Is my PH due to blood clots in my lungs?

Multiple or recurrent blood clots in the lungs (also known as pulmonary embolism) are a common cause of PH. The possibility of blood clots in the lungs may be assessed by specific tests:

(1) Nuclear Ventilation/Perfusion (V/Q) lung scan. This is actually 2 different scans: a ventilation lung scan and a perfusion lung scan, which are compared to each other.

  • This nuclear x-ray test uses small amounts of radioactive chemicals (also known as radio tracer) to study blood flow (also known as perfusion) and the flow of air (also known as ventilation) in your lungs. You breathe in one radio-tracer, and another radio-tracer is injected into a vein in your arm. Immediately afterward, a special gamma camera takes pictures of blood flow and air in your lungs
  • A V/Q scan doesn’t have any side effects or complications. There is a small risk of radiation exposure, but only small amounts of radio-tracer chemicals are used
  • Blood clots are typically seen as abnormal blood flow (also known as perfusion defects) in the presence of normal flow of air (also known as normal ventilation)

(2) CT angiogram

  • This is a type of CT scan which requires injection of an x-ray dye (also known as contrast material) into a vein in order to better see blood vessels
  • Risks of a CT angiogram involve exposure to x-ray radiation, as well as possible allergic reaction to the contrast material
  • CT angiogram is used to look for blood clots in the pulmonary arteries (also known as pulmonary embolism) which may be a cause of PH in some patients

(3) Pulmonary angiogram

  • This is an invasive test that requires pulmonary artery catheterization, and injection of x-ray dye (also known as contrast material) directly into each of the left and right pulmonary arteries, in order to see blood clots
  • Risks of pulmonary angiogram are similar to those of pulmonary artery catheterization, as well as risks such as allergic reaction to the dye
  • Pulmonary angiogram directly shows blood clots in the pulmonary arteries (also known as pulmonary embolism), as well as chronic damage to the pulmonary arteries from blood clots

Blood Clots in the Pulmonary Arteries

Ventilation/Perfusion Lung Scan (V/Q Scan)

Computed Tomography (CT Scan)

Pulmonary Artery Catheterization

Pulmonary Angiogram