TRA is recommended as the routine approach for CAG and PCI nowadays [1, 8]. PCI via TRA has lower risk of vascular complications, all-cause mortality and MACE, compared with PCI via transfemoral access (TFA) [2, 9]. Recently, dTRA has emerged as a novel approach for CAG and PCI. It was first introduced by Kiemeneij in 2017 and since then, the feasibility and safety of CC through dTRA have been proved by many studies [6, 7, 10]. Compared with TRA, this technique has advantages in faster hemostasis, lower risk of radial artery occlusion (RAO) and recanalizing RA stenosis or RAO [7, 11]. However, none of these previous studies reported the safety and feasibility of CAG and PCI via dTRA in case of RA anatomical variation, such as SRA.
SRA is a large branch vessel arises from the RA in the distal fourth of the forearm, 5 to 7 cm proximal from the distal wrist crease, with an incidence between 1 and 1.5% [3, 5]. SRA extends subcutaneously on the radial side of the forearm, over the tendon of the brachioradialis muscle, passes over the tendon of the extensor pollicis brevis into the AS and forms the deep palmar arch of the hand with the ulnar artery [3,4,5]. It becomes difficult to puncture RA in the traditional puncture site of the TRA in case of SRA. For instance, Hudcova et al. reported a difficult arterial catheter placement case with SRA, and eventually cannulation of the RA in the AS [3]. SRA was not identified before surgery in the case report of Uchino et al., and they failed to place arterial catheter in the usual RA puncture site after multiple attempts [4]. In our case report, the pulsation of the SRA was visible and could be detected by palpation. However, there was also a weak pulsation of the RA at the usual puncture site in the anterior region of the forearm. The RA, after the SRA split, ran a normal course deep into the muscles of the forearm might cause this situation, similar to the case report of Uchino et al. Ultrasonography with color Doppler was then performed, the course of the RA could not be observed at the routine puncture site but the existence and course of the SRA was confirmed. CAG and PCI through dTRA has many advantages and the SRA just ran down into the AS in our case, we therefore selected distal RA as the CC approach. After the assessment of the artery condition of the dTRA puncture site (Fig. 1c), we successfully performed CC via dTRA with no vascular complications occurred.
To the best of our knowledge, this is the first report that presents a case of SRA and CC in which was successfully performed via dTRA. According to the anatomical morphology of the SRA and the benefits of CC via dTRA, we think dTRA may be the best access among SRA patients with CC plan. Because SRA extends subcutaneously on the radial side of the forearm and there is no forearm muscle around SRA for protection, great care should be taken when inserting the arterial sheath to prevent vascular complications. This might be the potential disadvantage of the current SRA approach. However, the safety and feasibility of this technique should be verified by long-term follow up and in a large-scale population.