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Lung Disease & Respiratory Health Center

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Pulmonary Vascular Disease

Pulmonary vascular disease is the medical term for disease affecting the blood vessels leading to or from the lungs. Most forms of pulmonary vascular disease cause shortness of breath.

What Is Pulmonary Vascular Disease?

The definition of pulmonary vascular disease is simple: any condition that affects the blood vessels along the route between the heart and lungs.

Blood travels from the heart, to the lungs, and back to the heart. This process continually refills the blood with oxygen, and lets carbon dioxide be exhaled. Here's how the process works:

  • Oxygen-poor blood returns from the body's tissues through the veins back to the right side of the heart.
  • The right heart pumps oxygen-poor blood through the pulmonary arteries into the lungs. This blood becomes filled with oxygen.
  • The oxygen-rich blood returns from the lungs back to the left side of the heart. The left heart pumps the oxygen-rich blood into the body through the aorta and many other arteries.

Any part of the heart-lung blood circuit can become damaged or blocked, leading to pulmonary vascular disease.

Causes of Pulmonary Vascular Disease

The causes of pulmonary vascular disease vary according to which of the lungs' blood vessels are affected. Pulmonary vascular disease is divided into several categories:

Pulmonary Arterial Hypertension: Increased blood pressure in the pulmonary arteries (carrying blood away from the heart to the lungs). Pulmonary arterial hypertension can be caused by lung disease, autoimmune disease, or heart failure. When there is no apparent cause, it's called idiopathic pulmonary arterial hypertension.

Pulmonary Venous Hypertension: Increased blood pressure in the pulmonary veins (carrying blood away from the lungs, to the heart). Pulmonary venous hypertension is most often caused by congestive heart failure. A damaged mitral valve in the heart (mitral stenosis or mitral regurgitation) may contribute to pulmonary venous hypertension.

Pulmonary Embolism: A blood clot breaks off from a deep vein (usually in the leg), travels into the right heart, and is pumped into the lungs. Rarely, the embolism can be a large bubble of air, or ball of fat, rather than a blood clot.

Chronic Thromboembolic Disease: In rare cases, a blood clot to the lungs (pulmonary embolism) is never reabsorbed by the body. Instead, a reaction occurs in which multiple small blood vessels in the lungs also become diseased. The process occurs slowly, and gradually affects a large part of the pulmonary arterial system.

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