Patient-specific computational fluid dynamics of femoro-popliteal stent-graft thrombosis

Conti, Michele; Ferrarini, Anna; Finotello, Alice; Salsano, Giancarlo; Auricchio, Ferdinando; Palombo, Domenico; Spinella, Giovanni; Pane, Bianca

doi:10.1016/j.medengphy.2020.10.011

Cited by 14 publications

(13 citation statements)

References 35 publications

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“…Based on such considerations, we performed patientspecific CFD simulations in order to assess the impact of leg bending and the interplay among geometrical features on the local hemodynamic of two patients treated with endovascular stent-graft placement for PAA, experiencing intra-stent thrombosis. Moreover, we deepened and improved our previous study [10] by investigating the impact of the different inlet boundary conditions on the solution (in a similar way to Hua et al [17]), and assessing the hypothesis of non-Newtonian behavior of blood (using the Carreau model), in comparison with the usual approximation of blood as a Newtonian fluid.…”

Section: Introductionmentioning

confidence: 96%

“…In a more recent study led by Colombo et al [9], knee flexion and complete movement of walking have been assessed in an idealized model of FPA. Finally, the impact of leg bending on geometrical and hemodynamic features have been investigated in our previous work, where patient-specific CFD simulations have been performed on a single patient, using literature boundary conditions [10] and Newtonian model for blood rheology. Although it is known that blood is a non-Newtonian fluid [11], literature review about CFD modeling of the actual rheology of blood is controversial.…”

Section: Introductionmentioning

confidence: 99%

“…According to the literature, CFD provides a useful tool for understanding and predicting disease progression and hemodynamic-related post-stent complications. However, literature studies about patient specific CFD of popliteal stenting are scarce; in particular, many of them involve idealized geometry [3,9] and literature boundary conditions [3,10], without any information regarding the follow-up intra-stent thrombosis. Moreover, morphological variations during knee flexion in the FPA could significantly influence the local hemodynamic [9,10].…”

Section: Introductionmentioning

confidence: 99%

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Impact of leg bending in the patient-specific computational fluid dynamics of popliteal stenting

et al. 2021

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Endovascular treatment of the femoro-popliteal artery has recently become a valuable therapeutic option for popliteal arterial aneurysms. However, its efficacy remains controversial due to the relatively high rate of complications, such as stent occlusion as result of intra-stent thrombosis. The elucidation of the interplay among vessel geometrical features, local hemodynamics, and leg bending seems crucial to understand onset and progression of popliteal intra-stent thrombosis. To this aim, patient-specific computational fluid dynamic simulations were performed in order to assess the intra-stent hemodynamics of two patients endovascularly treated for popliteal arterial aneurysm by stent-grafts and experiencing intra-stent thrombosis. Both Newtonian and non-Newtonian blood rheological models were considered. Results were presented in terms of tortuosity, luminal area exposed to low (< 0.4 Pa) and high (> 1.5 Pa) time-averaged wall shear stress (TAWSS), area exposed to high (> 0.3) oscillatory shear index (OSI), and flow helicity. Study outcomes demonstrated that leg bending induced significant hemodynamic differences (> 50% increase) in both patients for all the considered variables, except for OSI in one of the two considered patients. In both leg configurations, stent-graft overlapping induced a severe discontinuity of the lumen diameter where the proximal stented zone is characterized by low tortuosity, low velocity, low helicity, low TAWSS, and high OSI; while the distal part has higher tortuosity, velocity, helicity, TAWSS, and lower OSI. Sensitivity study on applied boundary conditions showed that the different inlet velocity profiles for a given inlet waveform affect slightly the numerical solution; conversely, the shape and magnitude of the prescribed inlet waveform is determinant. Focusing on the comparison between the Newtonian and non-Newtonian blood models, the area with low TAWSS is greater in the Newtonian model for both patients, while no significant difference occurs between the surfaces with high TAWSS. GraphicAbstract Patient-specific computational fluid dynamic simulations were performed in order to assess the intra-stent hemodynamics of two patients endovascularly treated for popliteal arterial aneurysm and experiencing intra-stent thrombosis. Both Newtonian and non-Newtonian blood rheological models were considered. In both straight and bent leg configurations, stent-graft overlapping induced a severe discontinuity of the lumen diameter where the proximal stented zone is characterized by low tortuosity, low velocity, low helicity, low time-averaged wall shear stress (TAWSS), and high oscillatory index (OSI); while the distal part has higher tortuosity, velocity, helicity, TAWSS, and lower OSI.

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Section: Introductionmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Impact of leg bending in the patient-specific computational fluid dynamics of popliteal stenting

et al. 2021

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“…It has been reported that low WSS, high OSI and high RRT will promote platelet aggregation and ultimately lead to thrombus formation (31)(32)(33). Conti et al showed that the femoro-popliteal in-stent thrombosis is characterized by larger diameter, low tortuosity, low flow velocity, low helicity, and low wall shear stress (34). Leg bending induces an overall increase of arterial tortuosity, helix flow, and reduces flow velocity which may furtherly promote the luminal area exposed to thrombosis related hemodynamic parameters.…”

Section: Discussionmentioning

confidence: 99%

Hemodynamic Parameters Predict In-stent Thrombosis After Multibranched Endovascular Repair of Complex Abdominal Aortic Aneurysms: A Retrospective Study of Branched Stent-Graft Thrombosis

Liu

Yang

Liu

et al. 2021

Front. Cardiovasc. Med.

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Background: Branch vessel occlusion is reported in endovascular repair of aortic pathology. This study aimed to evaluate the hemodynamic indicators associated with in-stent thrombosis (IST) of a branched stent-graft (BSG) after endovascular aortic repair (EVAR) of a complex abdominal aortic aneurysm.Methods: A retrospective evaluation was performed based on the computed tomography (CT) scans and clinical data of three patients who underwent multi-branched endovascular repair. Patient-specific 3-dimensional models were reconstructed, and hemodynamic analysis was performed for IST. Hemodynamics-related parameters including time-averaged wall shear stress (TAWSS), oscillatory shear stress index (OSI), and relative residence time (RRT) were compared among the individual patients.Results: The flow velocity, TAWSS, OSI, and RRT were radically changed in the area of the IST. In BSGs, IST tended to occur in the regions of hemodynamic alteration near the bends in the device, where a decreased flow velocity (<0.6 m/s) and TAWSS (<0.8 Pa) and an elevated OSI (>0.2) and RRT (>5 s) were consistently observed.Conclusions: Hemodynamic perturbations in BSGs cause a predisposition to IST, which can be predicted by a series of changes in the flow parameters. Early hemodynamic analysis might be useful for identifying and remediating IST after multibranched endovascular repair.

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“…However, due to the low resolution of CT imaging, the models lack detailed description of the lumen surface and the stent geometry. Finally, Conti et al have performed CT angiography (CTA) on a single patient at a one-year follow-up of a popliteal aneurysm repair through stent-graft implantation 18 . They used this data as the basis of a proof-of-concept study, in which they performed CFD simulations and investigated the flow behaviors in the artery for straight- and bent-leg positions.…”

Section: Introductionmentioning

confidence: 99%

Towards a better understanding of the posttreatment hemodynamic behaviors in femoropopliteal arteries through personalized computational models based on OCT images

Gökgöl

Ueki

Abler

et al. 2021

Sci Rep

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The hemodynamic behavior following endovascular treatment of patients with peripheral arterial disease plays a significant role on the occurrence of restenosis in femoro-popliteal (FP) arteries. The atheroprone flow conditions that are generally accepted to promote restenosis can be calculated by computational fluid dynamics (CFD) analyses, and these results can be used to assess individualized treatment outcomes. However, the impact of endovascular therapy on the flow behaviors of FP arteries are still poorly understood, as the imaging modalities used in existing numerical works (X-ray angiography, computed tomography angiography) are unable to accurately represent the post-treatment arterial geometry due to their low resolutions. Therefore, this study proposes a new algorithm that combines intra-arterial lumen geometry obtained from high-resolution optical coherence tomography (OCT) images with centerlines generated from X-ray images to reconstruct the FP artery with an in-plane resolution of 10 µm. This superior accuracy allows modeling characteristic geometrical structures, such as angioplasty-induced arterial dissections, that are too small to be reconstructed with other imaging modalities. The framework is applied on the clinical data of patients treated either with only-percutaneous transluminal angioplasty (PTA) (n = 4) or PTA followed by stenting (n = 4). Based on the generated models, PTA was found to cause numerous arterial dissections, covering approximately 10% of the total surface area of the lumen, whereas no dissections were identified in the stented arteries. CFD simulations were performed to investigate the hemodynamic conditions before and after treatment. Regardless of the treatment method, the areas affected by low time-averaged wall shear stress (< 0.5 Pa) were significantly higher (p < 0.05) following endovascular therapy (pre-PTA: 0.95 ± 0.59 cm2; post-PTA: 2.10 ± 1.09cm2; post-stent: 3.10 ± 0.98 cm2). There were no statistical differences between the PTA and the stent groups. However, within the PTA group, adverse hemodynamics were mainly concentrated at regions created by arterial dissections, which may negatively impact the outcomes of a leave-nothing-behind strategy. These observations show that OCT-based numerical models have great potential to guide clinicians regarding the optimal treatment approach.

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Patient-specific computational fluid dynamics of femoro-popliteal stent-graft thrombosis

Cited by 14 publications

References 35 publications

Impact of leg bending in the patient-specific computational fluid dynamics of popliteal stenting

Impact of leg bending in the patient-specific computational fluid dynamics of popliteal stenting

Hemodynamic Parameters Predict In-stent Thrombosis After Multibranched Endovascular Repair of Complex Abdominal Aortic Aneurysms: A Retrospective Study of Branched Stent-Graft Thrombosis

Towards a better understanding of the posttreatment hemodynamic behaviors in femoropopliteal arteries through personalized computational models based on OCT images

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