Total of consecutive 49 PCI attempted via dRA procedure done by the operators who has experience of more than 30 dRA catheterization before from December 2020 to November 2021 at the University of Tokyo Hospital were retrospectively investigated. Patient data was collected from the hospital electronic medical records. Distal radial artery puncture was done with echo-guided method just before the PCI procedure. Long and short diameter of conventional radial artery(cRA) which is forearm radial aretery and dRA were measured by echo. However, operators never examined cRA or dRA by echo before PCI so they have not chosen the patients by echo-examined artery diameter. PCI strategy and devices used in the procedures were decided by the operators. 

About patient characteristics, mean age was 73±11 years old, consisting of 85.7%(42/49) male and 14.3%(7/49) female. Mean height was 162.9±9.1 cm, mean weight was 66.4±12.9 kg and mean BMI was 24.9±3.3. LVEF measured by echocardiography was 54.5±15.7%. Approach side of dRA was right in 69.4%(34/49) and left in 30.6%(15/49). Former dRA prcedeure of the same side was 14.3%(7/49). There were 6 cases(13.0%) of hemodialysis patients(non-AV fistula side). Concerning antithrombotic medication, 100%(46/46) were on DAPT(aspirin 100 mg + clopidogrel 75 mg or prasugrel 2.5 mg/3.75 mg/20 mg) and 22.4%(11/46) were on triple therapy(DAPT + warfarin or any DOAC:direct oral anticoagulant). The dRA success rate was 93.9%(46/49) and the procedure success rate was 100%(46/46). Diagnosis were STEMI: 2.0%(1/49), NSTEMI: 4.1%(2/49), unstable AP: 8.2%(4/49), stable AP: 26.5%(13/49), staged PCI: 28.6%(14/49) and other: 30.6%(15). Mean sheath insertion time(from the start of local anesthetic to finish of insertion of sheath) was about 5 minutes (294±160 secconds). There is one Chronic total occulusion case. Guiding catheter size was 6F in 89.1%(41/46) and 7F in 10.9%(5/46). Rotational atherectomy device was used in 4.3%(2/46) and orbital atherectomy device was used in 6.5%(3/46). Maximum Rota burr size was 1.75 mm. ELCA(excimer laser coronary angioplasty) was done in 4.3%(2/46). Scoring balloons were used in 60.9%(28/46), more than 1 DES(drug eluting stent) was deployed in 84.8%(39/46), DCB(drug coated balloon) was used in 26.1%(12/46). Imaging devices were used in 100%(46/46) consists of IVUS: 95.7% and OCT: 19.6%(9/46). Mean total radiation dose was 1472±956 mGy and mean volume of contrast medium was 147.5±62.3 ml. Bleeding, neurological and other major complication was 0%(0/46). Blood transfusion was performed in 1 case that is due to renal anemia and there is no case needed blood transfusion due to procedure related bleeding. Occlusion of dRA was not observed in any case. Diameter of cRA and dRA was 2.8±0.7 mm and 2.4 mm±0.7 mm, respectively.

PCI via dRA had high rate of dRA and procedure success when it is performed by physicians who has some experience of dRA. It is effective regardless of the preprocedural diagnosis(STEMI/NETEMI/uAP/eAP/other). As far as this study is concerned, no device(including Rota, OAC and ELCA) had limitation or malfunction during procedure. dRA had no major complications in this study population. From the result of this study, PCI via dRA seemed to be safe, feasible, and compatible for various situation and device. There are some limitations in this study. First, this is retrospective, single center study of very small study population.  Second, this study is not focused on comparison of dRA and other approaches(cRA, brachial approach, and femoral approach). Third, this study is not discussing on the comparison of long-time prognosis of PCI via dRA and other approaches. However, we hope it would be some help to understand the overview of current PCI via dRA.