Chronic thromboembolic pulmonary hypertension
Chronic thromboembolic pulmonary hypertension (CTEPH) is a long-term disease caused by a blockage in the blood vessels that deliver blood from the heart to the lungs (the pulmonary arterial tree). These blockages cause increased resistance to flow in the pulmonary arterial tree which in turn leads to rise in pressure in these arteries (pulmonary hypertension). The blockages either result from organised (or hardened) blood clots that usually originate from the deep veins of the lower limbs of the body (thromboembolism) and lodge in the pulmonary arterial tree after passing through the right side of the heart. The blockages may also result from scar tissue that forms at the site where the clot has damaged the endothelial lining of the pulmonary arteries, causing permanent fibrous obstruction (blood flow blockage). Most patients have a combination of microvascular (small vessel) and macrovascular (large vessel) obstruction. Some patients may present with normal or near-normal pulmonary pressures at rest despite symptomatic disease. These patients are labelled as having chronic thromboembolic disease (CTED).
| Chronic thromboembolic pulmonary hypertension | |
|---|---|
| Other names | CTEPH |
| Specialty | Pulmonology, cardiology |
| Usual onset | 63 years (median) |
| Duration | Long term |
| Risk factors | Splenectomy, inflammatory bowel disease, chronic thyroid hormone replacement, blood types other than O, malignancy, infected ventriculo-atrial shunt, permanent intravenous leads |
| Diagnostic method | Invasively measured mean pulmonary arterial pressure combined with specialist imaging |
| Treatment | Pulmonary endarterectomy, Balloon pulmonary angioplasty, medical treatment |
| Frequency | 5 cases per million |
Diagnosis is made after at least three months of effective blood thinning to discern this condition from subacute pulmonary embolism. Diagnostic findings for CTEPH are:
- Invasively (i.e., in the blood) measured mean pulmonary arterial pressure (mPAP) ≥25 mmHg;
- Mismatched perfusion defects on lung ventilation/perfusion (V/Q) scan and specific diagnostic signs for CTEPH seen by multidetector computed tomography angiography (MDCT), magnetic resonance imaging (MRI) or conventional pulmonary cineangiography (PAG), such as ring-like stenoses, webs/slits, chronic total occlusions (pouch lesions, or tapered lesions) and tortuous lesions.