Figure 4

Formation of an arteriovenous shunt around the arterial patch, as shown by angiography and pulse-oximetry. Angiography of the arterial patch-bearing left common jugular vein was performed on day 3 (A) and day 28 (B) with contrast agent in the early arterial phase. The arteriovenous shunt had not formed on day 3 (yellow arrowheads, the left subclavian artery). On day 28, an arteriovenous shunt had formed, and its blood flow originated from the second branch of the left subclavian artery (yellow arrowheads). The left common jugular vein, which was a drainage vein, was enhanced in the arterial phase (blue arrowheads). (C) Angiography on day 84 showed that the feeding artery of the arteriovenous shunt had grown and that the new blood vessels were larger than they had been on day 28. The ovals in B and C that are demarcated by red dashes contain new blood vessels. Representative images are shown in (A–C). (D) Oxygen saturation in the left common jugular vein over time. Between day 0 and day 7, the oxygen saturation did not change. However, on days 10–14, the oxygen saturation started to rise sharply. On day 14 and thereafter, the oxygen saturation exceeded 95%. Thus, the blood in the vein after day 14 was of arterial origin, which indicated that the shunt was established around that time point. Scale bar = 1 cm.