At least 100,000 cases of PE occur each year in the United States. PE is the third most common cause of death in hospitalized patients. If left untreated, about 30 percent of patients with PE will die. Most of those who die do so within the first few hours of the event. | At least 100,000 cases of PE occur each year in the United States. PE is the third most common cause of death in hospitalized patients. If left untreated, about 30 percent of patients with PE will die. Most of those who die do so within the first few hours of the event. |