Technique - Overview

Prevention and management of radial artery spasm

INTRODUCTION
Radial artery spasm frequently occurs during transradial coronary cannulation, but is usually mild, only noticeable by some friction during sheath removal. However, sometimes spasm is severe to such an extent that the sheath cannot be withdrawn, without applying substantial force. A rare case of rupture of the radial artery has been encountered during an attempt to withdraw the arterial sheath. However, forceful introduction of a 6F or larger bore sheath through a tiny radial artery has to be differentiated from spasm. Small radial arteries can be encountered in small females but also in large males (small normal RA, small atherosclerotic RA's, small multiple RA's, small abberant RA and previously used RA's). Considerable mismatch between the sheath and the RA can be estimated by palpation and more accurately by ultrasound.
Because frequently questions are asked concerning radial artery spasm, members of the Radial Force were called to describe their protocols dealing with the prevention and management of spasm. You will find a synthesis of these different advises in this section, which can be updated with your input.

BACKGROUND
The muscular radial artery is prone to spasm, also at distance, luxated by mechanical stimuli, such as puncture, sheath introduction, guidewire and guiding catheter manipulations. Anxious patients are more prone to spasm. Therefore the statement is justified that the incidence of spasm is inversely related to operator experience. The smoother the procedure, the less discomfort to the patients, the less anxiousness and the less spasm.

PREVENTIVE ACTIONS
Based on the knowledge of the basic mechanism of spasm, the preventive actions are easy to understand.
1. Proper patient selection.
As mentioned earlier, small radial arteries are more prone to spasm, so it is better to avoid them, especially during your learning curve. Furthermore, avoid at the beginning of your experience patients with a contraindication to the femoral approach, who often have tortuous and diseased subclavicular arteries that complicate and lengthen the procedure.
2. Proper patient sedation.
Especially anxious patients are prone to radial artery spasm.
First the patient has to be informed that catheter manipulations via the radial artery are stronger noticed compared to transfemoral catheter manipulations. Proper explanation will reduce anxiety.
Some i.v. sedation will be of value. Prophylactic i.v. pain killers (e.g fentanyl) might be of additional help.
The most efficacious is the neuroleptanalgesia with an on-site anaesthesiologist.
3. Pain reduction prior to the puncture.
The application of a topical lidocaine-prilocaine cream (EMLA®) has been suggested, two hours before the procedure on the puncture site. This has the advantage of obviating the subcutaneous infiltration of xylocaine, which can cause pain, hematoma, spasm and "blurring" of the radial pulse.
4. A quick and adequate single puncture.
A missed puncture might induce hematoma formation and spasm. Successful puncture of a spastic radial artery is more painful and will induce more spasm.
5. Intraarterial administration of a spasmolytic cocktail.
A spasmolytic cocktail can be administered following puncture, but before sheath introduction. If the cocktail is injected via the introduced sheath, the active drugs might never reach the arterial wall, unless a sheath with sideholes is used. Another alternative is to advance the sheath only for appr. one cm, before the cocktail is administered, followed by complete sheath introduction.
Suggested components of the cocktail are:
1. Nitroglycerin (200 mcg).
2. Verapamil (5 mg).
3. Xylocaine (50 mg) (Gives a severe burning sensation by it's acidity. Might also provoke spasm?)
4. Heparin (5-10.000 IU). Although not a spasmolytic agent, heparin is usually administered together with the other drugs intraarterially. However, there might be considerable spill during/following injection, making accurate dosage unreliable. In addition, heparin also induces a burning sensation by it's acidity.
5. Molsidomine (1-2 mg)
6. Sodium bicarbonate (4%, 1cc) to neutralize the pH of the cocktail if heparin and/or xylocaine are used.
6. Proper sheath selection.
A long sheath (20-25 cm) is recommended to prevent spasm by reducing mechanical stimuli during guiding catheter manipulation. However, these sheaths are harder to insert compared to short ones. In addition if spasm occurs it will usually involve the complete length of the sheath. It is possible that in that case the long sheath will be more difficult to retrieve compared to a short one. This is the reason that some operators prefer a short sheath. If you are a fast operator and if you do not require prolonged guiding catheter manipulations a short sheath might be advocated for spasm prevention. However, this will depend on your level of experience. At present there is limited experience with a new coated sheath made by Schneider/Namic. This sheath is introduced and retrieved very smoothly.
In addition you will find on this website some information on a side-hole sheath, allowing local delivery of spasmolytic agents. More information of the coated sheath and the sidehole sheath will appear soon under the Material section of this website.
7. Proper guidewire selection.
Dependent of the puncture device you can use 0.025" to 0.035" wires. Wires with a "hockey-stick" shaped tip are recommended, since these wires are easily advanced beyond sidebranches. A wire with a sharp "J" should be avoided since they can take a retrograde course once coming out of the tip of the needle. Presumably the use of hydrophillic coated wires might be of additional help to prevent spasm. Novel operators mght be helped with the use of exchange wires, since initially more guiding catheters are necessary for adequate cannulation. Using a long wire will reduce the need for wire manpulations to find the ascending aorta and will avoid repeat trauma.
8. Proper guiding catheter selection.
Today there are several guiding catheters designed for transradial coronary angioplasty. The most important matter is that you become familiar with (a) certain guiding catheter(s). This will result in rapid cannulation, without to many excessive manipulations. It is important to analyze the diagnostic film carefully prior to the procedure and to choose the guiding catheter accordingly. Also the use of 7F instead of 6F catheters might help in reducing spasm, since these catheters do provide better support resulting in less catheter exchanges.
An unsettled item is the spasmogenicity of the exterior plastic coating of the guiding catheter. There might be considerable difference in the incidence of spasm dependent on the manufacturer of the guide. This will be an interesting subject for further research.
9. Operator experience
It has been mentioned before, but an experienced operator will encounter less and less radial artery spasm, by less puncture failures and by shorter procedural time. Therefore it is generally recommended to do adapt the radial approach as your routine procedure.

MANAGEMENT OF SPASM
If despite all precautions radial artery spasm occurs or persists, consider the next recommendations and suggestions.

Do not allow the patient to experience to much pain. Better to consult an anesthesiologist for proper pain relieve.
Some spasm during sheath withdrawal is common. Tell your patients that removal of the sheath will be associated with discomfort. Take the sheath out fast (but gentle) once moving and usually the duration of discomfort (if any) is short.

If spasm is severe and much resistance is felt or if the sheath is stuck the following actions can be undertaken:
1. Nifidipin 10 mg s.l.
2. Proper analgesia and sedation (see above)
3. Warm compresses over the forearm might contribute to relaxation of the spastic artery
4. Nitroglycerin 200 microgram i.a.; repeated if necessary
5. Verapamil 2 mg i.a.. (Diltiazem can also be used)
6. There is limited experience with adenosin

If this does not result in easier sheath withdrawal wait for an hour and try again. During this time, again take good care for proper sedation and deep analgesia (morphine)

If nothing helps, an axillary block might be required to relax the radial artery. Never apply excessive force. This might result in rupture or avulsion of the radial artery.

Ultimately the vascular surgeon can be consulted to remove the sheath.