Coronary Flow in Patients with Three-Vessel Disease: Simulated Hemodynamic Variables in relation to Angiographically Assessed Collaterality and History of Myocardial Infarction.

International audienceWe study patients with stenoses of the left main coronary artery (LMCA), left anterior descending artery (LAD), and left circumflex branch (LCx) and with chronic occlusion of the right coronary artery (RCA), undergoing off-pump coronary surgery. An analog electrical model is used to provide quantitative estimations of the distribution of flows and pressures across the coronary network (in the stenosed native arteries, the collateral branches, the capillary areas, and so forth). The present paper demonstrates that the clinical information collected for the 10 patients included in the study (Rentrop score, history of myocardial infarction, left ventricular ejection fraction (LVEF)) are well correlated with the predicted hydrodynamic data. Patients with a good collaterality (Rentrop score = 3) or patients without anterior myocardial infarction have (i) less severe stenoses on the LMCA, (ii) lower microvascular resistances, (iii) higher grafts flow rates when the revascularization is performed, (iv) higher collateral flow rates towards the territory of the occluded artery, (v) better perfusion of this area, and (vi) better total perfusion of the heart

Method for Narrow Vascular Structure Segmentation in Ct Data.

International audienc

Transcatheter Aortic Valve Replacement Using Transaortic Access

OBJECTIVES The Registry of the Utilization of the TAo-TAVR approach using the Edwards SAPIEN Valve (ROUTE) was established to assess the effectiveness and safety of the use of transaortic (TAo) access for transcatheter aortic valve replacement (TAVR) procedures (NCT01991431). BACKGROUND TAVR represents an alternative to surgical valve replacement in high-risk patients. Whereas the transfemoral access route is used commonly as the first-line approach, transapical access is an option for patients not suitable for transfemoral treatment mainly due to anatomic conditions. TAo-TAVR has been shown to be a viable alternative surgical access route; however, only limited data on its effectiveness and safety has been published. METHODS ROUTE is a multicenter, international, prospective, observational registry; data were collected from 18 centers across Europe starting in February 2013. Patients having severe calcific aortic stenosis were documented if they were scheduled to undergo TAo-TAVR using an Edwards SAPIEN XT or a SAPIEN 3 valve. The primary endpoint was 30-day mortality. Secondary endpoints were intraprocedural or in hospital and 30-day complication rates. RESULTS A total of 301 patients with a mean age of 81.7 +/- 5.9 years and an Society of Thoracic Surgeons score of 9.0 +/- 7.6% were included. Valve success was documented in 96.7%. The 30-day mortality was 6.1% (18/293) (procedure-related mortality: 3.1%; 9 of 293). The Valve Academic Research Consortium-2 defined complications included myocardial infarction (1.0%), stroke (1.0%), transient ischemic attack (0.3%), major vascular complications (3.4%), life-threatening bleeding (3.4%), and acute kidney injury (9.5%). In 3.3% of patients, paravalvular regurgitation was classified as moderate or severe (10 of 300). Twenty-six patients (8.8%) required permanent pacemaker implantation. CONCLUSIONS TAo access for TAVR seems to be a safe alternative to the transapical procedure. (C) 2016 by the American College of Cardiology Foundation.Peer reviewe

Balloon-expandable transaortic transcatheter aortic valve implantation with or without predilation

Objective: It has been reported that balloon aortic valvuloplasty immediately before transfemoral or transapical transcatheter aortic valve implantation has mostly little to no clinical value. We aimed to provide data on the need for balloon aortic valvuloplasty in patients undergoing transaortic transcatheter aortic valve implantation. Methods: Patients undergoing transaortic transcatheter aortic valve implantation with the Edwards SAPIEN XT (Nyon, Switzerland) or 3 transcatheter heart valve were prospectively included at 18 sites across Europe. In the present analysis, we compare the periprocedural and 30-day outcomes of patients undergoing conventional (thorn balloon aortic valvuloplasty) versus direct (-balloon aortic valvuloplasty) transaortic transcatheter aortic valve implantation. Results: Of the 300 patients enrolled, 222 underwent conventional and 78 underwent direct transaortic transcatheter aortic valve implantation. Peak and mean transvalvular gradients were improved in both groups with no significant difference between groups. Procedural duration, contrast agent volume, and requirement for postdilation were also comparable. A trend toward fewer periprocedural complications was evident in the direct group (3.9% vs 11.3%; P = .053), with significantly lower rates of permanent pacemaker implantation (0% vs 5.0%; P = .034). Balloon aortic valvuloplasty omission had no significant effect on any of the 30-day safety and efficacy outcomes, including Valve Academic Research Consortium-2 composite end points (early safety events: 22.7% vs 17.4%, odds ratio, 1.17, 95% confidence interval, 0.53-2.62; clinical efficacy events: 20.5% vs 18.7%, odds ratio, 1.14, 95% confidence interval, 0.51-2.55). Conclusions: For many patients, balloon aortic valvuloplasty predilation seems to have little clinical value in transaortic transcatheter aortic valve implantation using a balloon expandable transcatheter valve and may result in a higher rate of periprocedural complications, particularly in terms of permanent pacemaker implantation.Peer reviewe

Transaortic transcatheter aortic valve implantation as a first-line choice or as a last resort? An analysis based on the ROUTE registry

OBJECTIVES: Transaortic transcatheter aortic valve implantation (TAo-TAVI) is a recently developed alternative to transapical (TA) or transfemoral (TF) TAVI. We aimed to analyse the effectiveness and safety of TAo-TAVI as a first line approach and to compare it to patients receiving TAo-TAVI as a last resort, which is current practice. METHODS: ROUTE is a prospective, multicentre registry to assess the clinical outcomes of TAo-TAVI. Patients without contraindications for TA-and TF-TAVI (TAo-first) were compared to patients with contraindications for both of these access routes (TAo-last). Outcome analysis was based on VARC II defined clinical end-points. RESULTS: Three hundred and one patients were included, of which 224 patients met TAo-first and 77 TAo-last criteria. The valve was delivered and catheter retrieved successfully in all patients. In the TAo-first group, rates of conversion to open surgery and requirement for a second valve were low and not different compared to TAo-last patients (1% vs. 3%, P = 0.46 and 1% vs. 3%, P = 0.46, respectively). This was also true for the rate of paravalvular regurgitation (>= moderate: 4% vs. 3%). All-cause mortality at 30-days was 6% vs. 5% (P = 0.76), rates of stroke 2% vs. 0% (P = 0.24), pacemaker implantation (11% vs. 4%, P = 0.093), and life-threatening bleeding 4% vs. 3% (P = 0.70). Valve safety (both 85%, P = 0.98) and clinical efficacy (80% vs. 82%; P = 0.73) did not differ between groups. CONCLUSIONS: Although comparative data to TA and TF procedures were not available in the present analysis, findings suggest that TAo may be considered not only as a last resort strategy when classical access routes are deemed unfeasible, but also as a potential first-line option, with only low rates of paravalvular regurgitation and permanent pacemaker implantation.Peer reviewe

Trends in SAVR with biological vs. mechanical valves in middle-aged patients: results from a French large multi-centric survey

Background/introductionCurrently, despite continued issues with durability ( 1), biological prosthetic valves are increasingly chosen over mechanical valves for surgical aortic valve replacement (SAVR) in adult patients of all ages, at least in Western countries. For younger patients, this choice means assuming the risks associated with a redo SAVR or valve-in-valve procedure.PurposeTo assess the use of mechanical vs. biological valve prostheses for SAVR relative to patient's age and implant time in a large population extracted from the French National Database EPICARD.MethodsPatients in EPICARD undergoing SAVR from 2007 to 2022 were included from 22 participating public or private centers chosen to represent a balanced representation of centre sizes and geographical discrepancies. Patients with associated pathology of the aorta (aneurysm or dissection) and requiring a vascular aortic prosthesis were excluded. Comparisons were made amongst centers, valve choice, implant date range, and patient age.ResultsWe considered 101,070 valvular heart disease patients and included 72,375 SAVR (mean age 71.4 ± 12.2 years). We observed a mechanical vs. biological prosthesis ratio (MBPR) of 0.14 for the overall population. Before 50 years old (y-o), MBPR was >1.3 (p < 0.001) while patients above 60 years-old received principally biological SAVR (p < 0.0001). Concerning patients between 50 and 60 years-old patients, MPVR was 1.04 (p = 0.03). Patients 50–60 years-old from the first and second study duration quartile (before August 2015) received preferentially mechanical SAVR (p < 0.001). We observed a shift towards more biological SAVR (p < 0.001) for patients from the third and fourth quartile to reach a MBPR at 0.43 during the last years of the series. Incidentally, simultaneous mitral valve replacement were more common in case of mechanical SAVR (p < 0.0001), while associated CABGs were more frequent in case of biological SAVR (p < 0.0001).ConclusionIn a large contemporary French patient population, real world practice showed a recent shift towards a lower age-threshold for biological SAVR as compared to what would suggest contemporary guidelines

Numerical simulation of the filling and curing stages in reaction injection moulding, using CFX

Mestrado em Engenharia MecânicaOs métodos habitualmente utilizados para a simulação de injecção em moldes envolvem um número considerável de simplificações, originando reduções significativas do esforço computacional mas, nalguns casos também limitações. Neste trabalho são efectuadas simulações de Reaction Injection Moulding (RIM) com o mínimo de simplificações, através da utilização do software de CFD multi-objectivos CFX, concebido para a simulação numérica de escoamentos e transferência de calor e massa. Verifica-se que o modelo homogéneo para escoamentos multifásicos do CFX, geralmente considerado o apropriado para a modelação de escoamentos de superfície livre em que as fases estão completamente estratificadas, é incapaz de modelar correctamente o processo de enchimento. Este problema é ultrapassado através da implementação do modelo não homogéneo juntamente com a condição de fronteira de escorregamento livre para o ar. A reacção de cura é implementada no código como uma equação de transporte para uma variável escalar adicional, com um termo fonte. São testados vários esquemas transitórios e advectivos, com vista ao reconhecimentos de quais os que produzem os resultados mais precisos. Finalmente, as equações de conservação de massa, quantidade de movimento, cura e energia são implementadas conjuntamente para simular os processos simultâneos de enchimento e cura presentes no processo RIM. Os resultados numéricos obtidos reproduzem com boa fidelidade outros resultados numéricos e experimentais disponíveis, sendo necessários no entanto tempos de computação consideravelmente longos para efectuar as simulações. ABSTRACT: Commonly used methods for injection moulding simulation involve considerable number of simplifications, leading to a significant reduction of the computational effort but, in some cases also to limitations. In this work, Reaction Injection Moulding (RIM) simulations are performed with minimum of simplifications, by using the general purpose CFD software package CFX, designed for numerical simulation of fluid flow and heat and mass transfer. The CFX’s homogeneous multiphase flow model, which is generally considered to be the appropriate choice for modelling free surface flows where the phases are completely stratified and the interface is well defined, is shown to be unable to model the filling process correctly. This problem is overcome through the implementation of the inhomogeneous model in combination with the free-slip boundary condition for the air phase. The cure reaction is implemented in the code as a transport equation for an additional scalar variable, with a source term. Various transient and advection schemes are tested to determine which ones produce the most accurate results. Finally, the mass conservation, momentum, cure and energy equations are implemented all together to simulate the simultaneous filling and curing processes present in the RIM process. The obtained numerical results show a good global accuracy when compared with other available numerical and experimental results, though considerably long computation times are required to perform the simulations

ECMO for COVID-19 patients in Europe and Israel

Since March 15th, 2020, 177 centres from Europe and Israel have joined the study, routinely reporting on the ECMO support they provide to COVID-19 patients. The mean annual number of cases treated with ECMO in the participating centres before the pandemic (2019) was 55. The number of COVID-19 patients has increased rapidly each week reaching 1531 treated patients as of September 14th. The greatest number of cases has been reported from France (n = 385), UK (n = 193), Germany (n = 176), Spain (n = 166), and Italy (n = 136) .The mean age of treated patients was 52.6 years (range 16–80), 79% were male. The ECMO configuration used was VV in 91% of cases, VA in 5% and other in 4%. The mean PaO2 before ECMO implantation was 65 mmHg. The mean duration of ECMO support thus far has been 18 days and the mean ICU length of stay of these patients was 33 days. As of the 14th September, overall 841 patients have been weaned from ECMO support, 601 died during ECMO support, 71 died after withdrawal of ECMO, 79 are still receiving ECMO support and for 10 patients status n.a. . Our preliminary data suggest that patients placed on ECMO with severe refractory respiratory or cardiac failure secondary to COVID-19 have a reasonable (55%) chance of survival. Further extensive data analysis is expected to provide invaluable information on the demographics, severity of illness, indications and different ECMO management strategies in these patients