While there are some risks involved in any invasive or minimally invasive procedure, coronary angiograms are widely used and complications are low, occurring in less than three percent of patients. These potential complications include:

• Bleeding in the area of the catheter insertion
• Abnormal heart rhythms arrhythmias
• Infection
• Allergic reaction to the dye
• Damage to the arteries
• Heart attack
• Stroke
• Air embolism (when air gets into the bloodstream, where it could cause damage)
• Death

The risk of complications is greater if people are over the age of 70, or have conditions such as diabetes, hardening of the arteries (atherosclerosis), kidney failure or carotid artery disease.