When thromboembolic pulmonary hypertension becomes chronic, it causes severe pulmonary hypertension. Unfortunately, this form of HP goes under diagnosed. The lesions involve clots (thrombi) within the lumen of the blood vessels and fibrous stenosis (blood vessel constriction) or total destruction of the pulmonary arteries. As a result, the pulmonary vascular resistance increases generating pulmonary hypertension and progressive right heart (right ventricle) failure. Current research suggests that this disease is initiated by pulmonary embolism (as a single or recurrent events) and followed by progressive pulmonary vessel remodeling (angiogenesis).
Thromboembolic Pulmonary Hypertension Causes
Although there can many causes of thromboembolic pulmonary hypertension, patients are at high risk if they have experienced recurrent pulmonary thromboendartectomy (PTE), splenectomy (spleen removal) or lupus anticoagulant syndrome (antiphospholipid antibody syndrome). PTE is an operation that removes blood clots from the pulmonary arteries. Lupus anticoagulant syndrome causes blood clot formation in blood vessels and is an autoimmune disease that produces antibodies against a particular phospholipid known as cardiolipin and β2 glycoprotein.
Thromboembolic Pulmonary Hypertension Symptoms
The symptoms of thromboembolic pulmonary hypertension are essentially the same as other forms of pulmonary hypertension which include:
- Progressive breathing difficulty upon exercise
- Hemotysis which means coughing and expulsion of bloody mucus
- Fainting spells and dizziness
- Syncope (brief loss of consciousness due to lack of oxygen)
- Edema which is fluid retention in the body
- Embolism due to clot formation (causes blood vessel obstruction)
- Systolic murmur of the tricuspid valve (regurgitation)
- Extended neck veins
- Ascites (swollen abdomen from fluid build up)
- Cyanosis such as blue lips and skin due to lack of oxygen
Thromboembolic Pulmonary Hypertension Diagnosis
Treatments for thromboembolic pulmonary hypertension is considerable different from PAH so it is of the essence to determine that the patient has thromboembolic type. One of the difficulties is that many patients have no history of pulmonary embolism which makes it difficult to diagnose properly. Some of these patients will be misdiagnosed.
Tests to Confirm Thromboembolic Pulmonary Hypertension
- Echocardiography – This is the first diagnostic tool used in any form of PH and there should be long-term follow-ups for the thromboembolic type of hypertension.
- Ventilation-perfusion scanning uses medical isotopes to observe air and blood circulation in a patients lungs. It can also observe blood clots if they are present.
- Computed tomography (CT) scans.
- Magnetic Resonance Imaging (MRI).
- Pulmonary angiography uses a dye and X-rays to observe how blood flows through the lungs. This is the standard tool for diagnosis of thromboembolic hypertension. This is often performed in conjunction with right heart catheterization.
Thromboembolic Pulmonary Hypertension Treatment
- Some forms of thromboembolic pulmonary hypertension require surgery, medical treatment or both.
- Endothelin receptor antagonists may be prescribed as they prevent blood vessel constriction. Endothelin is a powerful blood vessel constrictor.
- Endarterectomy is a surgical procedure that unblocks blood vessels. This procedure is done with complete circulatory arrest while the patient is in deep hypothermia between 18°C and 20°C. This procedure is reported to have great success.
- Phosphodiesterase inhibitors are used to allow blood vessels to relax.
- Prostacyclins work well as they relax blood vessels and prevent clot formation.
Thromboembolic Pulmonary Hypertension Prognosis
The mortality rate with individuals diagnosed with thromboembolic pulmonary hypertension is reported to be 90 percent within 3 years after diagnosis.