Medicine: Clots in the Lungs

One of the most deadly accidents that can befall the human circulatory system—as likely to kill quickly as a stroke or a heart attack—has no everyday English name. It is pulmonary embolism, in which the flow of used blood is blocked, nearly always by clots, in the pulmonary artery leading from the heart's lower right chamber to the lungs (see diagram). Medicine and surgery have been helpless to deal with severe cases of pulmonary embolism. Now a team of Houston doctors suggests that if victims can be operated upon promptly, a number may be saved with the aid of a heart-lung...