This document provides an introduction and overview of the transradial approach for neurointerventions. It discusses why the radial approach is preferable to the femoral approach, including lower bleeding risks and access site complications. It covers topics like assessing the radial artery, achieving arterial access using ultrasound guidance, administering a "radial cocktail" of medications, challenges that can be encountered, achieving hemostasis, and potential complications. The conclusion recommends embracing the radial approach as it offers safety benefits and improved patient outcomes and satisfaction compared to the traditional transfemoral approach.

1. An introduction to
transradial approach for
neurointerventions
Mohamed M.A. Zaitoun, MD
Associate Professor of Interventional Radiology
Faculty of Medicine, Zagazig University, Egypt
FINR-Switzerland
zaitoun2015@gmail.com

2. Disclosure
I have no actual or potential conflict of interest in relation to
this presentation.

3. Agenda
Introduction
Why Radial?
Test before puncture
RRA or LRA
Hand position
Local anaesthesia
Achieving access
Site of puncture
Cocktail
Catheter selection
Challenges
Achieving hemostasis
Complications
Recommendations

4. Introduction
In 1989, Lucien Campeau (June 20, 1927 – March 15,
2010) at the Montreal Heart Institute published a
paper that proposed the use of 5 French
diagnostic catheters to access the small radial
artery as a way to possibly cut bleeding
complication rates from the femoral approach.

5. Then, access changed from transfemoral to
transradial approach (TRA), as it has less bleeding
complications, decreased hospital mortality rate,
less access site complications, and is cost-effective
as compared to the transfemoral approach.

6. Class I recommendation to use the TRA as the preferred method of access
for any percutaneous coronary intervention irrespective of clinical
presentation.
> 60% reduction in access site complications and significant decreases in all-
cause mortality with TRA.

7. Support a "radial-first" strategy in the United States for
patients with acute coronary syndromes.

8. Why most INRs are reluctant to use the radial
approach ???
I am comfortable with the femoral approach, why to change?

9. AAA open surgery till 1992 (25%mortality) EVAR since 2010
(<5%).
CLI (amputation) until 1964, now bypass grafts and
angioplasty.

10. No complications occurred from the femoral approach
Didn’t occur doesn’t mean can’t occur.
2-5% major complications from femoral approach.
Zero% from TRA.

11. Why radial?
The radial artery is superficial, with no essential
structures nearby that could be injured.
As the hand has dual blood supply, an incidental
injury to the radial artery is much less harmful.
Because the radial artery is easily compressible,
access site complications are less common.

15. Patients can ambulate more quickly, and the
resulting shorter patient recovery time can lead to
decrease the patient length of hospital stay (LOS)
and the cost.

16. A great choice for patients with coagulopathy
(INR> 1.5), also for patients who received IV
rTPA/ NOAC.
TRA is also preferable in patients who have
difficulty lying flat (eg, those with congestive
heart failure, low back pain, cognitive
impairment).

17. In patients with obesity, the common femoral
artery may be difficult to locate, and post-
procedural control of the puncture site can
be challenging.

18. TRA should be considered for patients in whom
atherosclerotic calcifications may preclude TFA
cannulation (radial arteries tend to be less
affected by calcific plaque burden).
Patient Comfort and Preference: TRA?
Less pain, discomfort, and need for bed rest, as
well as the ability to ambulate earlier.

20. Relative contraindications for TRA include:
*Radial artery diameter < 2 mm.
*Patients with a dialysis fistula.
*Those nearing dialysis who may depend on the radial artery
for access.
*Severe vaso-occlusive disease (eg, Raynaud disease,
Takayasu arteritis, thromboangiitis obliterans).
*known complex radial or brachiocephalic anatomy.

21. Test before puncture
Barbeau test (a modified Allen test with a pulse
oximeter) to assess radioulnar collateral
circulation to determine eligibility for TRA.
However, recent data demonstrate no significant
difference in ischemia incidence and overall
outcomes between patients with normal and
abnormal Barbeau test results.

22. Although assessment of the RA pulse is important, performing an Allen or
Barbeau test to confirm the patency of dual arterial circulation to the hand
and intact palmar arch system is only of historicalinterest.

23. RRA or LRA
RRA is often preferred for reasons of operator
comfort.
LRA when intending to cannulate the left vertebro-
basilar segment.

24. Local anaesthesia
The local anaesthesia is obtained through the
subcutaneous injection of 2 mL 2% lidocaine and
1 ml of nitroglycerin 1 min before the radial artery
puncture, between 1 and 1.5 cm proximal to the
styloid process.
Subcutaneously infiltrated nitroglycerin leads to
significant vasodilation of radial artery, this
avoids pre-cannulation spasm of radial artery.

25. Achieving access
Patients are positioned supine, and an arm
extension board is inserted under the patient.
The right arm is placed tightly against the hip, with
the distal forearm and hand in a slightly supinated
position (approximately 45°) and the wrist
extended with a towel roll.
We place several towels under the forearm and
caudal to the hand to elevate it to hip level so the
catheters rest at thigh level rather than falling
down the side.

26. Arterial access may be obtained via either single- or double-
wall puncture technique.
Both techniques are safe and effective and are associated
with low rates of RAO and other complications.

27. TRA should be achieved using
sonographic guidance with a
single-wall puncture technique
and the Seldinger technique with
a 21-gauge echogenic-tip needle.
The double-wall technique is
associated with a higher first-
pass success rate.

28. Ultrasound reduces time and number of attempts to
achieve arterial access.

29. Use of ultrasound imaging may be helpful in
identifying an occluded RA that fills via retrograde
collaterals.
In addition, the use of ultrasound imaging that is
inclusive of the antecubital fossa may help reduce
crossover rates through the identification of radial
loops and other vascular anomalies.

31. Site of puncture
The radial artery is accessed 1 to 2 cm proximal to the radial
styloid process, i.e. proximal puncture site.

32. The main advantages are less arterial obstruction and short
hemostasis.
The main disadvantage is the difficulty in cannulation.

33. Cocktail
After arterial access is achieved, a combination of
medications (radial cocktail) is administered
through the sheath to reduce arterial spasm and
vascular tone.
The radial cocktail is a combination of
anticoagulants and spasmolytic:
*Anticoagulant (Heparin) 2500/5000 units
*Spasmolytic:
100-200 µg of nitroglycerin + 2.5 mg of verapamil.

34. 1 milligram (mg) is equal to 1000 micrograms (μg)

36. Contraindicated in:
Asymptomatic or symptomatic systolic dysfunction
Hypotension
Sinus bradycardia
Conduction abnormalities.
So you should ask for ECG and ECHO and cardiac
consultation before administration.

38. Catheter selection

40. Challenges
Variations in RA and aorto-subclavian anatomy may
pose a challenge to wire navigation and catheter
manipulation during TRA angiography and
increase procedural time.
If the hydrophilic wire does not traverse the upper
extremity vasculature easily, a 0.014-in wire may
be used under fluoroscopic guidance with a
subsequent exchange for a 0.035-in wire.

41. RA loops may straighten with wire exchange or by
gently pulling back the catheter with
counterclockwise torque.
Attempts to straighten a 360° loop, however, may
be futile and often are associated with patient
discomfort and greater radiation exposure and
contrast volume.

43. Achieving hemostasis
Nonocclusive “patent” hemostasis is a key
technique in minimizing risk of postprocedural
radial artery thrombosis.
Nonocclusive hemostasis is typically performed
using a wrist band device.

45. Complications
1. Spasm.
2. Vessel perforation.
3. Retained catheter.
4. Radial artery occlusion.
5. Radial artery pseudoaneurysm.

46. Recommendations
The cardiology and body interventional literature
has shown radial access to offer a variety of
advantages over traditional transfemoral access
including safety benefits such as lower
bleeding/vascular complications and mortality,
lower costs related to several factors, as well as
improved patient satisfaction.

47. The same benefits are now being realized in the
cerebrovascular literature and thus radial access
for neurointerventional procedures is an inevitable
paradigm shift.
As the training and experience continues to grow,
radial access should be embraced and adopted
into the toolbox of every practicing
neurointerventionalist.