In vitro characterisation of the patient-specific haemodynamics of an extracranial peripheral arteriovenous malformation using PIV.

Peripheral Arteriovenous Malformations (pAVMs) are congenital vascular anomalies characterised by abnormal connections between arteries and veins that bypass the capillary network. This bypass results on a high-flow and low resistance vascular structure termed nidus. The high-flow and complex angioarchitecture of pAVMs makes treatment challenging and often suboptimal, as evidenced by high recurrence rates. Current treatment strategies rely on qualitative imaging techniques. Quantitative haemodynamic information on pAVMs can provide insight into the pathology and potentially enhance intervention outcomes. We report an experimental study on pAVMs haemodynamics resolved using patient-specific 3D-printed phantoms and Particle Image Velocimetry. A 3D printable porous structure was implemented to reproduce the pressure drop the blood flow experiences as it passes through the nidus, derived from in vivo patient data. Velocity measurements past the nidus revealed complex flow patterns, due to the high flow nature of the pAVM and the vessel anatomy which could potentially serve as biomarkers to assess the efficacy of interventions and the disease severity and progression. To the best of our knowledge this is the first in vitro study to combine patient-specific phantoms and detailed velocity distributions in a pAVM. The in vitro approach reported herein can be used for in silico model validation, physical intervention testing and to inform data driven methodologies that could all optimise pAVM procedures and reduce recurrence rates.