Ultrasound-Guided Coronary Angiography Through a True Superficial Radial Artery in a Patient With an Absent Conventional Radial Pulse: A Case Report.

Transradial access (TRA) is the preferred vascular approach for diagnostic coronary angiography and percutaneous coronary intervention, offering lower bleeding rates, fewer vascular complications, earlier ambulation, and greater patient comfort compared with transfemoral access. However, anatomical variations of the radial artery can complicate conventional cannulation and may necessitate alternative access strategies. The true superficial radial artery (SRA) is an uncommon congenital variant in which the radial artery courses superficially over the dorsolateral wrist rather than along its usual deep path, often resulting in an absent or weak pulse at the conventional radial access site. A 62-year-old man with type 2 diabetes mellitus, hypertension, and active smoking, who presented with Canadian Cardiovascular Society (CCS) class II exertional angina. Examination before coronary angiography revealed complete absence of a palpable radial pulse at the conventional volar wrist site, but a distinct pulsation was identified over the dorsolateral aspect of the right wrist. Vascular ultrasound confirmed a true SRA and guided vascular access, allowing successful first-attempt insertion of a 6-French hydrophilic radial sheath. Diagnostic coronary angiography was completed without arterial spasm, bleeding, hematoma, or crossover to femoral access, with a procedure duration of 15 minutes, fluoroscopy time of 10 minutes, contrast volume of 45 mL, and radiation dose of 30 Gy·cm². Coronary angiography demonstrated chronic total occlusion of the left circumflex artery extending into the second obtuse marginal branch, with well-developed collateral circulation from the right coronary artery. The patient was subsequently referred for coronary artery bypass grafting. This case illustrates that careful vascular examination combined with vascular ultrasound can identify a true SRA in patients with an absent conventional radial pulse. Recognizing this rare anatomical variant can help preserve the transradial approach, avoid unnecessary femoral crossover, and allow safe completion of coronary angiography.