Efficacy evaluation and parametric study of the novel concave triple branched stent graft system based on hemodynamic analysis of first-in-man cases

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Background: Concave supra-arch triple branched stent-graft system (CS system) offers a new option for treating aortic arch pathologies. However, the efficacy of the innovative device still lacks objective evaluations. Patient-specific CS system design and treatment strategies remain unknown. This study aims to assess the effectiveness and to inform the patient-specific CS system design by evaluating the hemodynamic effects of key parameters. Methods: Simulations were conducted via pre- and post-operative computed tomography angiography datasets from five first-in-man study cases. Parametric studies on the CS system were developed by virtually adjusting concave degree (angle α) in scenarios with patient-specific aortic diameter. Boundary conditions were obtained through three-element Windkessel model. Quantitative and qualitative hemodynamic analyses were conducted via flow rate, pressure, time-averaged wall shear stress (TAWSS)-based parameters and energy loss. Results: CS system insertion effectively maintained supra-aortic trunks (SATs) blood flow, without significantly affecting ascending aortic (AA) pressure and hemodynamic environments, regardless of postoperative normotensive (120/80 mmHg) or hypertensive (180/140 mmHg) states. Larger concave angles improved SATs perfusion by approximately 1-2%, with hemodynamic variations becoming notably more pronounced when α increased beyond 150°. Specifically, increases in SATs flow were 0.6-0.7% from 120° to 150°, compared with 1.8-2.0% from 150° to 180°, while flow to the left subclavian artery decreased by ~0.45% and ~0.75% over the same ranges. AA pressure changes remained small, with CS implantation increasing systolic pressure by only ~1.2%. Larger aortic diameters or smaller diameter differences between AA and descending aorta (DA) further reduced postoperative AA pressure by approximately 0.1-2%. Notably, patients with smaller aortic diameters exhibited substantially larger hemodynamic changes: for example, TAWSS in the thoracic aorta increased by up to ~40% when D1 =30 mm, compared with only ~10% when D1 =48 mm. Conclusions: CS system shows improved hemodynamic features in treating aortic arch aneurysm and can maintain stability under both normotensive and hypertensive postoperative blood pressure conditions. Larger concave angle can improve surgical convenience, but may also increase the risk of pressure elevation. For patients with small aortic diameters, reducing the concave degree may help to optimize the hemodynamic environment. The findings presented herein provide objective evaluation for assessing CS system outcomes and patient-specific clinical decision making.

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