- Relevant clinical history and physical exam:
This patient is a 62 year-old male. He was admitted for stable angina pectoris. His coronary risk factors were hypertension, dyslipidemia, and ex-smoker.
• Patient history:
- 2008.10.1 admitted due to angina pectoris in other hospital
- CAG: proximal LAD 75%, mid RCA 99%delay with severe tortuousity
- 2008.10.3 PCI for proximal LAD 75% →　Cypher stent 3.5x18mm
- 2008.10.10 PCI for mid RCA 99%delay → failed PCI
- 2009.9.7 Admission in our hospital for angina pectoris

Lt.coronary angiogram shows no significant stenosis, and septal collateral channels to PDA. Right coronary angiogram reveals that mid-RCA is 99% stenosis with delay and severe tortuosity, RV branch connects to PDA, and its ostium is 90% stenosis. (Figure 1, Figure 2, Movie 1, Movie 2)
Coronary CT angiography shows the lesions was very tortuous with spotty calcium.(Figure 3)
• Femoral or radial sheath
- Bilateral Femoral sheath
• Guiding catheter
- Name: RCA; AL1 7Fr SH , LCA; VL 3.5 8Fr SH
• Guidewire
- Name: 0.014inch FielderFC, FielderXT, Miracle3g, Advance
• Used balloon
- Name: Ryujin OTW1.25x10mm, Maverick2 2.5x15mm, Voyager OTW2.5x15mm
• Used stent
- Name: Taxus Liberte
- Size: 3.5mm
- Length: 24mm

We attempted the antegrade approach initially, because microchannels were visible. If an antegrade wire couldn’t pass the lesion, we planned to switch to the retrograde approach immediately. Even if a wire crossed the lesion, device delivery was expected to be very hard due to the severe tortuous vessel.
We started the antegrade approach, and carefully manipulated a Fielder FC → XT wire using Finecross microcatheter. (Figure 4) A hydrophilic coating wire advanced to the side branch, but a wire couldn’t pass the tortuous lesion antegradely. We used wire step-up method. (Fielder XT-Fielder FC-Miracle 3g-Fielder XT with Corsair catheter)(Figure 5, Figure 6, Figure 7)
So, we switched to the retrograde approach. Tip injection revealed 3rd septal collateral channel connected to the PDA. (Figure 8) Fortunately a Fielder FC wire crossed through this channel to distal RCA. (Figure 9, Figure 10) A Corsair didn’t advance to the distal RCA,(Figure 11) so we performed entire septal dilatation with a 1.25x10mm Ryujin OTW balloon catheter. (Figure 12) Then we advanced a Finecross to the distal end of the lesion,(Figure 13) and attempted a retrograde wire passage through the lesion. However the retrograde wire advanced into subintimal space. (Figure 14) So the retrograde wire was advanced into the lesion as a knuckle wire to make a crack in subintimal space. (Figure 15) Then the antegrade wire could pass the lesion by Knuckle wire technique. (Figure 16)
Strong backup support is necessary to deliver any devices to the tortuous vessel. So we delivered a 2.5x15mm OTW balloon catheter to the distal RCA retrogradely, and inflated it to anchor the antegrade wire.(Figure 17) We could acquire strong backup support enough to deliver a 2.5x15 mm balloon catheter to the lesion antegradely, and balloon dilatation was performed. (Figure 18) However we couldn’t deliver a Taxus Liberte stent to the tortuous lesion with distal balloon anchor technique. So a wire crossed to PL branch to acquire more strong backup support by combination with distal balloon anchor and additional buddy wire technique.(Figure 19) Finally we could put a 3.5x24mm Taxus Liberte into the lesion.(Figure 20) CAG showed excellent final angiographic result. ( Movie 3, Movie 4)

Knuckle wire technique is effective in this severe tortuous and stenotic lesion when it expects to be hard to deliver the balloon to perform CART or reverse CART technique.
Combination with anchor balloon technique and buddy wire technique is effective to acquire strong backup support.