Duration of systole and diastole for hydrodynamic testing of prosthetic heart valves: comparison between ISO 5840 standards and in vivo studies

Bazan, Ovandir; Ortiz, Jayme Pinto

doi:10.5935/1678-9741.20160036

Cited by 7 publications

(5 citation statements)

References 9 publications

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“…We used a waveform with an approximately 50% systolic duration to better match in vivo conditions. 27 Pressure transducers and flow meters were zeroed before trials, and the baseline valve was reinstalled between experiments to reduce drift.…”

Section: Left Heart Simulator Design and Validationmentioning

confidence: 99%

Modeling conduit choice for valve-sparing aortic root replacement on biomechanics with a 3-dimensional–printed heart simulator

Paulsen

Kasinpila

Imbrie-Moore

et al. 2019

The Journal of Thoracic and Cardiovascular Surgery

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Objective: The optimal conduit for valve-sparing aortic root replacement is still debated, with several conduit variations available, ranging from straight tubular grafts to Valsalva grafts. Benefits of neosinus reconstruction include enhanced flow profiles and improved hemodynamics. Curiously, however, some clinical data suggest that straight grafts may have greater long-term durability. In this study, we hypothesized that straight tubular grafts may help maintain the native cylindrical position of the aortic valve commissures radially, resulting in preserved leaflet coaptation, reduced stresses, and potentially improved valve performance.Methods: Using 3D printing, a left heart simulator with a valve-sparing root replacement model and a physiologic coronary circulation was constructed. Aortic valves were dissected from fresh porcine hearts and reimplanted into either straight tubular grafts (n ¼ 6) or Valsalva grafts (n ¼ 6). Conduits were mounted into the heart simulator and hemodynamic, echocardiographic, and high-speed videometric data were collected.Results: Hemodynamic parameters and coronary blood flow were similar between straight and Valsalva grafts, although the former were associated with lower regurgitant fractions, less peak intercommissural radial separation, preserved leaflet coaptation, decreased leaflet velocities, and lower relative leaflet forces compared with Valsalva grafts.Conclusions: Valsalva grafts and straight grafts perform equally well in terms of gross hemodyanics and coronary blood flow. Interestingly, however, the biomechanics of these 2 conduits differ considerably, with straight grafts providing increased radial commissural stability and leaflet coaptation. Further investigation into how these parameters influence clinical outcomes is warranted. (J Thorac Cardiovasc Surg 2019;158:392-403) Variation (yellow arrows) between Valsalva graft and radial position of aortic commissures. Central MessageStraight grafts maintain the radial position of the aortic valve commissures in their native cylindrical conformation, preserving leaflet coaptation and decreasing regurgitation, cusp velocities, and forces. PerspectiveValve-sparing root replacement is an effective treatment for aortic root aneurysms, although the ideal conduit is unknown. While neosinus reconstruction is believed to generate more physiologic flow profiles and optimized hemodynamics, it does not appear to increase longterm clinical durability over straight grafts. Ex vivo testing was used to provide a mechanistic comparison and demonstrated decreased cusp velocities, forces, and regurgitation in straight grafts.

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Section: Left Heart Simulator Design and Validationmentioning

confidence: 99%

Modeling conduit choice for valve-sparing aortic root replacement on biomechanics with a 3-dimensional–printed heart simulator

Paulsen

Kasinpila

Imbrie-Moore

et al. 2019

The Journal of Thoracic and Cardiovascular Surgery

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“…In healthy patients the systole percent is about 25–35% of the cardiac cycle. 21 In patient suffering from heart failure the systole percent can reach 73% of the cardiac cycle. 22 …”

Section: Discussionmentioning

confidence: 99%

Initial simulated FFR investigation using flow measurements in patient-specific 3D printed coronary phantoms

Shepard

Sommer

Izzo

et al. 2017

Medical Imaging 2017: Imaging Informatics for Healthcare, Research, and Applications

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Purpose Accurate patient-specific phantoms for device testing or endovascular treatment planning can be 3D printed. We expand the applicability of this approach for cardiovascular disease, in particular, for CT-geometry derived benchtop measurements of Fractional Flow Reserve, the reference standard for determination of significant individual coronary artery atherosclerotic lesions. Materials and Methods Coronary CT Angiography (CTA) images during a single heartbeat were acquired with a 320×0.5mm detector row scanner (Toshiba Aquilion ONE). These coronary CTA images were used to create 4 patient-specific cardiovascular models with various grades of stenosis: severe, <75% (n=1); moderate, 50–70% (n=1); and mild, <50% (n=2). DICOM volumetric images were segmented using a 3D workstation (Vitrea, Vital Images); the output was used to generate STL files (using AutoDesk Meshmixer), and further processed to create 3D printable geometries for flow experiments. Multi-material printed models (Stratasys Connex3) were connected to a programmable pulsatile pump, and the pressure was measured proximal and distal to the stenosis using pressure transducers. Compliance chambers were used before and after the model to modulate the pressure wave. A flow sensor was used to ensure flow rates within physiological reported values. Results 3D model based FFR measurements correlated well with stenosis severity. FFR measurements for each stenosis grade were: 0.8 severe, 0.7 moderate and 0.88 mild. Conclusions 3D printed models of patient-specific coronary arteries allows for accurate benchtop diagnosis of FFR. This approach can be used as a future diagnostic tool or for testing CT image-based FFR methods.

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“…The LVM was established for a heart rate of 60 bpm with a systolic duration of 400 ms , a stroke volume of 70 mL, and an end‐diastolic volume of 120 mL. The aortic pressure (AoP) was increased successively, until it reached the range of 80–120 mm Hg , as shown in Fig.…”

Section: Methodsmentioning

confidence: 99%

In Vitro Hydrodynamic Evaluation of a Scaffold for Heart Valve Tissue Engineering

et al. 2018

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Although prosthetic heart valves have saved many lives, the search for a living substitute continues with the aid of tissue engineering. Much progress has been made so far, but the translation of this technology to clinical reality remains a challenge, especially due to the structural complexity of heart valves and the harsh environment they are in. In a joint effort, researchers from Federal University of ABC and Institute Dante Pazzanese of Cardiology have conceived a new bioresorbable scaffold for heart valve tissue engineering (HVTE), whose hydrodynamic performance was first assessed and described in this work. The scaffold was studied at the mitral position of a left heart simulator from Escola Politécnica of the University of São Paulo, under 60 bpm and with no cell seeding. In this condition, two-dimensional particle image velocimetry was performed to investigate the flow during diastolic and systolic phases. The results indicate that the scaffold can withstand the required intraventricular pressures for a simulated normal physiologic condition in a bioreactor. Furthermore, the averaged (N = 150) velocity vector maps showed a smooth and well-distributed flow during diastole and qualitatively demonstrated no-significant regurgitation at systole.

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Duration of systole and diastole for hydrodynamic testing of prosthetic heart valves: comparison between ISO 5840 standards and in vivo studies

Cited by 7 publications

References 9 publications

Modeling conduit choice for valve-sparing aortic root replacement on biomechanics with a 3-dimensional–printed heart simulator

Modeling conduit choice for valve-sparing aortic root replacement on biomechanics with a 3-dimensional–printed heart simulator

Initial simulated FFR investigation using flow measurements in patient-specific 3D printed coronary phantoms

In Vitro Hydrodynamic Evaluation of a Scaffold for Heart Valve Tissue Engineering

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