Chronic thromboembolic pulmonary hypertension (CTEPH) is a form of pulmonary hypertension (PH) caused by old blood clots in the lungs, also known as pulmonary emboli. Learn more about the risks of developing CTEPH after a pulmonary embolism.
In most patients with these blood clots, use of prescribed blood thinners can restore blood flow to the lungs and prevent development of CTEPH. However, a minority of patients may still develop CTEPH even with the use of blood thinners. In these patients, problems arise when some of the large blood vessels in the lungs are obstructed by old blood clots. However, doctors are now discovering that CTEPH can develop in another way: through changes in the small blood vessels in the lungs that are similar to pulmonary arterial hypertension (PAH). These small blood vessels become increasingly narrow and stiff in some CTEPH patients.
This is important because these patients may develop CTEPH without being able to recall a blood clot. It is also possible for CTEPH to develop from multiple small clots over a long period of time, as opposed to one or two large blood clots.