An angiogram is now performed routinely at most medical centers. It is relatively safe, and complications are rare. With an angiogram, the chance of a serious complication—such as a stroke, heart attack, or death—is 1 to 2 in 1,000.¹ Most of those who die already have a severe heart disorder or other disorder. The risk of complications and death is increased for older people.

Although the risk of any major problem caused by an angiogram is extremely small, there are a number of complications that can occur. In most cases, the complications occur within 2 hours after the test.

• There is a slight risk of developing an allergic reaction to the iodine contrast material. The reaction can be mild (itching or a rash) or severe (difficulty breathing or sudden shock). Death resulting from an allergic reaction is extremely rare. Most reactions can be controlled using medication. Be sure to tell your doctor if you have allergies of any kind (such as hay fever, iodine allergy, asthma, hives, or food allergies).
• There is a small risk that the catheter may damage an artery or dislodge a piece of clotted blood or fatty deposit from the artery wall. The dislodged object can block blood flow and cause damage to the heart (heart attack), brain (stroke), arm, leg, or intestine.
• Excessive bleeding from the needle site in the artery is rare but possible. In addition, a blood clot can form where the catheter was inserted. This may cause partial blockage of a blood vessel to the arm or leg.
• Damage to the kidneys is a possible risk that may lead to kidney failure. Contrast material used during the test can cause excessive water loss or direct damage to the kidneys. This is a special concern for people with kidney problems, diabetes, or dehydration. Special precautions are usually taken during the test to prevent problems for people with these conditions.
• There is always a slight risk of damage from being exposed to any radiation, including the low levels in X-rays used for this test. However, if this test is really needed, the risk of damage from the X-rays usually is very low compared with the potential benefits of the test.
• There is also a small risk of puncturing a hole in the heart, developing irregular heart rhythms, and tearing a blood vessel.

If you notice weakness in the muscles of your face, vision problems, or slurred speech or if your leg or arm becomes cool, pale, or numb during or after the procedure, notify your doctor immediately.

Ask your doctor how many of his or her patients have had problems after an angiogram.