Comparison of Two Generations of Self-Expandable Transcatheter Heart Valves in Nine Surgical Valves: An In Vitro Study.

(1) Background: This study aimed to analyse the hydrodynamic performance of two generations of self-expanding transcatheter heart valves (THV) as a valve-in-valve (ViV) in different surgical aortic valve (SAV) models under standardised conditions. The nitinol-based Evolut R valve is frequently used in ViV procedures. It is unclear whether its successor, the Evolut PRO, is superior in ViV procedures, particularly considering the previously implanted SAV model. (2) Methods: EvolutTM R 26 mm and EvolutTM PRO 26 mm prostheses were implanted in nine 21 mm labelled size SAV models (Hancock® II, Mosaic® UltraTM, EpicTM Supra, TrifectaTM GT, Perimount®, Perimount® Magna Ease, AvalusTM, IntuityTM, Freestyle®) to analyse their hydrodynamic performance under defined circulatory conditions in a pulse duplicator. (3) Results: Both THVs presented with the lowest effective orifice area (EOA) and highest mean pressure gradient (MPG) inside Hancock® II, whereas THVs in Intuity showed the highest EOA and lowest MPG. Evolut R and Evolut PRO showed significant hydrodynamic differences depending on the SAV. Both THVs performed similarly in porcine valves. Although the Evolut R performed better than Evolut PRO in stented bovine SAVs, the Evolut PRO was superior inside the Intuity. Further, the SAV model design markedly influenced the TAV's geometric orifice area and pin-wheeling index. (4) Conclusions: These findings show that the Evolut R and Evolut PRO perform differently depending on the previously implanted SAV model. THV selection for treatment of a specific SAV model should consider these results.

International Society for Heart and Lung Transplantation Guidelines for the Evaluation and Care of Cardiac Transplant Candidates-2024.

The "International Society for Heart and Lung Transplantation Guidelines for the Evaluation and Care of Cardiac Transplant Candidates-2024" updates and replaces the "Listing Criteria for Heart Transplantation: International Society for Heart and Lung Transplantation Guidelines for the Care of Cardiac Transplant Candidates-2006" and the "2016 International Society for Heart Lung Transplantation Listing Criteria for Heart Transplantation: A 10-year Update." The document aims to provide tools to help integrate the numerous variables involved in evaluating patients for transplantation, emphasizing updating the collaborative treatment while waiting for a transplant. There have been significant practice-changing developments in the care of heart transplant recipients since the publication of the International Society for Heart and Lung Transplantation (ISHLT) guidelines in 2006 and the 10-year update in 2016. The changes pertain to 3 aspects of heart transplantation: (1) patient selection criteria, (2) care of selected patient populations, and (3) durable mechanical support. To address these issues, 3 task forces were assembled. Each task force was cochaired by a pediatric heart transplant physician with the specific mandate to highlight issues unique to the pediatric heart transplant population and ensure their adequate representation. This guideline was harmonized with other ISHLT guidelines published through November 2023. The 2024 ISHLT guidelines for the evaluation and care of cardiac transplant candidates provide recommendations based on contemporary scientific evidence and patient management flow diagrams. The American College of Cardiology and American Heart Association modular knowledge chunk format has been implemented, allowing guideline information to be grouped into discrete packages (or modules) of information on a disease-specific topic or management issue. Aiming to improve the quality of care for heart transplant candidates, the recommendations present an evidence-based approach.

Outcomes of 576 patients with extracorporeal life support for the treatment of perioperative cardiogenic shock.

OBJECTIVES: This study aims to analyse the short- and long-term outcomes in patients who received extracorporeal life support for the treatment of perioperative low-output syndrome and identify risk factors for mortality. METHODS: All consecutive patients who received extracorporeal life-support system during or after cardiac surgery at a high-volume German cardiac centre between 2008 and 2017 were identified retrospectively and followed up to December 2023. This cohort was characterized, and long-term survival (>10 years) was analysed. Univariate and multivariable regression analyses were performed to identify risk factors for mortality. RESULTS: Five-hundred and seventy-six patients were included; 21.7% underwent isolated coronary bypass, 16.5% single valve surgery, 34.3% combined cardiac surgery and 13.2% heart transplantation. The system was implanted peripherally in 60.8% of patients. In-hospital and 1-year mortality for all patients was 66.0% and 77.7%, respectively. In the multivariable Cox adjustment, severe aortic valve stenosis, previous cardiac surgery and intra-aortic balloon pump were independent risk factors for in-hospital mortality (P < 0.05). Older age, severe mitral regurgitation and patients on insulin were predictors for long-term mortality (P < 0.05). However, peripheral cannulation significantly reduced mortality. There was no time-dependent interaction of perioperative stroke with mortality. For patients who were discharged alive, the estimated 10-year survival was 32.4%. CONCLUSIONS: Treatment of perioperative low-output syndrome with extracorporeal life-support systems is associated with poor outcome and only 34% of patients could be discharged successfully. Peripheral cannulation is prognostically favourable. Special attention should be paid to these patients because age, insulin therapy and severe mitral regurgitation are strong predictors for mortality after 10 years.

Characteristic calcification behavior of five surgical aortic valve bioprostheses models: An in vitro study.

Background and Aims: The durability of surgical aortic valve bioprostheses (SAV) is limited by the calcification of the leaflets, which results in degeneration. In clinical routine, there seems to be substantial variability in the degeneration of specific SAV models. Our study aims to establish an in vitro calcification model for prosthetic valves, characterizing the calcification behavior of different SAVs. Methods: Five commercially available SAV models (Epic™ Supra, Freestyle®, Intuity®, Perimount®, and Trifecta™) were perfused with double-distilled water and physiological buffer with a defined calcium concentration (CaCl2 = 1.5 mM) at 37°C over 32.9 million cycles in a Hi-Cycle tester which corresponds to approximately 1 patient-year (calcified group). Untreated prosthetic valves served as the negative control group (noncalcified group). Calcium titration, scanning electron microscopy (SEM), histological examination, and tissue thickness measurements were performed to evaluate noncalcified and calcified SAVs (n = 10). Results: Treatment in the Hi-Cycle tester with calcification buffer maintained significantly higher calcium absorption of SAVs compared to the control group (p < 0.001). Additionally, hydroxyapatite crystals were found in the calcified SAV in SEM. Porcine valves rarely demonstrated punctual calcification pattern, while bovine pericardial valves presented distinct planar calcification pattern in histological examination. Further, calcification content differed significantly depending on the SAV model, with the highest calcium content in Trifecta (213 µg/cm2) and the lowest in Epic Supra (8 µg/cm2) (p < 0.001). Conclusion: Data from our study revealed significant differences in leaflet calcification for the various aortic valve bioprostheses models. Further studies are necessary to investigate whether these findings can mimic the clinical data of the implanted prostheses.

European Society for Organ Transplantation (ESOT) Consensus Statement on the Use of Non-invasive Biomarkers for Cardiothoracic Transplant Rejection Surveillance.

While allograft rejection (AR) continues to threaten the success of cardiothoracic transplantation, lack of accurate and repeatable surveillance tools to diagnose AR is a major unmet need in the clinical management of cardiothoracic transplant recipients. Endomyocardial biopsy (EMB) and transbronchial biopsy (TBBx) have been the cornerstone of rejection monitoring since the field's incipience, but both suffer from significant limitations, including poor concordance of biopsy interpretation among pathologists. In recent years, novel molecular tools for AR monitoring have emerged and their performance characteristics have been evaluated in multiple studies. An international working group convened by ESOT has reviewed the existing literature and provides a series of recommendations to guide the use of these biomarkers in clinical practice. While acknowledging some caveats, the group recognized that Gene-expression profiling and donor-derived cell-free DNA (dd-cfDNA) may be used to rule out rejection in heart transplant recipients, but they are not recommended for cardiac allograft vasculopathy screening. Other traditional biomarkers (NT-proBNP, BNP or troponin) do not have sufficient evidence to support their use to diagnose AR. Regarding lung transplant, dd-cfDNA could be used to rule out clinical rejection and infection, but its use to monitor treatment response is not recommended.

Impact of Different Valve-in-Valve Positions on Functional Results of the New Generation of Balloon-Expandable Transcatheter Heart Valve.

OBJECTIVES: Very precise positioning of the transcatheter heart valve (THV) inside the degenerated SAV is a crucial factor for valve-in-valve (ViV) procedure to achieve optimal hemodynamic results. Therefore, our study aimed to investigate the impact of implantation depth on functional results after ViV procedures in a standardized in vitro setting. METHODS: THV (SAPIEN 3 Ultra 23-mm size) and three SAV models (Magna Ease, Trifecta, and Hancock II-all 21-mm size) were tested at different circulatory conditions in five different positions of the THV (2-6 mm) inside the SAV. Mean pressure gradient (MPG), effective orifice area (EOA), geometric orifice area (GOAmax), and pinwheeling index (PWImean) were analyzed. RESULTS: EOA and MPG of the THV did not differ significantly regarding the position inside the Magna Ease and the Hancock II (p > 0.05). However, EOA differed significantly, depending on the position of the THV inside Trifecta (2 vs. 5 mm; p = 0.021 and 2 vs. 6 mm; p < 0.001). The THV presented the highest EOA (2.047 cm2) and the lowest MPG (5.387 mm Hg) inside the Magna Ease, whereas the lowest EOA (1.335 cm2) and the highest MPG (11.876 mm Hg) were shown inside the Hancock II. Additionally, the highest GOAmax and the lowest PWImean of the THV were noticed inside the Magna Ease. The THV showed lower GOAmax and higher PWImean inside the Trifecta when placed in a deeper position. CONCLUSION: Deep implantation of the SAPIEN 3 Ultra inside the Trifecta correlates with impaired functional results. In contrast, the implantation position of the SAPIEN 3 Ultra inside the Magna Ease and the Hancock II did not have a significant effect on functional results.

Identification of a functional missense variant in the matrix metallopeptidase 10 (MMP10) gene in two families with premature myocardial infarction.

A positive family history is a major independent risk factor for atherosclerosis, and genetic variation is an important aspect of cardiovascular disease research. We identified a heterozygous missense variant p.L245P in the MMP10 gene in two families with premature myocardial infarction using whole-exome sequencing. The aim of this study was to investigate the consequences of this variant using in-silico and functional in-vitro assays. Molecular dynamics simulations were used to analyze protein interactions, calculate free binding energy, and measure the volume of the substrate-binding cleft of MMP10-TIMP1 models. The p.L245P variant showed an altered protein surface, different intra- and intermolecular interactions of MMP10-TIMP1, a lower total free binding energy between MMP10-TIMP1, and a volume-minimized substrate-binding cleft of MMP10 compared to the wild-type. For the functional assays, human THP-1 cells were transfected with plasmids containing MMP10 cDNA carrying the p.L245P and wild-type variant and differentiated into macrophages. Macrophage adhesion and migration assays were then conducted, and pro-inflammatory chemokine levels were evaluated. The p.L245P variant led to macrophages that were more adherent, less migratory, and secreted higher levels of the pro-inflammatory chemokines CXCL1 and CXCL8 than wild-type macrophages. Thus, the p.L245P variant in MMP10 may influence the pathogenesis of atherosclerosis in families with premature myocardial infarction by altering protein - protein interactions, macrophage adhesion and migration, and expression of pro-inflammatory chemokines, which may increase plaque rupture. These results could contribute to the development of selective MMP10 inhibitors and reduce the risk of atherosclerosis in families with a history of premature myocardial infarction.

Transcatheter or Surgical Treatment of Aortic-Valve Stenosis.

BACKGROUND: Among low-risk patients with severe, symptomatic aortic stenosis who are eligible for both transcatheter aortic-valve implantation (TAVI) and surgical aortic-valve replacement (SAVR), data are lacking on the appropriate treatment strategy in routine clinical practice. METHODS: In this randomized noninferiority trial conducted at 38 sites in Germany, we assigned patients with severe aortic stenosis who were at low or intermediate surgical risk to undergo either TAVI or SAVR. Percutaneous- and surgical-valve prostheses were selected according to operator discretion. The primary outcome was a composite of death from any cause or fatal or nonfatal stroke at 1 year. RESULTS: A total of 1414 patients underwent randomization (701 to the TAVI group and 713 to the SAVR group). The mean (±SD) age of the patients was 74±4 years; 57% were men, and the median Society of Thoracic Surgeons risk score was 1.8% (low surgical risk). The Kaplan-Meier estimate of the primary outcome at 1 year was 5.4% in the TAVI group and 10.0% in the SAVR group (hazard ratio for death or stroke, 0.53; 95% confidence interval [CI], 0.35 to 0.79; P<0.001 for noninferiority). The incidence of death from any cause was 2.6% in the TAVI group and 6.2% in the SAVR group (hazard ratio, 0.43; 95% CI, 0.24 to 0.73); the incidence of stroke was 2.9% and 4.7%, respectively (hazard ratio, 0.61; 95% CI, 0.35 to 1.06). Procedural complications occurred in 1.5% and 1.0% of patients in the TAVI and SAVR groups, respectively. CONCLUSIONS: Among patients with severe aortic stenosis at low or intermediate surgical risk, TAVI was noninferior to SAVR with respect to death from any cause or stroke at 1 year. (Funded by the German Center for Cardiovascular Research and the German Heart Foundation; DEDICATE-DZHK6 ClinicalTrials.gov number, NCT03112980.).

Non-femoral focused transaxillary access in TAVI: GARY data analysis and future trends.

BACKGROUND: In patients not suitable for transfemoral transcatheter aortic valve implantation (TAVI), several access strategies can be chosen. AIM: To evaluate the use and patient outcomes of transaxillary (TAx), transapical (TA), and transaortic (TAo) as alternative access for TAVI in Germany; to further evaluate surgical cutdown vs. percutaneous TAx access. METHODS: All patients entered the German Aortic Valve Registry (GARY) between 2011 and 2019 who underwent non-transfemoral TAVI were included in this analysis. Patients with TA, TAo, or TAx TAVI were compared using a weighted propensity score model. Furthermore, a subgroup analysis was performed for TAx regarding the percutaneous or surgical cutdown approach. RESULTS: Overall, 9686 patients received a non-transfemoral access. A total of 8918 patients (92.1%) underwent TA, 398 (4.1%) TAo, and 370 (3.8%) TAx approaches. Within the TAx subgroup, 141 patients (38.1%) received subclavian cutdown, while 200 (54.1%) underwent a percutaneous approach. The TA patients had a significantly lower 30-day survival than TAx patients (TA 90.92% vs. TAx 95.59%, p = 0.006; TAo 92.22% vs. TAx 95.59%, p = 0.102). Comparing percutaneous and cutdown TAx approaches, no significant differences were seen. However, more vascular complications occurred (TA 1.8%, TAo 2.4%, TAx 12.2%; p < .001), and the hospital length of stay was shorter (TA 12.9 days, TAo 14.1 days, TAx 12 days; p < .001) after TAx access. CONCLUSION: It may be reasonable to consider TAx access first in patients not suitable for TF-TAVI, because the 30-day survival was higher compared with TA access and the 1-year survival was higher compared with TAo access. It remains important for the heart teams to offer alternative access modalities for patients not amenable to the standard TF-TAVI approaches.

Ex vivo evaluation of 3 different right ventricular outflow tract substitutes.

OBJECTIVES: The Ross procedure represents an excellent treatment option in younger patients with aortic stenosis but is limited by poor availability of homografts. In this study, we investigated the hydrodynamic performance of 3 different types of right ventricular outflow tract replacement with pericardium or synthetic material. METHODS: Three different types of valved conduits were constructed using pericardium and/or synthetic material (Group PEPE: pericardial cusps and pericardial conduit, Group PEPR: pericardial cusps and Dacron conduit, Group PRPR: expanded polytetrafluoroethylene cusps and Dacron conduit). The conduits were designed according to the Ozaki method. Their hydrodynamic performance (effective orifice area, mean pressure gradient and leakage volume) were evaluated in a mock circulation loop at different hydrodynamic conditions. RESULTS: Hydrodynamic assessment showed significantly larger effective orifice area of PEPE and PEPR compared to PRPR under all conditions and there were no significant differences between PEPE and PEPR [for condition 2: PEPE 2.43 (2.35-2.54) cm2, PEPR: 2.42 (2.4-2.5) cm2, PRPR: 2.08 (1.97-2.21) cm2, adjusted pairwise comparisons: PEPE versus PEPR: P = 0.80, PEPE versus PRPR: P < 0.001, PEPR versus PRPR: P < 0.001]. Mean pressure gradient was significantly lower for PEPE and PEPR compared with PRPR, whereas no significant differences were seen between PEPE and PEPR. Leakage volume was significantly lower for PEPE and PEPR compared with PRPR under all conditions while leakage was similar between PEPE and PEPR. CONCLUSIONS: Pulmonary graft reconstruction with pericardium cusps showed superior hydrodynamic performance compared with polytetrafluoroethylene cusps. Our results suggest that it could be considered as an alternative substitute for right ventricular outflow tract replacement during the Ross procedure.

Comparison of contemporary transcatheter heart valve prostheses: data from the German Aortic Valve Registry (GARY).

BACKGROUND: Various second-generation transcatheter heart valve (THV) prostheses with high clinical efficacy and safety are available, but there is limited large-scale data available comparing their hemodynamic performance and clinical implications. OBJECTIVE: To compare the hemodynamic performance and short-term clinical outcome of four second-generation THV prostheses. METHODS: 24,124 patients out of the German Aortic Valve Registry who underwent transfemoral transcatheter aortic valve implantation (TAVI) (Evolut™ R n = 7028, Acurate neo™ n = 2922, Portico n = 878 and Sapien 3 n = 13,296) were included in this analysis. Propensity-score weighted analysis was performed to control for differences in age, left ventricular function, STS score and sex. Primary endpoint was survival at one-year, secondary endpoints were 30 days survival, pre-discharge transvalvular gradients, paravalvular leakage and peri-procedural complications. RESULTS: Thirty-day and one-year survival were not significantly different between the four patient groups. Transvalvular gradients in Evolut™ R and Acurate neo™ were significantly lower as compared to Portico and Sapien 3 at hospital discharge. This difference exists across all annulus sizes. Paravalvular leakage ≥ II occurred significantly less often in the Sapien 3 group (1.2%, p < 0.0001). Rate of severe procedural complications was low and comparable in all groups. Permanent pacemaker implantation rate at one year was lowest in the ACUARATE neo group (13.0%) and highest in the Evolut™ R group (21.9%). CONCLUSION: Albeit comparable short-term clinical outcomes there are certain differences regarding hemodynamic performance and permanent pacemaker implantation rate between currently available THV prostheses which should be considered for individual prosthesis selection.

Aortic Valve Repair Results in Better 1-Year Survival Than Replacement: Results From German Aortic Valve Registry.

BACKGROUND: Aortic valve (AV) repair is an evolving surgical strategy in the treatment of nonelderly adults with aortic regurgitation. We aimed to determine the 1-year outcome after AV repair vs surgical AV replacement (sAVR) using real-world data from the German Aortic Valve Registry. METHODS: A total of 8076 aortic regurgitation patients (mean age, 59.1 ± 15.0 years; 76% men; mean The Society of Thoracic Surgeons score, 1.3 ± 1.1), who underwent AV surgical procedures between 2011 and 2015, were identified from German Aortic Valve Registry. The AV was repaired in 2327 patients (29%), and the remaining 5749 patients (71%) underwent sAVR. A weighted propensity score model, including the variables of age, sex, and The Society of Thoracic Surgeons score, was used to correct for baseline differences between AV repair and sAVR cohorts. The primary end point was 1-year survival after AV repair vs sAVR. Secondary end points were freedom from cardiac events and AV reinterventions. RESULTS: Survival at 1 year was 97.7% (95% CI, 97.0%-98.5%) in the AV repair cohort vs 96.4% (95% CI, 95.9%-96.9%) in the propensity score-weighted sAVR cohort (log-rank P < .001). Cox regression revealed a significant advantage of AV repair vs sAVR (hazard ratio, 0.68; 95% CI, 0.51-0.90; P < .0001) on 1-year survival, which was independent of age. Cardiac event-free survival at 1 year was 85.7% (95% CI, 483.8%-87.7%) in the AV repair group vs 81.7% (95% CI, 80.7%-82.9%) in the sAVR group (log-rank P < .001). AV reintervention was required in 38 AV repair patients (1.6%) compared with 1.6% in the sAVR cohort (P = .59). CONCLUSIONS: AV repair surgery, whenever intraoperatively feasible, is associated with a significantly better 1-year survival and 1-year cardiac event-free survival compared with sAVR.

Heart failure related cardiogenic shock: An ISHLT consensus conference content summary.

In recent years, there have been significant advancements in the understanding, risk-stratification, and treatment of cardiogenic shock (CS). Despite improved pharmacologic and device-based therapies for CS, short-term mortality remains as high as 50%. Most recent efforts in research have focused on CS related to acute myocardial infarction, even though heart failure related CS (HF-CS) accounts for >50% of CS cases. There is a paucity of high-quality evidence to support standardized clinical practices in approach to HF-CS. In addition, there is an unmet need to identify disease-specific diagnostic and risk-stratification strategies upon admission, which might ultimately guide the choice of therapies, and thereby improve outcomes and optimize resource allocation. The heterogeneity in defining CS, patient phenotypes, treatment goals and therapies has resulted in difficulty comparing published reports and standardized treatment algorithms. An International Society for Heart and Lung Transplantation (ISHLT) consensus conference was organized to better define, diagnose, and manage HF-CS. There were 54 participants (advanced heart failure and interventional cardiologists, cardiothoracic surgeons, critical care cardiologists, intensivists, pharmacists, and allied health professionals), with vast clinical and published experience in CS, representing 42 centers worldwide. State-of-the-art HF-CS presentations occurred with subsequent breakout sessions planned in an attempt to reach consensus on various issues, including but not limited to models of CS care delivery, patient presentations in HF-CS, and strategies in HF-CS management. This consensus report summarizes the contemporary literature review on HF-CS presented in the first half of the conference (part 1), while the accompanying document (part 2) covers the breakout sessions where the previously agreed upon clinical issues were discussed with an aim to get to a consensus.

Consensus statements from the International Society for Heart and Lung Transplantation consensus conference: Heart failure-related cardiogenic shock.

The last decade has brought tremendous interest in the problem of cardiogenic shock. However, the mortality rate of this syndrome approaches 50%, and other than prompt myocardial revascularization, there have been no treatments proven to improve the survival of these patients. The bulk of studies have been in patients with acute myocardial infarction, and there is little evidence to guide the clinician in those patients with heart failure cardiogenic shock (HF-CS). An International Society for Heart and Lung Transplant consensus conference was organized to better define, diagnose, and manage HF-CS. There were 54 participants (advanced heart failure and interventional cardiologists, cardiothoracic surgeons, critical care cardiologists, intensivists, pharmacists, and allied health professionals) with vast clinical and published experience in CS, representing 42 centers worldwide. This consensus report summarizes the results of a premeeting survey answered by participants and the breakout sessions where predefined clinical issues were discussed to achieve consensus in the absence of robust data. Key issues discussed include systems for CS management, including the "hub-and-spoke" model vs a tier-based network, minimum levels of data to communicate when considering transfer, disciplines that should be involved in a "shock team," goals for mechanical circulatory support device selection, and optimal flow on such devices. Overall, the document provides expert consensus on some important issues facing practitioners managing HF-CS. It is hoped that this will clarify areas where consensus has been reached and stimulate future research and registries to provide insight regarding other crucial knowledge gaps.

Impact of different in vitro models on functional performance of the self-expanding transcatheter heart valve.

OBJECTIVES: Transcatheter heart valves (THVs) are investigated according to International Organization for Standardization requirements using in vitro heart simulators to evaluate hydrodynamic performance. In contrast to surgical valves, a THV's performance heavily depends on the configuration and shape of the aortic anulus. In International Organization for Standardization regulations, there is no detailed definition for the construction of a compartment in which a THV has to be tested. Therefore, the aim of this in vitro study was to compare different in vitro models for functional testing of THVs. METHODS: Porcine aortic conduits (23-mm diameter) were implanted in Dacron prostheses and calcified with double-distilled water and calcification buffer at 37°C over 83 million cycles in a Hi-Cycler (durability testing) mimicking nearly 3 patient-years. Hydrodynamic testing of Evolut PRO 26 mm was performed within 3 models (plexiglass, native conduit and calcified conduit; all 23-mm diameter) at a frequency of 64 bpm and different stroke volumes (55-105 ml). RESULTS: Calcified conduits showed significantly higher mean pressure gradients (MPG) and lower effective orifice areas (EOA) in comparison to native conduits (without THV; P < 0.001). EOA and MPG of Evolut PRO differed depending on the model tested. Calcified conduits resulted in the lowest EOA and highest MPG of the THV compared to plexiglass and the native conduit. Full expansion of the THV was least impaired in the native conduit, while lowest geometric orifice area, lowest minimal internal diameter and highest pin-wheeling index of Evolut PRO were seen in the calcified conduit. CONCLUSIONS: Full expansion and functional performance of the Evolut PRO THV depends on the configuration of the testing compartment in an in vitro setting.

Impact of heart rate, aortic compliance and stroke volume on the aortic regurgitation fraction studied in an ex vivo pig model.

INTRODUCTION: Drug therapy to reduce the regurgitation fraction (RF) of high-grade aortic regurgitation (AR) by increasing heart rate (HR) is generally recommended. However, chronic HR reduction in HFREF patients can significantly improve aortic compliance and thereby potentially decrease RF. To clarify these contrasts, we examined the influence of HR, aortic compliance and stroke volume (SV) on RF in an ex vivo porcine model of severe AR. METHODS: Experiments were performed on porcine ascending aorta with aortic valves (n=12). Compliance was varied by inserting a Dacron graft close to the aortic valve. Both tube systems were connected to a left heart simulator varying HR and SV. AR was accomplished by punching a 0.3 cm2 hole in one aortic cusp. Flow, RF, SV and aortic pressure were measured, aortic compliance with transoesophageal ultrasound probes. RESULTS: Compliance of the aorta was significantly reduced after Dacron graft insertion (0.55%±0.21%/mm Hg vs 0.01%±0.007%/mm Hg, p<0.001, respectively). With increasing HR, RF was significantly reduced in each steady state of the native aorta (HR 40 bpm: 88%±7% vs HR 120 bpm: 42%±10%; p<0.001), but Dacron tube did not affect RF (HR 40 bpm: 87%±8%; p=0.79; HR 120 bpm: 42%±3%; p=0.86). Increasing SV also reduced RF independent of the stiff Dacron graft. CONCLUSION: Aortic compliance did not affect AR in the ex vivo porcine model of AR. RF was significantly reduced with increasing HR and SV. These results affirm that HR lowering and negative inotropic drugs should be avoided to treat severe AR.

Functional interaction of aortic valve and ascending aorta in patients after valve-sparing procedures.

Pressure recovery (PR) is essential part of the post stenotic fluid mechanics and depends on the ratio of EOA/AA, the effective aortic valve orifice area (EOA) and aortic cross-sectional area (AA). In patients with advanced ascending aortic aneurysm and mildly diseased aortic valves, the effect of AA on pressure recovery and corresponding functional aortic valve opening area (ELCO) was evaluated before and after valve-sparing surgery (Dacron graft implantation). 66 Patients with ascending aortic aneurysm (mean aortic diameter 57 +/- 10 mm) and aortic valve-sparing surgery (32 reimplantation technique (David), 34 remodeling technique (Yacoub)) were routinely investigated by Doppler echocardiography. Dacron graft with a diameter between 26 and 34 mm were implanted. EOA was significantly declined after surgery (3.4 +/- 0.8 vs. 2.6 +/- 0.9cm2; p < 0.001). Insertion of Dacron prosthesis resulted in a significant reduction of AA (26.7 +/- 10.2 vs. 6.8 +/- 1.1cm2; p < 0.001) with increased ratio of EOA/AA (0.14 +/- 0.05 vs. 0.40 +/- 0.1; p < 0.001) and pressure recovery index (PRI; 0.24 +/- 0.08 vs. 0.44 +/- 0.06; p < 0.0001). Despite reduction of EOA, ELCO (= EOA corrected for PR) increased from 4.0 +/- 1.1 to 5.0 +/- 3.1cm2 (p < 0.01) with reduction in transvalvular LV stroke work (1005 +/- 814 to 351 +/- 407 mmHg × ml, p < 0.001) after surgery. These effects were significantly better in patients with Yacoub technique than with the David operation. The hemodynamic findings demonstrate a valve-vessel interaction almost entirely caused by a marked reduction in the ascending AA with significant PR gain. The greater hemodynamic benefit of the Yacoub technique due to higher EOA values compared to the David technique was evident and may be of clinical relevance.