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Aims : The valve-in-valve (ViV) procedure has become a valuable alternative for the treatment of failed surgical bioprostheses (BP) in high-risk patients. However, in small BP, the clinical outcomes have been suboptimal due to high post-procedural gradients. We aimed to examine the effect of size and position of the self-expanding transcatheter heart valve (THV) CoreValve on the haemodynamics of ViV within small BP. Methods and results : Sizes 23 and 26 mm of the CoreValve were implanted in sizes 19 and 21 mm of three BP models: Trifecta, Mitroflow and Epic Supra. The THV was tested in three positions -normal (manufacturer recommendation), low (4 mm below normal) and high (4 mm above normal)- using a pulse duplicator. Haemodynamics were assessed by Doppler echocardiography and flowmeter, and GOA with a high-speed camera. Higher implantation was associated with lower residual gradients (normal position: -9%, high: -25% versus low). High position was, however, associated with increased risk of regurgitation in the Mitroflow and embolisation in the Epic Supra. Using a 26 mm THV instead of a 23 mm was associated with larger EOAs in the Trifecta, smaller in the Mitroflow, and increased risk of embolisation in the Epic Supra. Conclusions : Supra-annular positioning of the CoreValve THV is associated with improved post-ViV haemodynamics in small surgical BP. The haemodynamic outcomes are highly dependent on the model and size of surgical BP.

Background and objectives: Transcatheter aortic valve- in-valve implantation (ViV) has emerged as a valuable technique to treat failed surgical bioprostheses (BPs) in patients with high risk for redo surgical aortic valve replacement (SAVR). Small BP size (≤21 mm), stenotic pattern of degeneration and pre-existing prosthesis– patient mismatch (PPM) have been associated with worse clinical outcomes after ViV. However, no study has evaluated the actual haemodynamic benefit associated with ViV. This study aims to compare haemodynamic status observed at post-ViV, pre-ViV and early after initial SAVR and to determine the factors associated with worse haemodynamic outcomes following ViV, including the rates of high residual gradient and ‘haemodynamic futility’. Methods: Early post-SAVR, pre-ViV and post-ViV echocardiographic data of 79 consecutive patients who underwent aortic ViV at our institution were retrospectively analysed. The primary study endpoint was suboptimal valve haemodynamics (SVH) following ViV defined by the Valve Academic Research Consortium 2 as the presence of high residual aortic mean gradient (≥20 mm Hg) and/or at least moderate aortic regurgitation (AR). Haemodynamic futility of ViV was defined as <10 mm Hg decrease in mean aortic gradient and no improvement in AR compared with pre-ViV. Results: SVH was found in 61% of patients (57% high residual gradient, 4% moderate AR) after ViV versus 24% early after SAVR. Pre-existing PPM and BP mode of failure by stenosis were independently associated with the primary endpoint (OR: 2.87; 95% CI 1.08 to 7.65; p=0.035 and OR: 3.02; 95% CI 1.08 to 8.42; p=0.035, respectively) and with the presence of high residual gradient (OR: 4.38; 95% CI 1.55 to 12.37; p=0.005 and OR: 5.37; 95% CI 1.77 to 16.30; p=0.003, respectively) following ViV. Criteria of ViV haemodynamic futility were met in 7.6% overall and more frequently in patients with pre-existing PPM and stenotic BP (18.5%) compared with other patients (2.0%). Vi

Aims: Bioprosthetic valve fracture (BVF) may improve transvalvular gradients and transcatheter heart valve (THV) expansion during VIV interventions. However, the optimal timing of BVF is unknown. We assessed the impact of timing of BVF (before versus after) for valve-in-valve (VIV) intervention, on hydrodynamic function and THV expansion. Methods and results: Three THV designs were assessed, a 23 mm SAPIEN 3 (S3), small ACURATE neo (ACn) and 23 mm Evolut R, deployed into 21 mm Mitroflow bioprosthetic surgical valves. We evaluated each THV in three groups: 1) no BVF, 2) BVF before VIV, and 3) BVF after VIV. Hydrodynamic testing was performed using a pulse duplicator to ISO 5840:2013 standard. Transvalvular gradients were lower when BVF was performed after VIV for the S3 (no BVF 15.5 mmHg, BVF before VIV 8.0 mmHg, BVF after VIV 5.6 mmHg), and the ACn (no BVF 9.8 mmHg, BVF before VIV 8.4 mmHg, BVF after VIV 5.1 mmHg). Transvalvular gradients were similar for the Evolut R, irrespective of performance of BVF or timing of BVF. BVF performed after VIV resulted in better expansion in all three THV designs. The ACn and Evolut R samples all had a mild degree of pinwheeling, and BVF timing did not impact on pinwheeling severity. The S3 samples had severe pinwheeling with no BVF, and significant improvement in pinwheeling when BVF was performed after VIV. Conclusions: BVF performed after VIV was associated with superior THV expansion in all three THV designs tested, with lower residual transvalvular gradients in the S3 and ACn THVs. The Evolut R had similar hydrodynamic performance irrespective of BVF timing. Timing of BVF has potential implications on THV function.

Background and objectives: Transcatheter aortic valve- in-valve implantation (ViV) has emerged as a valuable technique to treat failed surgical bioprostheses (BPs) in patients with high risk for redo surgical aortic valve replacement (SAVR). Small BP size (≤21 mm), stenotic pattern of degeneration and pre-existing prosthesis– patient mismatch (PPM) have been associated with worse clinical outcomes after ViV. However, no study has evaluated the actual haemodynamic benefit associated with ViV. This study aims to compare haemodynamic status observed at post-ViV, pre-ViV and early after initial SAVR and to determine the factors associated with worse haemodynamic outcomes following ViV, including the rates of high residual gradient and ‘haemodynamic futility’. Methods: Early post-SAVR, pre-ViV and post-ViV echocardiographic data of 79 consecutive patients who underwent aortic ViV at our institution were retrospectively analysed. The primary study endpoint was suboptimal valve haemodynamics (SVH) following ViV defined by the Valve Academic Research Consortium 2 as the presence of high residual aortic mean gradient (≥20 mm Hg) and/or at least moderate aortic regurgitation (AR). Haemodynamic futility of ViV was defined as <10 mm Hg decrease in mean aortic gradient and no improvement in AR compared with pre-ViV. Results: SVH was found in 61% of patients (57% high residual gradient, 4% moderate AR) after ViV versus 24% early after SAVR. Pre-existing PPM and BP mode of failure by stenosis were independently associated with the primary endpoint (OR: 2.87; 95% CI 1.08 to 7.65; p=0.035 and OR: 3.02; 95% CI 1.08 to 8.42; p=0.035, respectively) and with the presence of high residual gradient (OR: 4.38; 95% CI 1.55 to 12.37; p=0.005 and OR: 5.37; 95% CI 1.77 to 16.30; p=0.003, respectively) following ViV. Criteria of ViV haemodynamic futility were met in 7.6% overall and more frequently in patients with pre-existing PPM and stenotic BP (18.5%) compared with other patients (2.0%). Vi

Aims : The valve-in-valve (ViV) procedure has become a valuable alternative for the treatment of failed surgical bioprostheses (BP) in high-risk patients. However, in small BP, the clinical outcomes have been suboptimal due to high post-procedural gradients. We aimed to examine the effect of size and position of the self-expanding transcatheter heart valve (THV) CoreValve on the haemodynamics of ViV within small BP. Methods and results : Sizes 23 and 26 mm of the CoreValve were implanted in sizes 19 and 21 mm of three BP models: Trifecta, Mitroflow and Epic Supra. The THV was tested in three positions -normal (manufacturer recommendation), low (4 mm below normal) and high (4 mm above normal)- using a pulse duplicator. Haemodynamics were assessed by Doppler echocardiography and flowmeter, and GOA with a high-speed camera. Higher implantation was associated with lower residual gradients (normal position: -9%, high: -25% versus low). High position was, however, associated with increased risk of regurgitation in the Mitroflow and embolisation in the Epic Supra. Using a 26 mm THV instead of a 23 mm was associated with larger EOAs in the Trifecta, smaller in the Mitroflow, and increased risk of embolisation in the Epic Supra. Conclusions : Supra-annular positioning of the CoreValve THV is associated with improved post-ViV haemodynamics in small surgical BP. The haemodynamic outcomes are highly dependent on the model and size of surgical BP.

Objectives: We sought to determine to what extent systemic arterial compliance (SAC) might impact on afterload and left ventricular (LV) function in patients with aortic stenosis (AS). Background: Although AS and reduced SAC may often coexist in the same patient, their relative impact on LV function is not well understood. Methods: Systemic arterial compliance was calculated as the ratio of stroke volume index to arterial pulse pressure in 208 patients with at least moderate AS. As a measure of global afterload, we calculated the valvulo-arterial impedance (Zva), which theoretically accounts for the effects of both AS and SAC. Results: Patients were divided into four groups: group 1, moderate AS and normal SAC (n = 77; 37%); group 2, moderate AS and low SAC (n = 50; 24%); group 3, severe AS and normal SAC (n = 45; 22%); and group 4, severe AS and low SAC (n = 36; 17%). The prevalences of LV diastolic and systolic dysfunction were 60% and 6% in group 1, 86% and 12% in group 2, 82% and 16% in group 3, and 94% and 31% in group 4. In multivariate analysis excluding Zva, energy loss index and SAC were both independent predictors of LV dysfunction, but when Zva was entered into the analyses, it became the only hemodynamic variable to be independently associated with LV dysfunction. Conclusions: Reduced SAC is a frequent occurrence in elderly patients with AS, where it independently contributes to increased afterload and decreased LV function. Systemic arterial compliance should be taken into consideration when evaluating these patients with regard to diagnosis and treatment.

BACKGROUND: It has been reported that localized high velocity may be recorded by continuous-wave Doppler interrogation through the smaller central orifices of bileaflet mechanical heart valves (BMHV) and that this may result in overestimation of the transvalvular pressure gradient (TPG). However, the prevalence and clinical relevance of this phenomenon remain unclear, particularly for BMHVs in the mitral position. The objective of this in vitro study was to assess the presence and magnitude of localized high velocity in mitral BMHVs as well as its impact on TPG overestimation by Doppler. METHODS: Nine BMHVs were tested under nine different flow conditions (volumes and flow waveforms) in a simulator specifically designed to assess mitral valve hemodynamics. Flow velocity was measured at three different locations (leading edge, midleaflets, and trailing edge) within the central and lateral orifices of the BMHVs using pulsed-wave Doppler. TPG was measured by pulsed-wave and continuous-wave Doppler and by catheterization. RESULTS: The maximum flow velocity occurred within the central orifice of the BMHV in 61% of the 81 tested conditions. This locally higher velocity within the central orifice predominantly occurred at the leading edge of the prosthesis. Doppler overestimated mean TPG by an average of 5% to 10% compared with catheterization. The magnitude of the localized high velocity and ensuing overestimation of TPG by Doppler was more important at higher mitral flow volumes (P < .0001) as well as in BMHVs with smaller internal ring diameters (P < .0001). CONCLUSIONS: This study shows that the flow velocity distribution within the three orifices of mitral BMHVs is not uniform and that higher velocity occurs more frequently, but not always, within the inflow aspect of the central orifice. In most mitral BMHVs and flow conditions, this localized high-velocity phenomenon causes small overestimation of TPGs (<2 mm Hg and <10%) by Doppler and is thus not clinically releva

Objective: To determine the effect of systemic arterial hypertension on the indices of aortic stenosis (AS) severity. Methods: A severe supravalvar AS was created in 24 pigs. The maximum and mean pressure gradients across the stenosis were measured by Doppler echocardiography and by catheterisation. Both echocardiography and catheter data were used to calculate stenosis effective orifice area, energy loss coefficient, and peak systolic left ventricular wall stress. Measurements were taken both at normal aortic pressures and during hypertension induced by banding of the distal thoracic aorta in 14 pigs and by intravenous administration of phenylephrine in 10 pigs. Results: During hypertension, systemic arterial resistance downstream from the stenosis increased greatly (all animals: 71 (40)%), whereas total systemic arterial compliance decreased significantly (-38 (21)%). Hypertension resulted in a moderate increase in effective orifice area (29 (14)%) and energy loss coefficient (25 (17)%) and substantial decreases in catheter gradients (maximum: -40 (20)%; mean: -43 (20)%; peak to peak: -70 (23)%) and Doppler gradients (maximum: -35 (17)%; mean: -37 (16)%). In multivariate analysis, peak to peak gradient was significantly (p < 0.001) related to the energy loss coefficient, mean flow rate, and arterial compliance, whereas maximum and mean catheter gradients were related only to the energy loss coefficient and flow rate. Of major importance, maximum systolic left ventricular wall stress increased greatly during hypertension (43 (23)%). Conclusions: The severity of AS may be partially masked by the presence of coexisting hypertension. The markers of AS severity should thus be interpreted with caution in hypertensive patients and be re-evaluated when the patient is in a normotensive state.

The relation between the geometrical orifice area (GOA) and the effective orifice area (EOA) of mitral bioprosthesis has been previously studied in both in vitro and clinical studies. Although GOA gives a measurement of the actual geometric orifice, EOA could be considered as the minimum area formed by the fluid downstream of the prosthesis and is calculated by the continuity equation . However, those studies mainly concern prosthesis in aortic position, and those in mitral mostly test only one particular mitral flow pattern. The aim of this study is to insight the understudied impact of mitral flow profile and the type of bioprosthesis on both GOA and EOA. Five bioprostheses of identical label diameter were tested on a pulsed duplicator in different hydrodynamic mitral flow conditions. Mitral flow is defined by the E- and A-wave amplitude and ratio, the diastolic time and the stroke volume (SV).

BACKGROUND AND AIMS OF THE STUDY : Transvalvular mean pressure gradients (MPG) are important in the evaluation of aortic stenosis, but surprisingly they often differ in patients having similar valve effective orifice area (EOA) and stroke volume (SV). The study aim was to determine if these differences could be explained by variations in left ventricular ejection time (LVET). METHODS : A pulse duplicator system with a constant SV of 75 ml and incremental increases of LVET from 250 to 450 ms was used to measure MPG by Doppler echocardiography in three fixed stenoses (0.5, 1.0 and 1.5 cm2). The same variables were also measured at rest in 192 patients with isolated aortic stenosis (EOA <1.5 cm2) as well as during stress in a subgroup of 24 patients. RESULTS : In vitro, the increase in LVET produced marked decreases of MPG ranging from -40 mmHg (-45%) for the 0.5-cm2 stenosis to -22 mmHg (-61%) for the 1.5-cm2 stenosis. In vivo, MPG measured by Doppler correlated strongly (R2 = 0.83) with the MPG predicted by the formula: MPGpred [SV/(50xEOAxLVET)]2, and on this basis the relative contributions of EOA, SV and LVET to the variance of MPG were found to be 36, 34 and 13%, respectively. During stress, the contribution of LVET to the increase in MPG was variable, but was sometimes as important as that of SV. CONCLUSION : LVET may significantly and independently influence MPG in aortic stenosis. Clinically, variations of up to 15 mmHg in MPG may be observed uniquely on the basis of a change in duration of LVET, and hence the MPG cannot be used as a stand-alone parameter for serial evaluations or for comparisons of aortic stenosis severity between patients. A correction of MPG for LVET (in ms) such as MPGc = MPGx(LVET/300)2 might be helpful for rendering comparisons of MPG more meaningful in patients with aortic stenosis.

Objectives : We sought to determine whether the flow-dependent changes in Doppler-derived valve effective orifice area (EOA) are real or due to artifact. Background : It has frequently been reported that the EOA may vary with transvalvular flow in patients with aortic stenosis. However, the explanation of the flow dependence of EOA remains controversial and some studies have suggested that the EOA estimated by Doppler-echocardiography (EOADop) may underestimate the actual EOA at low flow rates. Methods : One bioprosthetic valve and three rigid orifices were tested in a mock flow circulation model over a wide range of flow rates. The EOADop was compared with reference values obtained using particle image velocimetry (EOAPIV). Results : There was excellent agreement between EOADop and EOAPIV (r2 = 0.94). For rigid orifices of 0.5 and 1.0 cm2, no significant change in the EOA was observed with increasing flow rate. However, substantial increases of both EOADop and EOAPIV were observed when stroke volume increased from 20 to 70 ml both in the 1.5 cm2 rigid orifice (+52% for EOADop and +54% for EOAPIV) and the bioprosthetic valve (+62% for EOADop and +63% for EOAPIV); such changes are explained either by the presence of unsteady effects at low flow rates and/or by an increase in valve leaflet opening. Conclusions : The flow-dependent changes in EOADop are not artifacts but represent real changes in EOA attributable either to unsteady effects at low flow rates and/or to changes in valve leaflet opening. Such changes in EOADop can be relied on for clinical judgment making.

We propose a new approach to quantification of intracardiac vorticity based on conventional color Doppler images —Doppler vortography. Doppler vortography relies on the centrosymmetric properties of the vortices. Such properties induce particular symmetries in the Doppler flow data that can be exploited to describe the vortices quantitatively. For this purpose, a kernel filter was developed to derive a parameter, the blood vortex signature (BVS), that allows detection of the main intracardiac vortices and estimation of their core vorticities. The reliability of Doppler vortography was assessed in mock Doppler fields issued from simulations and in vitro data. Doppler vortography was also tested in patients and compared with vector flow mapping by echocardiography. Strong correlations were obtained between Doppler vortography-derived and ground-truth vorticities (in silico: r2 = 0.98, in vitro: r2 = 0.86, in vivo: r2 = 0.89). Our results indicate that Doppler vortography is a potentially promising echocardiographic tool for quantification of vortex flow in the left ventricle.

Recent clinical studies reported that prosthesis-patient mismatch (PPM) becomes clinically relevant when the effective orifice area (EOA) indexed by the body surface area (iEOA) is <1.2-1.25 cm(2)/m(2). To examine the effect of PPM on transmitral pressure gradient and left atrial (LA) and pulmonary arterial (PA) pressures and to validate the PPM cutoff values, we used a lumped model to compute instantaneous pressures, volumes, and flows into the left-sided heart and the pulmonary and systemic circulations. We simulated hemodynamic conditions at low cardiac output, at rest, and at three levels of exercise. The iEOA was varied from 0.44 to 1.67 cm(2)/m(2). We normalized the mean pressure gradient by the square of mean mitral flow indexed by the body surface area to determine at which cutoff values of iEOA the impact of PPM becomes hemodynamically significant. In vivo data were used to validate the numerical study, which shows that small values of iEOA (severe PPM) induce high PA pressure (residual PA hypertension) and contribute to its nonnormalization following a valve replacement, providing a justification for implementation of operative strategies to prevent PPM. Furthermore, we emphasize the major impact of pulmonary resistance and compliance on PA pressure. The model suggests also that the cutoff iEOA that should be used to define PPM at rest in the mitral position is approximately 1.16 cm(2)/m(2). At higher levels of exercise, the threshold for iEOA is rather close to 1.5 cm(2)/m(2). Severe PPM should be considered when iEOA is <0.94 cm(2)/m(2) at rest.

The valve-in-valve (VinV) percutaneous procedure is a valuable alternative for the treatment of failed bioprosthetic surgical heart valves (SHV) in high-risk patients (Dvir et al. 2014). There is a few data about the effect of the position of implantation of the transcatheter heart valve (THV) on the hemodynamic performance of the VinV assembly (Azadani et al. 2009). Until now, no study has focused on the hemodynamic performance of the Medtronic CoreValve (CV) within the St-Jude Medical Trifecta (TF) bioprosthesis. The objective of this in vitro study was to (1) assess hemodynamic performance of the VinV implantation of the CV THV within the TF SHV, (2) evaluate the loss of hemodynamic performance due to VinV and (3) compare different VinV assemblies in order to guide clinicians for the selection and positioning of the CV.

BACKGROUND AND AIM OF THE STUDY: In patients with aortic stenosis (AS), it has been reported that the transvalvular pressure gradients (APs) may be reduced or even abolished in the presence of concomitant arterial hypertension, but the mechanisms underlying this phenomenon remain unclear. The study aim was to: (i) examine the relationship between systemic arterial hemodynamics and the peak-to-peak (deltaP(PtoP)), peak deltaP and mean deltaP; and (ii) propose and validate a new formula for the non-invasive estimation of the deltaP(PtoP) and of the peak left ventricular systolic pressure (LVSP) using Doppler echocardiography. METHODS: Two fixed stenoses (geometric orifice area 1.0 and 1.35 cm2) and one bioprosthesis (effective orifice area (EOA) 1.2 cm2) were tested in a mock flow circulation model. Systemic vascular resistance (R) was increased from 1,500 to 3,300 dyne.s/cm5, and systemic arterial compliance (C) was decreased from 2.9 to 0.9 ml/mmHg, while transvalvular flow was held constant. RESULTS: Neither C nor R had any significant impact on EOA, peak deltaP and mean deltaP. deltaP(PtoP) was decreased markedly, however, when C was reduced (bioprosthesis: -15 mmHg (-69%); orifice 1.35 cm2: -24 mmHg (-30%); cm2: (-13%)). Subsequently, an equation was proposed to predict deltaP(PtoP) from EOA, mean deltaP, and C measured by Doppler echocardiography. LVSP calculated by adding the predicted deltaP(Ptop) to systolic arterial pressure (SAP) was compared with LVSP measured directly in a dataset of 24 pigs with experimentally induced AS. There was a strong agreement between the estimated and measured LVSP (r = 0.97; mean absolute error 5 +/- 5 mmHg). CONCLUSION: deltaP(Ptop) should not be used to evaluate AS severity because, as opposed to peak and mean deltaPs, it is highly influenced by C. The new non-invasive method proposed in this study to estimate the LVSP may be useful for obtaining a more accurate estimate of global LV afterload in patients with AS.

The valve-in-valve (VinV) percutaneous procedure is a valuable alternative for the treatment of failed bioprosthetic surgical heart valves (SHV) in high-risk patients (Dvir et al. 2014). There is a few data about the effect of the position of implantation of the transcatheter heart valve (THV) on the hemodynamic performance of the VinV assembly (Azadani et al. 2009). Until now, no study has focused on the hemodynamic performance of the Medtronic CoreValve (CV) within the St-Jude Medical Trifecta (TF) bioprosthesis. The objective of this in vitro study was to (1) assess hemodynamic performance of the VinV implantation of the CV THV within the TF SHV, (2) evaluate the loss of hemodynamic performance due to VinV and (3) compare different VinV assemblies in order to guide clinicians for the selection and positioning of the CV