Barcelona, Spain, 30 August 2009: Survival in mechanical heart patients is continuously improving. The “Jarvik Flowmaker” left ventricular assist device has already achieved more than seven years of event-free survival with excellent quality of life. Building on this experience, even smaller devices (which can be implanted by less invasive methods) are under development. These will eventually be implanted by cardiologists with methods similar to minimally invasive transapical aortic valve replacement.
Heart failure is a common cause of debilitating symptoms and premature death. Relatively few countries have well developed cardiac transplant programmes, and in general the number of donor hearts is falling. An “off the shelf” mechanical solution has been sought since the 1980s.
Early blood pumps attempted to replicate the native heart by providing stroke volume and pulse pressure in the circulation. The necessity to empty and fill made these devices excessively large with substantial electrical power requirement. Miniaturised continuous flow pumps were developed in bioengineering laboratories during the 1990s. These are miniaturised axial flow or centrifugal pumps with rotational speeds up to 15,000 RPM. The pumping mechanisms do not damage the circulating blood cells and need only the same degree of anticoagulation as a mechanical heart valve. The pump removes blood from the failing left ventricle and conveys it to the aorta. Batteries and controller are now easily portable allowing the patient to return to virtually normal life.
One remarkable finding is that the rested heart muscle has the capacity to improve in structure and function so that some pumps may eventually be removed. Drug and stem therapy can be used to promote the recovery process.
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