Overview of Left Heart Cardiac Catheterization
Cardiac catheterization is a medical procedure where a doctor inserts a very thin tube called a catheter into a chamber or vessel of the heart. This procedure has a long history, going back four centuries. It all started with the work of William Harvey, who first described how blood circulates in the body, providing a foundation for how we understand the heart. Stephen Hales made a big step forward when he measured blood pressure for the first time in the early 17th century.
While initial experiments were conducted with animals, Werner Forssmann was the one who first performed this procedure on a human, specifically focusing on the right side of the heart, in 1929. A few decades later, around the 1950s, Zimmermann HA carried out the first left-sided cardiac catheterization. Numerous researchers, including Andre Cournard and Dickinson Williams, have worked on further improving the technique since then.
William Sores made another valuable contribution when he succeeded in mapping out the right coronary artery – one of the heart’s major blood vessels – using a special dye during an angiogram. Over the years, the development of various techniques involving x-rays and catheters has led to a revolution in the way professionals approach left-sided heart catheterization.
Today, left heart catheterization is not just used for diagnosis but also for treatment. It helps doctors understand how the heart and blood vessels are functioning and helps in assessing certain heart issues, specially checking for blockages. The main use of this technique is to evaluate coronary artery disease, a condition where the heart’s blood vessels get narrowed or blocked. Indeed, it is often considered the best test for diagnosing coronary artery disease.
As a treatment, left heart catheterization has come a long way in the past five decades. It is now used in various procedures, like opening clogged heart arteries (percutaneous coronary intervention), fixing birth defects of the heart, controlling irregular heartbeats (radiofrequency ablation of arrhythmias), and replacing faulty heart valves.
Overall, left heart catheterization has a crucial role in understanding the heart’s anatomy, assessing various heart issues, and providing treatment. This technique has its potential risks and complications, and its significance should never be underestimated.
Anatomy and Physiology of Left Heart Cardiac Catheterization
In the past, doctors would access the heart through the brachial and radial arteries in your arm – but this technique isn’t used anymore. Nowadays, doctors reach the heart via the radial or femoral arteries, which can be accessed with a simple needle puncture. The radial artery is the last branch of the brachial artery and it goes down the side of your forearm, providing blood to the back outside part of the forearm. The femoral artery continues from a larger artery called the external iliac artery and it’s an important source of blood supply for your lower leg.
The radial artery branches off from the brachial artery, which in turn continues from the axillary artery (found under the collarbone). The axillary artery becomes the subclavian artery when it passes the first rib. Meanwhile, the common femoral artery comes from the external iliac artery as it crosses a ligament in the lower abdomen. This external iliac artery is a bigger branch of the common iliac artery, which splits from the largest artery in the body, called the abdominal aorta, at around the lower back area.
It’s worth noting that in modern medicine, accessing the heart through the radial artery is usually preferred over the femoral artery. This is because it poses a smaller risk of bleeding complications.
Why do People Need Left Heart Cardiac Catheterization
Doctors use a procedure known as left heart catheterization for a variety of reasons, both to diagnose and treat heart conditions. Below are the particular reasons why this procedure may be performed:
- Reviewing and treating coronary artery disease. This is a condition where the heart’s blood vessels narrow, reducing blood flow to the heart.
- Checking and assessing bypass grafts. These are operations that improve blood flow to the heart when the coronary arteries are blocked.
- Investigating and treating coronary artery disease in individuals who have unexplained chest pain, especially if usual non-invasive tests can’t identify the issue.
- Assessing the seriousness of heart valve or muscle disorders, such as aortic stenosis (a narrowing of the heart’s aortic valve), aortic insufficiency (when the aortic valve doesn’t close properly), mitral stenosis (a narrowing of the heart’s mitral valve), mitral insufficiency (when the mitral valve doesn’t close properly) and cardiomyopathies (diseases of the heart muscle). The procedure can identify whether someone needs surgery if there are conflicting signs, symptoms, and results from an echocardiogram, a test that uses sound waves to create pictures of the heart.
- Investigating and treating irregular heartbeats, known as cardiac arrhythmias.
This procedure might also be used to treat birth defects of the heart, like atrial septal defect (ASD; a hole in the wall between the heart’s upper chambers), ventricular septal defect (VSD; a hole in the wall between the heart’s lower chambers) and patent ductus arteriosus (PDA; a blood vessel that doesn’t close as it’s supposed to after birth), using a method called percutaneous closure.
Furthermore, left heart catheterization might be performed for treatment of heart valve diseases, such as repairing or replacing a valve using minimally invasive methods (‘valvuloplasty’ or ‘percutaneous transcatheter valve replacement’).
When a Person Should Avoid Left Heart Cardiac Catheterization
The only definite reason a patient can’t have a left heart catheterization is if they refuse the procedure themselves. This test allows doctors to see how well the heart’s chambers and valves are working.
However, there are some conditions that could potentially make the procedure more risky. These include:
- High blood pressure that is not being controlled.
- Arrhythmia, which means the heart rhythm is not stable.
- Acute cerebrovascular accidents, also known as a stroke or a “brain attack” that’s happened recently.
- Active bleeding in the body.
- Allergy to the dye used for the test, which is called radiographic contrast.
- Problems with kidney function, which is referred to as renal dysfunction.
- Acute pulmonary edema, a condition when your lungs fill with fluid and makes it hard to lie flat.
- An untreated, serious infection in the body or sepsis.
- Severe coagulopathy, which means the blood does not clot normally.
- Encephalopathy, a condition which causes changes in brain function leading to confusion, memory loss, or coma.
- A lot of disease in the blood vessels in the arms or legs, known as significant peripheral vascular disease.
However, the doctor can still consider performing the test if they judge the potential benefits outweigh the risks. This depends on each patient’s unique situation.
Equipment used for Left Heart Cardiac Catheterization
When a doctor is performing a procedure called a left heart catheterization, they need specific equipment to do it safely and effectively. This is what they use:
A cardiac catheterization laboratory: This is a specific room in the hospital where heart procedures take place. It has all the necessary tools and a very sterile environment.
A fluoroscopy machine: This is a special x-ray machine used by doctors to see the real-time moving images of your heart so they can guide the catheter and see what they are doing inside your body.
Hemodynamic monitors: These devices continuously check and display your heart rate, blood pressure, and other important body functions while the procedure is taking place to ensure your safety.
Different diagnostic and guide catheters: Catheters are thin, flexible tubes that the doctor inserts into your body. The diagnostic catheters are used to diagnose, or figure out what’s wrong. Guide catheters help to guide the other instruments to the correct spot in your heart.
Guide wires: These are flexible and thin metal wires that are used to help direct the catheters and stents to the correct spot in your heart.
Manifold for contrast injection: The manifold is a device that allows the doctor to inject a contrast dye into your blood vessels. This dye helps the doctor to see your blood vessels better on the x-ray images.
Coronary wires, balloons, and stents for percutaneous coronary intervention: Percutaneous coronary intervention is a non-surgical procedure used to treat blocked coronary arteries. In this procedure, a balloon is inflated to widen narrowed or blocked coronary arteries. If needed, a small wire mesh tube, called a stent, can be placed in the artery to keep it open.
Who is needed to perform Left Heart Cardiac Catheterization?
A heart procedure, know as a ‘left heart catheterization’, takes many different types of medical experts to perform successfully. First, there’s a cardiologist, who is a doctor that specializes in matters of the heart. They are skilled in particular procedures, including left heart catheterizations.
Also present is a cardiovascular technologist. This professional aids the cardiologist during the procedure. A cardiac catheterization nurse is also needed. Their role is to administer any needed medicines.
In addition, there’s a type of technician called a ‘radiographer’. They help out by capturing any necessary images during the procedure. Lastly, to ensure you are not awake or in pain during the procedure, an anesthesiologist will assist. They administer medicine that will help you sleep or relax. Together, they make sure the procedure is safe and effective.
Preparing for Left Heart Cardiac Catheterization
If you’re going to have a medical procedure, the doctor may ask you to stop taking blood thinners a day before to lower the risk of excessive bleeding. This depends on how well your kidneys are working, which helps remove these medications from your body.
Before the procedure, the healthcare team will ask you for your medical history, with a particular focus on whether you have any allergies to contrast dyes, a substance used to improve the visibility of body structures in medical images. Additionally, they will perform a physical examination to check the site where they will insert the catheter or tube, as well as check your pulse in different parts of your body. They will also run several blood tests to check the levels of red blood cells, platelets, creatinine (a waste product that shows your kidney function), and clotting ability. You will be asked to give permission for the procedure after you have been fully informed about what it involves, including any risks and potential complications.
To protect your kidneys, especially if they’re not working perfectly, they’ll give you a type of saltwater solution known as normal saline through a vein. This helps to counter any possible harmful effects from the contrast dye used during the procedure.
Once you’re in the room where the procedure will take place, you’ll lie flat on your back on a special table. The healthcare team will clean the area of your body where they’ll insert the catheter and cover you with a sterile drape to prevent infection. They’ll also prepare all the tools they’ll use, including small tubes, needles, and other equipment, by flushing them with saline mixed with a blood-thinning medication called heparin.
For their part, the doctors and other healthcare workers present during your procedure will also follow strict cleanliness procedures. They’ll wear sterile clothing, including a special gown, gloves, and caps, as well as face shields for protection.
How is Left Heart Cardiac Catheterization performed
Arterial access is a procedure done to reach your arteries, the blood vessels that carry blood from the heart to the rest of the body. It can be performed either in the arm (radial access) or the groin area (femoral access), depending on the needed procedure. Before the procedure, you may be pre-medicated with medicines like midazolam, nalbuphine, or fentanyl to help reduce any anxiety that may cause spasms in the artery.
For radial access in the arm, the doctor will locate the pulse on your wrist, then give a local anesthetic to numb the area. With a special needle, they will then gently pierce the radial artery (which is located a couple of inches above your wrist), ensuring it’s placed correctly. To prevent any possible complications, medicines like nitroglycerine and heparin are then administered.
For femoral access in the groin, the doctor will look for specific anatomical landmarks for a successful insertion. The femoral artery will be located, which runs along the upper thigh and inwards toward the groin. After that, similar to radial access, local anesthesia will be given, and access will be secured in the artery.
Once the artery is accessed, a dye can then be injected, and images of the heart taken through a procedure called a coronary angiogram. This helps in identifying any blockages in the heart’s blood vessels. If a blockage is found, the doctor may also perform a percutaneous coronary intervention where a small balloon is inflated to open up the blocked artery or a stent (a small tube) is placed to keep the artery open.
In addition, a left ventriculogram may also be performed to evaluate the heart’s main pumping chamber, the left ventricle. A catheter, a thin, flexible tube, is advanced into the left ventricle to assess its performance and check for any abnormalities.
The doctor may also assess the aortic valve, which controls blood flow from the heart to the aorta, the body’s main artery. This is done by measuring the pressure gradient and the cardiac output. In particular, the aortic valve’s effectiveness is evaluated using an equation designed to calculate this.
The severity of aortic regurgitation (backward blood flow from the aorta to the heart due to a leaky valve) can also be assessed. The doctor will categorize the level of regurgitation from mild to severe based on the results from the angiogram.
Possible Complications of Left Heart Cardiac Catheterization
Having a left heart catheterization, a procedure where a long thin tube called a catheter is inserted into your heart by way of your blood vessels, is generally quite safe. However, there can still be some complications. Most of the rare cases where a patient unfortunately dies after a left heart catheterization are due to being seriously sick already.
The complications that could potentially happen are split into different categories. One category is complications at the site where the catheter was inserted into your body, like bleeding, a lump caused by blood (hematoma), a swelling filled with blood that mimics an aneurysm (pseudoaneurysm), abnormal connections between arteries and veins (arteriovenous fistulae), tearing of the artery (perforation), and splitting of the artery layers (dissection). While these kinds of complications are more common when the catheter is inserted through a vein in your leg (transfemoral approach) as against your wrist (trans-radial approach), use of sound waves to visualize the area (ultrasound) and special devices to close the insertion point have helped to greatly reduce these complications.
Stroke due to the procedure is extremely rare, occurring in less than 0.1% of diagnostic left heart catheterizations. It’s slightly higher at 0.4% for procedures involving opening up blocked arteries (percutaneous coronary intervention). Having a stroke during these procedures is more likely if you are older, have high blood pressure, diabetes, previously had a stroke, heart failure, hardening and narrowing of the arteries (atherosclerosis), and when the procedure is done in an emergency.
Heart attack is very unusual during left heart catheterization, reported as occurring in 0.2 out of every 10,000 procedures. However, when the heart attack is caused by tearing of the blood vessels that supply the heart muscle (coronary artery dissection), it happens in almost all cases. Another major but very rare complication is bleeding into the sac that surrounds the heart leading to compression of the heart (cardiac tamponade), reported as extremely low at 0.009%.
There are also complications related to the use of a substance known as contrast. This is a dye used to help visualize the structures within your body more clearly. Some people might react to this dye, causing skin rashes (urticaria), but in very rare cases it can lead to a severe allergic reaction (anaphylaxis). Another problem could be kidney damage (contrast-induced nephropathy), which is serious and more common if you already have issues with your kidneys, have heart failure, and decreased function of the left side of your heart. While there’s no specific treatment for this complication, it can generally be prevented by using less dye, ensuring that you’re not dehydrated, and preventing a response by your body that causes narrowing of the blood vessels to your kidneys (renal vasoconstriction).
What Else Should I Know About Left Heart Cardiac Catheterization?
Cardiac catheterization is a medical procedure that has become invaluable in treating severe heart conditions – for example, potentially life-saving in instances of a sudden heart attack. The procedure involves the insertion of a thin, flexible tube into the left side of the heart under emergency conditions to identify the blood vessel causing the issue. Once identified, a further invasive procedure known as percutaneous (through skin) coronary intervention is performed to preserve the endangered heart muscle tissue.
Thankfully, the procedure has seen significant advancements recently, one of which is a switch to inserting the catheter in the wrist (trans-radial) rather than the thigh (trans-femoral), as it’s more comfortable for the patient. Other improvements include using ultrasound imaging to guide the procedure, deploying smaller catheters, and capitalizing on increasing physician experience – all of which have contributed to lowering potential complications.
In the past 20 years, the field has seen another milestone with the advent of percutaneous valve replacement. This innovative procedure has significantly impacted the techniques used for left heart catheterization. The ability to measure heart pressure changes with this method has become particularly useful in diagnosing and predicting outcomes in patients with heart valve diseases and heart muscle disorders (cardiomyopathies).
