The most common complication of this test is a blood clot (hematoma) where the catheter was inserted. This is usually in the groin. A blood clot appears as a lump the size of a tennis ball under the skin. The medical staff usually notices this before you leave the imaging facility. A blood clot is treated by putting pressure on the site for a few hours to prevent it from getting bigger. You will be told to put cold packs on your groin for 24 hours to ease the pain. It takes a couple of weeks for the blood clot to heal.
A less common complication is transient ischemic attacks (TIA) or a stroke. A TIA or stroke is caused by less blood flow to your brain. You might have weakness of an arm or leg, have difficulty speaking and understanding words, or lose some vision or not remember things well. A TIA can last just a few hours. A stroke can last for days or weeks, or be permanent. The older you are, the greater the risk for a TIA or a stroke after a cerebral angiography. You might notice these symptoms at the time of the test or after you have left the imaging facility, sometimes days later.