M. Matangi1, DW. Armstrong1, C. Tobin1, D. Brouillard1 - (1) Kingston Heart Clinic, Kingston, Canada
Purpose. The toe-brachial index (TBI) is usually only recommended if the ankle-brachial index (ABI) is high, (≥1.30). We routinely perform the TBI on all patients and believe that the TBI provides very useful information. The purpose of our investigation was to compare the TBI with the ABI which is currently the standard for the diagnosis of peripheral arterial disease (PAD). Methods. Our cardiology database was searched for all patients who had both the ABI and TBI measured. There were 4,690 lower limbs. An abnormal ABI was ≤0.90 and an abnormal TBI was ≤0.70. A scattergram of ABI versus TBI was performed and the sensitivity, specificity, accuracy, negative predictive, positive predictive value, positive likelihood ratio and negative likelihood ratio (-LR) were calculated. Results. See Table 1 and Figure 1. Conclusions. A normal TBI has a very high sensitivity and negative predictive value which virtually excludes a diagnosis of PAD. The low -LR indicates that a patient without PAD is 10 tens more likely to have a normal TBI compared to a patient with PAD.