A heart cath and an angiogram are often confused, but they are not the same procedure. A heart cath, formally known as cardiac catheterization, describes the entire medical procedure where a thin, flexible tube is inserted into a blood vessel and guided to the heart. Coronary angiography, or angiogram, is one specific type of imaging test that is frequently performed during a cardiac catheterization to visualize the heart’s blood supply. The catheterization procedure serves as the method of access to the heart. A cardiac catheterization can be completed without an angiogram, though they are commonly paired together to diagnose coronary artery disease.
Cardiac Catheterization The Overarching Procedure
Cardiac catheterization establishes a direct route to the heart’s chambers and associated blood vessels. The procedure begins with the insertion of a catheter, a long, narrow tube, into a peripheral blood vessel, typically in the wrist (radial artery) or the groin (femoral artery). After local anesthetic, a needle punctures the artery, and a sheath is placed to keep the vessel open and allow the catheter to be introduced.
The physician uses continuous X-ray imaging, called fluoroscopy, to carefully maneuver the catheter through the body’s vascular network toward the heart. This technique provides real-time guidance, allowing the physician to navigate the catheter into the coronary arteries or heart chambers.
Coronary Angiography The Diagnostic Component
Coronary angiography is the specialized imaging test that utilizes the access achieved by the cardiac catheterization. Once the catheter tip is correctly positioned near the coronary arteries, a contrast medium, usually an iodine-based dye, is rapidly injected through the catheter. This contrast agent absorbs X-rays, making it opaque and visible on the fluoroscopy screen.
As the dye flows through the coronary arteries, it allows visualization of the heart’s blood vessels. The resulting moving X-ray images, or angiograms, clearly highlight any areas of narrowing, blockages, or other irregularities in blood flow. This detailed mapping of the coronary circulation is the primary diagnostic tool for identifying coronary artery disease.
Non-Imaging Functions of the Catheter
Cardiac catheterization is not limited to the visual diagnosis provided by an angiogram; it also performs several non-imaging diagnostic functions. Once the catheter is within the heart, it can be used to directly measure blood pressure within the different chambers and great vessels. These pressure readings offer precise information about heart function and can help diagnose conditions like heart failure or pulmonary hypertension.
The catheter also allows physicians to collect blood samples from specific locations within the heart to measure oxygen saturation levels. By comparing oxygen content between chambers, doctors can evaluate the efficiency of blood flow and detect abnormal connections or shunts within the heart structure. Furthermore, the catheter acts as a channel for interventional procedures, such as angioplasty and stenting, which can be performed immediately if a significant blockage is discovered during the angiography.
Patient Expectations During and After the Procedure
Preparation for cardiac catheterization typically requires patients to fast for six to eight hours before the procedure to minimize the risk of complications from sedation. An intravenous line is placed to deliver fluids and a mild sedative to help the patient relax; patients usually remain awake and able to follow instructions. A local anesthetic is injected at the access site, ensuring the patient does not feel pain during the insertion of the sheath and the movement of the catheter.
After the procedure is complete, the catheter and sheath are removed, and significant pressure must be applied to the access site to prevent bleeding from the artery. If the groin was used, patients must lie flat for several hours to allow the artery to seal properly. Most patients are monitored in a recovery area for a few hours before being discharged, though an overnight stay may be required if a therapeutic procedure, such as stenting, was performed alongside the angiography.