Impact of radial-to-aorta vascular anatomical variants on risk of failure in trans-radial coronary procedures.

OBJECTIVES: To assess the impact of an "operative" classification of vascular anatomic variants on the feasibility of trans-radial approach.

BACKGROUND: Vascular anatomic variants located from the wrist to the aorta may influence the feasibility of trans-radial procedures. Recently, a new "operative" classification of these variants was proposed.

METHODS: Consecutive trans-radial diagnostic or interventional catheterizations were considered. Vascular anatomic variants were classified according to 10 categories and sub-grouped according to the ABC classification (A: radial-brachial arterial axis; B: axillary-subclavian-anonymous axis; C: aortic arch). Primary study end-point was failure of trans-radial approach (necessity to cross-over to another approach to complete the procedure).

RESULTS: Three thousand four hundred seventy-seven consecutive radial procedures were considered. Anatomic variants were diagnosed in 308 procedures (8.8%): A variants: 7.2%, B variants: 1.9%; C variants: 0.3%. Failure occurred in 2.0% of procedures. Failure rate was 0.7% in the absence of variants vs.15.2% in the presence of any variant (P < 0.0001, OR 27.7, 95%CI 16.3-46.9). Each of the 10 variants was significantly associated with increased failure rate. Each of the three level-subgroups of variants was significantly associated to the risk of failure (failure 14.7% in A level, 13.9% in B level, 33.3% in C level; P < 0.0001 vs. absence of variants).

CONCLUSIONS: Failure of trans-radial procedures is associated to anatomic variants located from the wrist to the aorta. The "operative" ABC classification of anatomic variants is useful not only to categorize these anatomic variants, but also to predict the risk of failure of trans-radial approach.