A Make-or-Break Year for Artificial Hearts

A Make-or-Break

Year for

Artificial Hearts

MECHANICAL

DEVICES THAT

PERMANENTLY

REPLACE

HUMANHEARTS

MAY FINALLY BE

READY

THE HUMAN HEART IS A MARVEL OF

engineering. Inside the chest of the average

adult, that hard-working muscle beats about

100,000 times per day, pumping blood

through arteries that branch up toward the

brain and twine down to the toes. 􀂚 So it’s

no wonder that biomedical engineers have

had a tough time building a mechanical replica

to keep patients with heart failure alive

and well. Since the 1950s, ambitious researchers

have tried to build artificial hearts but

 have always come up

short. Now, four different

companies think they’ve

found the right technology,

and they’re out to prove it.

In 2017, clinical trials and

animal tests could finally

demonstrate that permanent

artificial hearts are

ready for the clinic.

About 5.7 million people

in the United States alone

are currently living with a

diagnosis of heart failure,

meaning their hearts are

gradually becoming less

effective at pumping blood.

Some of the worst-off

patients join the waiting

list for a heart transplant,

but donor hearts are

scarce and many people

die while waiting.

The Total Artificial

Heart from Arizonabased

SynCardia Systems

already has U.S. regulatory

approval as a “bridge

to transplant,” and now

the company is enrolling

patients in a clinical trial

that’s testing the device as

a permanent replacement.

SynCardia CEO Michael

Garippa says the trial is

small—just 28 patients—

because more than 1,600

temporary placements

have already proven that

the artificial heart is safe.

Garippa is confident that

the device is durable, too,

based on the simplicity of

its design. “There’s nothing

electronic inside the

body of the patient,” he

says. SynCardia’s heart

has two plastic chambers

to mimic the heart’s two

pumping chambers, and

each plastic chamber is

 bifurcated by a membrane

with air on one side

and blood on the other. A

patient with a SynCardia

heart carries around a

6-kilogram air compressor

attached to tubes that

penetrate the abdomen

to deliver air to the two

chambers, pushing on

their membranes to propel

the blood on the other

side. The compressor

thumps loudly at a steady

rate of 120 times per minute.

“It’s not a normal life,”

Garippa says, “but it’s way

better than these heart

failure patients have ever

had before.”

In France, a company

called Carmat is hoping

to do better. “Our system

is completely silent,”

says Piet Jansen, Carmat’s

chief medical officer. Like

SynCardia’s device, the

Carmat heart also has two

artificial chambers with

membranes that press

outward to pump blood.

But instead of compressed

air, it uses hydraulic fluid

driven by an implanted

pump. Carmat’s heart is

larger, heavier, and more

complex than SynCardia’s

device, but its designers

are proud of the sensors

that determine the

patient’s exertion level

and the microprocessor

that calculates an appropriate

and changeable

heart rate. Wires emerge

from the back of the

patient’s neck to connect

to a 3-kg battery pack.

Carmat’s first feasibility

study seemed rocky: Two

out of four patients died

within three months. But

industry analyst Andrew

Thompson, who recently

authored a report on artificial

hearts, says these

patients were extremely

sick—as might be expected

of people who volunteer

for an experimental treatment.

“It was not so much

a failure of the device

as a failure of the body,”

Thompson says.

European regulators

must have agreed,

because they approved

the major clinical trial

that Carmat launched

this past August. The

company expects surgeons

to implant its

devices in about 20

patients by the end of

2017 and hopes that its

artificial heart will be

certified as a permanent

replacement device for

Europeans in 2018.

Two other companies

not yet at the clinical

trial stage have

embraced a technical

approach that some

experts find more promising.

Both companies

rejected pulsating membranes

and instead use

centrifugal pumps with

whirling, fanlike blades

that propel the blood

forward, sending a constant

flow through the

arteries. A device from

Cleveland Heart (based

on technology developed

at the Cleveland Clinic)

kept two calves alive and

healthy through a 90-day

study in 2015. And in

Texas, a company called

Bivacor is currently conducting

90-day studies

with calves in cooperation

with the Texas Heart

Institute. Both companies

are still tweaking

their designs and working

toward human trials.

Gianluca Torregrossa,

a cardiac surgeon who

has implanted SynCardia

devices and written about

the progress of artificialheart

research, is eagerly

watching these two companies.

Torregrossa says

their “continuous flow”

designs have fewer points

of failure. “If the device

has fewer moving parts,

you have better chances,”

he says.

When it comes to clinical

trials, all of the technologies

have to prove

themselves under very

tough circumstances.

“Doctors don’t want to

refer a patient to a science

project unless the patient

has no options,” says

SynCardia’s Garippa. If

the technology works for

these worst-off patients,

the long wait for a reliable

artificial heart may be

over. The tryouts of 2017

could finally reveal an

engineering marvel made

by humans, not by biology.