Pulsatile stent graft: a new alternative in chronic ventricular assistance.
OBJECTIVE
Heart failure is currently one of the most common hospitalization causes. Several chronic circulatory assist devices have been tested and are highly complex. The objective is the description of a pulsatile endoprosthesis capable of applying a chronic pulse within the descending aorta, similar to that produced by intra-aortic balloon.


METHODS
Pulsatile stents composed of nickel-titanium were built and positioned to engage latex tubes simulating the aorta. Different electric currents were applied to units connected in series in order to cause structure contraction and displacement of a liquid column. There were two sequence tests: first composed of two metallic cages and the second composed of five cages. At first sequence tests was applied a voltage of 16.3 volts and a current of 5 amperes. In the second, voltage of 15 volts and current of 07 amperes.


RESULTS
In the first sequence was obtained the pulsatile effect of stent, with contraction of the tube and displacement of the water column sufficient to validate the pulsating effect of the endoprosthesis. The two structures ejected a volume of 2.6 ml per cycle, with a range of 29 mm in height of the column of water equivalent to 8% shrinkage during the pulse. In the second sequence, it reachead a variation of 7.4 mL per cycle.


CONCLUSIONS
The results obtained confirm the stent pulsatile contractility activated by electrical current. The continuity of the study and material improvement are necessary to obtain more efficient model from the point of view of energy and pulse, to allow ejection volumes comparable with the intra-aortic balloons.
Federal University of São Paulo (UNIFESP), São Paulo, SP, Brazil.
José Honório
JH
Palma
Diego Felipe
DF
Gaia
Guido
G
Caputi
Guilherme
G
Agreli
João Roberto
JR
Breda
Domingo M
DM
Braile
Enio
E
Buffolo
D001011:Aorta; D006333:Heart Failure / Q000628:therapy*; D006352:Heart Ventricles; D006353:Heart-Assist Devices; D006801:Humans; D008488:Medical Illustration; D009532:Nickel / Q000627:therapeutic use; D011474:Prosthesis Design / Q000379:methods*; D011673:Pulsatile Flow; D015203:Reproducibility of Results; D015607:Stents; D014025:Titanium / Q000627:therapeutic use
C040654:titanium nickelide; D009532:Nickel; D014025:Titanium