A 70-year-old man with CLTI and foot gangrene underwent the bypass from the left common femoral artery to the dorsalis pedis artery using a reversed saphenous vein graft 2 years earlier (Fig. 1a). During DUS surveillance, we initially found severe stenosis around the femoral artery, anastomotic site, and vein bypass graft, where the PSV was increased to 564 cm/s, and consequently planned re-intervention (Fig. 1b). His medical history included multiple coronary risk factors, including hypertension, diabetes mellitus, and associated nephropathy requiring hemodialysis, unstable angina, left thalamic hemorrhage, and ex-smoker status. Above all, his cardiac function had drastically deteriorated after repeated coronary intervention performed for the unstable angina. The ejection fraction finally decreased to below 20%, which made it impossible to perform open surgery under general anesthesia. We had no choice but to select endovascular intervention (POBA) under local anesthesia.
POBA
We performed a percutaneous puncture of the contralateral common femoral artery and POBA under the guidance of a 0.014-in. micro guide wire and 4.5-Fr guiding sheath. The first time, we used a 1.5 × 20-mm Coyote Balloon Dilation Catheter (Boston Scientific, Natick, MA, USA) and 2.0 × 40-mm and 3.0 × 60-mm SABER PTA dilatation catheters (Cordis, Santa Clara, CA, USA). The second time after 111 days later, we used 2.0 × 40-mm and 3.0 × 40-mm SABER PTA dilatation catheters. The third time after 115 days, we used 2.0 × 20-mm and 3.0 × 20-mm Rapidstream balloon catheters (Nipro Corporation, Osaka, Japan). In the final treatment using POBA after another 67 days, we used a 2.5 × 40-mm SABER PTA dilatation catheter and a 3.0 × 100-mm Rapidstream balloon catheter. All POBA was performed under nominal recommended pressure (8 atm for 3 mm). Dilatation was temporarily achieved after each procedure.
DCB
We used a 4.0 × 60-mm IN.PACT Admiral DCB (Medtronic Vascular, Santa Clara, CA, USA), whose excipient paclitaxel concentration was 3.5 μg/mm2, after pre-dilatation using 2.0 × 60-mm and 3.0 × 60-mm Rapidstream balloon catheters (Fig. 1c). Because the 4.0 mm in diameter was oversized, we dilated the balloon to less than the nominal recommended pressure (8 atm), which approximated 2 or 3 atm. The range of the DCB covered the site which appeared slightly stenotic (Fig. 1c arrow) without increase of PSV via DUS.
Change of PSV
We had set the threshold for the PSV value at 500 cm/s for re-intervention after bypass surgery and regularly monitored the PSV in this patient. During the follow up period, PSV increased beyond 500 cm/s twice (659 and 563 cm/s, respectively) and we performed POBA both times. The third and fourth POBA procedures were performed on the stenosis with PSVs of 299 and 358 cm/s because the bypass pulsation was found to be weakened remarkably. Thereafter, we performed DCB on the stenosis, the fifth re-intervention, when the PSV reached 564 cm/s. After the procedure using DCB was performed 10 months earlier, no remarkable graft stenosis has been noted till date. (Fig. 2).