The Physics of Guiding Catheter

The Physics of Guiding CatheterThe IKARI Guiding Catheter in TRIYuji Ikari, MD, PhD, FACCProfessor, Department of CardiologyTokai University School of Medicine

Radial Artery is SafeBrachial arteryRight forearm (below-elbow) angiographyUlnar arteryRadial arteryradial arteryradial nervecross-section of right wristmedian nerveulnar arteryradius ulnaulnar nerve★Occlusion is not a problem.★Less neurological problems★Less bleeding complications

Benefit of TRI• Lower bleeding complication rate• Shorter rest time• Less lumbar pain• Less neurologic complication• Shorter hosipital stay• Reduction in work of co-medical medical staffs• Better QOL

Difficulty in TRI• Puncture of radial artery due to small size• Low backup force of guide catheterSome doctors would say“Low backup force is a critical problem of TRI!Choose femoral approach!!”No! It is not true.They do not know PHYSICS.

Physics of guiding catheter ?• No textbook chapter• No published paper

History of Dr. Ikari as a radialist• In 1991, Dr Ikari started PCI• Many patients complained about lumbar pain.• In 1993-4,• First attempt of PCI via upper limb.• Dr Ikari found difficulty in guide catheters• In 1994, Palmaz-Schatz stent was approved inJapan• In 1995-6, , Dr Ikari tried to make a new catheterto overcome the weak backup force in TRI.• In 1996, Ikari-L L was completed.• In 1996, the first human case was successful.

Anatomy

Judkins typeIkari LeftPrototypes

First in Man in 1996Severe rheumatoid arthritisShe was impossible to lie in the supine position due to extremedeformity of hip and knee joints.She had anginal attack at rest.

Sales of Ikari guiding catheters25000200001500010000500007,15110,6203,2082,39910,0828,30886 5,272 6,37764 7792,2122001 2002 2003 2004 2005 2006 2007InternationalDomestic

Ikari L (IL)

Ikari-L L catheterJudkins Judkins Ikari

Ikari LBrachiocephalicangle

Consideration aboutbrachiocephalic angleABBrachiocephalic angle does not relate withbackup force.The angle makes it easier to engage.resistance (gram force)80706050403020100n.s.JL3.5 JL3.5 with angleJL3.5JL3.5 with angle

IL IFLRight upper limb approachLeft upper limb approachFemoral approach

IFL4.0 JL4.020mm35mm40mm10mm10mmIFL4.0JL4.0

Ikari L4 in TRI vs. Judkins L4 in TFIθiθf

Physics of backup force ofguide catheters in TRI and TFIIkari Y, et al.J Invasive Cardiol 2005; 17:636-41

Hypothesis; physics of backup force• Fcosθ = fcosθ’ + λθ’ θλ• fcosθ ’ + λFmax = ―――――cosθMaximum backup force isacheved ifθ=90degree; θ’= 0degree; orλ is large.Ikari et al. J Invasive Cardiol 2005 ;17:636-41

R5540R6520°R50C110A3010°R45402040R304070DB2030°φ3020

Judkins L can generate greaterbackup force in TFI than in TRI.AB70θrθfresistance (gram force)605040302010P

Judkins L 3.5 can generate greaterbackup force in TRI than JL4.θ4 θ 3.50resistance (gram force)5045403530252015105P

Deep engage increase backupforce in Judkins Lθ4θ4deepresistance(gram force)605040302010P

Consideration about the static frictionresistance(gram force)9080706050403020100P

JL and IL in TRIresistance (gram force)100806040200JL4P

ComparisonVODA JudkinsIkari-FIkari

Aresistance (gram force)10090807060504030C20100E****B C DJL4 JL4deep BL3.5 IL4 IL4powerθjθ4deepθbθiθip

Size of guide catheter is one of thedeterminants of backup forceresistance (gram force)160140120100806040200*6Fr 7Fr 8Fr*Judkins in TFI

Summary of Physics• Backup force of guide catheter does notdepend on approach site but on - - -• Size of guide catheter (f)• Catheter shape• Angle between the catheter and the reverse side ofthe aorta (θ(and θ’)• Attachment area on the reverse size of the aorta(λ)fcosθ ’+λFmax = ―――――cosθ

Which is better, Judkins in TFI orIkari in TRI?TRI > TFIIt used to be true thatbackup force in TFIwas stronger than TRIbefore invention ofIkari catheter.θiθf

Ikari in TRI vs. Judkins in TFI14012010080606 Fr7 Fr8 Fr40200IL in TRI IFL in TFI Judkins L in TFI

In Conclusion• Backup force is determined by physics notby approach site.• Thus, TRI is always better than TFI if youuse 6 Fr guiding.• The basic study of guiding cath maycontribute to slender PCI using 5 Fr, 4 Fror 3 Fr system.