Usefulness of the transfer function index for diagnosing peripheral arterial disease in patients with arterial calcification.

Unlabelled: The aim of this study was to investigate which parameters among the ankle brachial index (ABI), toe brachial pressure index (TBI) and transfer function index (TFI) are useful to accurately diagnose PAD in patients with / without arterial calcification, who have undergone some type of diagnostic imaging.

Patients and methods: A total of 102 patients with 192 limbs (mean age: 72.0 ± 8.4 years) underwent plain radiography, ABI, TBI and TFI. A receiver operating characteristics (ROC) analysis was performed to assess possible threshold values that predict PAD in these patients.

Results: T he a rea u nder t he c urve ( AUC) o f t he ABI, TBI and TFI were 83.0%, 87.9%, 93.1% in the all limbs group, respectively. In the non-calcified lesion group, the AUC of the ABI, TBI and TFI were 94.4%, 87.9%, 93.1%, respectively. In the calcified lesion group, the AUC of the ABI, TBI and TFI were 71.4%, 87.9% and 92.9%, respectively.

Conclusions: A cut-off value of TFI ≦ 1.025 exhibits a higher AUC for detecting the presence of PAD than the ABI and TBI. Therefore, the TFI is considered to be useful to estimate the presence of PAD in all types of patients, especially those with arterial calcification.