These anticoagulants themselves can lead to trouble. In a healthy person, oxygen-starved blood leaving the heart travels an intricate network of capillaries through the lungs for an oxygenating pit stop by the airways. Usually, if small fissures occur in this network, the body’s clotting agents show up to slap some circulatory duct tape on them until they heal. But for someone taking anticoagulants, the body can’t efficiently patch things up if any part of this tight blood-vessel network is breached, and things can spiral out of control.
In Wieselthaler’s case, blood eventually broke out of his patient’s pulmonary network into the lower right lung, heading directly for the bronchial tree. After days of coughing up much smaller clots, Wieselthaler’s patient bore down on a longer, deeper cough and, relieved, spit out a large, oddly shaped clot, folded in on itself. Once Wieselthaler and his team carefully