DVT expert treats NASA astronaut from Earth

In an astounding example of technology advancing health care, a blood clot in the jugular vein of an astronaut aboard the International Space Station (ISS) has been treated via telemedicine.

UNC School of Medicine blood clot expert and member of the UNC Blood Research Center Stephan Moll was contacted by NASA for his vast knowledge and treatment experience of deep-vein thrombosis (DVT) on Earth. This was the first time a blood clot had been found in an astronaut in space, so there was no established method of treatment for DVT in zero gravity.

The astronaut’s blood clot was asymptomatic, but was discovered when the astronaut was taking ultrasounds of the neck for a research study on how body fluid is redistributed in zero gravity.

“My first reaction when NASA reached out to me was to ask if I could visit the International Space Station (ISS) to examine the patient myself,” Moll said.

“NASA told me they couldn’t get me up to space quickly enough, so I proceeded with the evaluation and treatment process from here in Chapel Hill.”

Although the astronaut cannot be identified, we know that the patient was two months into a six-month NASA mission on the ISS when the DVT was discovered.

Moll explained that in a normal situation, a patient with DVT would be started on a course of blood thinners, which they would take for at least three months to prevent the clot from getting bigger and to lessen the harm it could cause if it moved to a different part of the body such as the lungs.

“There is some risk when taking blood thinners that if an injury occurs, it could cause internal bleeding that is difficult to stop,” Moll said.

“In either case, emergency medical attention could be needed. Knowing there are no emergency rooms in space, we had to weigh our options very carefully.”

Moll and a team of NASA doctors decided blood thinners would be the best course of treatment for the astronaut, but their pharmaceutical options were limited. The ISS keeps a small supply of medicines on board, and there was a limited amount of the blood thinner enoxaparin available. Moll advised NASA on what dosage of enoxaparin would effectively treat the DVT and last until NASA could get a new shipment of drugs — which Moll helped select — to the ISS.

Treatment aboard the ISS

Enoxaparin was delivered by subcutaneous injection, with the treatment lasting for about 40 days. On day 43 of the astronaut’s treatment, a supply of apixaban — a pill taken orally — was delivered to the ISS by a supply spacecraft.

Throughout the treatment process, which lasted more than 90 days, the astronaut performed ultrasounds of the neck with guidance from a radiology team on Earth in order to monitor the blood clot. Moll was also able to speak to the astronaut during this period through email and phone calls.

“When the astronaut called my home phone, my wife answered and then passed the phone to me with the comment, ‘Stephan, a phone call for you from space.’ That was pretty amazing,” Moll said.

“It was incredible to get a call from an astronaut in space. They just wanted to talk to me as if they were one of my other patients. And amazingly, the call connection was better than when I call my family in Germany, even though the ISS zips around Earth at 17,000 miles per hour.”

The astronaut stopped taking apixaban four days before the journey home — a decision made by Moll and his NASA counterparts because of how physically demanding and potentially dangerous the re-entry process can be for astronauts. They did not want an injury to be exacerbated by the use of blood thinners. The astronaut landed safely on Earth and the blood clot required no further treatment.

Moll continues to work with NASA and said there’s a need for more research of how blood and blood clots behave in space.

“Is this [DVT] something that is more common in space?” Moll asked.

“How do you minimise risk for DVT? Should there be more medications for it kept on the ISS? All of these questions need answering, especially with the plan that astronauts will embark on longer missions to the moon and Mars.”

The material for this case study was provided by University of North Carolina Health Care, with the study published in The New England Journal of Medicine.

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