Entrapped paradoxical thromboembolism.

A 67-year-old obese woman (BMI 38.3) was found at autopsy to have deep venous thrombosis of the left calf with bilateral peripheral and saddle pulmonary thromboemboli and a 165 mm long segment of paradoxical thromboembolus wedged between the right and left atria through a patent foramen ovale. Death was due to acute right-sided decompensation caused by obstruction of the pulmonary outflow tract from bilateral pulmonary thromboemboli. Paradoxical thromboemboli pass from the venous system into the systemic circulation through intracardiac or intrapulmonary shunts causing ischemic injury to the brain, heart, intestines, kidneys and limbs. Very rarely, as in this case, they may become entrapped in a patent foramen ovale. Due to its entrapment the paradoxical embolism did not play a role in the lethal episode.