Continuous extracorporeal femoral perfusion model for intravascular ultrasound, computed tomography and digital subtraction angiography

Abstract

Objectives: We developed a novel human cadaveric perfusion model with continuous extracorporeal femoral perfusion suitable for performing intra-individual comparison studies, training of interventional procedures and preclinical testing of endovascular devices. Objective of this study was to introduce the techniques and evaluate the feasibility for realistic computed tomography angiography (CTA), digital subtraction angiography (DSA) including vascular interventions, and intravascular ultrasound (IVUS).

Methods: The establishment of the extracorporeal perfusion was attempted using one formalin-fixed and five fresh-frozen human cadavers. In all specimens, the common femoral and popliteal arteries were prepared, introducer sheaths inserted, and perfusion established by a peristaltic pump. Subsequently, we performed CTA and bilateral DSA in five cadavers and IVUS on both legs of four donors. Examination time without unintentional interruption was measured both with and without non-contrast planning CT. Percutaneous transluminal angioplasty and stenting was performed by two interventional radiologists on nine extremities (five donors) using a broad spectrum of different intravascular devices.

Results: The perfusion of the upper leg arteries was successfully established in all fresh-frozen but not in the formalin-fixed cadaver. The experimental setup generated a stable circulation in each procedure (ten upper legs) for a period of more than six hours. Images acquired with CT, DSA and IVUS offered a realistic impression and enabled the sufficient visualization of all examined vessel segments. Arterial cannulating, percutaneous transluminal angioplasty as well as stent deployment were feasible in a way that is comparable to a vascular intervention in vivo. The perfusion model allowed for introduction and testing of previously not used devices.

Conclusions: The continuous femoral perfusion model can be established with moderate effort, works stable, and is utilizable for medical imaging of the peripheral arterial system using CTA, DSA and IVUS. Therefore, it appears suitable for research studies, developing skills in interventional procedures and testing of new or unfamiliar vascular devices.

Fig 1. Surgical access.

A. Situs after preparation of the infragenicular access to the distal popliteal artery using a medial access between Mm. gracilis/semitendinosus and M. gastrocnemius. B. Infragenicular outflow with introduced Fogarty embolectomy catheter in popliteal artery. C. Inguinal situs after preparation of the femoral bifurcation. D. Severed common femoral artery after proximal ligature of the common femoral artery and deep femoral artery. E. Introducer sheath placed in the stump of the common femoral artery and fixation by knotting and cable strap. F. Inguinal situs after insertion of the working introducer sheath in the distal common femoral artery with standard Seldinger technique.

Fig 2. Schematic illustration of the extracorporeal femoral perfusion setup.

Fig 3. Representative CTA images.

A. Three-dimensional image using virtual cinematic rendering technique (view from posterior) with partially captured proximal introducer sheaths and entirely visible distal outflow introducer sheath. B. Coronal maximum intension projection (view from anterior) of the contrasted superficial femoral and popliteal artery with arterial plaques. In addition, calcifications of the not-contrasted common femoral artery, ligated deep femoral artery, and proximal lower leg arteries are visible. C. Axial CTA slice showing a mixed plaque in the superficial femoral artery. D. Axial CTA slice with artifact by intraluminal air bubble.

Fig 4. Representative DSA images.

A. Fluoroscopy of the pelvis and left proximal femur with visible inflow and working introducer sheaths. B. DSA of the left proximal superficial femoral artery and contrasted working introducer sheath. C. Contrasted superficial femoral artery and muscle branches. D. DSA of the left proximal superficial femoral artery and contrasted outflow introducer sheath.

Fig 5. Representative fluoroscopy frames of vascular interventions.

A. Fluoroscopy image of the right upper leg with under-expansion of a self-expanding-stent inside the stenotic superficial femoral artery. B. Inflated PTA balloon inside a stented vessel segment for remodeling. C. Fluoroscopy frame of a stent-in-stent situation located in the distal right superficial femoral artery. D. Fluoroscopy frame of an endovascular dissection repair device (Tack Endovascular System, Philips Healthcare) with two expanded tacks (marked with white arrowheads) and four still mounted on the multi-delivery system.

Fig 6. Representative IVUS images.

A. DSA showing the IVUS catheter in intravascular position. B. IVUS image of an arterial segment with stenosis of ~80%. Imaging plane is marked with a black arrowhead in (A). (blue line: suspected vessel diameter; green line: residual perfused lumen). C. IVUS image generated in a stented vessel segment (metal reflex marked with a white arrowhead) with a low-grade in stent stenosis.