Radial catheterization procedure

# Overview
The transradial approach (TRA) for coronary/cardiac catheterization is slightly more challenging than the transfemoral route. It requires more maneuvers and catheter steering along the course of the radial artery to reach the level of the coronary sinus in the ascending aorta. The right transradial approach is usually preferred over the left side due to the ease of accessibility for the operating physician.

# Catheter/GuideWire Selection
Catheter selection is an important key in the success of the procedure. Standard catheters (e.g Judkin's Left and Judkins right) can be used for the TRA. However due to the common anomalies that could be seen along the course of the radial, subclavien, and axillary arteries, special dedicated Radial Catheters had been developed (e.g. Tiger, Jacky, and Kimmy). The most commonly used guidewires are those with hydrophilic coating, due to the expected tortuosity of the arterial course.

# Procedure
- Before the start of the procedure a time out should be taken to revise the indication, important labs, and the patency of the wrist circulation as discussed previously. Allen's test or Barbeau test.
- Make sure that all of the equipment is ready and recheck the sizes .
- The wrist should be shaved (if necessary) and cleansed in the usual sterile fashion. In addition, the groin should be prepped in case of access failure or the need for urgent IABP or a temporary venous pacemaker.
- Intravenous (IV) line should be started on the contralateral extremity. If an IV should be placed in the intervention extremity, it must be placed  proximal to the wrist preferably at the level of the elbow.
- Sterilization of the whole arm should be done using the standard sterile techniques and covered in sterile drapes except for the region of the radial artery - distal part of the palmar surface of the forearm - which is left exposed for easier access.
- Most operators prefer to give anxiolytics e.g Midazolam (1-2 mg) before the start of the procedure to decrease patient anxiety and hence decrease radial spasm.
- The arm should be fully extended; slightly elevated with full supination, and the wrist hyperextended.
- Palpation of the radial artery against the styloid process of the radius with the middle three fingers to find the point of maximal impulse "PMI" is performed.
- An amount of 0.5cc to 1.0 cc of local anesthetic is injected superficially over the PMI.
- Two techniques are used to puncture the radial artery to obtain access:-
Direct/single wall puncture : same technique used in the femoral approach.
Transfixation/ double wall puncture: in which a special kind of puncture needle 18-21 guage is used to puncture the vessel. An indicator at the needle cap would show successful penetration of the artery. Penetrate the other wall of the vessel then withdraw the needle leaving the canula inside the double puncture. Slowly withdraw the canula until a pulsatile flow of blood is noticed.
- Direct/single wall puncture : same technique used in the femoral approach.
- Transfixation/ double wall puncture: in which a special kind of puncture needle 18-21 guage is used to puncture the vessel. An indicator at the needle cap would show successful penetration of the artery. Penetrate the other wall of the vessel then withdraw the needle leaving the canula inside the double puncture. Slowly withdraw the canula until a pulsatile flow of blood is noticed.
- An exchange length 0.035-0.038 inch J-tip guidewire is inserted.
- A small incision is made to the skin at the entry of the wire to facilitate the sheath insertion.
- Radial sheath of 23 cm long and 4-6 Fr size should then be introduced.
- Through sidearm of the sheath, 5000 IU of heparin should be administered.
- To reduce spasm, 500 mcg of diltiazem can also be administered via the sidearm.
- Coronary catheters are then advanced along the guidewire into aorta.
- Left and right coronary arteries are then catheterized using a Judkins, Amplatz or multipurpose catheter.
- Hemostasis is achieved by direct pressure at the puncture site at the end of the procedure after removal of radial sheath.
- Radial pulse, and hand circulation should be monitored after the procedure for every 2 hours until discharge.
Radial sheath kits are now available which contain hydrophilic coated sheaths in sizes 4-6 Fr equipped with graduated introducers, various micropuncture needles and guidewires.

# Radial Compression Devices
Radial Compression Devices are used for hemostasis after the removal of the radial sheath.
In the picture below is one example of the devices used.

## Steps
5. Continuously monitor radial artery pulsation distal to the wrist band, and check pulse oximeter for intact hand circulation.
6. Remove wrist band after 1-2 hours according to patient status.

# Procedure Video
Below is a video demonstrating radial artery approach in cardiac catheterization followed by application of TR band