Radial Artery Catheterization
Cardiac catheterization is a minimally invasive procedure commonly used to diagnose and treat heart conditions. During catheterization, small tubes (catheters) are inserted into the circulatory system under x-ray guidance in order to obtain information about blood flow and pressures within the heart and to determine if there are obstructions within the blood vessels feeding the heart muscle (coronary arteries). Obstructions of the arteries are caused by plaque buildup, and when severe they can cause a variety of symptoms including chest pain and shortness of breath. A catheterization may be recommended on an elective basis if the symptoms are stable or on an emergency basis if the symptoms are sudden and the treating physician is concerned that they may represent an active or impending heart attack. On the basis of the location and number of obstructions, the treatment plan will include the use of specialized medications and possibly the placement of a stent or referral for bypass surgery to improve blood flow to the heart muscle and alleviate symptoms.
The catheters necessary for cardiac catheterization can be inserted either into the femoral artery (in the groin), or into the radial artery (in the wrist). The femoral artery is a larger vessel and provides a more direct route to the heart. Because of these advantages, the femoral artery has become the standard entry site for catheterization procedures. However, there has been a recent increase in the use of the radial artery for cardiac catheterization procedures.
Advantages of Radial Artery Catheterization
Any catheter placement into a blood vessel is associated with a risk of bleeding. After removal of the catheter from the femoral artery, the patient will need to lie flat without bending the leg for 2 to 6 hours to allow the artery to heal. In some cases, even with prolonged immobility, internal bleeding can occur and can be severe enough to require blood transfusions or surgery to repair the femoral artery. These complications are rare, but they may be less common if the catheter is inserted in the wrist. Because the radial artery is much smaller and located closer to the skin surface, internal bleeding is eliminated and any external bleeding can be easily compressed. After the catheter is removed from the radial artery, a compression device is placed around the wrist to apply pressure on the artery, and there is no requirement for the patient to remain immobile. In general, patients find radial catheterization more comfortable than femoral catheterization because they are able to sit up, walk, and eat immediately. This is a particular advantage for patients with back problems because there is no need for heavy pressure on the leg and prolonged immobility.
The Radial Artery Catheterization Procedure
Before beginning the procedure, the physician performing the procedure may test the blood supply to the hand. There are 2 arteries that supply blood to the hand (the radial artery and ulnar artery), and if both are working it is safe to proceed. The procedure can be performed from either wrist, and the physician may have specific reasons to use one side over the other. Both the groin (femoral) and the wrist (radial) may be prepped for the procedure in the rare event that the arteries in the arm do not allow catheters to get to the heart easily and the femoral artery needs to be used. A nurse administers medication through a vein for sedation. The cardiologist then delivers a local anesthetic to the wrist and inserts a short tube (sheath or introducer) into the radial artery (Figure, A). Medications are given through the sheath to relax the radial artery, which may cause a temporary burning sensation in the hand and arm. A blood thinner is also given to help prevent clots from forming in the artery. Catheters are then advanced through the sheath and guided to the heart, and the coronary angiogram (and stent placement if necessary) is performed. Once the procedure is complete, the catheters and sheath are removed from the radial artery, and a compression device is placed on the wrist (Figure, B), which is typically worn for 2 hours. The patient is allowed to sit up and eat after the procedure. It is recommended that no undue stress be put on the radial artery as it heals. Patients are asked to avoid lifting anything heavy (like suitcases or grocery bags) with that hand, but should otherwise be able to use the hand for activities such as eating and writing. By the third day after the procedure, normal activity with the hand can be resumed.
Risks of Radial Catheterization
Any invasive procedure carries some risk of significant bleeding. Using the radial artery rather than the femoral artery may reduce the risk of bleeding from the puncture site, particularly in patients who are obese or require blood thinning agents to treat their heart condition. There are, however, risks unique to radial artery catheterization. Though rare, spasm of the muscles lining the wall of the radial artery may be experienced by some patients. This can make it difficult for the cardiologist to maneuver the catheters and may cause the patient discomfort. This is temporary, and can be prevented and treated with medications in the majority of cases. Occasionally, it can be severe enough to necessitate switching to the femoral artery. Another potential risk is that the radial artery may close after the procedure. This may result because of a blood clot forming in the artery. Blood thinners given during the procedure help to prevent this, and with modern techniques it has become very rare, occurring in less than 2% of cases. When radial artery occlusion does occur, it generally causes no issue for the hand because there are redundant blood supplies to the hand.
Deciding Between the Radial and Femoral Approach
The biggest factor driving the decision to use the radial artery is the physician performing the procedure. The procedure can be more challenging technically, and the physician must have enough experience to feel comfortable with radial procedures. Many physicians are more comfortable with the femoral approach, and will therefore recommend it alone. There are a growing number of physicians in the United States, however, who prefer to use the radial artery as their default approach. There are also many physicians who use the radial approach in selective situations where the femoral approach may be more complicated, such as in obese patients or patients with obstructions in the blood vessels supplying the lower extremity. The femoral approach may be selected for patients in whom preservation of the radial artery is essential, such as patients requiring dialysis fistulas or patients who require the radial artery to be used for bypass surgery. The Table shows a comparison between the radial and the femoral approach.
For further information on cardiac catheterization, coronary angiography and angioplasty, please visit the National Heart, Lung, and Blood Institute Web site:
- © 2011 American Heart Association, Inc.
- Jolly SS,
- Yusuf S,
- Cairns J,
- Niemela K,
- Xavier D,
- Widimsky P,
- Budaj A,
- Niemela M,
- Valentin V,
- Lewis BS,
- Avezum A,
- Steg PG,
- Rao SV,
- Gao P,
- Afzal R,
- Joyner CD,
- Mehta SR