Coronary angiography is a diagnostic imaging procedure used by cardiologists to obtain a precise, internal view of the coronary arteries. It is a type of cardiac catheterization that identifies the location and severity of any blockages or narrowing within these vessels. The procedure uses a thin, flexible tube called a catheter, a radio-opaque contrast dye, and continuous X-ray imaging to visualize the coronary circulation.
Why Doctors Order Angiography
Physicians order angiography primarily to diagnose or assess the extent of coronary artery disease (CAD), which involves the buildup of fatty plaque within the arterial walls. It is often performed to investigate unexplained or persistent chest pain, known as angina, or to determine if symptoms like shortness of breath are caused by restricted blood flow.
Angiography is also a standard step following a heart attack to assess the damage and identify the responsible artery. The visual information gathered helps the medical team plan the most appropriate intervention. This direct visualization is necessary to evaluate heart function before major heart-related surgeries, such as heart valve replacement or bypass graft procedures. By revealing the precise anatomy of the heart’s vessels, the test guides decisions about future treatments, including stent placement or open-heart surgery.
The Steps of the Procedure
The procedure is performed in a cardiac catheterization laboratory, or “cath lab.” Before the test, the patient is connected to monitors to track heart rhythm, blood pressure, and oxygen levels. A mild sedative is administered to help the patient relax, though they remain awake and able to follow instructions. A local anesthetic is then injected to numb the chosen access site, which is either an artery in the wrist (radial approach) or the groin (femoral approach).
Once the area is numb, the cardiologist inserts a sheath, a short, hollow tube, into the artery to provide access to the vascular system. The thin, flexible catheter is then threaded through this sheath and navigated toward the heart. The physician uses fluoroscopy, a continuous X-ray projection, to watch the catheter’s movement in real-time on a screen. This guidance ensures the catheter tip is precisely positioned at the opening of a coronary artery.
To visualize the arteries, a small amount of iodine-based contrast dye is injected through the catheter and into the coronary vessel. The dye is opaque to X-rays, making the internal structure of the artery visible as it flows through. If a blockage is present, the flow of the dye will be slowed or completely stopped at that point, outlining the obstruction. The cardiologist captures a series of moving images from multiple angles, creating a permanent record, or angiogram, of the blood flow pattern.
Immediate Post-Procedure Care
Once the images are captured, the catheter and the sheath are carefully removed from the access site. Bleeding is controlled either by applying firm manual pressure or by using a specialized vascular closure device, such as a plug or suture. The method of access dictates the initial recovery instructions and the length of time required for monitoring.
Patients accessed through the radial artery in the wrist can usually sit up and walk around relatively quickly. If the femoral artery in the groin was used, the patient must lie flat on their back for several hours to ensure the artery seals properly and prevent bleeding. Nurses frequently check the insertion site for signs of bleeding or swelling and monitor the patient’s vital signs during this time.
Most diagnostic angiographies are outpatient procedures, allowing the patient to return home a few hours later. Patients should avoid strenuous activity, heavy lifting, and driving for one to three days until the access site has fully healed. They are also encouraged to drink plenty of fluids to help flush the contrast dye from their system.