Radial Coronary Angiogram
Dr. Sonny P. Jacob, MD in Internal Medicine, DM in Cardiology
Coronary angiogram is the procedure to visualise the lumen of arteries supplying heart muscle. Conventionally angiogram is done through the leg. A small tube is introduced through femoral artery(Artery in leg) into the aortic sinus. Radio opaque contrast is injected into coronary arteries to displace blood and special X-Ray is taken to see whether the arteries are clogged were and by how much. It helps the doctor to decide further treatment such as angioplasty or surgery or medical therapy.
The advantages of transfemoral approach are
- Technically easy
- Facilitates the use of larger catheters
It has some disadvantages like. Prolonged bed rest required (usually one hour per sheath size) or use of a closure device (which increases cost)
- It is commonly associated with back pain, urinary retention, and neuropathy than the radial approach.
- 0.5-4.0% incidence of vascular complications including pseudoaneurysm, a-v fistula
- Bleeding can be significant (before it is detected clinically)
In overweight or obese, and the femoral artery is buried deep underneath the fatty tissue, making it hard to access, and then equally hard to compress after the procedure -- a necessary step in stopping the bleeding. In some cases, bleeding that is not immediately visible to the eye can occur in a backwards fashion into the body cavity -- this can be seen as a discoloration, like a bruise, that expands and must be treated. The possibility of involvement of the femoral nerve also exists. These types of complications are small in number, often quoted at 3%.
To overcome the above mentioned approach, radial approach is widely used now.This approach for coronary angiography (CAG) was first reported in 1989-19991 by, a French-Canadian physician, Dr. Lucien Campeau, started using the right radial artery, which is located in the wrist, as an entry point for diagnostic catheterizations and subsequently transradial coronary angioplasty was reported in 1995 by Kiemeneij et al.2The advantages of the radial artery approach are numerous and include, a lower incidence of access site complications, earlier ambulation, decreased hospital stay and expenses.3 Even in obese patients, the radial artery is close to the skin surface, making the initial needle puncture simple and straight-forward. For the same reason, when the procedure has been completed, a short compression of the radial artery can stop the bleeding (achieve hemostasis) -- even when the patient has been aggressively anticoagulated with medicines to keep blood clots from forming, more and more common in the modern cath lab. Should any bleeding occur, it can be seen immediately. Finally, unlike the proximity of the femoral artery to the femoral nerve, the radial artery is not close to a major nerve, so the likelihood of "nicking" a nerve during the procedure is very low. A larger number of patients prefer this approach.4 In patients with peripheral vascular disease it offers an excellent alternative to the femoral approach.
Difficulties with this approach include, a deep and significant learning curve,5 increased fluoroscopy time,6 failure to adequately cannulate the coronary arteries,7difficulties due to anatomical variations in the arterial tree of the upper limb, more pain during the procedure7,8 and radial artery spasm.9 As of now this procedure continues to evolve and has generated considerable debate and comparison with the femoral approach.10-12
While complications are less common with the radial technique, the advantage experienced by all radial patients is that there is no longer any need to lie flat and still for 4-6 hours, or to experience what is sometimes a painful manual compression of the artery to curb the bleeding. Patients leave the catheterization lab and are able to sit up and walk almost immediately. Because of the simpler healing process for the arterial puncture in the wrist, certain patients may also be discharged home without having to spend the night.
The progress in the treatment of coronary artery disease has evolved to the point that when you compare heart bypass surgery from two decades ago with stenting done today via the transradial approach, what was a 4 hour major open heart operation, with general anesthesia, a week or more in the hospital and months of recovery, can now in some cases be performed as an outpatient procedure.
Is the Radial Approach for Everyone?
There are a few prerequisites for patients to be a candidate for the transradial approach. The first is confirmation of a dual, or "protected", blood supply to the hand. The radial artery loops around the hand and joins the ulnar artery. Both arteries supply blood to the hand and fingers. It is precisely this dual blood supply that makes the radial technique safe. Should the radial artery close up (a complication seen in a small percentage of cases) the clinical result tends to be benign, because the ulnar artery continues to function.
The first step a cardiologist takes in deciding on the radial approach is an Allen test to assess that both radial and ulnar arteries are functioning normally -- a simple test that can be done by compressing the arteries by hand at bedside or in the doctor's office. If they are not normal, then the femoral approach is preferred. Some other contraindications exist, such as the need to use larger devices during the angioplasty, pre-existing bypass grafts in certain areas or tortuous vessels that may prevent the catheter from navigating to the coronaries from the arm. About 30-40% of patients are not candidates for radial access.
While the complication rate with the radial approach is extremely low, there is always some risk with any medical procedure. It is important for patients to discuss the risks and benefits of the femoral vs. radial approaches, as these can vary for each individual.
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