Transvalvular Pressure Research Articles

Abstract 4132498: Hemodynamic and Clinical Outcomes with Balloon-Expandable Valves Versus Self-Expanding Valves in Patients with Small Aortic Annulus Undergoing Transcatheter Aortic Valve Implantation: A Meta-Analysis of Randomized Controlled Trials and Propensity Score Matched Studies

Background: Transcatheter aortic valve implantation (TAVI) is thought to be more effective than surgery for patients with small aortic annulus (SAA), however, the comparative efficacy of different transcatheter heart valves (THVs) remains uncertain. The objective of this meta-analysis was to compare the effects of balloon-expandable valves (BEVs) and self-expanding valves (SEVs) on hemodynamic parameters and clinical outcomes in patients with SAA who underwent TAVI. Methods: A thorough literature search was performed across PubMed/MEDLINE, Embase, and the Cochrane Library from their inception until May 2024 to identify eligible randomized controlled trials (RCTs) and propensity-score matched (PSM) studies. Clinical outcomes were evaluated using a random-effects model to pool risk ratios (RRs) with 95% confidence intervals (CIs). Results: The analysis included 8 studies; 2 RCTs and 6 PSM studies, with a total of 2,180 patients with SAA. BEVs were associated with a smaller indexed effective orifice area (MD: -0.18, 95% CI: -0.31 to -0.05) and a higher transvalvular mean pressure gradient (MD: 5.23, 95% CI 3.44 to 7.02) than SEVs. The risk for prosthesis-patient mismatch (PPM) (RR= 1.82, 95% CI: 1.27 to 2.60) and severe PPM (RR= 2.77, 95% CI: 1.93 to 3.98) was significantly higher for patients receiving BEVs than those receiving SEVs. However, no significant difference was observed between BEVs and SEVs regarding the risk of paravalvular leak (RR= 0.98, 95% CI: 0.57 to 1.69) and the permanent pacemaker implantation (RR= 0.78, 95% CI: 0.50 to 1.23). Although patients receiving BEVs showed a slightly lower risk of major bleeding events (RR= 0.69, 95% CI: 0.49 to 0.99), BEVs were associated with a significantly increased risk of 1-year cardiovascular mortality (RR= 1.61, 95% CI: 1.05 to 2.47) compared to those receiving SEVs. However, no significant differences were observed between BEVs and SEVs regarding 30-day all-cause mortality (RR= 1.19, 95% CI: 0.57 to 2.49), 1-year all-cause mortality (RR= 1.17, 95% CI: 0.89 to 1.53), stroke rates (RR= 0.83, 95% CI: 0.52 to 1.31) and any vascular complication (RR= 1.13, 95% CI: 0.72 to 1.75). Conclusion: In patients with SAA, SEVs showed reduced risks of PPM and severe PPM compared to BEVs, along with a larger indexed effective orifice area. Moreover, SEVs were associated with a lower risk of 1-year cardiovascular mortality.

Abstract 4140192: Time Trends in Outcomes of Trans-Catheter Aortic Valve Replacement with Balloon-expanding Versus Self-expanding Valves: A Meta-analysis of Randomized Controlled Trials

Background: The research on the outcomes of transcatheter aortic valve replacement with balloon-expandable valves (BEV) and self-expanding valves (SEV) are limited. Hypothesis: This study aims to compare the clinical and hemodynamic outcomes of BEV and SEV at short-term (30 days), mid-term (1 year), and long-term (>1 year) endpoints. Methods: PubMed, Embase, Scopus, and Cochrane Library databases were searched up to April 25, 2024, for randomized controlled trials (RCTs). Random-effect model (DerSimonian–Laird method) was used to pool the risk ratios (RR), mean differences (MD) and 95% confidence interval (CI) for binary and continuous outcomes, respectively. Results: A total of 11 RCTs comprising 4,325 patients (2,295 BEV, 2,030 SEV) were included. At short-term, the risk of cardiovascular (RR: 0.56, 95% CI: 0.36-0.87) and all-cause mortality (RR: 0.54, 95% CI: 0.35-0.81) were lower in the BEV group. However, no differences were noted between the two treatment modalities in longer follow-ups despite the lower risk of moderate to severe paravalvular leak (PVL) among BEV patients. The risk of stroke was comparable between two groups across all three follow-up endpoints, albeit a limited number of studies suggesting the BEV group showed a greater risk of clinical valve thrombosis in mid-term and long-term assessments. The need for permanent pacemaker implantation was lower in BEV arm in short-term (RR: 0.56, 95% CI: 0.37-0.87) and mid-term (RR: 0.78, 95% CI: 0.64-0.94). Yet, this difference was not observed in long-term follow-ups. Conversely, the SEV group had a larger effective orifice area with lower mean transvalvular pressure gradient from short-term (MD: 0.17, 95% CI: 0.07-0.26 and MD: 3.71, 95% CI: 2.64-4.78, respectively) to long-term (MD: 0.25, 95% CI: 0.17-0.32 and MD: 3.73, 95% CI: 3.19-4.27, respectively) periods. Conclusions: BEV is associated with reduced risk of clinical outcomes at short-term; however, most differences diminish in longer evaluations, except for moderate to severe PVL. Conversely, SEV is linked to better hemodynamic outcomes and a lower risk of clinical valve thrombosis across all follow-up durations.

Evaluating the Diagnostic Potential of Four-Dimensional Flow Magnetic Resonance Imaging in Aortic Stenosis Diagnosis: A Systematic Review and Meta-Analysis.

This systematic review and meta-analysis evaluates the potential of four-dimensionalflow magnetic resonance imaging(4DFM) in assessing aortic stenosis (AS) compared to traditional imaging modalities like two-dimensional phase contrast MRI (2D MRI) and transthoracic echocardiography (TTE). AS is a common and severe valvular heart disease, particularly in older adults, requiring accurate diagnosis for proper clinical management. Conventional imaging methods have limitations in capturing complex flow dynamics, prompting the need for advanced modalities like 4DFM. The objectives of the review were to determine whether 4DFM offers superior diagnostic metrics, including peak aortic jet velocity, transvalvular pressure gradients, and aortic valve area (AVA), and to identify potential advantages of 4DFM in overcoming the limitations of traditional modalities. This review included six cohort studies with 285 participants, examining the diagnostic accuracy of 4DFM in terms of peak aortic jet velocity, transvalvular pressure gradients, and aortic valve area (AVA). Studies were selected from MEDLINE (PubMed), Cochrane Library, and Google Scholar databases between December 2010 and October 2024. The study pool was limited by stringent inclusion criteria focusing on cohort studies that directly compared 4DFM with TTE or 2D MRI for AS assessment. The National Institutes of Health Quality Assessment Tool and Cochrane ROBINS-I tool were used to assess bias. Quantitative results showed that 4DFM typically measured higher AVA values than TTE, with a mean difference of 0.48 cm² (95% CI: -0.16 to 1.12). For mean pressure gradients, 4DFM reported slightly higher measurements in individual studies, but pooled results showed no significant difference compared to TTE (mean difference: 3.32 mmHg, 95% CI: -2.30 to 8.93). In terms of peak aortic jet velocity, 4DFM demonstrated a pooled mean difference of -0.18 m/s (95% CI: -0.44 to 0.08) compared to TTE. High heterogeneity was observed across studies (e.g., I² = 97% for peak velocity, I² = 93% for AVA), likely due to differences in patient populations, imaging protocols, and software for data analysis.4DFM demonstrates potential as a complementary imaging tool, particularly in complex AS cases where conventional methods like TTE may provide inconclusive results. Its capacity to capture intricate flow dynamics and deliver high spatial resolution could inform clinical decision-making, potentially influencing practice guidelines to integrate 4DFM as a supplementary tool. Limitations such as high costs, specialized training requirements, and access challenges currently restrict widespread adoption. Limitations of this review include small sample sizes, high heterogeneity, and variability in patient populations and imaging protocols. Despite these challenges, 4DFMI demonstrated superior spatial resolution and complex cardiovascular flow assessment, suggesting it could serve as a valuable complement to TTE for more detailed AS evaluation, particularly in complex cases.Future studies should aim to standardize imaging protocols, incorporate larger and more diverse populations, and conduct cost-benefit analyses to support the integration of 4DFM into clinical practice, potentially shaping future diagnostic guidelines.

Assessing boundary conditions in CFD for transvalvular pressure gradient calculation in cardiac hemodynamics

Abstract Background Computational fluid dynamics (CFD), which has the advantages of providing detailed pressure distribution, has been widely used for cardiac function assessment and heart disease diagnosis. However, the results are usually influenced by the boundary conditions. Particularly, the transvalvular pressure gradient, which serves as a crucial indicator for mitral stenosis and the efficacy of mitral valve surgery, can easily be miscalculated. Here, we assess the effects of widely used boundary conditions on the transvalvular pressure gradient computed based on the Bernoulli equation and the line probe, respectively. Purpose This study aims to determine the effects of boundary conditions on the transvalvular pressure gradient in CFD. Methods We constructed cardiac models including left atrium, left ventricle, aorta from CT and mitral valve from transesophageal echocardiography data (Figure 1). The intraventricular flow fields were computed using CFD tool with four different boundary conditions (BC) at the same cardiac output. BC1 involved specifying the total flow rate of the aorta, with zero pressure at the entrance of the pulmonary veins. BC2 maintained equal flow rates at the entrances of the pulmonary veins. BC3 followed Murray's law, where the flow rate ratio in the pulmonary veins is proportional to the 1.5 power of the area ratio. BC4 followed Poiseuille's law, where the flow rate ratio is proportional to the square of the area ratio. The results encompassed the mean transvalvular pressure gradient and peak transvalvular pressure gradient obtained through the Bernoulli equation and the line probe methods, respectively. Results Figures 2(A-D) present the contours of transvalvular pressure under peak flow velocity conditions and the isosurfaces of vorticity within the ventricle. The results show that the pressure within the atrium is notably lower in the BC2, leading to a 63% underestimation in the mean transvalvular pressure gradient and a 22.9% deviation in the peak transvalvular pressure gradient (Figure 2 F). The transvalvular pressure gradient for BC1, BC3, and BC4 do not exceed 10%. The results reveal that the pressure distribution and vorticity within the ventricle are consistent, primarily due to the influence of the mitral valve. Conclusion When evaluating transvalvular pressure gradient using CFD, it is crucial to specify appropriate boundary conditions. Using inappropriate boundary conditions may lead to underestimation of the transvalvular pressure gradient, thereby affecting further diagnostic decisions. In research studies, it is recommended to allocate flow in different branch vessels according to Murray's law, where the flow in different branch vessels is proportional to the 1.5 power of the vessel cross-sectional area.Modelling flow chartTransvalvular pressure gradient

Cardiac amyloidosis Echo-Score for patients with severe aortic stenosis. The AMY-TAVI trial

Abstract Background and Purpose A longitudinal strain pattern characterized by apical sparing (RELAPS>1) has been identified as indicative of cardiac amyloidosis (CA). We conducted an analysis to assess its diagnostic accuracy in individuals with severe aortic stenosis (AS) and explored novel echocardiographic variables for predictive value. Methods All patients diagnosed with AS who underwent transcatheter aortic valve implantation (TAVI) were prospectively enrolled. 2D-Speckle-tracking echocardiography was utilized to assess myocardial deformation parameters. Subsequent to TAVI, screening for CA was conducted through 99mTc-DPD scintigraphy and protein electrophoresis. Results A total of 324 patients were included (mean age 81.5 ± 5.8 years, 51% women). Among them, 38 individuals (11.7%) exhibited cardiac uptake in scintigraphy: 14 patients (4.3%) with grade 1, 13(4%) grade 2, and 11(3.4%) grade 3. RELAPS>1 was more prevalent in patients with AS-CA (74%vs.44%,p=0.006). We propose an echocardiographic prediction model (GRAM score) for CA in the context of AS that is more sensitive and specific than RELAPS >1 alone. This model incorporates the left ventricular mass index, maximum transvalvular aortic pressure gradient, RELAPS>1, and age (AUC: 0.85, 95% CI: 0.77–0.93). Conclusions While RELAPS >1 is more commonly observed in individuals with AS-CA, it is noteworthy that this pattern can also manifest in nearly half of AS patients without CA, diminishing its utility as a standalone screening tool. In light of this, our study puts forth a more sensitive and specific prediction score for identifying CA in patients with severe AS.GRAM score for predicting AS-CA

Echocardiographic Phenotype in Severe Aortic Stenosis With and Without Transthyretin Cardiac Amyloidosis: The AMY-TAVI Study.

The relative apical sparing pattern of left ventricular (LV) longitudinal strain (RELAPS]>1) has been described as a typical sign of cardiac amyloidosis (CA). The objective was to validate this pattern in concomitant CA and aortic stenosis (AS) and to identify new echocardiographic variables suggestive of CA in the presence of AS. 324 consecutive patients (age 81.5±5.8 years, 51% women) with AS who underwent transcatheter aortic valve implantation (TAVI) were prospectively included. 2D-Speckle-tracking echocardiography was performed. Following TAVI, 99mTc-DPD-scintigraphy and protein electrophoresis were performed to screen for CA. 38 patients (11.7%) showed cardiac uptake in scintigraphy: 14 patients (4.3%) with grade 1, 13 (4%) with grade 2, and 11 (3.4%) with grade 3. Patients with grades 2 and 3 (AS-CA group) had more LV hypertrophy (LV mass index: 188 vs.172 g/m2, p=0.032), lower transvalvular aortic pressure gradient (p<0.003), and higher prevalence of low-gradient AS (50% vs.19%, p=0.001), as well as greater diastolic and systolic dysfunction. Strain analysis was limited to 243 patients due to poor acoustic window and COVID-19 restrictions (81 lost: 79 in AS alone, 1 each in AS-DPD1 and AS-CA groups). RELAPS>1 was more prevalent in AS-CA group (74% vs.44%, p=0.006). An echocardiographic prediction model (GRAM score) for CA in the presence of AS, that is more sensitive and specific than RELAPS>1 alone, is proposed using the LV mass, maximum aortic gradient, and RELAPS>1, in addition to age (AUC:0.85, 95%CI: 0.77-0.93). RELAPS>1 is more prevalent in AS-CA but can occur in almost half of AS patients without CA, which reduces its value as a screening tool. A more sensitive and specific prediction score for CA in patients with severe AS is proposed.

Mid- and long-term outcomes of percutaneous balloon mitral valvuloplasty guided solely by echocardiography

Objective: To evaluate the mid-and long-term clinical outcomes of percutaneous balloon mitral valvuloplasty (PBMV) guided solely by echocardiography. Methods: A total of 71 patients with moderate to severe mitral stenosis who underwent PBMV guided solely by echocardiography at Fuwai Hospital, Chinese Academy of Medical Sciences, from January 2016 to December 2022 were retrospectively included. The clinical data and follow-up information were collected and analyzed. Results: Finally, 71 patients (11 males and 60 females) aged (48.6±12.4) years, including 3 pregnant women were included. One patient required surgical intervention due to moderate to severe mitral regurgitation, resulting in a procedure success rate of 98.6% (70/71). The procedural duration was (84.1±40.2) minutes, with the balloon diameter of (26.5±1.1) mm and number of dilatations of 2.9±0.7. The mean mitral transvalvular pressure gradient decreased from (12.6±6.1) mmHg (1 mmHg=0.133 kPa) preoperatively to (5.4±2.4) mmHg postoperatively, while the mitral valve orifice area increased from (0.9±0.2) cm² to (1.7±0.3) cm² (both P<0.001). Before discharge, 16 patients developed new mild mitral regurgitation, five developed new moderate mitral regurgitation, and one patient had a small amount of pericardial effusion absorbed by herself. No severe complications such as death, pericardial tamponade, or thromboembolism occurred during the perioperative period. The average follow-up duration was 12-84 (49.7±21.4) months. At two years postoperatively, the mean mitral transvalvular pressure gradient was (6.2±2.5) mmHg, and the mitral valve orifice area was (1.6±0.3) cm². Eight patients underwent surgical mitral valve replacement at an median of [M(Q1, Q3)] 18 (5, 53) months postoperatively, and one patient died during the follow-up period due to non-cardiac reasons. Conclusion: The mid-and long-term outcomes of PBMV guided solely by echocardiography are favorable.

Direct Implantation of Transcatheter Valve in Mitral Annular Calcification: A Multi-Center Study

BACKGROUNDMitral valve replacement (MVR) in the setting of severe annular calcification (MAC) is associated with high morbidity and mortality. Direct surgical implantation of a transcatheter heart valve (THV) through a trans-atrial approach is a strategy to mitigate surgical risk. This study reports the peri-operative and 1-year outcomes of MVR using a THV in patients with severe circumferential MAC at three Canadian centers. METHODSCharts were reviewed between 1/1/2018 and 30/9/2023 to identify patients with severe circumferential MAC who had undergone direct implantation of a THV. Primary outcomes were 30-day mortality, debilitating stroke, and 1-year mortality. Secondary outcomes included left ventricular outflow tract obstruction (LVOTO), degree of PVL, transvalvular mean pressure gradient, and length of stay. RESULTSTwenty-two patients at the three centres underwent direct implantation of a THV. Nineteen were female with mean age 70.41±9.33 years. A THV was successfully implanted in all patients. There were two deaths at 30-days. Four died from non-cardiac causes at 1-year, and 1 patient had a post-operative stroke. Seventeen (77%) patients had none/trace paravalvular leak, 4 had mild PVL, and one patient had mild-moderate PVL. Mean trans-valvular gradient was 4.42±4.40. There were no cases of LVOTO. CONCLUSIONSDirect deployment of a THV in patients with severe MAC may be a reasonable option. Thirty-day and 1-year mortality rates of 9% and 18%, respectively, suggest that this approach should be reserved for high-risk patients who are not able to undergo conventional strategies.

Characteristics of altered biventricular hemodynamics after arterial switch operation for patients with d-transposition of the great arteries with preserved ejection fraction: a four-dimensional (4D) flow cardiovascular magnetic resonance (CMR) study.

The long-term monitoring of biventricular function is essential to identify potential functional decline in patients following the arterial switch operation (ASO). The underlying pathophysiological mechanisms responsible for altered biventricular hemodynamics in ASO patients are not yet well understood. This study sought to: (I) compare the biventricular kinetic energy (KE) and vorticity of ASO patients and age- and sex-matched controls; (II) investigate the associations of four-dimensional (4D) flow biventricular hemodynamics parameters and neo-aortic root dilation, supravalvular pulmonary stenosis, and pulmonary artery transvalvular pressure difference. A total of 34 patients with dextro-transposition of the great arteries (D-TGA) who underwent ASO, and 17 age- and gender-matched healthy controls were prospectively recruited for this study. All the subjects underwent cine and 4D flow and late gadolinium enhancement scans, and all the patients underwent echocardiography within two weeks of cardiovascular magnetic resonance (CMR) imaging. The following four flow components were analyzed: direct flow, retained inflow, delayed ejection flow, and residual volume. In addition, the following six phasic blood flow KE parameters, normalized to the end-diastolic volume (EDV) and vorticity, were analyzed for both the left ventricle (LV) and right ventricle (RV): peak systolic phase, average systolic phase, peak diastolic phase, average diastolic phase, peak E-wave phase, and peak A-wave phase. The independent sample Student's t-test, Mann-Whitney U-test, univariable and multivariable stepwise regression analyses, intra and inter-observer variability analyses were used to compare patients and controls. In relation to the LV, the D-TGA patients had significantly decreased average vorticity, peak systolic vorticity, systolic vorticity, diastolic vorticity, and peak A-wave vorticity compared to the controls (all P<0.01). In relation to the RV, the pulmonary stenosis group had significantly increased peak E- and A-wave kinetic energy normalized to the end-diastolic volume (KEiEDV), and peak and average vorticity compared to the non-pulmonary stenosis group (all P<0.05). in the multivariable logistic regression model analysis, diastolic KEiEDV, peak E-wave KEiEDV peak A-wave KEiEDV, and average vorticity were associated a with transvalvular pressure difference (β=13.54, P<0.001 for diastolic KEiEDV; β=105.26, P<0.001 for peak E-wave KEiEDV; β=-49.36, P=0.027 for peak A-wave KEiEDV; and β=-56.37, P<0.001 for average vorticity). We found that 4D flow biventricular hemodynamics were more sensitive markers than the ejection fraction in the postoperative D-TGA patients. The RV diastolic KEiEDV parameters and average vorticity were risk factors for pulmonary artery obstruction in the multivariable model.

Natural History of Mitral Regurgitation After Transcatheter Aortic Valve Implantation

BackgroundThis study sought to determine the impact of mitral regurgitation (MR) on outcomes after transcatheter aortic valve implantation (TAVI). MethodsThis was an observational study of TAVI for aortic stenosis (AS) from November 2012 to December 2021; 25% of patients were excluded because post-TAVI echocardiograms were unavailable. Excluded patients had a higher Society of Thoracic Surgeons predicted risk of mortality score than included patients (5.6% vs 4.9%). Patients were dichotomized according to the severity of pre-TAVI MR: < moderate vs ≥ moderate. ResultsA total of 2250 patients underwent TAVI, of whom 329 (14.6%) had MR ≥ moderate before TAVI. Baseline MR ≥ moderate was associated with reduced survival (46.2% for MR ≥ moderate vs 58.7% for MR < moderate; P < .001) and a higher incidence of heart failure readmission at 5 years after TAVI; 11% of patients had progression or persistence of MR ≥ moderate at 1 year after TAVI, which was also associated with reduced survival. On multivariable logistic regression, increasing age, women, lower ejection fraction, prior acute coronary syndrome, concomitant aortic insufficiency ≥ moderate, low-flow low-gradient AS, pulmonary hypertension, baseline tricuspid regurgitation ≥ moderate, and lower mean pre-TAVI aortic transvalvular pressure gradient were associated with progression or persistence of MR ≥ moderate at 1 year after TAVI, whereas procedural variables and postprocedural complications were not. ConclusionsSignificant MR before and after TAVI was associated with reduced survival. Whereas various clinical variables were associated with significant MR after TAVI, periprocedural variables were not. Evolution of MR must be carefully surveilled after TAVI, and more data are needed to establish guidelines for managing mixed AS and MR.

An Increase in the Ratio of Brain Natriuretic Peptide to Peak Transvalvular Pressure Gradient Suggests Coexistence of Cardiovascular Complications in Elderly Aortic Stenosis Patients.

The aim of this study was to differentiate between elderly aortic stenosis (AS) patients with and without cardiovascular complications (CCs).In total, 156 consecutive patients with AS aged ≥ 70 years were enrolled. Patients were divided into 2 groups as follows: AS without CCs (group I; n = 110) and AS with CCs (group II; n = 46). Routine electrocardiographic and echocardiographic parameters, peak and mean transvalvular pressure gradients (TPGs), aortic valve area (AVA), brain natriuretic peptide (BNP) levels, and BNP/peak TPG ratio were measured.The mean ages in groups I and II were 80.4 ± 5.5 and 82.5 ± 7.2 years. Left ventricular hypertrophy was greater in group II than in group I. Left ventricular end-diastolic and end-systolic dimensions and left ventricular fractional shortening were normal in both groups. Peak and mean TPGs were greater in group II (67.2 ± 39.3 and 40.2 ± 26.4 mmHg) than in group I (52.0 ± 23.0 and 30.2 ± 13.9, both P < 0.005); however, the AVA showed no significant difference between the 2 groups. The median BNP levels were 65.9 and 433.7 pg/mL in groups I and II (P < 0.0001). A correlation between peak TPG and BNP levels was observed in both groups. The BNP/peak TPG ratio was < 3.0 in all patients of group I and ≥ 3.0 in almost all patients of group II (P< 0.0001). The area under the curve using BNP/peak TPG ratio was 0.9883.BNP and BNP/peak TPG ratio could differentiate between AS with and without CCs in elderly patients.

The relation between aortic morphology and transcatheter aortic heart valve thrombosis: Particle tracing and platelet activation in larger aortic roots with and without neo-sinus

Transcatheter aortic heart valve thrombosis (THVT) affects long-term valve durability, transvalvular pressure gradient and leaflet mobility. In this study, we conduct high-fidelity fluid–structure interaction simulations to perform Lagrangian particle tracing in a generic model with larger aortic diameters (THVT model) with and without neo-sinus which is compared to a model of unaffected TAVI patients (control model). Platelet activation indices are computed for each particle to assess the risk of thrombus formation induced by high shear stresses followed by flow stagnation. Particle tracing indicates that fewer particles contribute to sinus washout of the THVT model with and without neo-sinus compared to the control model (−34.9%/−34.1%). Stagnating particles in the native sinus of the THVT model show higher platelet activation indices than for the control model (+39.6% without neo-sinus, +45.3% with neo-sinus). Highest activation indices are present for particles stagnating in the neo-sinus of the larger aorta representing THVT patients (+80.2% compared to control).This fluid–structure interaction (FSI) study suggests that larger aortas lead to less efficient sinus washout in combination with higher risk of platelet activation among stagnating particles, especially within the neo-sinus. This could explain (a) a higher occurrence of thrombus formation in transcatheter valves compared to surgical valves without neo-sinus and (b) the neo-sinus as the prevalent region for thrombi in TAV. Pre-procedural identification of larger aortic roots could contribute to better risk assessment of patients and improved selection of a patient-specific anti-coagulation therapy.

Hemodynamic evaluation of biomaterial-based surgery for Tetralogy of Fallot using a biorobotic heart, in silico, and ovine models.

Tetralogy of Fallot is a congenital heart disease affecting newborns and involves stenosis of the right ventricular outflow tract (RVOT). Surgical correction often widens the RVOT with a transannular enlargement patch, but this causes issues including pulmonary valve insufficiency and progressive right ventricle failure. A monocusp valve can prevent pulmonary regurgitation; however, valve failure resulting from factors including leaflet design, morphology, and immune response can occur, ultimately resulting in pulmonary insufficiency. A multimodal platform to quantitatively evaluate the effect of shape, size, and material on clinical outcomes could optimize monocusp design. This study introduces a benchtop soft biorobotic heart model, a computational fluid model of the RVOT, and a monocusp valve made from an entirely biological cell-assembled extracellular matrix (CAM) to tackle the multifaceted issue of monocusp failure. The hydrodynamic and mechanical performance of RVOT repair strategies was assessed in biorobotic and computational platforms. The monocusp valve design was validated in vivo in ovine models through echocardiography, cardiac magnetic resonance, and catheterization. These models supported assessment of surgical feasibility, handling, suturability, and hemodynamic and mechanical monocusp capabilities. The CAM-based monocusp offered a competent pulmonary valve with regurgitation of 4.6 ± 0.9% and a transvalvular pressure gradient of 4.3 ± 1.4 millimeters of mercury after 7 days of implantation in sheep. The biorobotic heart model, in silico analysis, and in vivo RVOT modeling allowed iteration in monocusp design not now feasible in a clinical environment and will support future surgical testing of biomaterials for complex congenital heart malformations.

Quantification of anatomical aortic valve area by multi-detector computed tomography: A pilot 3D-morphological modeling of the stenotic aortic valve

BackgroundAortic-valve-stenosis (AS) is a frequent degenerative valvular-disease and carries dismal outcome under-medical-treatment. Transvalvular pressure gradient reflects severity of the valve-disease but is highly dependent on flow-conditions and on other valvular/aortic characteristics. Alternatively, aortic-valve-area (AVA) represents a measure of aortic-valve lesion severity conceptually essential and practically widely-recognized but exhibits multiple-limitations. MethodsWe analyzed the 4D multi-detector computed tomography(MDCT) of 20 randomly selected patients with severe AS. For each-patient, we generated the 3D-model of the valve and of its calcifications, and we computed the anatomical AVA accounting for the 3D-morphology of the leaflets in three-different-ways. Finally, we compared our results vs. Doppler-based AVAE measurements and vs. 2D-planimetric AVA-measurements. Results3D-reconstruction and identification of the cusps were successful in 90% of the cases. The calcification patterns where highly-variable over patients, ranging from multiple small deposits to wide and c-shaped deposits running from commissure-to-commissure.AVAE was 82 ± 15 mm2. When segmenting 18 image planes, AVATight, AVAProj-Ann, AVAProj-Tip and their average AVAAve were equal to 80 ± 16, 88 ± 20, 93 ± 21 and 87 ± 19 mm2, respectively, while AVAPlan was equal to 143 ± 50 mm2. Linear-regression of the three measurements vs. AVAE yielded regression slopes equal to 1.26, 1.13 and 0.93 for AVAProj-Ann, AVAProj-Tip and AVATight, respectively. The respective Pearson-coefficients were 0.85,0.86 and 0.90. Conversely, when comparing AVAPlan vs. AVAE, linear regression yielded a slope of 1.73 and a Pearson coefficient of 0.53. ConclusionsWe described a new-method to obtain a set of flow-independent quantifications that complement pressure gradient measurements and combine the advantages of previously proposed methods, while bypassing the corresponding-limitations.

Balloon Valvuloplasty in Congenital Critical Aortic Valve Stenosis in Neonates and Infants: A Rescue Procedure for the Left Ventricle.

Congenital critical aortic valve stenosis (CAVS) is a life-threatening disease requiring urgent treatment. First-line therapy is still controversial. The aim of our study was (1) to analyze retrospectively the patients of our institution who underwent balloon aortic valvuloplasty (BAV) due to CAVS and (2) describe the techniques for improved feasibility of intervention using microcatheters and retrieval loops. Twelve patients underwent 23 BAVs: 1 BAV was performed in 3 patients, 2 BAVs were performed in 7 patients, and 3 BAVs were performed in 2 patients. The peak trans-valvular pressure gradient (Δp) and left ventricular shortening fraction (LVSF) improved significantly in the first two interventions. In the first BAV, Δp decreased from 73.7 ± 34.5 mmHg to 39.8 ± 11.9 mmHg (p = 0.003), and the LVSF improved from 22.3 ± 13.5% to 31.6 ± 10.2% (p = 0.001). In the second BAV, Δp decreased from 73.2 ± 33.3 mmHg to 35.0 ± 20.2 mmHg (p < 0.001), and the LVSF increased from 26.7 ± 9.6% to 33.3 ± 7.4% (p = 0.004). Cardiac surgery during the neonatal period was avoided for all children. The median time to valve surgery was 5.75 years. Few complications occurred, namely mild-to-moderate aortic regurgitation, one remediable air embolism, and one intimal injury to the ascending aorta. We conclude that BAV is a successful emergency treatment for CAVS, resulting in left ventricular relief, clinical stabilization, and a time gain until cardiac surgery.

Quantification of functional hemodynamics in aortic valve disease using cardiac computed tomography angiography

Background and Objective:Cardiac computed tomography angiography (CTA) is the preferred modality for preoperative planning in aortic valve stenosis. However, it cannot provide essential functional hemodynamic data, specifically the mean transvalvular pressure gradient (MPG). This study aims to introduce a computational fluid dynamics (CFD) approach for MPG quantification using cardiac CTA, enhancing its diagnostic value. Methods:Twenty patients underwent echocardiography, cardiac CTA, and invasive catheterization for pressure measurements. Cardiac CTA employed retrospective electrocardiographic gating to capture multi-phase data throughout the cardiac cycle. We segmented the region of interest based on mid-systolic phase cardiac CTA images. Then, we computed the average flow velocity into the aorta as the inlet boundary condition, using variations in end-diastolic and end-systolic left ventricular volume. Finally, we conducted CFD simulations using a steady-state model to obtain pressure distribution within the computational domain, allowing for the derivation of MPG. Results:The mean value of MPG, measured via invasive catheterization (MPGInv), echocardiography (MPGEcho), and cardiac CTA (MPGCT), were 51.3 ± 28.4 mmHg, 44.8 ± 19.5 mmHg, and 55.8 ± 25.6 mmHg, respectively. In comparison to MPGInv, MPGCT exhibited a higher correlation of 0.91, surpassing that of MPGEcho, which was 0.82. Moreover, the limits of agreement for MPGCT ranged from −27.7 to 18.7, outperforming MPGEcho, which ranged from −40.1 to 18.0. Conclusions:The proposed method based on cardiac CTA enables the evaluation of MPG for aortic valve stenosis patients. In future clinical practice, a single cardiac CTA examination can comprehensively assess both the anatomical and functional hemodynamic aspects of aortic valve disease.

Evaluation of Aortic Valve Pressure Gradients for Increasing Severities of Rheumatic and Calcific Stenosis Using Empirical and Numerical Approaches

The evaluation and accurate diagnosis of the type and severity of aortic stenosis relies on the precision of medical imaging technology and clinical correlations and the expertise of medical professionals. The application of the clinical correlation to different aortic stenosis morphologies and severities is investigated. The manner in which numerical techniques can be used to simulate the blood flow through pathological aortic valves was analysed and compared to the ground-truth CFD model. Larger pressure gradients are estimated in all severities of rheumatic aortic valves compared to calcific aortic valves. The zero-dimensional morphology-insensitive model underpredicted the transvalvular pressure gradient with the greatest error. The 1D model underestimated the pressure gradient in rheumatic cases and overestimated the pressure gradient in calcific cases. The pressure gradients estimated by the clinical approach depends on the location of the flow vena contracta and is sensitive to the severity and type of valve lesion. Through the analysis of entropy generation within the flow domain, the dominant parameters and regions driving adverse pressure gradients were identified. It is concluded that sudden expansion is the dominant parameter leading to higher pressure gradients in rheumatic heart valves compared to calcific ones.

Sex-related differences in outcome of thoracic aortic surgery.

Sex-related dissimilarities' influence on outcomes following thoracic aortic surgery is poorly understood. Our aim is to examine sex-related disparities in patients undergoing thoracic aortic aneurysm (TAA). A total of 455 cases undergoing thoracic aortic aneurysm (TAA) surgery were consecutively enrolled between December 2009 and December 2015 in a Chinese hospital. Primary outcomes, including overall mortality and related risk factors, were evaluated. Cox regression is utilized to recognize the independent risk factor of these consequences. Females, compared to males, had greater indexed aortic diameters and higher aortic transvalvular pressure differences. For the location of aortic aneurysms, females had a higher rate of aortic arch involvement, while males had a higher rate of root involvement. Females underwent less frequent complex proximal aortic operations compared with males (29.5% versus 46.9%; p < 0.001). Women and men both had a lower rate of aortic transvalvular pressure difference and LV volume index 7 days after thoracic aortic surgery. The overall mortality for the women's groups (11%) was suggestively greater compared to 4.9% for the men's groups (p = 0.026). Renal failure and aortic arch involvement were the main risk factors associated with males' survival, while maximum indexed aortic diameter and cross-clamp time were the risk factors associated with females' survival. The outcome after TAA surgery was less favorable in women with significantly increased overall mortality. It highlights the need to focus on implementing personalized surgery strategies and gender-specific guidelines in treating female patients following TAA surgery.

In Vitro Comparison of a Closed and Semi-closed Leaflet Design for Adult and Pediatric Transcatheter Heart Valves

Transcatheter heart valve replacements (TVR) are mostly designed in a closed position (c) with leaflets coaptating. However, recent literature suggests fabricating valves in semi-closed (sc) position to minimize pinwheeling. With about 100,000 children in need of a new pulmonary valve each year worldwide, this study evaluates both geometrical approaches in adult as well as pediatric size and condition. Three valves of each geometry were fabricated in adult (30 mm) and pediatric (15 mm) size, using porcine pericardium. To evaluate performance, the mean transvalvular pressure gradient (TPG), effective orifice area (EOA), and regurgitation fraction (RF) were determined in three different annulus geometries (circular, elliptic, and tilted). For both adult-sized valve geometries, the TPG (TPGC = 2.326 ± 0.115 mmHg; TPGSC = 1.848 ± 0.175 mmHg)* and EOA (EOAC = 3.69 ± 0.255 cm2; EOASC = 3.565 ± 0.025 cm2)* showed no significant difference. Yet the RF as well as its fluctuation was significantly higher for valves with the closed geometry (RFC = 12.657 ± 7.669 %; RFSC = 8.72 ± 0.977 %)*. Recordings showed that the increased backflow was caused by pinwheeling due to a surplus of tissue material. Hydrodynamic testing of pediatric TVRs verified the semi-closed geometry being favourable. Despite the RF (RFC = 7.721 ± 0.348 cm2; RFSC = 5.172 ± 0.679 cm2), these valves also showed an improved opening behaviour ((TPGC = 20.929 ± 0.497 cm2; TPGSC = 15.972 ± 1.158 cm2); (EOAC = 0.629 ± 0.017 cm2; EOASC = 0.731 ± 0.026 cm2)). Both adult and pediatric TVR with semi-closed geometry show better fluiddynamic functionality compared to valves with a closed design due to less pinwheeling. Besides improved short-term functionality, less pinwheeling potentially prevents early valve degeneration and improves durability. *Results are representatively shown for a circular annulus geometry.

Fish swim bladders as valve leaflets enhance the durability of transcatheter aortic valve replacement devices

Transcatheter aortic valve replacement (TAVR) has emerged as an effective therapy for inoperable patients with severe aortic stenosis (AS). However, calcification-induced limited durability restricts its application. Fish swim bladders (FSB), which are resistant to calcific degeneration, offer a viable solution to this challenge. In this study, we developed a new TAVR device using FSB as the valve leaflet. Furthermore, the in vitro durability, in vivo performance, and size selection of this TAVR device were assessed by an experimental study and finite element analysis. A self-expandable TAVR device was fabricated by suturing the FSB films into a 23 mm nitinol alloy frame. Further, hemodynamic performance, such as effective orifice area, transvalvular pressure difference and regurgitant fraction, the durability was tested by the pulsatile flow test and accelerated fatigue test, according to the ISO 5840-3. The effect of release size on hydrodynamic performance was also investigated. Finally, the in vivo performance of the TAVR device were examined using a porcine implantation model. The results showed that the strength of the FSB films satisfied the requirements for valve leaflets. The hemodynamic performance of the FSB TAVR device met the requirements of ISO 5840-3 standards. After 400 million cycles, the FSB showed no fiber loss, torn, perforation, or other valve failure phenomena. In porcine models, the devices were well-positioned, functioned well with no stenosis immediately after the operation. Collectively, we successfully developed a TAVR device with FSB as valve leaflets that exhibited good fatigue resistance. Statement of significanceThe source of material for the leaflets of commercialized biological heart valves (BHVs) is mainly bovine pericardium, but this material suffers the following problems: large and uneven thickness of the material, the presence of α-Gal and Neu5Gc antigens, and the susceptibility to structural valve degradation (SVD). New material for BHVs leaflets is rarely reported. In this study, we prepared a transcatheter aortic valve (TAV) and performed long-term in vitro and short-term in vivo studies using fish swim bladder (FSB) as the leaflets. The study confirmed that FSB TAV device can complete 400 million fatigue tests and maintain the good morphology of the leaflets, and that it still maintains good functionality after a certain amount of compression, indicating that FSB is a promising material for leaflets.