Beyond heart transplantation: potentials and problems of the shape memory alloy fibers in the treatment of heart failure.
Heart failure can be treated with devices that mechanically support the circulation. The improvement of these devices would benefit many patients, especially those refractory to maximal pharmacological treatment and ineligible for heart transplantation. This study examined whether the shape memory alloy (SMA) fibers, which are fibers that contract when electric current flows through them and relax passively when that flow is interrupted, can be wrapped around the failing heart and assist in its pumping action. A band of SMA fibers was wrapped around a silicon cylindrical chamber which simulated a dilated heart and its pumping action was tested in a circulatory mockup. This rudimentary device was innovatively controlled by pulse width modulation. The band was made of only six fibers but yet produced the considerable pressure of 20 mm Hg and a stroke volume of 11.8 ml with modest energy demands. A SMA device could assist a severely failing heart, but there are limiting factors to overcome before designing highly effective devices.
From the *Foundation for Research and Technology Hellas, Heraklion, Crete, Greece; and †University of Crete, Heraklion, Crete, Greece.
Paris D
PD
Kalogerakos
Jannie
J
Hassoulas
Vlassis S
VS
Ladopoulos
D000497:Alloys / Q000737:chemistry*; D001794:Blood Pressure; D006321:Heart / Q000503:physiopathology; D006333:Heart Failure / Q000628:therapy*; D006339:Heart Rate; D016027:Heart Transplantation; D006353:Heart-Assist Devices; D006801:Humans; D011312:Pressure; D011474:Prosthesis Design; D013318:Stroke Volume
D000497:Alloys