Her is an interesting snippet:
An analogous situation was reported in this week's New England Journal of Medicine -- Sept. 13th. But this involved air travel. The title of the article is "Severe Pulmonary Embolism Associated with Air Travel." It was a study done over a seven year period.. - and it involved 135 million passengers who arrived in the Paris airport. 56 people had confirmed pulmonary embolism on arrival. They were hospitalized, studied extensively and some interesting findings were reported. Source
>> 135 million passengers who arrived in the Paris airport. 56 people had confirmed pulmonary embolism on arrival <<
I talked once to a foreign service officer who had served at the American Consulate in Beijing. He said it was routine for the Consulate to arrange shipping back home of the remains of elderly American tourists who had suffered fatal strokes and cardiac problems (especially due to DVT) on those ultra-long flights from the USA to China.