PhysioSize your blood flow
Optimising the lumen is the key to enhanced drainage. The space between the smartcanula and the vein wall is no longer a channel; instead, blood directly drains into the
smartcanula along its entire length. A shorter path at lower velocities leads to a
decreased pressure drop and increased flow.
The Concept
The smartcanula can be stretched over a mandrel and collapsed before intra-vascular insertion. In its “low-profile” configuration, the smartcanula is slid over a guidewire and positioned within the target vessel.
Once in position, the guide wire and the mandrel are removed. Due to its memory, the smartcanula expands and provides an unsurpassed lumen. Simple traction is enough for reduced diameter and removal.
Mathematical simulation of velocity contours for a standard 18F canula with a flow of 4 l/min by computational fluid dynamics (CFD): Pressure drop accounts for 140 mmHg.
For the same 18F access aperture and flow, CFD shows for an expanding design significantly lower velocity contours. Pressure drops in this setting account only for 49 mmHg.
Schematic craniocaudal view of the inferior vena cava, the iliac, and the femoral veins. At the target level, which is defined as the position providing optimal drainage, standard canulas use only a canula small fraction of the available cross-sectional area.
The diameter of a self-expanding canula is not limited by the diameter of the access vessel. As a result, drainage is superior and a pump or vacuum is not necessary for augmentation of venous return.
In vivo assessment of a standard canula within the inferior vena cava by intra-vascular ultrasound (IVUS=*). The luminal diameter of the standard accounts for 7.2 mm. The cross-sectional area accounts for 40.7 mm2 (a fraction of the vein).
The smartcanula in vivo as seen by IVUS* (same vena cava as shown above). The lumen of smartcanula is 10 mm and the cross-sectional area accounts for 78.5 mm2: almost double!
Publications
Virtually Wall-Less versus Standard Thin-Wall Venous Cannula in the Minimally Invasive Mitral Valve Surgery: Single-Center Experience.
Conclusions: The virtually wall-less cannula should be preferred in minimally invasive mitral valve surgery due to its superior performance in terms of venous drainage compared with the standard thin-wall cannula.
2023
Single-Center Experience With a Self-Expandable Venous Cannula During Minimally Invasive Cardiac Surgery.
Conclusions: The venous smart canula® allows for optimal venous drainage at low negative drainage pressures, facilitating sufficient perfusion in MICS.
2022
Femoral Venous Cannulation for Minimally Invasive Surgery: Three Years Experience with Wall-less, Self-expandable Cannula
Conclusions: Wall-less cannula ensure higher flow, in most cases without vacuum assistance. Surgical set up resulted easier and quicker with excellent visibilty, reducing operative times. No advantages in terms of quality of cardiopulmonary bypass and enzymatic peaks were demonstrated.
2021
Clinical Experience With A Self-expandable Venous Cannula During Cardiopulmonary Bypass In Minimally Invasive Cardiac Surgery
Conclusions: Venous drainage via a single femoral self-expandable metallic stent venous cannula results in optimal venous drainage. This low-profile cannulation technique facilitates perfusion in minimally invasive cardiac valve surgery requiring low negative-drainage-pressures. Figure 1. A1-2) Stretched cannula mesh with a semirigid obturator, ready for low-profile insertion.
2018
Clinical Experience in Minimally Invasive Cardiac Surgery With Virtually Wall-Less Venous Cannulas
Conclusions: The performance of virtually wall-less venous cannulas designed for augmented peripheral venous drainage was tested in MICS and provided excellent flows at minimal vacuum levels, confirming an increased performance over traditional thin wall cannulas. Superior results can be expected for routine use.
2018
Performance increase in venous drainage for mini-invasive heart surgery: superiority of self-expanding cannulas
Conclusions: Our experimental evaluation demonstrated the superior performance of the Smartcanula with its self-expanding design in comparison with the reference commercially available standard cannulas. The Smartcanula with its small diameter is particularly welcome for minimally invasive surgery.
2014
Temporary caval stenting improves venous drainage during cardiopulmonary bypass
Conclusions: The 43 cm self-expanding 36F smartcanula outperforms the 28F standard wire armed cannula at low drainage pressures and without augmentation. Temporary caval stenting with long self-expanding venous cannulas provides even better drainage (+51%).
2008
Routine use of self-expanding venous cannulas for cardiopulmonary bypass: benefits and pitfalls in 100 consecutive cases
Conclusions: Full or more than target flow was achieved in 97% of the patients studied undergoing CPB with self-expanding venous cannulas and gravity drainage. Remote venous cannulation with self-expanding cannulas provides similar flows as central cannulation. Augmentation of venous return is no longer necessary.
2008
