Cardiac catheterization

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Cardiac catheterization is a procedure in which a thin flexible tube (a catheter) is inserted into a heart chamber or a blood vessel. Doctors use it to diagnose problems and to treat some heart conditions.

What it’s used for
- Coronary catheterization (heart arteries): See if the arteries that supply the heart are narrow or blocked, which can cause chest pain or a heart attack.
- Diagnostic tests: Measure pressures inside the heart and lungs, estimate how much blood the heart pumps, and check heart valve function.
- Treatment: If there are blockages, doctors can open them using balloons and place stents to improve blood flow (percutaneous coronary intervention, or PCI).
- Valve and congenital heart disease work: Catheters can help replace a valve without open-heart surgery, or treat certain congenital heart problems. They can also help place devices like pacemakers or assess shunts (abnormal blood flow paths).

How the procedure is done
- Access: Vessels are usually reached through the wrist (radial artery) or groin (femoral artery), or sometimes through a vein in the neck (internal jugular). The Seldinger technique is used to enter the vessel and thread a wire, then slide a catheter over the wire.
- Imaging: Fluoroscopy (live X-ray) with contrast dye helps doctors see the catheters inside the heart and arteries.
- What happens next: The doctor may inject contrast to visualize blood flow, take measurements, or perform treatment with balloons, stents, or other tools. After the procedure, the catheter is removed and the access site is closed.

Types and uses
- Left heart catheterization: Goes to the left side of the heart and the coronary arteries to measure pressures, view blockages, and guide interventions.
- Right heart catheterization: Goes into the right side of the heart to measure pressures and blood flow, useful for assessing heart failure, pulmonary hypertension, and shock.
- Other applications: Checking valve gradients, evaluating blood flow to the lungs, testing for heart shunts, and sometimes guiding valve replacement or septal repairs.

Risks and limitations
- Cardiac catheterization carries risks such as stroke, heart attack, or rarely death. Kidney injury from contrast dye and exposure to radiation are possible.
- The benefits must outweigh the risks. It is usually reserved for people with suspected serious heart disease or when non-invasive tests are unclear.
- Some people are at higher risk due to other health conditions, such as diabetes, kidney disease, severe artery disease, obesity, or unstable heart conditions.

Notes on care and decision-making
- The choice to perform catheterization depends on symptoms, test results, and overall health.
- It provides direct information about heart function and blood flow and can often lead to immediate treatment if needed.
- If multiple arteries are blocked, doctors might consider coronary artery bypass surgery (CABG) instead of a catheter-based approach.

A brief history
- The development of cardiac catheterization began with early experiments by Forssmann and Bernard. It became a routine clinical practice in the mid-20th century, and the work of Forssmann and Cournand earned the Nobel Prize in Physiology or Medicine in 1956.