Case Report: When crossing is not enough: restoring functional access in an extreme brachial artery loop during...

Successful traversal of severely tortuous upper-limb arterial anatomy does not necessarily constitute functional access, yet this distinction remains poorly emphasized in the transradial literature. Existing bailout strategies primarily focus on successful traversal, whereas restoration of effective catheter mechanics through geometric correction may represent a distinct procedural challenge. We report a case of primary percutaneous coronary intervention performed via right radial access in a 73-year-old woman presenting with acute inferior ST-elevation myocardial infarction, complicated by a near-complete circular brachial artery loop. Despite successful guidewire traversal and distal advancement of a guiding catheter toward the aortic root, functional access could not be established. The underlying mechanism was not failure of traversal, but failure of geometric correction. Despite successful catheter passage, the loop persisted without meaningful straightening, resulting in inadequate catheter support and ineffective torque transmission. This case highlights the distinction between crossability - the ability to traverse a tortuous segment - and correctability - the ability of that segment to undergo geometric realignment sufficient to restore functional catheter performance. When correctability is not achieved through initial navigation, a structured escalation strategy becomes necessary. Sequential exchange to progressively higher-support guidewires, performed as protected intraluminal exchanges within the indwelling guiding catheter, ultimately achieved effective loop straightening and restored functional access. Primary PCI was completed with a door-to-balloon time of 36 minutes, demonstrating that a correctability-focused escalation strategy can be executed without compromising reperfusion efficiency in time-sensitive settings. This experience supports a mechanism-based, stepwise framework for managing extreme upper-limb arterial tortuosity - one that treats geometric correction as a distinct procedural objective and guides escalation decisions based on functional access assessment rather than traversal success alone. This reframing offers a practical framework for recognizing when successful traversal alone is insufficient to establish functional access, for guiding structured escalation, and for informing more deliberate access-site crossover decisions in acute revascularization settings.