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  • 1
    Online Resource
    Online Resource
    Tipless transseptal cannula concept combines improved hemodynamic properties and risk‐reduced placement: An in silico proof‐of‐concept
    Wiley ; 2021
    In:  Artificial Organs Vol. 45, No. 9 ( 2021-09), p. 1024-1035
    Details
    In: Artificial Organs, Wiley, Vol. 45, No. 9 ( 2021-09), p. 1024-1035
    Abstract: As a leading cause of death worldwide, heart failure is a serious medical condition in which many critically ill patients require temporary mechanical circulatory support (MCS) as a bridge‐to‐recovery or bridge‐to‐decision. In many cases, the TandemHeart system is used to unload the left heart by draining blood from the left atrium (LA) to the femoral artery via a transseptal multistage cannula. However, even though the correct positioning of the cannula is crucial for a safe treatment, the long cannula tip currently used in transseptal cannulas complicates positioning, making the cannula vulnerable to displacement during MCS. To overcome these limitations, we propose the development of a new tipless transseptal cannula with improved hemodynamic properties. We discuss the tipless cannula concept by comparing it to the common multistage cannula concept using computational fluid dynamics simulations and assess the flow field in the LA, the wall shear stresses (WSS), and the pressure loss. Across the two distinct time points of end‐systole and end‐diastole and two drainage flow rates of 3.5 and 5.0 L/min, we find a more homogeneous inlet flow pattern for the tipless cannula concept, accompanied by a remarkably reduced area of platelet‐activating WSS (up to 10‐times smaller area compared to the multistage cannula). Moreover, pressure loss is up to 14.5% lower in the tipless cannula concept, confirming overall improved hemodynamic properties of the tipless cannula concept. Finally, a diameter‐dependent study reveals that lower WSS and pressure losses can be further reduced by large‐lumen designs for any simulation setting. Overall, our results suggest that a tipless cannula concept remedies the crucial disadvantages of a long‐tip multistage cannula by reducing the risk of misplacement, and it furthermore promotes optimized hemodynamics. With this successful proof‐of‐concept, we underscore the potential for and encourage the realization of further experimental investigations regarding the development of a tipless transseptal cannula for MCS.
    Type of Medium: Online Resource
    ISSN: 0160-564X , 1525-1594
    URL: Issue
    URL: Article
    DOI: 10.1111/aor.v45.9
    DOI: 10.1111/aor.13964
    Language: English
    Publisher: Wiley
    Publication Date: 2021
    detail.hit.zdb_id: 2003825-2
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  • 2
    Online Resource
    Online Resource
    Virtual Fitting and Hemodynamic Simulation of the EVAHEART 2 Left Ventricular Assist Device and Double-Cuff Tipless Inflow Cannula
    Ovid Technologies (Wolters Kluwer Health) ; 2019
    In:  ASAIO Journal Vol. 65, No. 7 ( 2019-09), p. 698-706
    Details
    In: ASAIO Journal, Ovid Technologies (Wolters Kluwer Health), Vol. 65, No. 7 ( 2019-09), p. 698-706
    Abstract: Inflow malposition during surgery, postoperative pump migration, inflow obstruction, and right ventricular compression are major contributors to low flow and adverse events in patients with ventricular assist devices (VADs). These position abnormalities can lead to adverse events including ischemic stroke. To address these problems, we conducted a virtual anatomical fitting study and hemodynamic simulation on iterative cannula designs, resulting in the EVAHEART 2 with the novel double-cuff tipless (DCT) inflow cannula and smaller pump design. Anatomical fitting was based on computed tomography scans of six patients with heart failure, and a fluid-structure-integration (FSI) model of the left ventricle with a lumped parameter model of the entire cardiovascular system during VAD support was created. Using this model, the hemodynamics of three inflow cannula insertion lengths for two patient-specific ventricles were calculated for both full and partial VAD support. The DCT cannula with the smaller pump housing proved resistant to obstruction even when the pump housing was adjusted. The complete system also had a smaller pump pocket size than the other designs and avoided position abnormalities that commonly lead to adverse events. Compared with conventional cadaver studies, virtual fitting and numerical simulations are more beneficial and economical for iteratively designing medical devices.
    Type of Medium: Online Resource
    ISSN: 1058-2916
    URL: Article
    DOI: 10.1097/MAT.0000000000000867
    Language: English
    Publisher: Ovid Technologies (Wolters Kluwer Health)
    Publication Date: 2019
    detail.hit.zdb_id: 2083312-X
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  • 3
    Online Resource
    Online Resource
    Optimizing cerebral perfusion and hemodynamics during cardiopulmonary bypass through cannula design combining in silico, in vitro and in vivo input
    Springer Science and Business Media LLC ; 2021
    In:  Scientific Reports Vol. 11, No. 1 ( 2021-08-18)
    Details
    In: Scientific Reports, Springer Science and Business Media LLC, Vol. 11, No. 1 ( 2021-08-18)
    Abstract: Cardiopulmonary bypass (CPB) is a standard technique for cardiac surgery, but comes with the risk of severe neurological complications (e.g. stroke) caused by embolisms and/or reduced cerebral perfusion. We report on an aortic cannula prototype design (optiCAN) with helical outflow and jet-splitting dispersion tip that could reduce the risk of embolic events and restores cerebral perfusion to 97.5% of physiological flow during CPB in vivo, whereas a commercial curved-tip cannula yields 74.6%. In further in vitro comparison, pressure loss and hemolysis parameters of optiCAN remain unaffected. Results are reproducibly confirmed in silico for an exemplary human aortic anatomy via computational fluid dynamics (CFD) simulations. Based on CFD simulations, we firstly show that optiCAN design improves aortic root washout, which reduces the risk of thromboembolism. Secondly, we identify regions of the aortic intima with increased risk of plaque release by correlating areas of enhanced plaque growth and high wall shear stresses (WSS). From this we propose another easy-to-manufacture cannula design (opti 2 CAN) that decreases areas burdened by high WSS, while preserving physiological cerebral flow and favorable hemodynamics. With this novel cannula design, we propose a cannulation option to reduce neurological complications and the prevalence of stroke in high-risk patients after CPB.
    Type of Medium: Online Resource
    ISSN: 2045-2322
    URL: Article
    DOI: 10.1038/s41598-021-96397-2
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2021
    detail.hit.zdb_id: 2615211-3
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  • 4
    Online Resource
    Online Resource
    Inflow from a Cardiopulmonary Assist System to the Pulmonary Artery and Its Implications for Local Hemodynamics—a Computational Fluid Dynamics Study
    Springer Science and Business Media LLC ; 2023
    In:  Journal of Cardiovascular Translational Research Vol. 16, No. 4 ( 2023-08), p. 842-851
    Details
    In: Journal of Cardiovascular Translational Research, Springer Science and Business Media LLC, Vol. 16, No. 4 ( 2023-08), p. 842-851
    Abstract: When returning blood to the pulmonary artery (PA), the inflow jet interferes with local hemodynamics. We investigated the consequences for several connection scenarios using transient computational fluid dynamics simulations. The PA was derived from CT data. Three aspects were varied: graft flow rate, anastomosis location, and inflow jet path length from anastomosis site to impingement on the PA wall. Lateral anastomosis locations caused abnormal flow distribution between the left and right PA. The central location provided near-physiological distribution but induced higher wall shear stress (WSS). All effects were most pronounced at high graft flows. A central location is beneficial regarding flow distribution, but the resulting high WSS might promote detachment of local thromboembolisms or influence the autonomic nervous innervation. Lateral locations, depending on jet path length, result in lower WSS at the cost of an unfavorable flow distribution that could promote pulmonary vasculature changes. Case-specific decisions and further research are necessary. Graphical Abstract
    Type of Medium: Online Resource
    ISSN: 1937-5387 , 1937-5395
    URL: Article
    DOI: 10.1007/s12265-022-10349-3
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2023
    detail.hit.zdb_id: 2422411-X
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