After five heart attacks and 20 months of waiting for an eligible donor, former Vice President Dick Cheney received a heart transplant on Saturday.
Part of the reason he was able to hold out so long (the average waiting time is 250 days) was because of a special device that took over the left ventricle’s job. That is, pumping blood to most of the body. The implant was powered by batteries that he carried in a fanny pack and Cheney told NBC News in January that it’s a “wondrous device.”
You also may have heard of the man released from a Seattle hospital last week to await a heart transplant. His heart was completely replaced by a mechanical device developed by SynCardia Systems. This device is powered by a rig that the patient carries around in a backpack. And it can keep him functioning – and out of the hospital – until a donor heart arrives.
Pretty impressive stuff. But there’s a new technology being developed that’s even more groundbreaking. Because it doesn’t keep your ticker beating just temporarily. It replaces the heart entirely… forever. And it could make the donor list a thing of the past.
Let me explain…
Living Without a Heartbeat
Doctors Billy Cohn and Bud Frazier of the Texas Heart Institute have discovered an unusual solution for creating a mechanical heart replacement: Get rid of the pulse.
As Cohn told Popular Science’s Dan Baum, “I think we’re on the verge, right now, of solving the artificial heart problem for good. All we had to do was get rid of the pulse.”
Sounds counterintuitive, I know. But they’ve proven that the system works time and time again.
Take Abigail, for instance. She’s one of the 38 calves that received a test device.
Cohn says, “If you listened to her chest with a stethoscope, you wouldn’t hear a heartbeat. If you examined her arteries, there’s no pulse. If you hooked her up to an EKG, she’d be flat-lined… By every metric we have to analyze patients, she’s not living… [But] she’s a vigorous, happy, playful calf.”
You see, the actual beat of a heart isn’t necessary for your body to survive. The heart is the only organ that depends on that particular action. As Cohn says, a pulse “is essential for the heart, because it can only get nourishment in between heartbeats. If you remove that from the system, none of the other organs seem to care much.”
So how exactly did they put this principle to work?
Archimedes Goes High Tech
It all starts with the device mentioned above that has kept Dick Cheney’s heart functioning since 2010 – Thoratec’s (Nasdaq: THOR) HeartMate II. It’s a device modeled after the Archimedes screw, which is ordinarily used to pump water from wells. Basically, a rotor sends blood flowing through the body using a continuous whirling motion.
Now, instead of implanting one of these devices close to the heart like in Cheney’s case, Cohn and Frazier thought that using two similar devices could replace the whole organ. And by replacing the heart with two continuous flow chambers, you’re left with no heartbeat at all.
Instead, the only sound you’ll hear is something more akin to “a dentist’s drill or the underwater whine of an outboard motor,” according to Baum.
The device runs on a VHS-sized battery that’s worn outside the body. While that might not seem very convenient, Baum points out that it’s “not as bad as sitting day and night beside a hissing compressor the size of a dishwasher.” Which is currently the case for many patients on the donor list.
And ultimately, without the pumping action, the doctors say the device should last longer – and produce fewer complications – than other artificial solutions used today. Frazier says, “These pumps don’t wear out… We haven’t pumped one to failure to date.”
Better yet, they’ve already shown that the device can work in humans, too. Back in March, they successfully implanted the mechanical heart in 55-year-old Craig Lewis, who suffered from an organ disorder. And the heart worked flawlessly for a month, before he passed away “due to the underlying disease,” according to NPR.
Making it available for mainstream use is another story, though. And Baum says that a trial-ready device would take “another three or four years to develop… and then another six or seven for the trials necessary for FDA approval.”
But with five million people living with heart disease in the United States – and approximately 2,000 donor hearts to go around each year – this should be worth the wait. That is, at least until Organovo (OTCQB: ONVO) can print you one from scratch.