Overview of Radial Artery Coronary Bypass
A coronary artery bypass graft (CABG) operation is a type of heart surgery that’s carried out to improve blood flow to heart muscles. This is usually the recommended treatment for severe heart disease that affects several blood vessels. It uses several veins and arteries to create new pathways for blood flow around the blocked arteries. The left internal mammary artery, a blood vessel located in the chest, is mostly used because people who receive this type of graft live longer.
However, if grafts are taken from the saphenous vein in the leg, the life span could be shorter due to an increased risk of blockages, especially after heart attacks. Within the first year after surgery, 10 to 15% of these grafts become blocked, and by the tenth year, the blockage could increase to 50%.
Because of this, doctors sometimes use other arteries as alternatives. But using two grafts from the internal mammary artery is generally avoided because it could lead to a higher risk of chest infection.
The radial artery, a blood vessel in the forearm, has become a popular choice after the left internal mammary artery because it’s easy to remove and stretch to reach the major heart arteries. It was first used for this purpose in 1973, but doctors stopped using it after discovering that it got blocked too often. However, it was reintroduced in 1992, and with improved techniques and medication to prevent spasms, the chances of it staying open increased to more than 90% in the first and fifth years after the operation.
It’s still unclear whether using the radial artery for grafts give better long-term results than using the saphenous vein. Some studies suggest that using the radial artery might lead to better results after surgery, but there could be some bias in these findings. However, a combination of data from five separate clinical trials reveals lower rates of death, heart attack, or needing another revascularization procedure five years after surgery when using the radial artery as compared to the saphenous vein.
Anatomy and Physiology of Radial Artery Coronary Bypass
The brachial artery is a main blood vessel in your arm. This artery splits into two smaller arteries (the ulnar and radial arteries) near the top of your forearm. The radial artery is the smaller of the two, and it passes along the outer (or thumb-side) of your wrist, going underneath a couple of tendons and heading towards the spaces between your first and second hand bones (metacarpals).
When it reaches the hand, this radial artery connects with a branch from the ulnar artery to form a loop called the deep palmar arch. The radial artery also supplies blood to different places along its route, like the forearm and wrist, and it branches out in the hand.
From a perspective of its structure, the radial artery is mostly made of muscle tissue, which makes it likely to instinctively tighten or contract (spasm). It’s similar in many ways to the internal mammary artery (an artery in your chest), especially in its muscle parts.
The radial artery is great for handling high arterial pressure (high blood pressure), similar in size to heart arteries, and long enough to reach all heart arteries. Plus, doctors can easily access it without causing patient mobility issues. These characteristics make this artery a more preferred choice compared to other options known as SVGs, in regards with less side-effects and fatal incidents.
Why do People Need Radial Artery Coronary Bypass
The American College of Cardiology (ACC) and the American Heart Association (AHA) released a joint guideline in 2021. This guideline advises that during heart bypass surgery, the radial artery (one of the main arteries in your arm) is a better choice than the saphenous vein (a large vein that runs along the leg) for restoring blood flow to the second most important blood vessels close to the heart. This advice comes after the heart’s left anterior descending coronary artery. This recommendation is backed by evidence that the radial artery tends to stay open longer than the saphenous vein after surgery. Additionally, the radial artery has been associated with fewer heart-related complications and better survival rates after surgery. Thus, the ACC and the AHA have given this method a “Class I” safety rating, which means that it’s considered safe and effective.
When a Person Should Avoid Radial Artery Coronary Bypass
In some cases, doctors can’t use a specific blood vessel called the radial artery as a graft during a heart bypass surgery (CABG). These are some of the reasons:
An abnormal Allen test, which checks the blood supply to the hand, may indicate it’s not safe to use the radial artery. Any injury or damage to the radial artery from a previous accident or medical procedure, like catheterization or cannulation (inserting a small tube), can also make it unusable
If there’s a noticeable narrowing of the radial artery found on a special type of imaging test known as an ultrasound, then it’s not safe to use the artery. Similarly, if a person is using the radial artery for a procedure called hemodialysis that filters waste from the blood, it should not be used for grafting.
Conditions such as Vasculitis, which involves inflammation of the blood vessels, or Raynaud’s disease, that affects blood flow to your fingers and toes, can also prevent the use of the radial artery for this surgery.
Equipment used for Radial Artery Coronary Bypass
When your doctor performs a radial artery bypass graft – a type of heart surgery – they need a variety of different tools and equipment. This includes:
A cardiopulmonary machine: This machine temporarily takes over the work of your heart and lungs during the surgery.
A surgical drape: This is a large sheet used to keep the surgical area clean and free from germs.
A sternal saw: This is a specialized tool used to cut through the sternum (breastbone) to access the heart.
Clamps, retractors, forceps, and scissors: These are standard surgical tools used to hold tissues and vessels in place, keep the surgical area open, and cut through tissues as needed.
Needle holder: This tool is basically a specialized type of clamp used to securely hold a needle while the doctor stitches together tissues.
Dilators and dissectors: These tools are used to gently separate tissues and expand vessels during the procedure.
Suction cannula: a tube used to remove blood and other fluids from the surgical area to keep it clear.
Sutures and needles: These are used to stitch together tissues after the surgery.
Arterial and venous cannula: These are special tubes inserted into the arteries and veins to manage blood flow during the operation.
Cardioplegia cannula: This tube delivers a special solution to the heart that temporarily stops it, allowing the surgeon to operate on a still heart.
Who is needed to perform Radial Artery Coronary Bypass?
In a radial artery bypass graft surgery, several specially trained medical professionals work together. The main doctor, a cardiothoracic surgeon, is skilled in surgeries that involve the heart and chest. Helping the surgeon is a cardiothoracic surgery assistant. An anesthesiologist is also part of the team; they are responsible for making sure you stay asleep and don’t feel any pain during the surgery.
An interventional cardiologist, a doctor who specializes in heart diseases and treatments, might also be involved. A scrub technician helps ensure all the surgical tools are ready and organized. Another important person during surgery is the anesthesia technician, who assists the anesthesiologist in giving and monitoring the anesthesia.
A perfusionist, who runs the cardiopulmonary bypass machine (a machine that temporarily takes over the function of the heart and lungs during surgery), is also needed.
Lastly, there’s an operating room nurse who assists before, during, and after the surgery. They ensure everything runs smoothly and provide care after the procedure. Each of these professionals plays a key role in your surgery and recovery.
Preparing for Radial Artery Coronary Bypass
Before going through a Coronary Artery Bypass Graft surgery (CABG), where the radial artery is used, several preparation steps are necessary:
* There are a few basic tests you’ll need to have, such as complete blood count and tests to check your kidney and liver function. These tests also look at your blood’s ability to clot and the balance of your body’s electrolytes (minerals like sodium and potassium that our bodies need to function properly). Other tests include an electrocardiogram, which records the heart’s electrical activity, and an echocardiogram which gives a picture of your heart using sound waves.
* Blood products like red blood cells, platelets, and fresh frozen plasma might also have to be arranged before your surgery.
* You’ll need to stop eating 6 hours before your operation.
* It’s important to keep taking aspirin, especially if you have acute coronary syndrome, which is a term for conditions caused by sudden, reduced blood flow to the heart. However, heart medications like ticagrelor and clopidogrel should be stopped 5 days before the surgery, and prasugrel should be stopped 7 days before the surgery.
* Taking antidepressants before the surgery could help reduce anxiety.
The radial artery, one of the major blood vessels carrying oxygen-rich blood to the hand, can be taken from the arm you use less. Before surgery, a special test (a modified Allen test) is conducted to check the blood flow to your hand. It uses pulse oximetry (a method of measuring the oxygen level in your blood).
Good blood flow (an Allen test result less than 10 seconds) is necessary to use the radial artery for the procedure.
Lastly, take medicines which widens (or dilates) your blood vessels, such as calcium channel blockers and nitrates. This is important to prevent the radial artery graft from getting too tight (or ‘spasming’), and to make sure the blood vessel is wide enough (or ‘vasodilated’).
How is Radial Artery Coronary Bypass performed
The harvesting of the radial artery, which is a small artery in the forearm, can now be done using minimally invasive techniques. These methods are being looked at because they might improve the way the incision looks after and results in better recovery. Right now, the two main methods to ensure the success of the procedure are the “no-touch technique” and taking out the graft (tissue) together with the radial artery, including the veins and fat around it.
To begin with, the hand that’s not commonly used for tasks is prepared. Then a small, curved cut is made on the forearm. Special tools that use heat are used to gently separate the tissues underneath the skin, without hurting the nerve that lies on top of the radial artery. This is done carefully to avoid any damage to the smaller branches of the artery.
The next step involves carefully separating the covering of the veins and radial artery, enabling the extraction process. This begins in the middle of the forearm and requires careful handling to lift the artery from the muscle area it’s attached to. After that, any smaller branches of the arteries are sealed off using a special tool that uses sound waves to create heat and cut tissues.
Once the radial artery is free, the next step involves preparing the ends of the artery, first on the end further away from the body by tying it off and sealing it. After this, the end of the artery near the wrist is checked to make sure there is enough blood flow from another artery. Then, the end closer to the body is also sealed off. A special liquid containing medicine to prevent clotting and a muscle relaxant is used to rinse the artery before and after it’s cut. This artery is then stored in the same liquid until it’s ready to be attached in the new location.
A tool that uses heat is used to stop any bleeding from the radial artery graft. Before the wound is closed, the hand is checked carefully to make sure bleeding has stopped and to reduce the risk of a serious condition where pressure builds up in a muscle compartment. Finally, the wound is closed with stitches before administering a blood-thinning medication systemically, meaning it will affect the entire body. The deep tissues are stitched using a certain type of dissolvable suture and the skin is closed in a similar fashion.
Possible Complications of Radial Artery Coronary Bypass
After having radial bypass graft surgery, there can be some complications. Here are some that could happen:
* Numbness in the skin because of damage to the nerves on the side of your body, which is the most common complication.
* Severe lack of blood supply to the hand.
* An infection at the place where the doctor made an incision for the surgery.
* Injury to the center and radial nerves, which control various movements and sensations in your hand and arm.
* Spasm or sudden contraction of the radial artery, which is more severe as compared to a dilation of the internal thoracic artery.
* A problem with the lower left chamber of the heart, making it not work properly.
* A stroke, which occurs when blood supply to part of your brain is interrupted.
* An acute renal injury, which is a sudden kidney damage.
* Cardiac tamponade, which is a serious condition where fluid collects in the sac around the heart, causing high pressure.
* Infection in the lungs.
* Irregular heart beats, which are also known as ‘cardiac arrhythmia’.
These are possibilities and doctors will closely monitor you for these after the surgery to ensure they can be treated promptly should they happen.
What Else Should I Know About Radial Artery Coronary Bypass?
The radial artery graft is a procedure often chosen after trying the left internal mammary graft. Various studies have shown that this method tends to result in better long-term success rates for patients.
Unlike a different method involving the right internal thoracic artery, the radial artery graft is not linked to a higher chance of getting an infection in the chest wound. Also, unlike methods involving the right gastroepiploic artery or the inferior epigastric artery, the radial artery graft can be used safely in patients who have obesity or have had abdominal surgeries in the past.
