Chronic thromboembolic pulmonary hypertension (or “chronic pulmonary embolism”) is a dysfunction of the heart’s right ventricle that results from changes to the structure or function of the lungs. Changes to lung structure or function cause increased resistance to blood flow through the lungs which leads to high blood pressure in the lungs and called “pulmonary hypertension.”
What is Chronic Pulmonary Embolism?
The veins in our body carry blood to and from the heart. When blood is returned to the heart it also travels, through the pulmonary arteries, to the lungs where it receives oxygen. The blood then travels away from the heart, carrying the oxygen to other parts of the body.
Sometimes blood clots form within veins, usually in the lower body. Blood clots may happen because of a major physical illness, or be caused by a person being immobile. In some instances, genetic or inherited characteristics may also increase a person’s chances of forming blood clots. In a small percentage of patients, blood clots can break away from the vein walls. When this happens, they travel through the blood’s circulatory system until they reach the lungs, where the clots become trapped. This is called a pulmonary embolism and it affects the oxygen exchange in a person’s body, making it difficult for the lungs to function properly.
The heart’s right ventricle is not well suited to excessive mechanical demands, being adapted to pump blood through the normally low-resistance, high-capacity lung circulatory path. Symptoms of pulmonary embolism can include shortness of breath, chest pain, fatigue, and dizziness.
Pulmonary embolism is the second most common cause of cardiac death in North America after coronary artery disease. However, in the majority of individuals, if a patient withstands the initial pulmonary embolus, the blood clot will dissolve and normal circulation will return.
Pulmonary Thromboendarterectomy (Surgery for Chronic Pulmonary Embolism)
In a small number of patients (0.5-2.5%), for unknown reasons a blood clot does not dissolve. This means the blood pressure remains elevated in the right side of the circulation, causing a persistent strain on the right side of the heart (right ventricle). This is called a chronic pulmonary embolism (or “chronic thromboembolic pulmonary hypertension”).
Individuals with this disorder experience symptoms ranging from shortness of breath while moving around or exercising, to chest pain, fainting spells, and severe leg and abdominal swelling. The best treatment for this problem is a surgical procedure called a pulmonary thromboendarterectomy. The procedure involves open-heart surgery and uses a heart/lung machine to stop the patient’s circulation while the surgeon works to open the arteries and remove the chronic blood clot.