LVAD Outflow Graft Angle and Thrombosis Risk

Aliseda, Alberto; Chivukula, Venkat Keshav; McGah, Patrick M.; Prisco, Anthony R.; Beckman, Jennifer; Garcia, Guilherme J. M.; Mokadam, Nahush A.; Mahr, Claudius

doi:10.1097/mat.0000000000000443

Cited by 76 publications

(81 citation statements)

References 55 publications

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“…While the results highlighted here are for the subset of particles traveling towards the cerebral circulation, the trends are fully consistent with statistics for all platelets, and irrespective of outflow graft angle 14 : intermittent AV opening has a globally beneficial effect on both RT and SH for all injected particles.…”

Section: Resultssupporting

confidence: 78%

“…CFD simulations of blood flow, including platelet-surrogate dynamics, are performed for the different conditions 14 . Briefly, image segmentation was performed on Gadolinium-enhanced magnetic resonance angiography (MRA) images of patient vasculature of the ascending aorta and great vessels.…”

Section: Methodsmentioning

confidence: 99%

“…TP is intended to rank-order the relative thrombogenic potential of the different cases investigated 14 (on a normalized scale from 0 to 1), but not to evaluate an absolute risk of thrombosis (i.e. a value of 1 represents a higher risk than 0.5, but does not indicate that the probability of thrombosis is twice as high).…”

Section: Methodsmentioning

confidence: 99%

“…Wall shear stress), following the atherosclerosis mechanotransduction pathway, and were limited to steady flow models 7–11 . In reality, platelet activation and aggregation, essential to understanding thrombus initiation and propagation, 12,13 are associated with shear stress and residence time of flowing platelets and require modeling and computation via a different methodology (Lagrangian 14 ). This holistic approach makes it feasible to quantify the mechanical stimuli experienced by platelets as well as the endothelium, providing more complete metrics for evaluating thrombogenicity.…”

Section: Introductionmentioning

confidence: 99%

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Intermittent Aortic Valve Opening and Risk of Thrombosis in Ventricular Assist Device Patients

et al. 2017

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This study evaluates quantitatively the impact that intermittent Aortic Valve opening has on the thrombogenicity in the aortic arch region for patients under Left Ventricular Assist Device therapy. The influence of flow through the Aortic Valve, opening once every five cardiac cycles, on the flow patterns in the ascending aortic is measured in a patient-derived CT-image-based model, after LVAD implantation. The mechanical environment of flowing platelets is investigated, by statistical treatment of outliers in Lagrangian particle tracking, and thrombogenesis metrics (platelet residence times and activation state characterized by shear stress accumulation) are compared for the cases of no Aortic Valve opening and intermittent Aortic Valve opening. All hemodynamics metrics are improved by Aortic Valve opening, even at a reduced frequency and flow rate. Residence times of platelets or microthrombi are reduced significantly by transvalvular flow, as are the shear stress history experienced and the shear stress magnitude and gradients on the aortic root endothelium. The findings of this device-neutral study support the multiple advantages of management that enables Aortic Valve opening, providing a rationale for establishing this as a standard in long-term treatment and care for advanced heart failure patients.

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Section: Resultssupporting

confidence: 78%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Intermittent Aortic Valve Opening and Risk of Thrombosis in Ventricular Assist Device Patients

et al. 2017

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“…Studies conducted where the AV remained closed found that stagnation typically occurs immediately distal to the AV [11, 14, 34]. A previous study by our group followed up on these results demonstrating that including residual cardiac function in the simulation eliminated stagnation [35]. This finding demonstrates the importance of optimizing VAD speed to allow for intermittent AV opening.…”

Section: Discussionmentioning

confidence: 74%

Impact of LVAD Implantation Site on Ventricular Blood Stagnation

Prisco¹,

Aliseda

Beckman

et al. 2017

ASAIO Journal

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Treatment of end-stage heart failure includes cardiac transplantation or ventricular assist device (VAD) therapy. While increasingly prevalent, current VAD therapy has inherent complications, including thrombosis. Studies have demonstrated that VAD implantation alters intra-cardiac blood flow, creating areas of stagnation that predispose to thrombus formation. Two potential surgical configurations exist for VAD implantation: through the apical or diaphragmatic surfaces of the heart. We hypothesized that diaphragmatic implantation causes more stagnation than apical implantation. We also hypothesized that intermittent aortic valve (AV) opening reduces stagnation of blood inside the left ventricle (LV) when compared to a closed AV. To test these hypotheses, a human left-ventricle geometry was re-created in silico and a VAD inflow cannula was virtually implanted in each configuration. A computational indicator-dilution study was conducted where “virtually-dyed blood” was washed out of the LV by injecting blood with no dye. Simulations demonstrated a substantial reduction in stagnation with intermittent AV opening. In addition, virtual dye was cleared slightly faster in the apical configuration. Simulations from our study demonstrate the clinical importance of VAD management to allow intermittent opening of the AV to prevent subvalvular stagnation, and it also suggests that apical configuration might be more hemodynamically favorable.

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