The outer limits of medicine: How doctors treated an astronaut's blood clot in space

Jorge L. Ortiz, USA TODAY

Physician and space travel devotee Stephan Moll’s first wish when NASA reached out for a consultation was to examine the patient in person – at the International Space Station.

Given the impracticality of that desire, the coagulation expert and University of North Carolina professor settled for an approach that combined old-fashioned medicine with cutting-edge means.

Moll hopes the resolution of the astronaut’s blood clot in the internal jugular vein not only leads to further research on travel in zero-gravity but also inspires wider use of telemedicine.

NASA has not revealed the patient’s name or the time frame of the incident to protect the privacy of the astronaut, who was two months into a six-month mission at the ISS. The astronaut detected the blood clot – known in medical terms as a deep vein thrombosis, or DVT – while doing neck ultrasound examinations as part of a NASA study on the effects of weightlessness on blood flow.

Though the astronaut did not show any symptoms or have a family history of blood clots, the discovery of the potentially perilous condition in such a remote locale called for a quick determination of which action to take, if any.

“On Earth we would feel comfortable just observing the person and not treating with blood thinners, because if things get worse, you can always do some intervention,’’ Moll said. “There are emergency rooms here, but in space you don’t have that option.’’

University of North Carolina professor Stephan Moll, an expert on coagulation who is a fan of space travel, was invited to visit NASA facilities in Houston after the agency asked for his help in treating an astronaut with a blood clot.

Moll pointed out blood clots are not always dangerous and usually dissolve on their own. Occasionally they develop on the legs of passengers traveling long stretches in cramped conditions.

Moll was concerned about the possibility that the DVT could have expanded from the neck area toward the brain, perhaps leading to stroke-like symptoms. There was also the chance the clot would take a different path toward the heart and result in a pulmonary embolism.

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After assessing the risk of those outcomes against the likelihood the astronaut may bleed from an injury at the ISS, Moll and the NASA physicians decided to treat the patient with blood thinners, which were available in limited supply. New dosages arrived 43 days later via a supply aircraft – not quite like the typical visit to the corner drugstore.

All along, the astronaut kept doctors apprised of the condition’s progress with regular ultrasound checkups.

“In this space case, the power of telemedicine from the International Space Station to the doctor’s office on Earth is remarkable,’’ said Craig Greben, chief of interventional radiology at Northwell Health in New Hyde Park, N.Y. “The astronaut patient-performed, radiologist-guided ultrasound with real-time image transmission to Earth allowed for prompt image interpretation and diagnosis by the radiologists and blood thinner prescription by the clinicians.’’

The case certainly presented unique challenges. For one, there wasn’t any similar history for the doctors to lean on in devising a treatment plan. This was the first known instance of a U.S. astronaut developing a DVT while in outer space. Even on Earth, there has been little documentation of how isolated inter-jugular clots behave without treatment and how often they reoccur.

In addition, it was difficult and time-consuming for the astronaut to receive the shots of medicine because the liquid clung to the vial in zero gravity. The second supply that arrived later was in pill form.

But in many ways, finding a course of action called for the same process medical practitioners have been following forever: Communicate with the patient to ascertain the problem, research the available literature and come up with a treatment. In this instance, the interaction with the astronaut was conducted through e-mail and calls on a remarkably clear line.

“It was almost like a regular clinic visit,’’ said Moll, who fulfilled a longtime dream when he was invited to visit NASA facilities in Houston. “However, in my field of hematology and coagulation, telemedicine or electronic consultations (like this) will and should play a big role in the future, so people don’t have to travel to the clinic.’’

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It’s still not clear whether the lack of gravity or other factors in outer space contribute to the development of blood clots, though Moll said the NASA study found that in half the astronauts the blood flood was abnormal, but the body adjusts to it.

In a case study published on the New England Journal of Medicine – written by four physicians, including Moll and NASA flight engineer Serena Auñon-Chancellor – the authors call for further research into blood viscosity and the risk of clots in weightless conditions.

That request is seconded by Maja Zaric, interventional cardiologist at Lenox Hill Hospital in New York City.

“The study results open the door for much needed research dedicated to space medicine and subjects exposed to zero-gravity state,’’ she said, “and will surely have major implications on future space endeavors.’’

This article originally appeared on USA TODAY: NASA astronaut treated for blood clot at International Space Station