Medical mystery: Blood clots formed during lengthy flight

In October 2017, Robert Conti-D’Antonio felt some soreness in his chest and sides. He brushed it off as muscle soreness after recently getting back into a regular exercise routine.

By November, when the feeling still hadn’t subsided, the West Chester resident made an appointment with his family doctor.

His family doctor thought his symptoms — chest pain that worsened when he took a deep breath — suggested pneumonia, an infection that inflames the air sacs in one or both lungs, which may fill with fluid.

She ordered a chest X-ray to confirm her suspicion. The scan showed no abnormalities.

Two weeks later, Conti-D’Antonio, now 65, woke up from a nap with sharp chest pains and also experienced trouble breathing. His wife, Marcia, drove him to the nearest emergency room.

There, doctors asked him a series of questions, including whether he had recently been on an airplane. Conti-D’Antonio explained that, six weeks earlier, he and Marcia had flown home from a trip to Tokyo — a 14-hour flight.

His answer quickly led them to a diagnosis.

After hearing of his travels, doctors in the ER ordered a CT scan to confirm their diagnosis. The scan showed blood clots in both of Conti-D’Antonio’s lungs.

Blood clots are more likely to form during periods of inactivity, such as during a lengthy plane or car ride.

This prolonged immobility slows blood flow in the legs, which contributes to the formation of clots. In some cases, these clots can break off and travel through the veins to the arteries in the lung, causing a blockage known as a pulmonary embolism (PE). Depending on the size and location of the blood clot, PE can be life-threatening due to strain on the right side of the heart.

In Conti-D’Antonio’s case, his clots were quite large, but given his overall healthy status, they were not life threatening.

Conti-D’Antonio was immediately given an injectable form of a blood thinner, which prevents the clot from getting bigger while the body slowly dissolves the clot on its own.

He was discharged from the hospital the next day and made a follow-up appointment with his family doctor.

Having PE puts you at an increased risk of future PE, which is why his family doctor recommended he see a pulmonologist to manage his risk.

In December 2017, Conti-D’Antonio was referred to my office. I followed him closely over the first year with a series of imaging tests to make sure his large clots resolved on their own.

Conti-D’Antonio also was very scared about the possibility of another blood clot. He worried that he would never be able to travel again, one of his favorite activities to do with Marcia.

I explained that incidences of PE due to long flights are actually very rare and that because he is an otherwise healthy person, I was not convinced that we could attribute this blood clot to the long flight alone.

I recommended he see a hematologist to undergo genetic testing to determine whether that contributed to his blood clot. Extensive blood work revealed he had a genetic mutation that made him more prone to clotting.

The long flight put him at even higher risk.

Genetic testing is not recommended for everyone. While a genetic mutation puts a patient at a higher risk for experiencing a first blood clot, it does not predict the risk for having another clot. However, it can be helpful for family members to know their risk .

After hearing how important traveling was to Conti-D’Antonio, we decided to keep him on a low-dose blood thinner indefinitely to decrease his risk of a future clot. Not all patients requires long-term blood thinner treatment, but speaking with patients is important to determine the course of treatment that can best preserve their quality of life.

For patients who are on a long-term blood thinner, treatment guidelines recommend a yearly check-in with a doctor to evaluate their bleeding risk and ensure that are no new medications that may interact with the blood thinner, making it less effective or more dangerous for bleeding.

Fortunately, Conti-D’Antonio did not have any impairments following his PE. But not every patient is as lucky. A recently published study found that 10% to 15% of patients continue to have some kind of pulmonary or cardiac impairment two years out.

Since his PE five years ago, Conti-D’Antonio and his wife have taken many trips without any complications. He now takes precautions on long flights, such as wearing compression socks and doing exercises in the aisle of the plane to avoid prolonged immobility. In June, they enjoyed a two-week trip to Spain.

Parth M. Rali is the director of Temple Health’s Pulmonary Embolism Response Team (PERT) Program and an associate professor in the Division of Thoracic Medicine and Surgery at Lewis Katz School of Medicine at Temple University. He serves as chair of the National PERT Consortium Protocol Committee.