Figure 1.
Principal design of the tip of the Extroducer.
Different designs of intrusion depth limiting collars were tested for optimal stopping ability in a safe manner. Here, a principal drawing of the design is depicted with an intrusion depth limiting collar.
Figure 2.
Ex vivo and simulation data from penetration forces and blood-flow in the catheter lumen.
In a. graph showing data from a loading cell connected to a longitudinally cut aorta mounted in free air with the first bar corresponding to force applied to penetrate the vessel wall from inside and out and the second bar corresponding to perforation by the depth limiting collar, an “overshooting” of the system. Error bars are Standard deviations. In b. graph showing flow rates (Y-axis) plotted against lumen radius (X-axis). The flow rate becomes small as the lumen radius is reduced. At radii over 50 micrometer, turbulent flow gives lower flow rates (open symbols) which is taken into account in the calculations with COMSOL Multiphysics as compared to a perfect laminar flow (filled symbols). In c. graph illustrating velocity fields of circular Poiseuille flows (filled symbols) and COMSOL Multiphysics (open symbols) in an Extroducer device with a 2 mm long lumen, wherein the velocity fields, driven by a pressure of 200 mmHg (Y-axis), are plotted against different lumen radius (X-axis). This shows turbulence impact in reducing the velocity in the central part of the velocity fields. At a 50 micrometer radius COMSOL Multiphysics is identical to the circular Poiseuille flow but at higher radii the impact of turbulence becomes apparent.
Figure 3.
Histology of vessel perforation.
Microphotograph showing the vessel perforation made by the Extroducer body with an outer diameter of 194 µm. The Extroducer makes a penetration that is on average 70 µm in diameter, indicated by arrows in this histological vessel sample stained by hematoxilin and eosin. VW indicates vessel wall and VL indicates vessel lumen, respectively. Scale bar: 20 µm.
Figure 4.
Radiological and microsurgical examples of the intervention.
For full control over the procedure in the large animal trials, both a surgical microscope and high resolution angiographical series was used. In a. digital subtraction angiogram showing a detached Extroducer tip without hemorrhage, dissection or thromboembolic complications. In b. photograph showing the microsurgical view of the detached Extroducer tip. In c. x-ray image showing the detached Extroducer tip with guide catheter. In d. photograph from post-operative dissection showing the detached Extroducer tip with methylene blue injected in the surrounding tissue. In e. digital subtraction angiogram showing an extra vascular injection of 25 µl contrast agent through the Extroducer system.
Figure 5.
Follow up digital subtraction angiography.
Digital subtraction angiography series in the subclavian artery at different time points after detachment of the Extroducer tip.