What Is Cardiac Catheterization?

You’ve experienced chest discomfort during exercise. Your doctor sent you to a cardiologist, who ordered a stress test, and the results indicate your heart needs more oxygen than its blood supply can provide. So, your cardiologist recommends a cardiac catheterization, or cardiac “cath.”

What Is a Cardiac Catheterization?

Marcus St. John, M.D., an interventional cardiologist and medical director of the Cardiac Catheterization Lab with Miami Cardiac & Vascular Institute at Baptist Hospital of Miami, describes a cardiac cath as an invasive diagnostic procedure to determine if blockages exist in the arteries that bring blood to the heart muscle, as well as the location and severity of these blockages.

During the procedure, a hollow tube, known as a catheter, is inserted into either the femoral artery of the groin or the radial artery of the wrist. A dye that can be seen with X-ray imaging is injected into the artery through the catheter. This X-ray, known as an angiogram, shows any narrowing of the arteries from a buildup of plaque, caused by the process of atherosclerosis, on the arteries’ internal walls. If plaque –    made mostly of cholesterol – exists, a diagnosis of coronary artery disease is made.

Radial or Femoral Artery Access

Dr. St. John says that until recently, most cardiac catheterizations took place through a puncture in the groin. The diameter and location of the femoral artery allows for the easy threading of the catheter up to the arteries of the heart. But, using the femoral artery poses a bleeding risk and requires patients to lie flat on their backs for several hours after the procedure to prevent bleeding. Furthermore, if the femoral artery is compromised in any way, doctors must look for other ways to access the arteries of the heart.

As a result, over the past decade, doctors have begun using the radial artery, located in the wrist, to perform cardiac catheterizations in some people. Dr. St. John says this approach reduces the risk of bleeding and allows for quicker mobilization and an earlier release from the hospital following the catheterization. Sometimes in very tall patients, however, catheters may not be long enough to reach the heart from the wrist. In other patients, the radial artery may be too small or arteries along the way too tortuous to allow this approach to be used.

Still, at Miami Cardiac & Vascular Institute, there’s movement toward performing more catheterizations through the wrist, and as many as half of cardiac caths are now performed this way at the Institute, he says, adding that the goal is to improve patient safety, comfort and reduce the time a patient must stay in the hospital.

Cardiac Caths for Treatment

Most cardiac catheterizations, as described, are performed to diagnose coronary artery disease. But, cardiac caths are also used in a procedure to open blocked arteries, as when a patient is having a heart attack. That procedure, using a heart catheter to access a blocked artery for treatment, is called a percutaneous coronary intervention, or PCI.

“During a PCI, we perform an angioplasty and stenting.” Dr. St. John said. “We deploy a balloon through the catheter to the site of the blockage, inflate the balloon to push back the plaque, restoring blood flow, much like a plumber opens a clogged drain.”

Then, a metal mesh device, called a stent, may be placed in the artery to permanently prop open that portion of the blood vessel. It is important to note that stents do not prevent heart attacks in patients with coronary artery disease, but they are important in the treatment of heart attacks and as part of a treatment strategy in patients with chest pain resulting from blockages in heart arteries.

Treating and Preventing Atherosclerosis

Whether a cardiac catheterization is used to diagnose a problem, like atherosclerosis and coronary artery disease, or to treat these or a heart attack, Dr. St. John says the goal is the same – to keep blood flowing to the heart and reduce the risk of future heart attacks. If coronary artery disease is evident following a cardiac cath, the number of narrowed vessels or blockages and how severe they are will help doctors decide the best course of treatment.

“For most blockages, medication, such as a statin to reduce plaque buildup, may be all that’s needed to slow down atherosclerosis and prevent future heart attacks,” Dr. St. John said. “If a patient has a tightly blocked artery that has caused a heart attack already, we will place a stent in that artery through a PCI to keep it propped open.” If a patient has many blockages in different parts of the coronary arteries, Dr. St. John says open heart surgery to bypass those arteries may be most effective in preventing heart attacks.

Reducing Heart Attack Risk Factors

With each of these treatment options, Dr. St. John urges healthy lifestyle changes as well. He says that any acquired risk factors must be reduced or eliminated to prevent the progression of coronary artery disease and future heart attacks. These risk factors include:

• Smoking
• High blood pressure
• High cholesterol
• Diabetes
• Sedentary lifestyle and obesity
• A diet high in saturated fat, sugar and salt

Working with your doctor to address these risk factors through lifestyle modification and, when needed, medication, is key to reducing your likelihood of heart attack.

“Cardiac catheterizations are useful tools to diagnose and treat coronary artery disease in some patients,” Dr. St. John said. “But prevention is paramount by reducing risk factors in the first place. Take steps today for a healthy life.”

Tags: Baptist Hospital of Miami, Marcus St. John M.D., Miami Cardiac & Vascular Institute