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A. Karabegovic, C. Janeczek, M. Hinteregger, M. Gföhler:
"Results of in-vitro tests on a 2:1 prototype of a percutaneous ventricular assist device";
Talk: The 14th International Symposium on Computer Methods in Biomechanics and Biomedical Engineering, Tel Aviv; 2016-09-20 - 2016-09-22; in: "CMBBE2016 book of abstracts", (2016).

A miniature, Helium operated percutaneous ventricular assist device (pVAD) has been developed for usage as a bridge-to-recovery in combination with the intra-aortic balloon pump. Its limited dimensions of less than 50 mm in length and 6 mm in diameter enable positioning of the device between the left ventricle and the aorta, where it may assist the damaged heart by delivering flow up to 2.5 l/min.
In order to test the pVAD prior to animal trials, a pulsatile mock circulatory loop has been constructed that can replicate various acute changes of haemodynamic parameters.
Construction of the circulatory loop started by simulating circulatory diseases in a lumped parameter model. Mechanical assembly was actuated by manipulating pressure in an evacuated reservoir representing the left ventricle. Behavior of the aortic pressure was defined using an aortic compliance and a pair of resistances, while an open reservoir replicated the mitral side.
The 2:1 pVAD prototype was tested in the mock circulation at various circulatory parameters. Results from tests at 81 bpm and ejection fraction of 50% are shown in Figure below. The area enclosed by the PV loops represents the ventricular work that shrinks with increasing speeds. This indicates an unloading effect on the left ventricle - at 15000 rpm the pVAD decreases the work performed by heart by 41%.
At speeds above 13000 rpm the aortic valve remains closed during systole. This implies that no pulse would be measured from the patient. Further increase of speed may result in an onset of suction that can lead to additional complications such as the collapse of ventricular walls. The development of suction detection and prevention algorithms will be possible after first in-vivo studies on the 1:1 heart pump prototype.