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Ankle-brachial index (ABI)

A Peripheral Vascular Intervention term on the RCIS exam blueprint, defined for cath lab and EP clinicians.

Calculated as the ratio of ankle systolic pressure to brachial systolic pressure; a normal ABI is roughly 1.0–1.4, values below 0.9 indicate PAD, and very low values (below 0.4) suggest critical limb ischemia. Notably, ABI can be falsely elevated in heavily calcified, non-compressible vessels (common in diabetics), requiring alternative testing such as toe-brachial index in that scenario.

Domain: Peripheral Vascular Intervention · Blueprint: RCIS exam guide

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Written and reviewed by John-Philip (JP) Maarschalk, BSN, RN, CNML — a nurse manager who runs operations for the cardiac cath lab, electrophysiology, and interventional service lines at an academic health system in North Carolina. He hires and develops the staff who sit for these exams. More about JP and how this content is made →
Cardiac Codex is an independent study tool published by MdoubleA LLC, not affiliated with or endorsed by CCI or any certifying body. This glossary entry is exam-preparation information, not medical advice or a substitute for clinical judgment. Always verify current clinical practice against primary sources and institutional protocol.