A line as big as a pinkie finger permanently sticking out of the skin creates infection risk and can serve as an unwanted conversation-starter for patients with advanced heart failure — serious drawbacks even for devices that can extend a person’s life.

“Committing a patient to a driveline for life has kept this field from blossoming,” said Dr. William Cohn, a renowned surgeon and researcher at the Texas Heart Institute.

Now Eden Prairie’s Sunshine Heart is teaming with a St. Paul company to make a heart pump that runs on power transmitted through the skin. The idea has excited some investors, though many hurdles remain, including getting positive clinical results from researchers and marketing approval from regulators.

The idea of powering a medical device with transcutaneous energy, or power sent wirelessly through the skin, is already used in low-energy devices like neurostimulators and hearing implants. But none of the heart-pump makers around the country have figured out how to make it work for their higher-powered machines with moving parts.

Sunshine Heart officials are hopeful. They announced last week that the company will begin human testing of their device, known as the C-Pulse II, sometime next year. Cohn is leading the international study. Like most new medical devices, the first implants are expected to take place in countries outside the U.S.

Sunshine Heart’s device fits in a class of complex heart implants called mechanical circulatory support devices, which pump blood when a patient’s heart can’t, even with a pacemaker. Another company in the field is California-based Thoratec Corp., which St. Jude Medical plans to acquire for $3.4 billion. (Thoratec is a minority owner of Sunshine Heart, the company has disclosed in regulatory filings, which means St. Jude would own part of Sunshine Heart if that deal takes place.)

“Certainly everybody in this field is working on wireless energy transmission,” Minnetronix CEO Rich Nazarian said. Sunshine Heart’s device “has a bunch of advantages and is potentially far less invasive to the patient. It is far less traumatic.”

The C-Pulse does not touch blood. Rather, it features a balloon similar to a blood-pressure cuff, which is placed around the heart’s main artery under the skin. By precisely inflating and deflating the balloon, the machine removes some of the workload from the heart while improving circulation.

A key reason TETS could work for the C-Pulse II is it can be turned off without harm to the patient. More complex devices embedded in the blood stream can create immediate health problems if they stop pumping, which is a risk when power flows to a coil that sits invisibly under the skin.

“It’s easier for us because the ramifications of disconnection are nonexistent,” Sunshine Heart CEO Dave Rosa said. “The worst thing that would happen is, your symptoms would come back.”

Heart failure is one of the most common heart conditions. It happens when the heart becomes weakened and can’t pump enough blood to adequately feed the body’s functions, causing shortness of breath and fatigue during normal exercise.

Circulatory-assist devices are intended for patients with Class III or Class IV cases, which are advanced stages where a patient has symptoms of heart failure after little or no physical activity.

The C-Pulse is intended for both classes of patients, while devices made by Thoratec and its competitor HeartWare are only intended for the most severe Class IV cases. An analyst with financial-media outlet Benzinga noted in March that Sunshine seemed considerably undervalued, given that its devices would serve a much bigger patient population than HeartWare, of Massachusetts. Sunshine Heart shares closed at $2.99 Wednesday; the price has ranged from $2.41 to $6.90 over the past year.

Major hurdles remain. For one, Sunshine Heart still has not gotten FDA approval for its first C-Pulse system, which includes a driveline.

The company told investors on Monday it has restarted its clinical trial of the device, following an investigation that found four patient deaths were not device-related. All 27 of its study hospitals are expected to resume that work later this month, if they haven’t already.

Then it will be up to the company to do clinical testing of the C-Pulse II, which is slated to start in the fall of 2016. Researchers will look to see if the design is feasible, safe and durable over short periods of time. Although initial trial work is expected to happen overseas, Rosa said Sunshine Heart has hired a consultant who could help in getting permission to do early trial work domestically.

“We are considering the potential to do this in the U.S. We’ll see,” Rosa said.