You gotta have heart (Part 1)

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One of the leading causes of death is still heart failure.  Which is why improvements in heart transplantation and the development of an artificial heart have been high on the “to do” list for years.  How many?  Since at least when I began working on my artificial kidney about four decades ago.

Right now, if you are lucky enough to get a heart transplant, you’ve bought yourself another decade of life.  But, most folks get assistance devices, to help them bridge the time between now and when they may get an artificial heart.  Think of Dick Cheney, who had a pacemaker implanted when he was Vice-President, and then got a mechanical assist device, then a pulse-less assist device, and then a heart transplant. (Proving once and for all that there was heart somewhere in his body…)

English: Graphic presentation of an LVAD, left...
English: Graphic presentation of an LVAD, left ventricular assist device. (Photo credit: Wikipedia)

But, most folks never get that heart transplant in time.  So, Drs. Billy Cohn and Bud Frazier, (and most recently, the addition of a new team leader- Daniel Timms, a biomedical engineer)   of the Texas Heart Institute are working to perfect their twin LVAD, two left ventricular assistance devices, married together to yield a pulse-free mechanical heart.  Not intended to be a bridge (although it could be), the goal is for this device to keep folks alive long-term.

An LVAD provides continuous flow, very similar in concept to an Archimedes Screw (the sort of pump that is used to propel sewage or irrigation water).  [By the way, now you understand how I switched back and forth from artificial organs to water reuse and recycle.   The basic principles….] By marrying the two LVADs, it’s hoped that the right and left ventricular functions of the heart can be replaced.

Their device was tested in 70 calves, keeping the animals alive for about one month.  That was while they demonstrated a flat-line EKG (heart activity monitor), indicating no heart beat and no pulse.  Finally, the inventors were permitted to try it in a patient with little chance of survival.  Instead of dying in days, the patient (Craig Lewis, 55)  was kept alive for six weeks, when his disease managed to wipe away his kidneys and liver.  Which proved that a pulse was not critical for life- just oxygenated blood flow.

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Timms’ improvement to the concept involved the use of a large and small blade, operating on opposing rotor sides.  And, suspending the whole device in a magnetic field that controls the blades oscillations (considerable, due to the 2000 rpm speed of the rotors).

Moreover, Timms’ has employed 3D printing to make the parts he needs.  In so doing, the team can quickly modify and print new parts, evaluate the performance characteristics of the change in a most rapid fashion.  A 3D plastic printed version has been tried in a calf.  Now, they are using titanium, which is more durable and less prone to rejection.

Once they have perfected this design (or maybe just optimized it well), they expect to try it in a human.

 

 

 

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