A nanobody against the VWF A3 domain detects ADAMTS13-induced proteolysis in congenital and acquired VWD.

von Willebrand factor (VWF) is a multimeric protein, the size of which is regulated via ADAMTS13-mediated proteolysis within the A2 domain. We aimed to isolate nanobodies distinguishing between proteolyzed and non-proteolyzed VWF, leading to the identification of a nanobody (designated KB-VWF-D3.1) targeting the A3 domain, the epitope of which overlaps the collagen-binding site. Although KB-VWF-D3.1 binds with similar efficiency to dimeric and multimeric derivatives of VWF, binding to VWF was lost upon proteolysis by ADAMTS13, suggesting that proteolysis in the A2 domain modulates exposure of its epitope in the A3 domain. We therefore used KB-VWF-D3.1 to monitor VWF degradation in plasma samples. Spiking experiments showed that a loss of 10% intact VWF could be detected using this nanobody. By comparing plasma from volunteers to that from congenital von Willebrand disease (VWD) patients, intact-VWF levels were significantly reduced for all VWD types, and most severely in VWD type 2A-group 2, in which mutations promote ADAMTS13-mediated proteolysis. Unexpectedly, we also observed increased proteolysis in some patients with VWD type 1 and VWD type 2M. A significant correlation (r = 0.51, P < .0001) between the relative amount of high-molecular weight multimers and levels of intact VWF was observed. Reduced levels of intact VWF were further found in plasmas from patients with severe aortic stenosis and patients receiving mechanical circulatory support. KB-VWF-D3.1 is thus a nanobody that detects changes in the exposure of its epitope within the collagen-binding site of the A3 domain. In view of its unique characteristics, it has the potential to be used as a diagnostic tool to investigate whether a loss of larger multimers is due to ADAMTS13-mediated proteolysis.

Shear Forces Induced Platelet Clearance Is a New Mechanism of Thrombocytopenia.

BACKGROUND: Thrombocytopenia has been consistently described in patients with extracorporeal membrane oxygenation (ECMO) and associated with poor outcome. However, the prevalence and underlying mechanisms remain largely unknown, and a device-related role of ECMO in thrombocytopenia has been hypothesized. This study aims to investigate the mechanisms underlying thrombocytopenia in ECMO patients. METHODS: In a prospective cohort of 107 ECMO patients, we investigated platelet count, functions, and glycoprotein shedding. In an ex vivo mock circulatory ECMO loop, we assessed platelet responses and VWF (von Willebrand factor)-GP Ibα (glycoprotein Ibα) interactions at low- and high-flow rates, in the presence or absence of red blood cells. The clearance of human platelets subjected or not to ex vivo perfusion was studied using an in vivo transfusion model in NOD/SCID (nonobese diabetic/severe combined Immunodeficient) mice. RESULTS: In ECMO patients, we observed a time-dependent decrease in platelet count starting 1 hour after device onset, with a mean drop of 7%, 35%, and 41% at 1, 24, and 48 hours post-ECMO initiation (P=0.00013, P<0.0001, and P<0.0001, respectively), regardless of the type of ECMO. This drop in platelet count was associated with a decrease in platelet GP Ibα expression (before: 47.8±9.1 versus 24 hours post-ECMO: 42.3±8.9 mean fluorescence intensity; P=0.002) and an increase in soluble GP Ibα plasma levels (before: 5.6±3.3 versus 24 hours post-ECMO: 10.8±4.1 µg/mL; P<0.0001). GP Ibα shedding was also observed ex vivo and was unaffected by (1) red blood cells, (2) the coagulation potential, (3) an antibody blocking VWF-GP Ibα interaction, (4) an antibody limiting VWF degradation, and (5) supraphysiological VWF plasma concentrations. In contrast, GP Ibα shedding was dependent on rheological conditions, with a 2.8-fold increase at high- versus low-flow rates. Platelets perfused at high-flow rates before being transfused to immunodeficient mice were eliminated faster in vivo with an accelerated clearance of GP Ibα-negative versus GP Ibα-positive platelets. CONCLUSIONS: ECMO-associated shear forces induce GP Ibα shedding and thrombocytopenia due to faster clearance of GP Ibα-negative platelets. Inhibiting GP Ibα shedding could represent an approach to reduce thrombocytopenia during ECMO.

Transcatheter heart valve explant with infective endocarditis-associated prosthesis failure and outcomes: the EXPLANT-TAVR international registry.

BACKGROUND AND AIMS: Surgical explantation of transcatheter heart valves (THVs) is rapidly increasing, but there are limited data on patients with THV-associated infective endocarditis (IE). This study aims to assess the outcomes of patients undergoing THV explant for IE. METHODS: All patients who underwent THV explant between 2011 and 2022 from 44 sites in the EXPLANT-TAVR registry were identified. Patients with IE as the reason for THV explant were compared to those with other mechanisms of bioprosthetic valve dysfunction (BVD). RESULTS: A total of 372 patients from the EXPLANT-TAVR registry were included. Among them, 184 (49.5%) patients underwent THV explant due to IE and 188 (50.5%) patients due to BVD. At the index transcatheter aortic valve replacement, patients undergoing THV explant for IE were older (74.3 ± 8.6 vs. 71 ± 10.6 years) and had a lower Society of Thoracic Surgeons risk score [2.6% (1.8-5.0) vs. 3.3% (2.1-5.6), P = .029] compared to patients with BVD. Compared to BVD, IE patients had longer intensive care unit and hospital stays (P < .05) and higher stroke rates at 30 days (8.6% vs. 2.9%, P = .032) and 1 year (16.2% vs. 5.2%, P = .010). Adjusted in-hospital, 30-day, and 1-year mortality was 12.1%, 16.1%, and 33.8%, respectively, for the entire cohort, with no significant differences between groups. Although mortality was numerically higher in IE patients 3 years postsurgery (29.6% for BVD vs. 43.9% for IE), Kaplan-Meier analysis showed no significant differences between groups (P = .16). CONCLUSIONS: In the EXPLANT-TAVR registry, patients undergoing THV explant for IE had higher 30-day and 1-year stroke rates and longer intensive care unit and hospital stays. Moreover, patients undergoing THV explant for IE had a higher 3-year mortality rate, which did not reach statistical significance given the relatively small sample size of this unique cohort and the reduced number of events.

Cerebral Microbleeds During Transcatheter Aortic Valve Replacement: A Prospective Magnetic Resonance Imaging Cohort.

BACKGROUND: Cerebral microbleeds (CMBs) have been observed in healthy elderly people undergoing systematic brain magnetic resonance imaging. The potential role of acute triggers on the appearance of CMBs remains unknown. We aimed to describe the incidence of new CMBs after transcatheter aortic valve replacement (TAVR) and to identify clinical and procedural factors associated with new CMBs including hemostatic measures and anticoagulation management. METHODS: We evaluated a prospective cohort of patients with symptomatic aortic stenosis referred for TAVR for CMBs (METHYSTROKE [Identification of Epigenetic Risk Factors for Ischemic Complication During the TAVR Procedure in the Elderly]). Standardized neurologic assessment, brain magnetic resonance imaging, and analysis of hemostatic measures including von Willebrand factor were performed before and after TAVR. Numbers and location of microbleeds on preprocedural magnetic resonance imaging and of new microbleeds on postprocedural magnetic resonance imaging were reported by 2 independent neuroradiologists blinded to clinical data. Measures associated with new microbleeds and postprocedural outcome including neurologic functional outcome at 6 months were also examined. RESULTS: A total of 84 patients (47% men, 80.9±5.7 years of age) were included. On preprocedural magnetic resonance imaging, 22 patients (26% [95% CI, 17%-37%]) had at least 1 microbleed. After TAVR, new microbleeds were observed in 19 (23% [95% CI, 14%-33%]) patients. The occurrence of new microbleeds was independent of the presence of microbleeds at baseline and of diffusion-weighted imaging hypersignals. In univariable analysis, a previous history of bleeding (P=0.01), a higher total dose of heparin (P=0.02), a prolonged procedure (P=0.03), absence of protamine reversion (P=0.04), higher final activated partial thromboplastin time (P=0.05), lower final von Willebrand factor high-molecular-weight:multimer ratio (P=0.007), and lower final closure time with adenosine-diphosphate (P=0.02) were associated with the occurrence of new postprocedural microbleeds. In multivariable analysis, a prolonged procedure (odds ratio, 1.22 [95% CI, 1.03-1.73] for every 5 minutes of fluoroscopy time; P=0.02) and postprocedural acquired von Willebrand factor defect (odds ratio, 1.42 [95% CI, 1.08-1.89] for every lower 0.1 unit of high-molecular-weight:multimer ratio; P=0.004) were independently associated with the occurrence of new postprocedural microbleeds. New CMBs were not associated with changes in neurologic functional outcome or quality of life at 6 months. CONCLUSIONS: One out of 4 patients undergoing TAVR has CMBs before the procedure and 1 out of 4 patients develops new CMBs. Procedural or antithrombotic management and persistence of acquired von Willebrand factor defect were associated with the occurrence of new CMBs. REGISTRATION: URL: https://www. CLINICALTRIALS: gov; Unique identifier: NCT02972008.

BAlloon expandable vs. SElf expanding transcatheter vaLve for degenerated bioprosthesIs: design and rationale of the BASELINE trial.

BACKGROUND: Surgical aortic valve bioprostheses may degenerate over time and require redo intervention. Transcatheter aortic valve replacement (TAVR) is a less invasive alternative to redo surgery. The BAlloon Expandable vs. SElf Expanding Transcatheter VaLve for Degenerated BioprosthesIs (BASELINE) trial was designed to compare the performance of the balloon-expandable SAPIEN-3 Ultra and the self-expanding EVOLUT PRO+ valve systems in symptomatic patients with a failing surgical bioprosthesis. METHODS: The BASELINE trial is an investigator-initiated, non-funded, prospective, randomized, open-label, superiority trial enrolling a total of 440 patients in up to 50 sites in 12 countries in Europe and North-America. The primary endpoint is device success at 30-days defined by the Valve Academic Research Consortium-3 Criteria as the composite of technical success, freedom from mortality, freedom for surgery or intervention related to the device or to a major vascular or access-related or cardiac structural complication with an intended performance of the valve (mean gradient <20 mmHg and less than moderate aortic regurgitation). The co-primary endpoint at 1 year is defined as the composite of all-cause death, disabling stroke, rehospitalization for heart failure or valve related problems. Independent Core Laboratories will conduct uniform analyses of echocardiography (pre-, post-, 1-year post-procedure), multi-sliced computed tomography (pre-, and if available post-procedure) and cine-fluoroscopy studies. CONCLUSIONS: The BASELINE trial is a head-to-head comparative trial investigating the 2 most used contemporary transcatheter heart valves for the treatment of a failing surgical aortic bioprosthesis. (ClinicalTrials.gov number NCT04843072).

Transcatheter Aortic Valve Replacement in Bicuspid Aortic Valve Stenosis.

After 15 years of successive randomized, controlled trials, indications for transcatheter aortic valve replacement (TAVR) are rapidly expanding. In the coming years, this procedure could become the first line treatment for patients with a symptomatic severe aortic stenosis and a tricuspid aortic valve anatomy. However, randomized, controlled trials have excluded bicuspid aortic valve (BAV), which is the most frequent congenital heart disease occurring in 1% to 2% of the total population and representing at least 25% of patients 80 years of age or older referred for aortic valve replacement. The use of a less invasive transcatheter therapy in this elderly population became rapidly attractive, and approximately 10% of patients currently undergoing TAVR have a BAV. The U.S. Food and Drug Administration and the "European Conformity" have approved TAVR for low-risk patients regardless of the aortic valve anatomy whereas international guidelines recommend surgical replacement in BAV populations. Given this progressive expansion of TAVR toward younger and lower-risk patients, heart teams are encountering BAV patients more frequently, while the ability of this therapy to treat such a challenging anatomy remains uncertain. This review will address the singularity of BAV anatomy and associated technical challenges for the TAVR procedure. We will examine and summarize available clinical evidence and highlight critical knowledge gaps regarding TAVR utilization in BAV patients. We will provide a comprehensive overview of the role of computed tomography scans in the diagnosis, and classification of BAV and TAVR procedure planning. Overall, we will offer an integrated framework for understanding the current role of TAVR in the treatment of bicuspid aortic stenosis and for guiding physicians in clinical decision-making.

Outcomes of emergency transcatheter aortic valve replacement in patients with cardiogenic shock: A multicenter retrospective study.

Rescue transcatheter aortic valve replacement (TAVR) in patients with cardiogenic shock is challenging, and there is limited literature on these critical patients. The aim of this study was to determine the characteristics and outcomes of patients undergoing TAVR, feasibility and safety of the procedure, and 1-year mortality factors. Thirty-eight patients with severe aortic disease and cardiogenic shock admitted to two French hospitals from 2015 to 2019 were included. The patients were critical, 78.9% of them had a left ventricular ejection fraction of <30%, and all of them received inotropic support. "Valve-in-valve" procedures were performed in 15.8% and 13.2% underwent balloon aortic valvuloplasty before TAVR. Edwards Sapien3® and Medtronic CoreValve EvolutR® were used. The survival probability remained reasonable for patients with cardiogenic shock who underwent rescue TAVR. The 30-day mortality rate was 7.9% and 21.1% at 1 year. No patient died during the intervention. The procedure was safe, with few complications except for acute kidney failure, the development of a left bundle branch block, and the need for pacemaker implantation. Both functional and echocardiographic results were good at 1 year, although 29% of the patients underwent rehospitalization within 1 year. The development of a left bundle branch block was found to be a mortality risk factor. This procedure is a safe and effective therapy with acceptable survivorship in critically ill patients. The benefits to their quality of life should be evaluated in future studies, and the need for providing early cardiac resynchronization therapy must be emphasized.

Vascular Endothelial Damage in the Pathogenesis of Organ Injury in Severe COVID-19.

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Balloon-Expandable Versus Self-Expanding Transcatheter Aortic Valve Replacement: A Propensity-Matched Comparison From the FRANCE-TAVI Registry.

BACKGROUND: No randomized study powered to compare balloon expandable (BE) with self expanding (SE) transcatheter heart valves (THVs) on individual end points after transcatheter aortic valve replacement has been conducted to date. METHODS: From January 2013 to December 2015, the FRANCE-TAVI nationwide registry (Registry of Aortic Valve Bioprostheses Established by Catheter) included 12 141 patients undergoing BE-THV (Edwards, n=8038) or SE-THV (Medtronic, n=4103) for treatment of native aortic stenosis. Long term mortality status was available in all patients (median 20 months; interquartile range, 14 to 30). Patients treated with BE-THV (n=3910) were successfully matched 1:1 with 3910 patients treated with SE-THV by using propensity score (25 clinical, anatomical, and procedural variables) and by date of the procedure (within 3 months). The first coprimary outcome was ≥ moderate occurrence of paravalvular regurgitation or in-hospital mortality, or both. The second coprimary outcome was 2-year all-cause mortality. RESULTS: In propensity-matched analyses, the incidence of the first coprimary outcome was higher with SE-THV (19.8%) compared with BE-THV (11.9%; relative risk, 1.68 [95% CI, 1.46-1.91]; P<0.0001). Each component of the outcome was also higher in patients receiving SE-THV: ≥ moderate paravalvular regurgitation (15.5% versus 8.3%; relative risk, 1.90 [95% CI, 1.63-2.22]; P<0.0001) and in hospital mortality (5.6% versus 4.2%; relative risk, 1.34 [95% CI, 1.07-1.66]; P=0.01). During follow up, all cause mortality occurred in 899 patients treated with SE-THV (2-year mortality, 29.8%) and in 801 patients treated with BE-THV (2-year mortality, 26.6%; hazard ratio, 1.17 [95% CI, 1.06-1.29]; P=0.003). Similar results were found using inverse probability of treatment weighting using propensity score analysis. CONCLUSION: The present study suggests that use of SE-THV was associated with a higher risk of paravalvular regurgitation and higher in-hospital and 2-year mortality compared with use of BE-THV. These data strongly support the need for a randomized trial sufficiently powered to compare the latest generation of SE-THV and BE-THV. CLINICAL TRIAL REGISTRATION: https://www.clinicaltrials.gov. Unique identifier: NCT01777828.

A dedicated Y-shaped percutaneous ECMO cannula for femoral 2-in-1 vascular access during high-risk procedures.

High-risk transcatheter procedures requiring hemodynamic support are growing and require multiple vascular access that may be challenging in cases of peripheral artery disease or lack of radial access and exposure to a higher risk of vascular complications. We report the novel utilization of a Y-shaped arterial extracorporeal membrane oxygenation (ECMO) cannula used as a single femoral access to perform percutaneous coronary intervention (PCI) and aortography during high-risk transcatheter aortic valve replacement (TAVR). The utilization of this 2-in-1 ECMO cannula may simplify vascular access and reduce vascular and bleeding complications during high-risk ECMO-supported transcatheter procedures.

Transcatheter aortic valve replacement (TAVR) as bridge therapy restoring eligibility for liver transplantation in cirrhotic patients.

Severe aortic stenosis is a widespread valve disease, constituting a contraindication to organ transplantation due to cardiovascular morbidity and projected mortality. Mortality after conventional surgical aortic valve replacement in cirrhotic patients depends upon the Child-Pugh class. In the past few years, transcatheter aortic valve replacement has progressively become the treatment of choice for high-risk patients with severe aortic stenosis. Here, we report the cases of 3 cirrhotic patients who became eligible for liver transplantation after successful transcatheter aortic valve replacement as bridge therapy.

Outcomes of transcatheter mitral valve replacement for degenerated bioprostheses, failed annuloplasty rings, and mitral annular calcification.

Aims: We sought to evaluate the outcomes of transcatheter mitral valve replacement (TMVR) for patients with degenerated bioprostheses [valve-in-valve (ViV)], failed annuloplasty rings [valve-in-ring (ViR)], and severe mitral annular calcification [valve-in-mitral annular calcification (ViMAC)]. Methods and results: From the TMVR multicentre registry, procedural and clinical outcomes of ViV, ViR, and ViMAC were compared according to Mitral Valve Academic Research Consortium (MVARC) criteria. A total of 521 patients with mean Society of Thoracic Surgeons score of 9.0 ± 7.0% underwent TMVR (322 patients with ViV, 141 with ViR, and 58 with ViMAC). Trans-septal access and the Sapien valves were used in 39.5% and 90.0%, respectively. Overall technical success was excellent at 87.1%. However, left ventricular outflow tract obstruction occurred more frequently after ViMAC compared with ViR and ViV (39.7% vs. 5.0% vs. 2.2%; P < 0.001), whereas second valve implantation was more frequent in ViR compared with ViMAC and ViV (12.1% vs. 5.2% vs. 2.5%; P < 0.001). Accordingly, technical success rate was higher after ViV compared with ViR and ViMAC (94.4% vs. 80.9% vs. 62.1%; P < 0.001). Compared with ViMAC and ViV groups, ViR group had more frequent post-procedural mitral regurgitation ≥moderate (18.4% vs. 13.8% vs. 5.6%; P < 0.001) and subsequent paravalvular leak closure (7.8% vs. 0.0% vs. 2.2%; P = 0.006). All-cause mortality was higher after ViMAC compared with ViR and ViV at 30 days (34.5% vs. 9.9% vs. 6.2%; log-rank P < 0.001) and 1 year (62.8% vs. 30.6% vs. 14.0%; log-rank P < 0.001). On multivariable analysis, patients with failed annuloplasty rings and severe MAC were at increased risk of mortality after TMVR [ViR vs. ViV, hazard ratio (HR) 1.99, 95% confidence interval (CI) 1.27-3.12; P = 0.003; ViMAC vs. ViV, HR 5.29, 95% CI 3.29-8.51; P < 0.001]. Conclusion: The TMVR provided excellent outcomes for patients with degenerated bioprostheses despite high surgical risk. However, ViR and ViMAC were associated with higher rates of adverse events and mid-term mortality compared with ViV.

Von Willebrand Factor Multimers during Transcatheter Aortic-Valve Replacement.

BACKGROUND: Postprocedural aortic regurgitation occurs in 10 to 20% of patients undergoing transcatheter aortic-valve replacement (TAVR) for aortic stenosis. We hypothesized that assessment of defects in high-molecular-weight (HMW) multimers of von Willebrand factor or point-of-care assessment of hemostasis could be used to monitor aortic regurgitation during TAVR. METHODS: We enrolled 183 patients undergoing TAVR. Patients with aortic regurgitation after the initial implantation, as identified by means of transesophageal echocardiography, underwent additional balloon dilation to correct aortic regurgitation. HMW multimers and the closure time with adenosine diphosphate (CT-ADP), a point-of-care measure of hemostasis, were assessed at baseline and 5 minutes after each step of the procedure. Mortality was evaluated at 1 year. A second cohort (201 patients) was studied to validate the use of CT-ADP in order to identify patients with aortic regurgitation. RESULTS: After the initial implantation, HMW multimers normalized in patients without aortic regurgitation (137 patients). Among the 46 patients with aortic regurgitation, normalization occurred in 20 patients in whom additional balloon dilation was successful but did not occur in the 26 patients with persistent aortic regurgitation. A similar sequence of changes was observed with CT-ADP. A CT-ADP value of more than 180 seconds had sensitivity, specificity, and negative predictive value of 92.3%, 92.4%, and 98.6%, respectively, for aortic regurgitation, with similar results in the validation cohort. Multivariable analyses showed that the values for HMW multimers and CT-ADP at the end of TAVR were each associated with mortality at 1 year. CONCLUSIONS: The presence of HMW-multimer defects and a high value for a point-of-care hemostatic test, the CT-ADP, were each predictive of the presence of aortic regurgitation after TAVR and were associated with higher mortality 1 year after the procedure. (Funded by Lille 2 University and others; ClinicalTrials.gov number, NCT02628509.).

V stenting technique with covered stents for the management of ostial circumflex perforation: Good or bad idea?

We report the case of a redo Ross surgery complicated by an ostial left circumflex occlusion requiring emergent percutaneous coronary intervention. The latter was complicated by coronary perforation treated by two covered stents with V-stenting technique. After immediate success, the clinical course was marked by acute stent thrombosis requiring emergent coronary bypass. Learning objectives: Ostial left circumflex perforation is a rare and potentially fatal complication that is challenging to manage. V stenting technique with two covered stents could be used as a life-saving procedure, but is associated with a high thrombotic risk.

Residual tricuspid regurgitation after tricuspid transcatheter edge-to-edge repair: Insights into the EuroTR registry.

AIMS: Data on the prognostic impact of residual tricuspid regurgitation (TR) after tricuspid transcatheter edge-to-edge repair (T-TEER) are scarce. The aim of this analysis was to evaluate 2-year survival and symptomatic outcomes of patients in relation to residual TR after T-TEER. METHODS AND RESULTS: Using the large European Registry of Transcatheter Repair for Tricuspid Regurgitation (EuroTR registry) we investigated the impact of residual TR on 2-year all-cause mortality and New York Heart Association (NYHA) functional class at follow-up. The study further identified predictors for residual TR ≥3+ using a logistic regression model. The study included a total of 1286 T-TEER patients (mean age 78.0 ± 8.9 years, 53.6% female). TR was successfully reduced to ≤1+ in 42.4%, 2+ in 40.0% and 3+ in 14.9% of patients at discharge, while 2.8% remained with TR ≥4+ after the procedure. Residual TR ≥3+ was an independent multivariable predictor of 2-year all-cause mortality (hazard ratio 2.06, 95% confidence interval 1.30-3.26, p = 0.002). The prevalence of residual TR ≥3+ was four times higher in patients with higher baseline TR (vena contracta >11.1 mm) and more severe tricuspid valve tenting (tenting area >1.92 cm2). Of note, no survival difference was observed in patients with residual TR ≤1+ versus 2+ (76.2% vs. 73.1%, p = 0.461). The rate of NYHA functional class ≥III at follow-up was significantly higher in patients with residual TR ≥3+ (52.4% vs. 40.5%, p < 0.001). Of note, the degree of TR reduction significantly correlated with the extent of symptomatic improvement (p = 0.012). CONCLUSIONS: T-TEER effectively reduced TR severity in the majority of patients. While residual TR ≥3+ was associated with worse outcomes, no differences were observed for residual TR 1+ versus 2+. Symptomatic improvement correlated with the degree of TR reduction.