This was a 90-year-old man with history of complete AV block, post permanent pacemaker implantation, coronary artery disease, post percutaneous coronary intervention, diabetes mellitus, chronic kidney disease, dyslipidemia, hypertension and old stroke. He was wheelchair-bound and had totally dependent activity of daily life. He suffered from worsening gangrene wound and pain over right big and 2nd toes within 1 month.

Ankle-Brachial index was 0.63 on theright and 0.78 on the left. Clinical diagnosis was right foot critical limb ischemia with Rutherfordcategory 6. There was no improvement despite antibiotcstherapyand he did not want amputation. Serum creatinine was 0.87.

Angiography from left CFA showed extremely tortuous bilateral iliac arteries. We did right CFA ipsilateral approach instead. Angiogram showed total occlusion from orifice of right SFA with a tapered stump but heavily calcified. It was a long CTO with distal stump at TPT and there was another total occlusion at TPT. ATA was totally occluded. Peroneal artery was left to supply foot.

He went through 3 procedures and stayed for 13 days.1^st EVT:Do ipsilateral approach at right CFA due to tortuosity of bilateral iliac arteries. We tried antegrade wire escalation ( to Astato 30), knuckle wire technique ( with Hi-torque Connect and CXI) but no progress. And Echo-guided, fluoro-guided distal puncture at peroneal artery failed.2^nd EVT:For heavy calcified proximal cap, we used a V18 with microcatheter to do knuckle wire technique and advanced to distal SFA. We did distal puncture at peroneal artery, advanced to popliteal artery and escalated wire to Astato 30 to try penetrate distal cap but failed. R-CART with 4.0 balloon at middle and distal SFA, then externalized retrograde wire. After balloon angioplasty at SFA with 4.0 balloon, angiogram showed multiple extravasations at SFA. The patient developed shock. We did prolonged balloon inflation during resuscitation, but in vain. 3 cover stents were deployed at proximal to distal SFA. No more extravasation.※2 days later, the right thigh swelled and hemorrhagic shock recurred. CT showed a pseudoaneurysm at distal stents junction and the stents were distant from true SFA on transverse cuts. A "bypass" was created.3^rd EVT:Stents migrated. A cover stent was deployed to cover pseudoaneurysm. No more bleeding afterward.

It was a "hard" case. To conquer the CTO, we escalated wire and did knuckle wire technique with .018" wire but unexpectedly caused "bypass". To limit dissection, pre-procedural image, like CT would help. While subintimal tracking with knuckle wire technique, a smaller loop made with a softer wire and a microcatheter may do less harm. Intravascular imaging by IVUS would help making sure the wire position and choosing proper size for ballooning.For extravasation, prolonged balloon inflation at extravascular space is not effective. External compression and surgery are options. Using long covered stents or proper stent overlapping area minimize complications caused by stent migration.