Biomedical engineering

Heart pump invented at the Polytechnique

Mechanical engineering and hydraulics would seem unrelated to cardiology. Yet when it wanted to develop the smallest cardiac pump in the world, the Montréal Institute of Cardiology (ICM) turned to a mechanical engineer specializing in hydraulics, André Garon. The pump is 22 millimetres in diameter and weighs 55 grams in its present version. This miniature turbine, whose blades are driven by an electric motor, is carved from a piece of titanium. It is inserted into the left ventricle through the aorta.

Currently, cardiologists use cardiac pumps to gain time when the heart shows signs of weakness, for example in cases of silent infarct – which leads to necrosis of the cardiac muscle in the long run – untreated high blood pressure, or when a virus lodges in the heart. “Without cardiac aid,” says the École Polytechnique professor, “cardiologists would not have the time they need to find a donor or choose the right treatment.” He adds, however, that when development is complete the ventricular pump can be implanted permanently. “We want to manufacture a highly reliable pump with a service life between 5 and 10 years. This will be used for persons in their fifties, the most frequent candidates for cardiac surgery, who want to stay active and enjoy a good quality of life.”

Beyond the technical challenges, the work of André Garon and his team of eight consists in delivering a pump whose social cost is acceptable. “Our reference cost,” he says, “is the cost of a defibrillator, or about $30,000. This device is installed on patients suffering from cardiac arrhythmia without regard to age or physical condition. Cardiologists know that devices that compensate for weakened hearts now exist, but they are much too expensive, up to $250,000.”

The idea for this pump was hatched by two ICM surgeons, Louis-Conrad Pelletier and Michel Carrier, who head up the clinical aspect of the project. “The ICM had developed an initial design,” says Garon, a mathematician who specializes in hydraulics, “but it was difficult to build in a commercially competitive form. As a result, we worked from a new design.”

The project received vital support from two limited partnerships, Polyvalor and T2C2. “The grants,” says André Garon, “enable us to continue our research for three to five years with relative peace of mind.”