Cardiac catheterization is a generally safe, commonly performed procedure, but it carries some risks. The overall risk of serious complications is low, while common risks are more frequent but typically manageable. Here’s a concise guide to how serious it is and what to expect. Direct answer

• Overall seriousness: Usually safe with a low likelihood of major complications; most patients recover quickly, and most individuals tolerate the procedure well when performed by experienced teams.

• Most common risks: Bleeding or hematoma at the insertion site, bruising, infection, and allergic reaction to contrast dye are the most frequent issues, but they are typically minor and treatable.

• Less common but more serious risks: Blood clots, damage to a blood vessel or heart, irregular heart rhythms (arrhythmias), heart attack, stroke, and, rarely, kidney complications or radiation exposure from imaging. These serious events are uncommon, especially in diagnostic catheterizations, but they can occur.

• Mortality risk: Extremely low in modern practice; major complications during diagnostic catheterization are typically less than 1%, with mortality around 0.05% in large series, though exact risk depends on individual health, the indication for the test, and the procedure type (diagnostic vs. interventional).

• Factors that influence risk: Age, existing heart or kidney disease, diabetes, vascular disease, prior heart procedures, emergency vs. planned procedures, and the use of radial (wrist) versus femoral (groin) access can affect risk and recovery time; experienced teams and modern techniques often minimize risk.

What to discuss with your clinician

• Indication and alternatives: Why the catheterization is recommended and whether noninvasive tests might answer the same questions in your case.

• Specific risks for you: Your medical history, current medications (including anticoagulants), allergies (especially to contrast dye), kidney function, and prior surgeries or heart conditions.
• What to expect: Step-by-step of the procedure, anesthesia or sedation plan, access site (wrist vs groin), how long it typically lasts, and what recovery looks like at home and in hospital.

• Warning signs after the procedure: Increased bleeding, severe pain at the insertion site, fever, chest pain, shortness of breath, or signs of stroke or weakness should prompt immediate medical attention.

If you’d like, I can tailor this to your specific situation (age, health conditions, diagnostic vs. interventional intent) and summarize the exact risk estimates from reputable sources for your case.