Chronic thromboembolic pulmonary hypertension (CTEPH) is a form of pulmonary hypertension caused by old blood clots in the lungs (pulmonary emboli). In most patients who have suffered a blood clot, blood thinners are enough to restore blood flow to the lungs, improving breathing and exercise tolerance, and preventing development of pulmonary hypertension.
However, a minority of patients will not respond adequately to blood thinners, and may develop CTEPH. In these patients, problems arise not only from lung segments being obstructed by clots, but because seemingly healthy blood vessels (supplying uninvolved lung segments) may develop progressive narrowing, similar to pulmonary arterial hypertension (PAH).
Importantly, patients may develop CTEPH without any history of 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.
What are the symptoms of CTEPH?
The symptoms of CTEPH are non-specific, and similar to other types of pulmonary hypertension. The most common symptoms of CTEPH are shortness of breath and exercise intolerance. Less frequent symptoms include a dry cough, chest pain, and heart palpitations. As the disease progresses, symptoms of light-headedness or exercise-related dizziness may occur. Abdominal and lower extremity swelling may develop as lung pressures increase, and the right ventricle, which pumps blood into the lungs, begins to weaken.
How common is CTEPH and who gets it?
Approximately 1% of patients with an acute pulmonary embolism will develop CTEPH. People who have very large pulmonary emboli may be at increased risk of developing CTEPH. Patients who already manifest some pulmonary hypertension at the time of diagnosis of a pulmonary embolism may also have an increased likelihood of developing CTEPH. Some underlying blood clotting disorders are more common in patients with CTEPH, though not all clotting disorders increase risk. Additionally, some chronic medical conditions are associated with increased CTEPH risk.
What are the differences and similarities between CTEPH and other types of PH?
The symptoms of CTEPH are quite similar to those of pulmonary arterial hypertension (PAH) and the other types of PH. For some patients chest pain may be a more prominent feature of CTEPH, possibly due to scarring in the lungs from a prior blood clot. The distinguishing feature of CTEPH is that it is the only type of PH that truly has a potential “cure” for those who are eligible for pulmonary thromboendarterectomy, or PTE surgery.
This article was originally written by Gautam V. Ramani, MD, Assistant Professor of Medicine at the University of Maryland School of Medicine, and Myung H. Park, MD, FACC, Director of the Pulmonary Vascular Diseases Program at the University of Maryland Heart Center.