A clot in a major vein can measure several inches. If a relatively big embolus were to reach the heart and lungs, death could result. People who have an embolus often experience severe chest pain and shortness of breath. They will often seek a physician, concerned about a possible heart attack. Because these symptoms may occur several days after a flight, an association between the flight and the symptoms may not be noticed.
Some people are especially at risk.
These include women over 40 years old or on birth control pills, those with a history of DVT or varicose veins, tall people, obese people, cancer patients, people who have had a recent surgery or major injury, people with a strong family history of DVT, and others on certain medications like diuretics. Smokers are also at increased risk. The link between DVT and flying continues to be hotly debated. Some experts are focusing their attention on aircraft seats. Stanley Mohler, aerospace medicine specialist at Wright State University, points out that the airline seat was primarily designed to meet crash standards rather than the health concerns.