Renal Vein

What is the renal vein?

The renal vein is a blood vessel that carries blood from your kidney to your heart. “Renal” is another word for kidney.

Most people have two kidneys, and each one has its own renal vein.

What is the function of the renal artery and renal vein?

Your renal arteries and renal veins are part of your circulatory system. Your circulatory system carries (circulates) blood throughout your body. Your blood:

• Moves oxygen, hormones and nutrients to your organs, muscles and tissues.
• Helps your body get rid of waste products, including carbon dioxide, acids and excess water.

Your renal arteries carry blood with high levels of oxygen (oxygenated blood) from your heart to your kidneys. After your kidneys filter toxins and organic residues from your oxygen-rich blood, your renal veins carry the deoxygenated and filtered blood from your kidneys to your heart.

Where are they located?

Your kidneys sit in the back of your abdomen (belly), below your ribcage and above your waist.

Your left renal vein is on the left side of your body, behind your splenic vein and pancreas. Your left renal vein is farther away from your inferior vena cava, so it’s longer — about 2 to 4 inches (6 to 10 centimeters).

Your right renal vein is on the right side of your body, behind the top of your small intestine (duodenum). Your right renal vein is about ¾ of an inch to 1.5 inches (2 to 4 centimeters) in length.

What drains into the renal vein?

Because your left renal vein is longer and farther away from your inferior vena cava, it receives blood from other organs in your body, including your:

• Left ureteral vein. Your ureteral vein drains blood from your left ureter. Your ureters are tubes of muscle that carry pee (urine) from your kidneys to your bladder.
• Left gonadal vein. Your gonads are your sex organs (ovaries or testicles).
• Left adrenal vein. Your adrenal glands are at the top of your kidneys. They help produce hormones, including cortisol, epinephrine (adrenaline), norepinephrine (noradrenaline) and others.
• Left inferior phrenic vein. Your inferior phrenic veins drain blood from your diaphragm. Your diaphragm is a muscle that helps you breathe.

Your right renal vein only receives blood from your right kidney.

Where does blood go after the renal vein?

Your kidneys filter (clean) waste products from your blood. They also utilize oxygen and glucose (sugar) in your blood as energy sources to filter it. Then, your renal veins send the filtered (clean) and deoxygenated blood into your inferior vena cava. Your inferior vena cava is a large vein that carries deoxygenated blood from the lower part of your body to your heart.

What are the common conditions and disorders that affect renal veins?

Common conditions that affect your renal veins include:

• Nutcracker syndrome. Nutcracker syndrome affects your left renal vein. It causes your abdominal aorta and superior mesenteric artery to squeeze on your left renal vein. This causes the blood pressure inside your vein to rise, compromising blood flow to your kidney.
• Renal vein thrombosis. Certain conditions — such as blood-clotting disorders, cancer and nephrotic syndrome — may cause a blood clot to form in your renal vein.

What happens if the renal vein is blocked?

Renal vein blockage may cause:

• Severe pain.
• Blood in your pee (hematuria).
• Dizziness when you stand up (orthostatic hypotension).
• Male infertility or female infertility.
• Kidney damage.
• Less pee than normal (oliguria).
• A piece of the blood clot breaks free from the renal vein and moves to your lungs (pulmonary embolism).

What are common tests to check the health of the renal veins?

A healthcare provider may order the following imaging tests to help check the health of your renal veins:

• CT (computed tomography) scan.
• Duplex/Doppler ultrasound.
• Magnetic resonance imaging (MRI).
• Ultrasound.
• Venogram.

A provider may also order a pee test (urinalysis) to check if you have high protein levels (proteinuria) or blood in your pee. The presence of either may indicate kidney damage.

How can I protect my renal veins?

It’s a good idea to get a yearly physical exam to check your risk of developing blood clots. To help improve the health of your renal veins, they may recommend:

• Blood pressure medications.
• Anticoagulant medications (blood thinners).
• Regular exercise to get your blood pumping.
• Drinking plenty of fluids, especially water.
• Eating plenty of fruits and vegetables.
• Quitting smoking.