Question: I have blood clots in my lungs. At first my doctor told me I'd be on medication for six months, but now she says a year. Why?

Dr. Hibberd's Answer:
Blood clots in the lungs prevent the air you breathe in from interacting with the de-oxygenated blood returning from the body via the right side of the heart. The gas exchange to oxygenate your blood requires free blood flow, not clotted vessels. Blood thinners are used to reduce the recurrence of lung clots (known as pulmonary emboli) and to permit the lungs to function. Otherwise you risk lung failure, and failure of the right heart so commonly seen with lung clotting situations.

Blood thinners such as Coumadin are used from three to six months to prevent venous thrombosis (DVT) in legs and from six to 12 months to prevent recurrences of pulmonary emboli that can be rapidly fatal once the clots have lodged in a lung.

It may be that your doctor has performed some specialized testing for hypercoagulable states, and has detected a condition such as protein C deficiency that requires lifelong Coumadin treatment to control, and wishes to prevent additional pulmonary emboli. There are alternative anti-clotting regimens available, so be sure to discuss your options for management with your consulting hematologist.