Diastolic versus systolic ankle-brachial pressure index using ultrasound imaging & automated oscillometric measurement in diabetic patients with calcified and non-calcified lower limb arteries

BACKGROUND Ankle-brachial pressure index-systolic (ABI-s) can be falsely elevated in the presence of calcified lower limb arteries in some diabetic patients and therefore loses its value in this cohort of patients. We aim at investigating the feasibility of using the diastolic (ABI-d) instead of ABI-s to calculate the ABI in diabetic patients with calcified limb arteries. METHODS A total of 51 patients were chosen from the diabetic foot clinic. Twenty six of these patients had calcified leg arteries by Duplex scan (Group A) and 25 patients did not have calcifications in their leg arteries (Group B). Twenty five healthy volunteers were enrolled in the study for group C and they were matched with other participants from group B and A in age and sex. ABI measurement was performed using "boso ABI-system 100 machine". Systolic ABI (ABI-s) and diastolic ABI (ABI-d) were calculated based on bilateral brachial and ankle oscillometric pressures. ABI is considered normal when it is ≥0.9. Repeated measures ANOVA test was used to test for comparing mean scores for ABI-s and ABI-d across the three groups. Statistical significance is considered when P < .05. RESULTS The mean age of all participants (±SD) was 64.30 ± 7.1 years (range, 50-82 years). ABI-s mean ± SD was 1.3 ± 0.10 (range, 1.18-1.58) in group A patients, 1.07 ± 0.05 (range, 1-1.16) in group B patients, and 1.06 ± 0.05 (range, 1-1.16) in group C volunteers. While ABI-d mean ± SD was 1.07 ± 0.05 (range, 1.1-1.17) in group A patients, 1.06 ± 0.05 (1-1.14) in group B patients, and 1.05 ± 0.04 (range, 1.01-1.14) in group C volunteers. In group A, repeated measures ANOVA test showed statistical significant difference between ABI-s and ABI-d (P < 0.001) whereas in group B & C was not (P > 0.05). CONCLUSIONS ABI-d may be helpful and can be used as a complementary measure instead of ABI-s in falsely elevated ABI caused by partial incompressible vessel.