Transvalvular Pressure Research Articles

Stentless Versus Stented Aortic Valve Replacement for Aortic Stenosis

BackgroundThe differences in long-term outcomes of aortic valve replacement for aortic stenosis between stentless and stented bioprostheses are controversial. MethodsBetween 2007 and 2018, 1173 patients underwent aortic valve replacement for aortic stenosis, including 559 treated with a stentless valve and 614 with a stented valve. A propensity score matched cohort with 348 pairs was generated by matching for age, sex, body surface area, bicuspid aortic valve, chronic lung disease, previous cardiac surgery, coronary artery disease, renal failure on dialysis, valve size, concomitant procedures, and surgeon. The primary endpoints of the study were long-term survival and incidence of reoperation. ResultsImmediate postoperative outcomes were similar between the stentless and stented groups with an overall operative mortality of 2.9% (P = .19). Kaplan-Meier estimation for long-term survival was comparable between the stentless and stented valves in both the whole cohort and the propensity score matched cohort (10-year survival 59% vs 55%, P = .20). The hazard ratio of stentless vs stented valve for risk of long-term mortality was 1.12 (P = .33). The 10-year cumulative incidence of reoperation due to valve degeneration was 5.5% in the stentless group and 4.7% in the stented group (P = .25). The transvalvular pressure gradient at 5-year follow-up was significantly lower in the stentless group (7 vs 11 mm Hg, P < .001). ConclusionsBoth stented and stentless valves could be used in aortic valve replacement for aortic stenosis. We recommend stented valves for aortic valve replacement in patients with aortic stenosis for their simplicity of implantation.

Sutureless Valve in Bicuspid Aortic Stenosis: Modified Technique and Midterm Outcome.

The sutureless valve has gained popularity for degenerative aortic valve stenosis but not congenital bicuspid aortic valve (BAV) due to anatomical challenges. We reviewed our modified implant techniques for patients with BAV. From June 2015 to June 2019, 66 patients with aortic valve stenosis were treated with the Perceval sutureless valve, 20 of whom had BAV. The demographics, type of BAV (the Sievers classification), and associated pathologies, surgical outcomes, and midterm hemodynamics were recorded. The median age was 64 (range: 49-81) years and the Society of Thoracic Surgeons score was 2.186 (range: 0.407-6.384). Annular plication was performed in 9 (75%) of 12 type 0 and 3 (37.5%) of 8 type I, with implanted valve sizes of M, L, and XL in 6, 10, 4 cases, respectively. Three patients, all type 0 in the initial learning periods, required intraoperative redeployment due to malposition of the valve. The final implant was successful in all without conversion to traditional prosthesis. The median extubation time was 4 hours and the durations of intensive care unit and hospital stay were 1 and 6 days. At a median follow-up of 46 (23-72) months, there was one late mortality due to hemorrhagic stroke sequel. The last echo revealed none had more than mild paravalvular leakage and the mean transvalvular pressure gradient remained stable at 9.70 (range: 6.94-15.0) mm Hg. The sutureless valve can achieve satisfactory outcomes in BAV without paravalvular leakage and excellent hemodynamics. It may serve as the benchmark for transcatheter aortic valve implantation in this unique population.

Hemodynamic performance of INSPIRIS RESILIA aortic bioprosthesis for severe aortic stenosis: 2-year follow-up in Japanese cohort.

The INSPIRIS RESILIA aortic bioprosthesis (Edwards Lifesciences LLC, Irvine, USA) was fixed in novel tissue preservation technology to ensure long-term durability. Hemodynamic performance after aortic valve replacement (AVR) for severe aortic stenosis (AS) has not been published in the Japanese cohort. Twenty-nine patients underwent AVR with INSPIRIS RESILIA bioprosthesis for severe AS between November 1, 2018 and December 31, 2020. The mean age was 75.1 ± 4.5years with 19 female patients. Body surface area was 1.58 ± 0.19 m2 and New York Heart Association functional class was 2.2 ± 0.5. Hemodynamic performance was assessed using follow-up transthoracic echocardiographic data collected at 3-6months, 1year and 2years. The mean follow-up time was 19.2 ± 7.2months, with a 100% follow-up rate. One patient died of postoperative heart failure. The preoperative mean and peak transvalvular pressure gradients (PGs) were 51.9 ± 18.4mmHg and 89.3 ± 34.9mmHg, respectively, and effective orifice area 0.72 ± 0.26 cm2. They improved at 10.2 ± 3.5mmHg (p < 0.0001), 19.3 ± 6.6mmHg (p < 0.0001) and 1.73 ± 0.47cm2 (p < 0.0001) at discharge. The mean transvalvular PG at 3-6months (n = 24), 1year (n = 25) and 2years (n = 15) was 11.2 ± 3.8mmHg (p < 0.0001), 11.1 ± 3.2mmHg (p < 0.0001) and 11.2 ± 3.3mmHg (p < 0.0001), respectively. Left ventricular mass index decreased from 123.0 ± 35.0g/m2 before surgery to 113.4 ± 35.0g/m2 (p = 0.0133) at discharge. It has dropped to 88.0 ± 25.0g/m2 (p = 0.0007) at 2years. Constrictive pericarditis caused heart failure in one patient. INSPIRIS RESILIA bioprosthesis showed improved hemodynamic performance in the early postoperative phase. There were fewer valve-related events observed.

Impact of severe mitral annular calcification on mitral regurgitation after transcatheter aortic valve implantation

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Transcatheter aortic valve implantation (TAVI) has become the standard of care treatment in patients with severe aortic stenosis who are at intermediate or high risk for surgical aortic valve replacement. Mitral annular calcification (MAC) is frequent in patients with aortic stenosis, and its presence is associated with increased cardiovascular morbidity and mortality. Not infrequently, it is associated with significant morphologic and functional abnormalities of the mitral valve apparatus. Purpose The aim of this work is to evaluate the relationship between severe MAC and the presence and development of significant mitral regurgitation after TAVI. Methods We retrospectively analyzed all patients who underwent TAVI at a tertiary center from October 2014 to November 2019. Clinical, echocardiographic and procedure-related data were collected until a follow-up of 6 months. Statistical analysis was conducted on IBM SPSS® Statistics software. Descriptive statistics were calculated for all variables. Sample T-test, Chi-square and Wilcoxon sign test were used. A p-value &amp;lt; 0.05 was considered significant. The presence and severity of MAC was defined according to echocardiographic data. Severe MAC was defined by the presence of calcification of more than half of the mitral annular circumference. Results A total of 343 patients were enrolled in the study. The mean age of the population was 80 ± 8 years, 45% were male. Mean functional area was 0.75 ± 0.18 cm2, mean transvalvular pressure gradient was 48 ± 15 mmHg and the mean left ventricular ejection fraction (LVEF) was 54 ± 14%. MAC was detected in 231 (67%) patients. In 44 (19%) of these patients, MAC was graded as severe. Patients with severe MAC tended to have higher prevalence of moderate (27.3 vs 20.4%, p = 0.30) as well as severe (4.5 vs 1.8%, p = 0.24) mitral regurgitation at baseline. After TAVI, the prevalence of moderate mitral regurgitation at 6 months was similar between both groups (22.5 vs 20.4%, p = 0.76). Although not reaching statistical significance, patients with severe MAC had higher prevalence of severe mitral regurgitation at 6 months post-procedure (12.2 VS 5.0%, p = 0.07) as well as higher incidence of worsening of mitral regurgitation (34.2 vs 23.7%, p = 0.16). The proportion of patients that had improvement (13.2 vs 15.0%, p = 0.76) or no change (52.6 vs 61.3%, p = 0.31) in the degree of mitral regurgitation was similar in both groups. Conclusion The presence of severe MAC at baseline echocardiography in patients undergoing TAVI may be associated with worsening of mitral regurgitation after the procedure. These patients tend to have higher prevalence of severe mitral regurgitation post-TAVI. Further studies are needed in order to further elucidate this association.

In silico modelling of aortic valve implants – predicting in vitro performance using finite element analysis

The competing structural and hemodynamic considerations in valve design generally require a large amount of in vitro hydrodynamic and durability testing during development, often resulting in inefficient “trial-and-error” prototyping. While in silico modelling through finite element analysis (FEA) has been widely used to inform valve design by optimising structural performance, few studies have exploited the potential insight FEA could provide into critical hemodynamic performance characteristics of the valve. The objective of this study is to demonstrate the potential of FEA to predict the hydrodynamic performance of tri-leaflet aortic valve implants obtained during development through in vitro testing. Several variations of tri-leaflet aortic valves were designed and manufactured using a synthetic polymer and hydrodynamic testing carried out using a pulsatile flow rig according to ISO 5840, with bulk hydrodynamic parameters measured. In silico models were developed in tandem and suitable surrogate measures were investigated as predictors of the hydrodynamic parameters. Through regression analysis, the in silico parameters of leaflet coaptation area, geometric orifice area and opening pressure were found to be suitable indicators of experimental in vitro hydrodynamic parameters: regurgitant fraction, effective orifice area and transvalvular pressure drop performance, respectively.

Different measurements require different benchmarks: One size does not fit all

Key Points Echocardiographic Doppler measurements do not account for the pressure recovery phenomenon and therefore estimate higher transvalvular pressure gradients (TPG) than invasive catheter‐based measurements. An observed 3‐4 mmHg mean TPG difference between self‐expanding and balloon‐expandable transcatheter valves has been observed consistently, but no clinical significance has been reported. A necessary novel classification system must provide a range of normal and abnormal values for each measurement modality and each valve type.

Low-Gradient Aortic Stenosis; the Diagnostic Dilemma.

ABSTRACTLow-gradient (LG) aortic valve stenosis (AS) constitutes a significant subset among patients with severe aortic stenosis. This entity represents one of the most challenging heart conditions when it comes to diagnosis and management, mainly because of the discrepancy between the small aortic valve area (≤1.0 cm2) that is considered a severe AS, and low mean transvalvular pressure gradient (<40 mmHg), which is one of the criteria for nonsevere AS. LG AS is divided according to transvalvular aortic flow rate into normal-flow LG AS and low-flow LG (LFLG) AS; the latter category can be divided further according to left ventricular ejection fraction (LVEF) into classical LFLG AS if LVEF is depressed or paradoxical LFLG AS if LVEF is preserved. The primary diagnostic challenge in patients with LG AS is to confirm that AS is truly severe and not pseudosevere, which is assessed mainly by either dobutamine stress echocardiography or multidetector computed tomography. The management of symptomatic true severe LG AS is mainly by aortic valve replacement (AVR), whether surgical or transcatheter approach. Patients with LG severe AS have a generally worse prognosis and higher mortality compared with patients with high-gradient severe AS. Despite the survival benefit of AVR in patients with true severe LG AS, these patients have higher surgical risk post-AVR compared with high-gradient AS patients. Early recognition and correct diagnosis of a patient with LG AS is crucial to improve their mortality and morbidity.

Fluid-structure interaction simulation of calcified aortic valve stenosis.

Calcified aortic valve stenosis (CAVS) is caused by calcium buildup and tissue thickening that impede the blood flow from left ventricle (LV) to aorta. In recent years, CAVS has become one of the most common cardiovascular diseases. Therefore, it is necessary to study the mechanics of aortic valve (AV) caused by calcification. In this paper, based on a previous idealized AV model, the hybrid immersed boundary/finite element method (IB/FE) is used to study AV dynamics and hemodynamic performance under normal and calcified conditions. The computational CAVS model is realized by dividing the AV leaflets into a calcified region and a healthy region, and each is described by a specific constitutive equation. Our results show that calcification can significantly affect AV dynamics. For example, the elasticity and mobility of the leaflets decrease due to calcification, leading to a smaller opening area with a high forward jet flow across the valve. The calcified valve also experiences an increase in local stress and strain. The increased loading due to AV stenosis further leads to a significant increase in left ventricular energy loss and transvalvular pressure gradients. The model predicted hemodynamic parameters are in general consistent with the risk classification of AV stenosis in the clinic. Therefore, mathematical models of AV with calcification have the potential to deepen our understanding of AV stenosis-induced ventricular dysfunction and facilitate the development of computational engineering-assisted medical diagnosis in AV related diseases.

Pericardial Versus Porcine Valves for Surgical Aortic Valve Replacement.

There still are controversies on which type between bovine pericardial and porcine valves is superior in the setting of aortic valve replacement (AVR). This study aims to compare clinical outcomes of AVR using between pericardial or porcine valves. The study involved consecutive 636 patients underwent isolated AVR using stented bioprosthetic valves between January 2000 and May 2016. Of these, pericardial and porcine valves were implanted in 410 (pericardial group) and 226 patients (porcine group), respectively. Clinical outcomes including survival, structural valve deterioration (SVD) and trans-valvular pressure gradient were compared between the groups. To adjust for potential selection bias, inverse probability treatment weighting (IPTW) was conducted. The mean follow-up duration was 60.1±50.2 months. There were no significant differences in the rates of early mortality (3.1% vs. 3.1%; p=0.81) and SVD (0.3%/patient-year [PY] vs. 0.5%/PY; p=0.33) between groups. After adjustment using IPTW, however, landmark mortality analyses showed a significantly lower late (>8 years) mortality risk in pericardial group over porcine group (hazard ratio [HR], 0.61; 95% confidence interval, [CI] 0.41-0.90; p=0.01) while the risks of SVD were not significantly difference between groups (HR, 0.45; 95% CI, 0.12-1.70; p=0.24). Mean pressure gradient across prosthetic AV was lower in the Pericardial group than the Porcine group at both immediate postoperative point and latest follow-up (p values <0.001). In patients undergoing bioprosthetic surgical AVR, bovine pericardial valves showed superior results in terms of postoperative hemodynamic profiles and late survival rates over porcine valves.

Evolving Solutions in the Surgical Treatment of Isolated Pulmonary Valve Stenosis

Background: Surgical treatment of isolated pulmonary valve stenosis in infants and children has evolved over the years, shifting from the original exclusive aim at lowering right ventricle pressure to the current concomitant focus on preserving pulmonary valve function. In our study, we sought to analyze the effect of such evolving philosophy on long-term results. Methods: All consecutive patients treated in our center between July 1983 and March 2019 were included. Patients were categorized into 2 groups based on the introduction into treatment practice of sparing valve techniques (1995). Actuarial survival, freedom from reintervention on the right outflow tract, transvalvular mean pressure gradient decrease, and pulmonary valve function at follow-up were analyzed. Results: One hundred twenty-three patients operated before (Group I, n=81) or since (Group II, n=42) 1995 were enrolled in the study. Mean age and weight were 3.0 ± 0.36 years and 16.6 ± 1.7kg, respectively. Early mortality occurred exclusively in 3 patients of Group 1. Transvalvular mean pressure gradient decreased in the entire patient population (from 63.28 ± 12.9mmHg to 16.46 ± 7.9mmHg). At a mean follow-up interval of 4.9 ± 33 years, freedom from death was comparable, but freedom from right ventricular outflow tract reintervention was significantly greater in Group II. Although the transvalvular gradient remained stable over time in non-reoperated survivors (mean value of 16.46 ± 7.9mmHg), pulmonary valve function on 2D-Echo showed severe incompetence in 2 patients of Group I and just mild to moderate incompetence in 20 patients of Group II, with a significantly negative effect of unsuccessful preoperative pulmonary balloon valvuloplasty (14/20 vs 6/20, p=0.025) in the latter. Conclusion: Current pulmonary valve sparing techniques are associated with better results, particularly in terms of freedom from re-interventions and pulmonary valve function at follow-up. Balloon valvuloplasty prior to surgery may worsen operative results, promoting pulmonary insufficiency and therefore should probably be avoided in all patients in whom anatomical characteristics predict failure of percutaneous therapy.

336 Right ventricular mechanics in patients affected by pulmonary valve stenosis, before and after percutaneous pulmonary angioplasty

Abstract Aims Pulmonary valve stenosis accounts for 6–9% of all congenital heart diseases. The main effect of this obstructive lesion is a rise in right ventricular pressure; this overload leads to multiple changes in shape, dimensions, and volume of the ventricle. The diagnosis is based on transthoracic echocardiography and invasive heart catheterization. Usually the stenosis is classified into mild, moderate, and severe based on pressure gradient between right ventricle and pulmonary artery and on the ratio between right ventricle and left ventricle systolic pressure. Percutaneous balloon valvuloplasty is the treatment of choice in severe pulmonary valve stenosis in patients of all ages; alternatively surgical valvotomy is an option in selected cases. The aim of this study is to evaluate the mechanical changes of the right ventricle in patients undergoing balloon pulmonary valvuloplasty using transthoracic and speckle-tracking echocardiography (STE). Furthermore, we sought to investigate the correlation between haemodynamic and echocardiographic parameters to better evaluate the degree of pulmonary valve stenosis before and after treatment. Methods and results Forty-three pediatric patients (19 males), mean age 3.2 ± 4.9 years with severe pulmonary valve stenosis and indication for percutaneous balloon valvuloplasty were recruited at the University Hospital of Padua. All patients underwent standard transthoracic echocardiography (TTE), STE with analysis of right ventricle global longitudinal strain (RVGLS) one day before and one day after the procedure. For each patient were collected invasive parameters during the interventional procedure before and after balloon valvuloplasty. After the procedure, there was an immediate statistically significant reduction of both peak-to-peak transpulmonary gradient (Dp post) and ratio between the systolic pressure of right and left ventricle (RV/LV ratio) with a drop of 29.3 ± 14.67 mmHg and 0.43 ± 0.03, respectively. Post-procedural echocardiography showed peak and mean transvalvar pressure gradient drop (50 ± 32.23 and 31 ± 17.97, respectively). The degree of pulmonary valve regurgitation was mild in 8% of patients before the procedure, following the intervention it reached 29% with a statistically significant increase (P = 0.007). However, the incidence of pulmonary valve moderate and severe regurgitation remained stable after the procedure. The analysis of right ventricular function and mechanics showed a significant improvement of Fractional Area Change (FAC) immediately after the procedure (40.11% vs. 44.42%, P = 0,01). On the other hand, right ventricular longitudinal systolic function parameters, TAPSE (P = 0.60) and longitudinal strain (P = 0.31), did not improve significantly after intervention. Finally, pre-procedural invasive RV/LV ratio showed good correlation to echocardiographic transvalvular peak and mean pressure gradient (R = 0.375, P = 0.019 and R = 0.40, P = 0.012, respectively), as well as with FAC (R = 0.31, P = 0.05), TAPSE (R = 0.62, P &amp;lt; 0.001), and RVGLS (R = 0.46, P = 0.01). Conclusions Percutaneous balloon pulmonary valvuloplasty represents an efficient and safe procedure to relieve severe pulmonary valve stenosis. Interestingly, the analysis of right ventricular mechanics on echocardiography demonstrated an immediate global systolic function improvement following afterload reduction. Conversely, longitudinal systolic function did not show improvement immediately after intervention, possibly due to the necessity of longer time to recover. Finally, invasive preprocedural RV/LV ratio demonstrated better correlation with echocardiographic evaluation of stenosis degree and right ventricular function compared to invasive peak-to-peak pressure gradient. Therefore, RV/LV ratio should be preferred for the assessment of pulmonary valve stenosis.

229 Long-term clinical and echocardiographic outcome following TAVR in patients with severe aortic stenosis and different transvalvular flow state

Abstract Aims Haemodynamic classifications of severe aortic stenosis (AS) have important prognostic implications, with low flow state (defined on the basis of a stroke volume index, SVi&amp;lt;35 mL/m2) known to be a predictor of worse prognosis. As transcatheter aortic valve replacement (TAVR) has become widely used for patients with severe AS, issues were raised concerning its efficacy in patients with different haemodynamic classifications combining transvalvular flow state and pressure gradients. In fact, data on TAVR outcomes in patients with low gradient (LG) AS are limited and in some cases controversial. The aim of this study was to evaluate the efficacy and long-term clinical and echocardiographic outcome of TAVR in patients with different transvalvular flow-gradient patterns. Methods In this single centre study, 1078 patients (mean age 81±7 years) with severe symptomatic AS (AVA&amp;lt;1 cm2) undergoing TAVR were categorized according to flow-gradient patterns as follow: 867 patients (80%) with normal flow-high gradient (NF-HG: mean transaortic gradient DP mean&amp;gt;40 mmHg), 94 (9%) with paradoxical low flow LG (pLF-LG: DP mean&amp;lt;40 mmHg, ejection fraction EF &amp;gt; 50%, and SVi&amp;lt;35 mL/m2), and 117 (11%) classical LF-LG (DP mean&amp;lt;40 mmHg, EF &amp;lt; 50%, SVi&amp;lt;35 mL/m2). Results TAVR was feasible in all AS subtypes with similar rate of unsuccessful procedure (1.3% NF-HG, 1.1% pLF-LG, 0% LF-LG P=470). Valvular function after TAVR was excellent over time with respect to aortic pressure gradient (mean and peak) and aortic valve area regardless of flow state group (Figure A). Overall, intraoperative (P=957) and 30-day mortality (P=817) did not differ significantly among the 3 groups. Longer follow-up showed that, compared to NF-HG patients, pLF-LG had similar all-cause mortality rate [HR 1.35(0.95–1.90), P=0.094] up to 5 years and LF-LG had a significant higher mortality rate [HR 1.89(1.43–2.49), P&amp;lt;0.001],(Figure B). Moreover, LF-LG patients had higher rehospitalization for heart failure (NF-HG: 3%, pLF-LG: 6%, LF-LG 10%, P=0.001). Conclusions We provided evidence that TAVR is an effective procedure in all patients with severe AS regardless of transvalvular flow-gradient patterns. A careful haemodynamic classifications of severe AS is of utmost importance for identifying patients who benefits the most from TAVR procedure.

Abstract 9848: Image Guided Computational Model of the Mitral Valve in Heart Failure with Functional Mitral Regurgitation - A Platform for Preclinical Procedure Planning

Introduction: Therapeutic benefit of correcting functional mitral regurgitation (FMR) is increasingly recognized, since positive results from COAPT trial indicate a significant reduction in hospitalization rate and mortality. However, this benefit is strongly dependent on the extent of reduction in FMR with the MitraClip system, which is often variable and unpredictable. We report a patient-specific, 3D echo derived computational model of the mitral valve that faithfully mimics the FMR-like valve for procedure planning. Methods: FMR datasets were obtained in two pigs that received a myocardial infarction via percutaneous occlusion of the left circumflex artery. 3D echo was performed 3 months after infarction, and images were segmented to obtain annular and leaflet geometry, and papillary muscle (PM) locations in the ventricle. Chordal distribution was developed (Fig. A) based on anatomical measurements in hearts as they are not visible on echo. The PMs were sub-divided into three heads with marginal, strut and basal chordae emerging from these heads as seen in real hearts (Fig. B) . In FMR state, the PM locations are displaced, imposing a pre-strain on the chordae. Valve closure simulation was modeled by pre-straining the chordae and applying transvalvular pressure gradient on the leaflets, and stress analysis was performed. Results: Agreement in the truth dataset (echo image) and the model (simulated data) are shown in Fig. C , indicating fidelity of the model. Peak stresses were observed on A2 and P2 segments near the strut chordae insertion regions with maximum values of 7.62 and 4.93 MPa for each dataset (Fig. D) , which corresponds well with the previously reported findings. Conclusions: A proposed FMR modeling workflow allowed to obtain a realistic systolic configuration of the mitral valve. Such models may be used to virtually implement various FMR repair techniques, allowing to predict post-repair outcomes and optimize FMR repair at a patient-specific level.

Stent deformation in a sutureless aortic valve bioprosthesis: a pilot observational analysis using imaging and three-dimensional modelling.

The goal of this analysis of the Perceval aortic bioprosthesis was to investigate the ovalization/deformation of the Perceval prosthesis stent after implantation and its propensity for cusp dysfunction, fluttering, fibrosis and blockage. Between August 2014 and May 2019, a total of 134 patients (52% female) underwent aortic valve replacement with the Perceval bioprosthesis. We reconstructed three-dimensional models of the Perceval stent using thorax computed tomography scans for 16 patients employing the software Mimics (Materialise NV, Leuven, Belgium) and analysed the ovality of the stents. Radial force (RF) measurements were performed to compare the stiffness of the Perceval bioprosthesis to that of other valves. The three-dimensional reconstructions showed that all Perceval stents exhibited some degree of deformation and ovalization. Ovality in the annulus and commissure section of the Perceval stents ranged from 6.8% to 45% with mean values of 13.6% and 21.9%, respectively. The RF of the Perceval prosthesis was noticeably lower than that of the Edwards Intuity and several transcatheter aortic valve implantation devices. The stent adopted the preoperative shape of the aorta in the 2 patients for whom pre- and postoperative computed tomography data existed. The Perceval bioprostheses were deformed to different degrees in all analysed cases. The comparably low RFs might be an explanation for the propensity towards this deformation, which can lead to fluttering, a reduction of the cusps' mobility. This condition could potentially result in fibrosis as well as increased transvalvular pressure gradients and might be the cause for the increase in lactate dehydrogenase and the decrease in platelet count.

In vitro estimation of the energy loss through turbulence in a porcine aortic valve stenosis model and silicone ascending aorta phantom using backlight particle tracking velocimetry

Abstract Introduction Patients suffering from low-flow, low-gradient aortic stenosis present a decreased stroke volume due to decreased contraction or relaxation function of the left ventricle. As a low stroke volume tends to cause a low transvalvular flow, transvalvular pressure gradient (TVPG) and effective orifice area, the clinician cannot rely on those parameters with confidence for the evaluation of aortic stenosis severity. Hence new diagnostic parameters have to be developed. Energy loss through turbulence associated with aortic stenosis represented the wasted left ventricle work. Currently, echocardiographic measurement of the turbulence intensity is not validated for clinical evaluations of aortic stenosis. Methods Two porcine aortic valves were harvested and inserted in a flow loop that replicates the pulsatile flow of the heart. A stiffening of the valves was achieved by treating them with formaldehyde. The stiffening was externally confirmed by a custom-made force-displacement device quantifying the rigidity of the leaflet yielding two stiffness grades per valve. Each valve was tested under three different mean flow rates (1, 2.5, and 4 l/min) at each of the two stiffness grades. Moreover the pressure in the left ventricle chamber and in the aortic chamber was recorded to calculate the TVPG. Particle tracking velocimetry measurements into the transparent silicone ascending aorta phantom allowed the computation of the turbulent kinetic energy (TKE), to evaluate the energy loss due to turbulence. Results We could confirm the enhanced rigidity of the valve leaflets with our custom device (data not shown) and measure a consistent increase in TVPG across all mean flow rates between the two stiffness grades. Moreover, an explicit increase of the TKE in the aortic phantom could be measured after the stiffening process (73.1% under 1 l/min, and 43% under both 2.5 and 4 l/min). In addition, a good correlation (R = 0.86) between the mean TVPG and the TKE was found. Conclusions This project demonstrated the possibility of quantifying the energy loss attributed to turbulence for porcine valves in vitro for native and added stiffness grade. This project lays the foundation for the development of a new diagnostic tool for the assessment of stenosis severity in patients with low-flow, low-gradient aortic stenosis in cardiac imaging tool such as echocardiography. Funding Acknowledgement Type of funding sources: None. TVPG and its correlation with TKEIntensity graphs of the TKE

Real-world experience with the cusp overlap deployment technique for procedural optimization during self-expanding transcatheter aortic valve implantation: our city best practice trial

Abstract Background Aortic valve stenosis treated by transcatheter aortic valve implantation (TAVI) is a fast-growing section in interventional cardiology. Optimal implantation depth (ID) of self-expanding TAVI devices is an important condition for hemodynamic and clinical outcomes. The cusp overlap technique (COT) offers optimized fluoroscopic projections for TAVI with self-expanding devices due to improved anatomic discrimination by elongation of the left ventricular outflow tract and isolation of the non-coronary cusp (NCC) for better assessment of ID. Purpose This single-center observational study aims to investigate short-term clinical performance, safety, and efficiency outcomes regarding optimized ID in patients undergoing transfemoral TAVI with self-expanding prostheses and COT. Methods From September 2020 to December 2020, a total of 71 patients underwent TAVI with a newer-generation self-expanding device and COT. The optimal fluoroscopic projection was generated by overlapping the right (RCC) and left coronary cusps (LCC) on the multidetector computed tomography annular plane. Final ID was assessed by the arithmetic mean of distances measured from NCC and LCC to the distal prosthesis end. Outcomes were compared with a control cohort of 339 patients who underwent TAVI from January 2016 to August 2020 with a three-cusp coplanar view only during valve deployment. Results ID was significantly reduced in the COT cohort (4.3±1.9 vs. 5.0±2.3 mm; p=0.012) with better achievement of optimal ID (2–4 mm) (63.4% vs. 49.9%; p=0.03) and optimization of delta NCC-LCC ID symmetry (1.4±1.3 vs. 1.7±1.3 mm; p=0.026). The rate of pacemaker implantation following TAVI could be reduced (9.9% vs. 19.4%; p=0.05). Six of the seven patients receiving pacemaker in the COT cohort (85.7%) showed ID above membranous septum length. COT resulted in notably higher rates of device repositioning by recapturing (57.8% vs. 16.2%; p&amp;lt;0.001) compared to control cohort. Though, procedure time was prolonged in the COT cohort (82.0±26.5 vs. 74.9±27.5 min; p=0.05) while radiation dose and amount of contrast medium did not differ between the cohorts. No difference was observed in hemodynamic outcomes regarding transvalvular pressure gradients and at least moderate paravalvular leak. Patients implanted with COT had a shorter length of hospital stay (7.1±6.0 vs. 10.3±6.8 days; p&amp;lt;0.001), possibly due to a lower complication rate regarding new conduction disturbances and pacemaker implantation. Conclusion TAVI using the cusp overlap deployment technique is associated with an optimized implantation depth and a low rate of procedural complications. Therefore, a reduction of new pacemaker implantations and shortened length of hospital stay could be achieved. Funding Acknowledgement Type of funding sources: None.

In vitro Doppler versus catheter transvalvular pressure gradients in balloon-expandable versus self-expanding transcatheter aortic valves.

The objective of this in vitro study was to compare Doppler versus catheter transvalvular pressure gradients (TPG) in third generations balloon-expandable (BE) versus self-expanding (SE) transcatheter heart valves (THV). TPG is a key parameter to assess and follow valve hemodynamic function following transcatheter aortic valve implantation (TAVI). It remains uncertain and debated whether, and to which extent, TPGs differ according to the type of THV, that is, BE versus SE and to the method used for TPG measurement, that is, Doppler echocardiography versus cardiac catheterization. The CoreValve EVOLUT PRO 26 mm and the SAPIEN 3 23 mm THVs were tested in a left heart simulator using a 21 mm aortic annulus under following conditions: heart rate: 70 bpm, mean aortic pressure: 100 mmHg, stroke volume: 30, 70 and 100 ml. Mean TPGs were measured by continuous-wave Doppler and by micro-tip pressure catheters positioned in the left ventricle and at 50 mm downstream to the tip of the THV leaflets. Doppler TPGs (9.5 ± 3.9 mmHg) were on average 40.5 ± 13.9% higher (p < 0.001) than catheter TPGs (6.3 ± 3.4 mmHg). Both Doppler and catheter TPGs were lower (p=0.003) in the SE versus BE THVs (Doppler: 8.7 ± 3.5 vs. 10.7 ± 4.6; catheter: 5.0 ± 1.7 mmHg vs. 7.1 ± 2.2). The Doppler versus catheter difference in TPG increased with the higher flow conditions. The Doppler versus catheter difference in TPG was similar in BE versus SE THVs (3.6 ± 1.1 vs. 3.7 ± 1.4 mmHg or 42 ± 9 vs. 47 ± 9%; p=0.58) overall and in each flow conditions. The Doppler TPGs are, on average, 40% higher than the catheter TPGs for both BE and SE THVs. The SE THV had lower Doppler and catheter TPGs compared to the BE THV, at normal and high flow states. The absolute and percent differences between Doppler versus catheter TPGs were similar in BE versus SE THVs.

Pulmonary valve tissue engineering strategies in large animal models.

In the last 25 years, numerous tissue engineered heart valve (TEHV) strategies have been studied in large animal models. To evaluate, qualify and summarize all available publications, we conducted a systematic review and meta-analysis. We identified 80 reports that studied TEHVs of synthetic or natural scaffolds in pulmonary position (n = 693 animals). We identified substantial heterogeneity in study designs, methods and outcomes. Most importantly, the quality assessment showed poor reporting in randomization and blinding strategies. Meta-analysis showed no differences in mortality and rate of valve regurgitation between different scaffolds or strategies. However, it revealed a higher transvalvular pressure gradient in synthetic scaffolds (11.6 mmHg; 95% CI, [7.31-15.89]) compared to natural scaffolds (4,67 mmHg; 95% CI, [3,94-5.39]; p = 0.003). These results should be interpreted with caution due to lack of a standardized control group, substantial study heterogeneity, and relatively low number of comparable studies in subgroup analyses. Based on this review, the most adequate scaffold model is still undefined. This review endorses that, to move the TEHV field forward and enable reliable comparisons, it is essential to define standardized methods and ways of reporting. This would greatly enhance the value of individual large animal studies.

Midterm Outcomes of Stented Versus Stentless Bioprosthetic Valves After Aortic Root Replacement

To determine the impact of aortic root replacement (ARR) with a stentless bioprosthetic valve on midterm outcomes compared to a stented bioprosthetic valve-graft conduit. This was an observational study of aortic root operations from 2010 to 2018. All patients with a complete ARR for nonendocarditis reasons were included, while patients undergoing valve-sparing root replacements or primary aortic valve replacement or repair were excluded. Of the patients with a complete ARR, bioprosthetic valve implants were included, while mechanical valve implants were excluded. Patients were dichotomized into the stented ARR group and the stentless ARR group. A total of 1:1 nearest neighbor propensity matching was employed to assess the association of stentless valves with short-term and midterm outcomes. A total of 455 patients underwent a complete ARR with a bioprosthetic valve implant for nonendocarditis reasons, of which 212 (46.6%) received a stented valve, while 243 (53.4%) received a stentless valve. After matching, postoperative outcomes were similar across each group (P > 0.05), including operative mortality and adverse neurologic events. Median follow-up for the entire cohort was 4.41 years (95% CI: 4.01, 4.95). At 1 year follow-up, aortic regurgitation ≥ 2+ and ejection fraction were similar across each group (P > 0.05); however, the stentless valve group had lower aortic valve velocity and transvalvular pressure gradient. Finally, reoperations and survival were similar for each group over the study's follow-up (P > 0.05). Stentless valves may provide hemodynamic benefits after ARR; however, the clinical impact of those benefits for survival and reoperation may not yet be evident in the midterm.

Computed Tomography-Based Assessment of Transvalvular Pressure Gradient in Aortic Stenosis.

Background: In patients with aortic stenosis, computed tomography (CT) provides important information about cardiovascular anatomy for treatment planning but is limited in determining relevant hemodynamic parameters such as the transvalvular pressure gradient (TPG).Purpose: In the present study, we aimed to validate a reduced-order model method for assessing TPG in aortic stenosis using CT data.Methods: TPGCT was calculated using a reduced-order model requiring the patient-specific peak-systolic aortic flow rate (Q) and the aortic valve area (AVA). AVA was determined by segmentation of the aortic valve leaflets, whereas Q was quantified based on volumetric assessment of the left ventricle. For validation, invasively measured TPGcatheter was calculated from pressure measurements in the left ventricle and the ascending aorta. Altogether, 84 data sets of patients with aortic stenosis were used to compare TPGCT against TPGcatheter.Results: TPGcatheter and TPGCT were 50.6 ± 28.0 and 48.0 ± 26 mmHg, respectively (p = 0.56). A Bland–Altman analysis revealed good agreement between both methods with a mean difference in TPG of 2.6 mmHg and a standard deviation of 19.3 mmHg. Both methods showed good correlation with r = 0.72 (p < 0.001).Conclusions: The presented CT-based method allows assessment of TPG in patients with aortic stenosis, extending the current capabilities of cardiac CT for diagnosis and treatment planning.