Overview of Percutaneous Transluminal Coronary Arteriography
Percutaneous transluminal coronary arteriography, also known as an invasive coronary angiogram, is a key tool used to diagnose heart disease. Heart disease is the main cause of death in the United States, with approximately 20.1 million adults affected by it. Over a million coronary angiograms are carried out each year in the US. The first coronary angiogram was performed by Dr. Sones in 1958 and since then the methods and techniques used in this field has significantly improved.
This procedure gives us a clear picture of the heart’s structure and helps us understand how serious any blockages (referred to as ‘stenosis’) in the heart’s arteries or in any bypass grafts might be. In medical terms, we say that stenosis is ‘hemodynamically significant,’ meaning it’s potentially serious, if more than 70% of the artery is blocked.
Having a coronary angiogram is generally safe and provides valuable information about the heart’s health. However, it’s important to know that like any medical procedure, it can have complications. These can include pain, bleeding, injury from radiation exposure, sudden kidney damage, a major heart attack, stroke, need for a blood transfusion, an infection at the site where the procedure was done, symptoms from small blockages breaking off and traveling in the bloodstream (athero-embolism), irregular heart rhythms (arrhythmias), and even death.
If the blockage is between 50-70%, doctors will carry out further tests such as physiological assessment, intravascular ultrasound (IVUS) – which uses sound waves to look at your blood vessels from the inside, or optical coherence tomography (OCT) which takes detailed images of tissues in the body. This helps to provide the most accurate understanding of how severe the blockage is, and based on this information, doctors decide which treatment options are best.
Anatomy and Physiology of Percutaneous Transluminal Coronary Arteriography
The left main heart artery begins from the aorta, which is the main and largest artery in your body, and it splits into two main parts: the left anterior descending artery and the left circumflex artery. The left anterior descending artery has branches which provide blood to the front and sides of the heart, as well as the structures between the heart’s chambers. It also caters to the tip of the heart. The left circumflex artery has branches that supply the back and sides of the heart.
The right coronary artery also begins from the aorta, and it runs along the groove where the heart’s chambers meet, then divides into the posterolateral branch and the posterior descending artery. It also has a branch that feeds the heart’s upper chambers and an artery that supplies the right lower chamber. The main artery feeding the back of the heart generally decides the dominant side of the heart’s blood flow, more often it is the right side.
There might be a slightly different set-up in the heart arteries for 1-2% of the people. For example, the left circumflex artery could be coming from the right side of the heart, though this generally doesn’t cause any issues. Quite rarely, someone might have heart arteries travelling between the aorta and the main artery that supplies the lungs. This can be problematic.
The larger heart arteries break down into smaller ones, the size of these get smaller and smaller until they become tiny blood vessels called capillaries. Blood travelling in the heart majorly flows when the heart relaxes in between beats. The major arteries of the heart bring blood to these smaller arteries. These little arteries and capillaries are key to regulating and controlling the blood flow into heart’s tissues. They also determine resistance to blood flow at a micro-level in the heart. The ability of the heart to increase its blood flow, depending on the body’s need is contingent upon the blood movement, regulation of flow, and exchange of oxygen and other nutrients at the level of these tiny blood vessels.
We also have tests to see if the blood flow in the heart is adequate; one is called the fractional flow reserve and the other test looks at resistance to flow in these tiny vessels.
Why do People Need Percutaneous Transluminal Coronary Arteriography
A coronary angiogram is a type of test that doctors use to check the blood vessels of your heart. There are many reasons why a doctor might recommend this test. Below are some of the common reasons:
If you have stable angina, a type of chest pain, but the pain doesn’t go away even though you’re taking two different types of medicines for it.
If you have a type of chest pain called unstable angina.
If you’ve had a certain kind of heart attack, known as non-ST-elevation MI.
If you’ve had a test that shows your risk of having a heart attack or dying from heart disease could be higher than 3% per year. This could be because of several heart-related issues seen in your tests, such as stress affecting more than 10% of your heart muscle or more than two of your heart’s areas (coronary territories), certain changes in your heart’s pumping function, or high levels of calcium in your heart’s arteries.
If you have blockage of more than 50% in the left main artery of your heart, or blockage of more than 70% in multiple arteries.
If exercise triggers abnormal heart rhythms or sudden death, which has been successfully counteracted (resuscitated).
If you have abnormal persistent heart rhythms with no clear cause, or chest pain with unclear cause.
If you’ve had a heart attack with ST-elevation MI, which is a more severe type of heart attack.
If you’ve had a heart attack that lead to mechanical complications such as issues with your heart’s valves or the wall dividing the chambers of your heart.
If you’re in a serious condition called cardiac shock, where your heart can’t pump enough blood around your body.
If there’s a suspicion of a heart-related issue, such as significant disease in the heart valves or in the sac enclosing the heart, or if there’s a suspicion of issues with the large vessel (aorta) close to the heart, then this test might be necessary before any surgery.
If you’re a heart transplant patient and experience symptoms of heart disease after your surgery or if there’s a suspicion of abnormal formation of the blood vessels of the heart from birth.
When a Person Should Avoid Percutaneous Transluminal Coronary Arteriography
There are certain situations where a medical procedure to improve blood flow to the heart, known as coronary revascularization, should not be performed. For example, if a person has a very limited time left to live and the procedure won’t improve their quality of life or extend their life, then it shouldn’t be done.
Additionally, there are certain conditions that could make non-emergency heart scans risky. These include:
– Sudden kidney problems on top of chronic kidney disease or being in the final stages of kidney disease.
– Active bleeding or a severe blood condition that makes it hard for them to stop bleeding. This could be due to having very low platelets – the blood cells that help your body form clots to stop bleeding.
– Having used certain blood-thinning medications recently.
– Recent clot or bleeding in the brain.
– Severe infections that have spread throughout the body or untreated bacteria in the blood.
– Issues with understanding or following commands.
– Sudden severe shortness of breath due to fluid in the lungs.
– If a patient who can’t tolerate the dye used in the procedure refuses pre-treatment for an allergic reaction to the dye.
Also, after a heart attack, if attempts to restart the heart have been unsuccessful and certain risk factors are present – such as a very acidic body (PH less than 7.2), high levels of lactate (above 7) which is a sign of the lack of oxygen, being older than 85, being in the final stages of kidney disease, taking longer than 30 minutes to restart the heart, no one being there to perform CPR, and the heart attack happening without anyone witnessing it – then this revascularization procedure shouldn’t be performed.
Equipment used for Percutaneous Transluminal Coronary Arteriography
For arterial access, healthcare providers might use either a small (25G) or a larger (18G) needle. It’s strongly suggested doctors use a vascular ultrasound to gain access to the common femoral and radial arteries. In terms of contrast agents – substances used to enhance the visibility of structures or fluids within the body – using agents with a lower osmolality (measure of particles in a solution), like Iohexol and Iopamidol, and Iso-osmolar contrast agents (equal particle concentration), like Iodixanol, can reduce the risk of kidney complications.
When approaching either from the thigh (femoral) or wrist (radial), the inventory will include a variety of tools, such as a band bag, bowls, clamps, a drape, medical cups, needles, sponges, syringes and more. All these tools are used to ensure the operation runs smoothly and the patient is as comfortable as possible.
Fluoroscopy, a kind of medical imaging that shows a continuous X-ray image on a monitor, is usually used for both femoral and radial approaches.
In terms of medication, Lidocaine is used for numbing, Midazolam is used for sedation, Fentanyl is a pain reliever, and Propofol is a general anesthetic (only if backup from an anesthesiologist is available). Aspirin and Heparin are blood thinners. The selection and use of different catheters, or tubes for draining or injecting fluids, and sheaths, tubes to protect another medical device, are detailed and will vary depending on the approach. Mentioned devices are used to support and guide the procedure, ensuring that the medic can precisely guide the instruments throughout the operation.
For radial, ulnar (inner arm), and brachial (upper arm) procedures, similar medications are used and also Nitroglycerin, Nicardipine, and Verapamil, which help widen blood vessels. A variety of specific radial catheters, like the Tiger and Jacky catheters, are preferred for these procedures.
Who is needed to perform Percutaneous Transluminal Coronary Arteriography?
The heart procedure room, often known as the cardiac catheterization lab, has a team of specialist healthcare providers. Each member of the team plays a distinct role, ensuring that you receive effective and safe care. Here’s who’s on that team:
The doctor who is in charge of the lab, called the cath lab medical director, oversees everything that happens in the room. They are like the captain of a ship, guiding the whole team.
The cath lab nurse manager is a senior nurse who looks after the nursing staff and makes sure all nursing procedures are followed correctly.
The interventional or invasive cardiologist is a heart doctor who uses special equipment to look at and treat problems in your heart through a procedure called cardiac catheterization.
The cath lab nurse helps the doctors during this procedure and looks after you before, during, and after the procedure.
Then there’s the cath lab technician. They are trained to handle and operate the medical equipment used in the lab.
The janitor keeps the lab clean and sanitized to reduce the risk of infection.
A chaplain provides spiritual and emotional support if you need it.
The pharmacist makes sure you get the right medicines before and after the procedure. They work closely with the doctors to ensure your medication is safe and effective.
An echo technician uses a special machine to take pictures of your heart (an echocardiogram) that the cardiologist uses to understand your heart’s health.
And eventually, a transporter ensures that you’re moved safely to and from the lab, whether it’s from your room or the recovery area after the procedure.
All-in-all, each person on this team has an important role to play in your care during your time in the cardiac catheterization lab.
Preparing for Percutaneous Transluminal Coronary Arteriography
Firstly, the nurse or the person in charge from the Cath lab (where heart procedures are performed) will call you with certain instructions to be followed. These are: don’t eat or drink anything for 6-8 hours before the procedure; avoid taking blood thinning medicines; arrange transportation for returning home after the procedure; revisit your routine medications; check if you have any allergies; and go through your lab tests including blood work, chest X-ray, urinalysis, etc. They would also explain why you are getting the heart exam (coronary angiogram), the duration of the procedure and what time you need to visit the Cath lab.
Next, a Cath lab nurse will accompany you from the registration desk to the lab. Here, your belongings will be securely stored and you’ll be asked to change into a surgical dress. The nurse will note down your vital statistics like heart rate, blood pressure, temperature, and breathing rate. You’ll also have IV (Intravenous) lines inserted, preferably in both arms, and connected to a heart and blood pressure monitor. There will be a baseline EKG done, which is a type of test to measure your heart’s electrical activity. You’ll go through all of your blood work and preoperative testing again with the nurse, followed by a short medical exam. You might also receive IV fluids depending on your general health (Normal saline is a suitable choice).
Next, the cardiologist who will perform the procedure will explain all the pros and cons of your heart procedure in detail and ask for your written consent.
After this, the doctor will do a quick physical examination to determine the best way to access your heart (either from your wrist or your groin). They’ll decide the type of catheters (tubes) that will be used during your procedure.
Then, a technician in the Cath lab will connect certain devices that monitor pressure and cleanse all the catheters that will be used during the procedure. The technician will also prepare all the necessary equipment, based on the doctor’s choices.
The next part of the process is for you to lie flat on the Cath lab table, and you’ll be covered with a clean, sterile drape. The area of your body (groin or wrist) where the catheter will be inserted will be cleaned and sterilized. Meanwhile, the technician will organize the equipment close to the table and get the C-arm (a device to see the inside of your body) ready.
Following this, the Cath lab nurse will prepare medications like lidocaine (a local anesthetic) and moderate sedation, and also get the vascular ultrasound ready (a type of imaging that looks at your blood vessels and blood flow).
Before the procedure begins, there is a routine safety check, or ‘Pre-procedure time-out’, which the Cath lab technician or nurse will take care of.
Finally, another nurse or technician will be stationed to enter all of your recorded data in the Cath lab’s reading room during the procedure.
How is Percutaneous Transluminal Coronary Arteriography performed
Before beginning the procedure, the patient will be mildly sedated and numbed in the area where the doctor needs to access an artery. This is to ensure the patient is comfortable and doesn’t feel pain during the process.
The doctor will need to reach your arteries, which are big blood vessels that transport blood from your heart to the rest of your body. They can do this through different areas:
– The femoral artery in your thigh: The doctor will use a special device that uses sound waves (ultrasound) and a type of x-ray (fluoroscopy) to guide a large needle into the artery. They’ll then put a tiny tube called a wire through the needle into the artery. They’ll confirm they’re in the right place by checking the blood flow, then remove the needle. Next, they’ll insert a tube (sheath) backwards over the wire into the artery, connect it to an IV line, and inject a contrast dye through the tube to get clear images of the artery. The tube will be flushed out regularly.
– The radial artery in your wrist or the ulnar artery in your forearm can also be accessed with a needle under ultrasound guidance. Once blood flow is confirmed to be correct, a small wire is advanced into either the radial or ulnar artery. The rest is similar to the femoral artery process but smaller sheath sizes are used and medications are given to keep the artery open and prevent blood clotting.
For the procedure, the doctor will need to access specific arteries in your heart, depending on what they need to see. They will use the catheters and wires to guide and engage with the arteries while getting pictures by injecting the contrast dye into each artery. This will help them see any blockages or problems. It’s very important that they check the pressure and EKG (a test that measures your heart rhythm) before each injection to ensure there’s no blockage in the artery.
If you have previous bypass grafts, the doctors may need to access these grafts using the same steps as above, essentially using imaging techniques to help guide catheters and wires to the correct location.
After all the pictures have been taken, the doctor will review them closely. They’ll remove the catheters using guidance from the fluoroscope. Depending on where the artery was accessed, they can use a special device to close up the femoral artery, or a bandage for radial or ulnar artery access sites. After recovery and confirmation that the patient is stable, discussions regarding results and future steps will occur. This could include an outpatient follow-up and review of medications before discharging.
Possible Complications of Percutaneous Transluminal Coronary Arteriography
Surgeries, just like other medical procedures, come with potential risks and complications. These complications can occur shortly after the procedure (early complications) or may develop after a period of time (delayed complications).
Early complications might include:
- Bleeding at the site where the doctor entered your body (Access site hematoma).
- Sudden damage to your kidneys (Acute Kidney Injury).
- Having a stroke, which can be caused by a clot (embolic) or bleeding (hemorrhagic) in the brain.
- Formation of a clot in the blood vessels (thromboembolic events).
- Severe decrease in red blood cells leading to need for a blood transfusion (Acute blood anemia requiring blood transfusion).
- Pain at the site where the doctor entered your body (Access site pain).
- Heart attack due to sudden blockage of a blood vessel in the heart (Myocardial infarction, Abrupt closure of coronary artery).
- Emergency heart surgery to restore blood flow (Emergency Coronary artery bypass surgery).
- Sudden buildup of fluid in the lungs making it hard to breathe (Acute pulmonary edema).
- Irregular heart rhythms (VT/Vfib).
- Blocking of blood vessels due to cholesterol or fatty deposits (atheroemboli).
- Injuries caused by exposure to radiation.
- An abnormal connection between an artery and a vein (A-V fistula).
- A sac formed by the ballooning out of the wall of a blood vessel (Pseudoaneurysm).
- In worst cases, death can occur.
Delayed complications might include:
- Infection at the site where the doctor entered your body (Access site infection).
- Sudden damage to your kidneys (Acute Kidney Injury).
- Bleeding at the site where the doctor entered your body (Access site hematoma).
- Injuries caused by exposure to radiation, which is more common in overweight patients or if the procedure takes a long time.
- Chronic fluid buildup in the lungs that suddenly gets worse (Acute on chronic pulmonary edema).
- In some cases, death can occur.
What Else Should I Know About Percutaneous Transluminal Coronary Arteriography?
A coronary angiogram is a test that visualizes the blood vessels of your heart (coronary arteries) and checks for any blockages or narrowing (stenosis). It’s a useful tool for heart specialists to decide the best treatment approach if needed. The ways in which coronary angiograms are performed have advanced greatly over the past 20 years, making this test much safer and having fewer complications. A coronary angiogram can also be done as an outpatient procedure, meaning you don’t need to stay overnight in the hospital. Nonetheless, like any medical procedure, it’s not totally without risk of complications.
