Paradox of the Relationship between Cardio-Ankle Vascular Index and Ankle-Brachial Index in Patients with Lower Extremity Artery Disease

Difference in right and left cardio-ankle vascular index as a useful marker for evaluation of leg ischemia in patients with lower extremity arterial disease

OBJECTIVES

Cardio-ankle vascular index (CAVI) is a blood pressure-independent measure of heart-ankle pulse wave velocity and is used as an indicator of arterial stiffness. However, there is a paradox that CAVI is inversely associated with leg ischemia in patients with lower extremity arterial disease (LEAD). The aim of this study was to clarify the significance of the absolute value of left and right difference in CAVI (diff-CAVI).

METHODS

The subjects were 165 patients with LEAD who had received medication therapy. Relationships between diff-CAVI and leg ischemia were investigated. Leg ischemia was evaluated by decrease in leg arterial flow using ankle-brachial index (ABI) and by symptoms using the Rutherford classification.

RESULTS

There was a significant inverse correlation between diff-CAVI and ABI. The odds ratio for low ABI of the 3rd versus 1st tertile groups of diff-CAVI was 7.03 with a 95% confidence interval of 2.71 ∼ 18.22. In ROC analysis, the cutoff value of diff-CAVI for low ABI was 1.05 with a sensitivity of 61.1% and a specificity of 87.1%. The median of diff-CAVI was significantly higher in subjects with grade 2 of the Rutherford classification than in subjects with its grade 1.

CONCLUSIONS

diff-CAVI showed an inverse association with ABI and a positive association with symptoms of leg ischemia. Thus, diff-CAVI is thought to be a useful indicator of leg ischemia in LEAD patients.