Case 1
A 79-year-old man undergoing hemodialysis owing to diabetes mellitus presented with claudication of the left lower limb. The patient’s ankle–brachial index was 0.70 on the left side. A 6-Fr guiding sheath (Destination® guiding sheath; TERUMO) was inserted into the right common femoral artery via the contralateral approach. Control angiography showed a tandem stenotic lesion in the left proximal superficial femoral artery (SFA) and total occlusion of the left middle to distal aspects of the SFA (Fig. 2a, b). First, a 0.014-in. guidewire (Gladius MGES® guidewire; Asahi Intec, Aichi, Japan) and 2.6-Fr microcatheter (Ichibanyari PAD2® microcatheter; Kaneka, Tokyo, Japan) seemed to be advanced into the subintimal space. We advanced AnteOwl (AnteOwl WR® IVUS; TERUMO) into the CTO. IVUS showed that the guidewire was in the subintimal space proximal to the CTO. We decided to perform the IVUS-guided parallel wiring technique using AnteOwl. We converted the direction of IVUS findings to angiography using the following five steps. (1) First, we performed rotational angiography from the right anterior oblique (RAO) 40° view to left anterior oblique (LAO) 40° view, the direction of which was the orthogonal axis against the CTO, to identify the upper side of the transducer and IVUS wire. Because the AnteOwl has an asymmetric transducer and IVUS wire, we were able to determine which was above and which was below from rotational angiography at an angle perpendicular to the IVUS catheter to see which was above. (2) The transducer was on the left side in the RAO 30° view, and the transducer and IVUS wire almost overlapped in the LAO 15° view (Fig. 2c, d). Based on these findings, we confirmed that the transducer was at the bottom and the IVUS wire was at the top. (3) The detector direction at which the transducer and IVUS wire coincided on the angiographic image was LAO 15° (Fig. 2e). (4) Next, the detector direction at which the transducer and target plaque were maximally separated was RAO 30°, which was at 45° rotation to the clockwise direction from LAO 15° to RAO 30° (Fig. 2e). (5) The IVUS findings revealed a target true lumen at which to aim on the right side of the IVUS catheter at RAO 30° (Fig. 2e, f). By rotating RAO 30° on the IVUS image to 6 o’clock according to the direction of guidewire advancement, the angiographic image and the IVUS image were visually matched (Fig. 2h, i). We advanced a 0.014-in. guidewire (Astato XS9–40® guidewire; Asahi Intec) and 2.6-Fr microcatheter (Ichibanyari PAD2® microcatheter; Kaneka) a few millimeters to the right (LAO side) of IVUS on angiography, and we advanced through the intraplaque route and succeeded in penetrating the lesion (Fig. 2g–i). After the predilation, we dilated a 6.0- × 150-mm drug-coated balloon (In.Pact Admiral®; Medtronic, Minneapolis, MN, USA) at the SFA lesion to prevent restenosis (Fig. 2i, j). The final angiography showed good antegrade flow with no dissection or residual stenosis (Fig. 2k).
Case 2
A 76-year-old woman with hypertension and old cerebral hemorrhage presented with ulceration and gangrene of the left foot. Preoperative contrast-enhanced computed tomography showed total occlusion beyond the left external iliac artery (Fig. 3a). First, we treated the external iliac artery to the common femoral artery using a transradial approach. Next, we treated FP CTO using an ipsilateral antegrade approach. When performing EVT on the ipsilateral side, the posture was reversed from the standard position, with the left-hand side of the operator on the foot side and the right-hand side on the head side (Fig. 3k). Control angiography showed total occlusion from the SFA proximal to the popliteal artery (Pop A) (Fig. 3b, c). We advanced a 0.014-in. guidewire (Gladius MGES® guidewire; Asahi Intec) and 2.6-Fr microcatheter (Ichibanyari PAD2® microcatheter; Kaneka) to the Pop A. We advanced AnteOwl IVUS into the CTO (Fig. 3d). Because it was a subintimal route from the distal aspect of the SFA shown in the IVUS findings, we performed an IVUS-guided parallel wiring technique through the intraplaque route. AnteOwl had a pullback system; thus, performing the parallel wiring technique in real time was possible while observing the lesion in front without inserting and removing the IVUS catheter advanced to the distal aspect of the CTO. By reflecting the IVUS findings into an angiographic image in the same manner as in Case 1, we performed the following steps. From rotational angiography, the transducer was on the upper side. The IVUS-wire and transducer coincided with about RAO 20°. And LAO 16° was maximally separated of IVUS and target plaque. We found that the left side (RAO side) of the IVUS catheter on angiography should be aimed at the distal aspect of the SFA (Fig. 3e–g). IVUS showed the 1st guidewire had advanced spirally in the proximal part of the Pop A, and we found that the right side (LAO side) of the IVUS catheter (opposite the distal SFA) should be aimed at the Pop A (Fig. 3h–j). We advanced a 0.014-in. guidewire (Astato XS9–40® guidewire; Asahi Intec) and 2.6-Fr microcatheter (Ichibanyari PAD2® microcatheter; Kaneka) and succeeded in accessing the lesion (Fig. 4 a, b). After the predilation, we deployed three drug-eluting stents (Eluvia® drug-eluting stent; Boston Scientific, Marlborough, MA, USA) from the SFA to the Pop A. The final angiography showed good antegrade flow (Fig. 4 c–e).