Physical and Computer Modelling of Blood Flow in a Systemic-to-pulmonary Shunt

Małota, Z.; Nawrat, Zbigniew; Kostka, P.; Mizerski, Jeremi; Nowiński, Krzysztof; Waniewski, Jacek

doi:10.1177/039139880402701112

Cited by 10 publications

(7 citation statements)

References 14 publications

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“…5). A similar complex flow pattern at the entrance to and exit from the graft, with eddies in the pulmonary artery, was found by laser visualization in a physical model of mB-T (24).…”

Section: Discussionsupporting

confidence: 70%

The Effects of Graft Geometry on the Patency of a Systemic‐to‐Pulmonary Shunt: A Computational Fluid Dynamics Study

Waniewski¹,

Kurowska

Mizerski³

et al. 2005

Artificial Organs

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Abstract:The modified Blalock-Taussig shunt is a palliative operation for some congenital heart diseases. An artificial conduit with antithrombotic surface placed between the subclavian (or innominate) and the pulmonary artery supplies blood to the lungs in defects with decreased pulmonary flow. Clotting of the graft is the main cause of its failure. Stenosis of the arteries is also observed. The objective of the present study was to investigate the flow pattern in the graft to investigate the possibility that clotting is initiated by the stimulation of platelets by high shear stress, and the possible effect of the pathological wall shear stress on the stenosis formation. The model included the left subclavian artery (LSA), the left pulmonary artery (LPA), and the graft. The three-dimensional relative position and size of the arteries was obtained from a CT scan of real anatomy. Four different types of the graft with two different diameters (3 and 4 mm) and two different shapes (straight and curved) of the pipe, and one variable diameter pipe were inserted in the model. A pulsatile flow of 0.81 L/min on average was assumed at the inlet to LSA, and 80% of the flow was directed through the graft. Computer simulations demonstrated a complex flow pattern with eddies and low velocity regions in the arteries at the anastomoses with the graft in all five models. An eddy was also found inside the straight 4 mm graft. A high pathological shear rate was present within the graft, with higher values in the 3 mm grafts. The fractional volume with a high ( > 2500 L/s) shear rate was between 2.5% and 4.5%, and that with a very high ( > 7500 L/s) shear rate between 0 and 1.5% of the model volume, and depended on the graft geometry and the phase of the cardiac cycle. Pathologically high ( > 3.5 Pa) and pathologically low ( < 1.0 Pa) wall shear stress, which may induce neointimal growth, was found in LSA and LPA. We conclude that the activation of platelets by high shear rate is possible within the graft, followed by their subsequent aggregation in the eddies with a low flow rate. Flow-induced changes of the vessel wall thickness (stenosis) can also appear, especially in the pulmonary artery.

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“…5). A similar complex flow pattern at the entrance to and exit from the graft, with eddies in the pulmonary artery, was found by laser visualization in a physical model of mB-T (24).…”

Section: Discussionsupporting

confidence: 70%

The Effects of Graft Geometry on the Patency of a Systemic‐to‐Pulmonary Shunt: A Computational Fluid Dynamics Study

Waniewski¹,

Kurowska

Mizerski³

et al. 2005

Artificial Organs

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“…In a multiscale model, unbalanced flow distribution between the left and the right pulmonary arteries was noted in the modified B‐T shunt, and it was more remarkable with larger shunt sizes 8 . A complex flow pattern with large eddies and flow channeling in the vicinity of the graft and within it, which may yield high shear stress and modify blood properties, was observed in flow visualization and computer simulations 9 …”

mentioning

confidence: 94%

“…8 A complex flow pattern with large eddies and flow channeling in the vicinity of the graft and within it, which may yield high shear stress and modify blood properties, was observed in flow visualization and computer simulations. 9…”

mentioning

confidence: 99%

The Blalock-Taussig Shunt

Yuan

Shinfeld

Raanani

2009

Journal of Cardiac Surgery

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Background and aim of the study: Even though the Blalock-Taussig (B-T) shunt, either classic or modified, has been advocated and successfully employed in clinical practice for more than half a century, a systemic review on this procedure is still scanty. This warrants us a zest in making a comprehensive survey on this subject. Methods: Articles were extensively retrieved from the MEDLINE database of National Library of Medicine USA if the abstract contained information relevant to the B-T shunt in terms of the conduit options, modified surgical techniques, surgical indications, short-and long-term results, complications, and prognosis. Further retrieval was undertaken by manually searching the reference list of relevant papers. Results: Classical or modified B-T shunts, either on ipsilateral or contralateral side to the aortic arch, can be performed on patients of any age with minimum postoperative complications and low operative mortality. Expended polytetrafluoroethylene has gained satisfactory long-term patency rate in the construction of the modified B-T shunt. Excellent pulmonary artery growth was observed in the patients with a modified B-T shunt, and it has shown superb prognosis over the classic with regard to hemodynamics, patency rate, and survival. Conclusions: The modified B-T shunt that was developed on basis of the classic fashion remains the preferable palliative procedure aiming at enhancing pulmonary blood flow for neonates and infants with complicated cyanotic congenital heart defects. The modified B-T shunt is technically simpler with less dissection, and blood flow to the respective arm is not jeopardized. It has been proved to be of low risk, excellent palliation, and is associated with excellent pulmonary artery growth, has become the most effective palliative shunt procedure of today. doi: 10.1111/j.1540-8191.2008.00758.x (J Card Surg 2009;24:101-108) Complex cyanotic congenital heart disease may occasionally be unsuitable for surgical correction, but for palliative procedure only. 1 In 1945, prior

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“…The dynamic measurements were taken at the Foundation of Cardiac Surgery Development on the hybrid model [20,21] of a human vascular system. The prosthesis was driven by the POLPDU-402 driving unit, allowing to change the heart-supporting parameters up to SDP max = +300 mmHg, DDP max = −75 mmHg and AHR max = 120BPM.…”

Section: Methodsmentioning

confidence: 99%

Acoustic system for the estimation of the temporary blood chamber volume of the POLVAD heart supporting prosthesis

Konieczny

Opilski

Pustelny

et al. 2012

BioMedical Engineering OnLine

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BackgroundThe paper presents a newly researched acoustic system for blood volume measurements for the developed family of Polish ventricular assist devices. The pneumatic heart-supporting devices are still the preferred solution in some cases, and monitoring of their operation, especially the temporary blood volume, is yet to be solved.MethodsThe prototype of the POLVAD-EXT prosthesis developed by the Foundation of Cardiac Surgery Development, Zabrze, Poland, is equipped with the newly researched acoustic blood volume measurement system based on the principle of Helmholtz’s acoustic resonance. The results of static volume measurements acquired using the acoustic sensor were verified by measuring the volume of the liquid filling the prosthesis. Dynamic measurements were conducted on the hybrid model of the human cardiovascular system at the Foundation, with the Transonic T410 (11PLX transducer - 5% uncertainty) ultrasound flow rate sensor, used as the reference.ResultsThe statistical analysis of a series of static tests have proved that the sensor solution provides blood volume measurement results with uncertainties (understood as a standard mean deviation) of less than 10%. Dynamic tests show a high correlation between the results of the acoustic system and those obtained by flow rate measurements using an ultrasound transit time type sensor.ConclusionsThe results show that noninvasive, online temporary blood volume measurements in the POLVAD-EXT prosthesis, making use of the newly developed acoustic system, provides accurate static and dynamic measurements results. Conducted research provides the preliminary view on the possibility of reducing the additional sensor chamber volume in future.

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Physical and Computer Modelling of Blood Flow in a Systemic-to-pulmonary Shunt

Cited by 10 publications

References 14 publications

The Effects of Graft Geometry on the Patency of a Systemic‐to‐Pulmonary Shunt: A Computational Fluid Dynamics Study

The Effects of Graft Geometry on the Patency of a Systemic‐to‐Pulmonary Shunt: A Computational Fluid Dynamics Study

The Blalock-Taussig Shunt

Acoustic system for the estimation of the temporary blood chamber volume of the POLVAD heart supporting prosthesis

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