemodynamics proximal to the TAV. The findings contribute to a better understanding of flow dynamics in TAV configurations, providing insights for future studies in TAV-related experiments as well as numerical simulations. Additionally, they help mitigate the uncertainties associated with patient-specific geometries, offering increased flexibility in computational modeling.

Effect of Ascending Aortic Curvature on Flow in the Sinus and Neo-sinus Following TAVR: A Patient-Specific Study.

Patient-specific aortic geometry and its influence on the flow in the vicinity of Transcatheter Aortic Valve (TAV) has been highlighted in numerous studies using both in silico and in vitro experiments. However, there has not yet been a detailed Particle Image Velocimetry (PIV) experiment conducted to quantify the relationship between the geometry, flow downstream of TAV, and the flow in the sinus and the neo-sinus. We tested six different patient-specific aorta models with a 26-mm SAPIEN 3 valve (Edwards Lifesciences, Irvine, CA, USA) in a left heart simulator with coronary flow. Velocities in all three cusps and circulation downstream of TAV were computed to evaluate the influence of the ascending aorta curvature on the flow field. The in vitro analysis showed that the patient-specific aortic curvature had positive correlation to the circulation in the ascending aorta (p = 0.036) and circulation had negative correlation to the particle washout time in the cusps (p = 0.011). These results showed that distinct vortical flow patterns in the ascending aorta as the main jet impinges on the aortic wall causes a recirculation region that facilitates the flow back into the sinus and the neo-sinus, thus reducing the risk of flow stagnation and washout time.

Effect of leaflet laceration on transcatheter aortic valve replacement fluid mechanics and comparison with surgical aortic valve replacement.

BACKGROUND: Leaflet thrombosis after surgical aortic valve replacement (SAVR) and transcatheter aortic valve replacement (TAVR) may be caused by blood flow stagnation in the native and neosinus regions. To date, aortic leaflet laceration has been used to mitigate coronary obstruction following TAVR; however, its influence on the fluid mechanics of the native and neosinus regions is poorly understood. This in vitro study compared the flow velocities and flow patterns in the setting of SAVR vs TAVR with and without aortic leaflet lacerations. METHODS: Two valves, (23-mm Perimount and 26-mm SAPIEN 3; Edwards Lifesciences) were studied in a validated mock flow loop under physiologic conditions. Neosinus and native sinus fluid mechanics were quantified using particle image velocimetry in the left and noncoronary cusp, with an increasing number of aortic leaflets lacerated or removed. RESULTS: Across all conditions, SAVR had the highest average sinus and neosinus velocities, and this value was used as a reference to compare against the TAVR conditions. With an increasing number of leaflets lacerated or removed with TAVR, the average sinus and neosinus velocities increased from 25% to 70% of SAVR flow (100%). Diastolic velocities were substantially augmented by leaflet laceration. Also, the shorter frame of the SAVR led to higher flow velocities compared with the longer frame of the TAVR, even after complete leaflet removal. CONCLUSIONS: Leaflet laceration augmented TAVR native and neosinus flow fields, approaching that of SAVR. These findings may have potential clinical implications for the use of single or multiple leaflet lacerations to reduce leaflet thrombosis and thus potentially improve TAVR durability.

Percutaneous Cavopulmonary Assist: From Design to 96 Hour Survival in Lethal Cavopulmonary Failure Sheep.

We are developing a clinically practical percutaneous double lumen cannula (DLC)-based cavopulmonary assist (CPA) system to support failing Fontan patients. In this study, our CPA DLC was redesigned for even blood flow, minimal recirculation, and easy insertion/deployment. After bench testing, this new CPA system was evaluated for 4 hours (n = 10) and 96 hours (n = 5) in our clinically relevant lethal cavopulmonary failure (CPF) sheep model for ease of cannulation/deployment, reversal of CPF hemodynamics/end-organ hypoperfusion, and durability/biocompatibility. Cavopulmonary failure was achieved in all sheep. All DLCs were successfully inserted/deployed into Fontan anatomy. Cavopulmonary assist reversed CPF with normalized central venous pressure and cardiac output. All survival sheep were ambulatory with normal eating/drinking. One sheep was euthanized after 6 hours from cannula kinking, and one sheep died of hypokalemia after 8 hours. Three sheep survived 96 hours with normal hemodynamics. Free hemoglobin was only 3.7 ± 1.2 mg/dl at 96 hours, indicating negligible hemolysis. Creatinine, blood urea nitrogen, and lactate increased from hypoperfusion but normalized by 72 hours CPA. Necropsy showed only a small, immobilized thrombus ring at umbrella attachment to DLC. Our DLC-based system provided total ambulatory CPA in a lethal CPF sheep model with 96 hour survival and complete reversal of hemodynamics and end-organ hypoperfusion.

Transcatheter Hepatic Conduit-Azygous Vein Connection Reduces Pulmonary Arteriovenous Malformations in a Cyanotic Fontan Patient.

The authors report a closed-chest, transcatheter large-vessel connection (hepatic conduit to azygous vein) to reverse pulmonary arteriovenous malformations in a 10-year-old patient after Fontan for heterotaxy/interrupted inferior vena cava, with an increase in oxygen saturation from 78% to 96%. Computational fluid dynamics estimated a 14-fold increase in hepatic blood flow to the left pulmonary artery (from 1.3% to 14%). (Level of Difficulty: Advanced.).

Effect of Native Aortic Leaflet Geometry Modification on Transcatheter Aortic Valve Neo-sinus and Aortic Sinus Flow: An In-vitro Study.

PURPOSE: Leaflet thrombosis is a potentially fatal complication after transcatheter aortic valve replacement (TAVR). Blood flow stagnation in the neo-sinus and aortic sinuses are associated with increased thrombus severity. Native aortic leaflet modification may be a potential strategy to improve the neo-sinus and aortic sinus fluid dynamics. However, limited data exist on the effect of leaflet geometry modification on the flow within the neo-sinus and aortic sinus regions. We evaluate the effect of aortic leaflet modification on the neo-sinus and aortic sinus flow stagnation after simulated TAVR. METHODS: Particle image velocimetry measurements were performed under nominal (5 LPM) and low (2.5 LPM) cardiac output conditions for an intact leaflet (control) case, and 3 modified leaflet geometries. Aortic leaflet geometry modification via leaflet splay was simulated with increasing splay geometry (leaflet splay distance: 5 mm-narrow, 10 mm-medium, and 20 mm-wide). RESULTS: Leaflet geometry modification influenced flow features throughout the cardiac cycle, at both cardiac outputs, and allowed for flow communication between the neo-sinus and aortic sinus regions compared to the control. In the aortic sinus, flow stagnation reduced by over 64% at 5LPM, and over 36% at 2.5LPM for all simulated modified leaflet geometries compared to the control. However, only the medium and wide splay geometries enabled a reduction in neo-sinus flow stagnation compared to the control case. CONCLUSIONS: These findings suggest that aortic leaflet geometry modification (of at least 10 mm leaflet splay distance) may reduce flow stasis and potentially decrease valve thrombosis risk.

HIF1A inhibitor PX-478 reduces pathological stretch-induced calcification and collagen turnover in aortic valve.

HIF1A is significantly upregulated in calcified human aortic valves (AVs). Furthermore, HIF1A inhibitor PX-478 was shown to inhibit AV calcification under static and disturbed flow conditions. Since elevated stretch is one of the major mechanical stimuli for AV calcification, we investigated the effect of PX-478 on AV calcification and collagen turnover under a pathophysiological cyclic stretch (15%) condition. Porcine aortic valve (PAV) leaflets were cyclically (1 Hz) stretched at 15% for 24 days in osteogenic medium with or without PX-478. In addition, PAV leaflets were cyclically stretched at a physiological (10%) and 15% for 3 days in regular medium to assess its effect of on HIF1A mRNA expression. It was found that 100 µM (high concentration) PX-478 could significantly inhibit PAV calcification under 15% stretch, whereas 50 µM (moderate concentration) PX-478 showed a modest inhibitory effect on PAV calcification. Nonetheless, 50 µM PX-478 significantly reduced PAV collagen turnover under 15% stretch. Surprisingly, it was observed that cyclic stretch (15% vs. 10%) did not have any significant effect on HIF1A mRNA expression in PAV leaflets. These results suggest that HIF1A inhibitor PX-478 may impart its anti-calcific and anti-matrix remodeling effect in a stretch-independent manner.

Early outcomes following transatrial transcatheter mitral valve replacement in patients with severe mitral annular calcification.

OBJECTIVE: Implantation of a transcatheter valve-in-mitral annular calcification (ViMAC) has emerged as an alternative to traditional surgical mitral valve (MV) replacement. Previous studies evaluating ViMAC aggregated transseptal, transapical, and transatrial forms of the procedure, leaving uncertainty about each technique's advantages and disadvantages. Thus, we sought to evaluate clinical outcomes specifically for transatrial ViMAC from the largest multicenter registry to-date. METHODS: Patients with symptomatic MV dysfunction and severe MAC who underwent ViMAC were enrolled from 12 centers across the United States and Europe. Clinical characteristics, procedural details, and clinical outcomes were abstracted from the electronic record. The primary end point was all-cause mortality. RESULTS: We analyzed 126 patients who underwent ViMAC (median age 76 years [interquartile range {IQR}, 70-82 years], 28.6% female, median Society of Thoracic Surgeons score 6.8% [IQR, 4.0-11.4], and median follow-up 89 days [IQR, 16-383.5]). Sixty-one (48.4%) had isolated mitral stenosis, 25 (19.8%) had isolated mitral regurgitation (MR), and 40 (31.7%) had mixed MV disease. Technical success was achieved in 119 (94.4%) patients. Thirty (23.8%) patients underwent concurrent septal myectomy, and 8 (6.3%) patients experienced left ventricular outflow tract obstruction (7/8 did not undergo myectomy). Five (4.2%) patients of 118 with postprocedure echocardiograms had greater than mild paravalvular leak. Thirty-day and 1-year all-cause mortality occurred in 16 and 33 patients, respectively. In multivariable models, moderate or greater MR at baseline was associated with increased risk of 1-year mortality (hazard ratio, 2.31; 95% confidence interval, 1.07-4.99, P = .03). CONCLUSIONS: Transatrial ViMAC is safe and feasible in this selected, male-predominant cohort. Patients with significant MR may derive less benefit from ViMAC than patients with mitral stenosis only.

Long-term durability of a new surgical aortic valve: A 1 billion cycle in vitro study.

Background: This study assessed the long-term hemodynamic functional performance of the new Inspiris Resilia aortic valve after accelerated wear testing (AWT). Methods: Three 21-mm and 23-mm Inspiris valves were used for the AWT procedure. After 1 billion cycles (equivalent to 25 years), the valves' hemodynamic performance was compared with that of the corresponding zero-cycled condition. Next, 1 AWT cycled valve of each valve size was selected at random for particle image velocimetry (PIV) and leaflet kinematic tests, and the data were compared with data for an uncycled Inspiris Resilia aortic valve of the same size. PIV was used to quantitatively evaluate flow fields downstream of the valve. Valves were tested according to International Standards Organization 5840-2:2015 protocols. Results: The 21-mm and 23-mm valves met the International Organization for Standardization (ISO) durability performance requirements to 1 billion cycles. The mean effective orifice areas for the 21-mm and 23-mm zero-cycled and 1 billion-cycled valves were 1.89 ± 0.02 cm2 and 1.94 ± 0.01 cm2, respectively (P < .05) and 2.3 ± 0.13 cm2 and 2.40 ± 0.11 cm2, respectively (P < .05). Flow characterization of the control valves and the study valves demonstrated similar flow characteristics. The velocity and shear stress fields were also similar in the control and study valves. Conclusions: The Inspiris Resilia aortic valve demonstrated very good durability and hemodynamic performance after an equivalent of 25 years of simulated in vitro accelerated wear. The study valves exceeded 1 billion cycles of simulated wear, 5 times longer than the standard requirement for a tissue valve as stipulated in ISO 5840-2:2015.

Gradient and pressure recovery of a self-expandable transcatheter aortic valve depends on ascending aorta size: In vitro study.

Objective: In this study we aimed to understand the role of interaction of the Medtronic Evolut R transcatheter aortic valve with the ascending aorta (AA) by evaluating the performance of the valve and the pressure recovery in different AA diameters with the same aortic annulus size. Methods: A 26-mm Medtronic Evolut R valve was tested using a left heart simulator in aortic root models of different AA diameter (D): small (D = 23 mm), medium (D = 28 mm), and large (D = 34 mm) under physiological conditions. Measurements of pressure from upstream to downstream of the valve were performed using a catheter at small intervals to comprehensively assess pressure gradient and pressure recovery. Results: In the small AA, the measured peak and mean pressure gradient at vena contracta were 11.5 ± 0.5 mm Hg and 7.8 ± 0.4 mm Hg, respectively, which was higher (P < .01) compared with the medium (8.1 ± 0.4 mm Hg and 5.2 ± 0.4 mm Hg) and large AAs (7.4 ± 1.0 mm Hg and 5.4 ± 0.6 mm Hg). The net pressure gradient was lower for the case with the medium AA (4.1 ± 1.2 mm Hg) compared with the small AA (4.7 ± 0.8 mm Hg) and large AA (6.1 ± 1.4 mm Hg; P < .01). Conclusions: We have shown that small and large AAs can increase net pressure gradient, because of the direct interaction of the Medtronic Evolut R stent with the AA (in small AA) and introducing higher level of turbulence (in large AA). AA size might need to be considered in the selection of an appropriate device for transcatheter aortic valve replacement.

Assessing the Hemodynamic Impact of Anterior Leaflet Laceration in Transcatheter Mitral Valve Replacement: An in silico Study.

Background: A clinical study comparing the hemodynamic outcomes of transcatheter mitral valve replacement (TMVR) with vs. without Laceration of the Anterior Mitral leaflet to Prevent Outflow Obstruction (LAMPOON) has never been designed nor conducted. Aims: To quantify the hemodynamic impact of LAMPOON in TMVR using patient-specific computational (in silico) models. Materials: Eight subjects from the LAMPOON investigational device exemption trial were included who had acceptable computed tomography (CT) data for analysis. All subjects were anticipated to be at prohibitive risk of left ventricular outflow tract (LVOT) obstruction from TMVR, and underwent successful LAMPOON immediately followed by TMVR. Using post-procedure CT scans, two 3D anatomical models were created for each subject: (1) TMVR with LAMPOON (performed procedure), and (2) TMVR without LAMPOON (virtual control). A validated computational fluid dynamics (CFD) paradigm was then used to simulate the hemodynamic outcomes for each condition. Results: LAMPOON exposed on average 2 ± 0.6 transcatheter valve cells (70 ± 20 mm2 total increase in outflow area) which provided an additional pathway for flow into the LVOT. As compared to TMVR without LAMPOON, TMVR with LAMPOON resulted in lower peak LVOT velocity, lower peak LVOT gradient, and higher peak LVOT effective orifice area by 0.4 ± 0.3 m/s (14 ± 7% improvement, p = 0.006), 7.6 ± 10.9 mmHg (31 ± 17% improvement, p = 0.01), and 0.2 ± 0.1 cm2 (17 ± 9% improvement, p = 0.002), respectively. Conclusion: This was the first study to permit a quantitative, patient-specific comparison of LVOT hemodynamics following TMVR with and without LAMPOON. The LAMPOON procedure achieved a critical increment in outflow area which was effective for improving LVOT hemodynamics, particularly for subjects with a small neo-left ventricular outflow tract (neo-LVOT).

Bioprosthetic Aortic Valve Hemodynamics: Definitions, Outcomes, and Evidence Gaps: JACC State-of-the-Art Review.

A virtual workshop was organized by the Heart Valve Collaboratory to identify areas of expert consensus, areas of disagreement, and evidence gaps related to bioprosthetic aortic valve hemodynamics. Impaired functional performance of bioprosthetic aortic valve replacement is associated with adverse patient outcomes; however, this assessment is complicated by the lack of standardization for labelling, definitions, and measurement techniques, both after surgical and transcatheter valve replacement. Echocardiography remains the standard assessment methodology because of its ease of performance, widespread availability, ability to do serial measurements over time, and correlation with outcomes. Management of a high gradient after replacement requires integration of the patient's clinical status, physical examination, and multimodality imaging in addition to shared patient decisions regarding treatment options. Future priorities that are underway include efforts to standardize prosthesis sizing and labelling for both surgical and transcatheter valves as well as trials to characterize the consequences of adverse hemodynamics.

Clinical Impact of Computational Heart Valve Models.

This paper provides a review of engineering applications and computational methods used to analyze the dynamics of heart valve closures in healthy and diseased states. Computational methods are a cost-effective tool that can be used to evaluate the flow parameters of heart valves. Valve repair and replacement have long-term stability and biocompatibility issues, highlighting the need for a more robust method for resolving valvular disease. For example, while fluid-structure interaction analyses are still scarcely utilized to study aortic valves, computational fluid dynamics is used to assess the effect of different aortic valve morphologies on velocity profiles, flow patterns, helicity, wall shear stress, and oscillatory shear index in the thoracic aorta. It has been analyzed that computational flow dynamic analyses can be integrated with other methods to create a superior, more compatible method of understanding risk and compatibility.

Fontan Geometry and Hemodynamics Are Associated With Quality of Life in Adolescents and Young Adults.

BACKGROUND: Despite favorable short-term outcomes, Fontan palliation is associated with comorbidities and diminished quality of life (QOL) in the years after completion. We hypothesized that poor Fontan hemodynamics and ventricular function are associated with worse QOL. METHODS: This was a single-center study of Fontan survivors aged more than 12 years. Subjects completed a cardiac magnetic resonance scan and QOL questionnaire. Cardiac magnetic resonance-derived variables included Fontan geometry, and hemodynamics. Computational fluid dynamics simulations quantified power loss, pressure drop, and total cavopulmonary connection resistance across the Fontan. Quality of life was assessed by completion of the Pediatric Quality of Life Inventory. Longitudinal and cross-sectional comparisons were made between cardiac magnetic resonance and computational fluid dynamics parameters with patient-reported QOL. RESULTS: We studied 77 Fontan patients, median age 19.7 years (interquartile range, 17.1 to 23.6), median time from Fontan completion 16 years (interquartile range, 13 to 20). Longitudinal data were available for 48 patients; median time between cardiac magnetic resonance and QOL was 8.1 years (interquartile range, 7 to 9.4). Median patient-reported Pediatric Quality of Life Inventory total score was 80 (interquartile range, 67.4 to 88). Greater power loss and smaller left pulmonary artery diameter at baseline were associated with worse QOL at follow-up. Greater pressure drop was associated with worse QOL at the same time point. CONCLUSIONS: For Fontan survivors, measures of computational fluid dynamics hemodynamics and geometry are associated with worse QOL. Interventional strategies targeted at optimizing the Fontan may improve QOL.

Impact of Anchor Location on Mitral Neochordae Forces: An In Vitro Study.

PURPOSE: This study examined changes in force distribution between the neochordae corresponding to different ventricular anchor locations. DESCRIPTION: Seven porcine mitral valves were mounted in a left heart simulator. Neochordae (expanded polytetrafluoroethylene) originated from either a simulated left ventricular apex, papillary muscle base, or papillary muscle tip location. The neochordae were attached at three sites along the P2 leaflet segment: P2Lateral; P2Center, and P2Medial. Mitral regurgitation was induced by cutting posterior leaflet P2 marginal chordae. The forces on each neochord required to restore normal mitral valve coaptation were quantified for different ventricular anchoring origins and leaflet insertion sites. EVALUATION: The results showed that under both normotensive and hypertensive conditions, the force exerted was much higher at P2Center than either P2Lateral or P2Medial, independent of ventricular anchor location. Also, forces on both P2Lateral and P2Medial were not statistically different. CONCLUSIONS: Artificial neochordae treatment for all anchoring locations was effective in correcting induced mitral regurgitation. The P2 central neochordae had a significantly higher force than both lateral neochords under all conditions.

The role of flow stasis in transcatheter aortic valve leaflet thrombosis.

OBJECTIVE: With the recent expanded indication for transcatheter aortic valve replacement to low-risk surgical patients, thrombus formation in the neosinus is of particular interest due to concerns of reduced leaflet motion and long-term transcatheter heart valve durability. Although flow stasis likely plays a role, a direct connection between neosinus flow stasis and thrombus severity is yet to be established. METHODS: Patients (n = 23) were selected to minimize potential confounding factors related to thrombus formation. Patient-specific 3-dimensional reconstructed in vitro models were created to replicate in vivo anatomy and valve deployment using the patient-specific cardiac output and idealized coronary flows. Dye was injected into each neosinus to quantify washout time as a measure of flow stasis. RESULTS: Flow stasis (washout time) showed a significant, positive correlation with thrombus volume in the neosinus (rho = 0.621, P < .0001). Neither thrombus volume nor washout time was significantly different in the left, right, and noncoronary neosinuses (P ≥ .54). CONCLUSIONS: This is the first patient-specific study correlating flow stasis with thrombus volume in the neosinus post-transcatheter aortic valve replacement across multiple valve types and sizes. Neosinus-specific factors create hemodynamic and thrombotic variability within individual patients. Measurement of neosinus flow stasis may guide strategies to improve outcomes in transcatheter aortic valve replacement.