The blood vessel that carries ‘impure’ blood from the heart to the lungs is the pulmonary artery. It is the artery of the lung. It is one of the only two arteries that carry deoxygenated blood. All other arteries carry ‘pure’ or oxygen-rich blood. The main pulmonary artery begins at the base of right lower chamber of heart and divides into right and left pulmonary arteries which carry ‘impure’ blood from the heart to the right and left lung respectively.
This artery may be affected in different ways:
a. Conditions like heart failure, COPD, lung disease, scleroderma, etc. can increase the pressure of the pulmonary artery leading to pulmonary hypertension.
b. Pulmonary artery stenosis is a defect that is exists at birth. There is narrowing of the artery making it difficult for blood to reach the lungs.
c. A blood clot, less commonly air or fat, can break off and travel from elsewhere in the body through the bloodstream to the lungs and block the pulmonary artery or its branches. This condition is called pulmonary embolism.
d. Frequent blood clots in chronic thromboembolic disease can block and narrow the artery.
e. Rarely, the left branch may originate from the right branch instead of from main pulmonary artery. This condition is called pulmonary artery sling.
Tests to diagnose these conditions may include electrocardiogram, chest X-ray, MRI, CT scan, pulmonary angiography, heart catheterization, etc. Treatments include medications, balloon dilation, stent placement and surgery.