The Significance Of ABPI And TBPI In Evaluating Blood Supply Of Lower Limb In Type 2 Diabetes Mellitus

Objective: Measurement of ankle systolic blood pressure(ASBP)and ankle brachial pressure indices(ABPI) is a simple non-invasive method of assessing lower limb arterial blood supply. However, its use in type 2 diabetes has been questioned due to the presence of medial artery calcification. Measurement of toe systolic blood pressure(TSBP)and toe brachial pressure indices(TBPI) has been advocated as an alternative but it is technically more difficult. The aim of this study was to obtain information to guide clinicians as to when pressure measurements should be taken at the toe.Methods: Brachial systolic pressure, ASBP and TSBP were measured by Doppler ultrasound on 41 subjects with type 2 diabetes and 23 control subjects. Then, we counted and categorized patients according to ABPI and TBPI.Results: The correlation of the ASBP with TSBP was low. The influence of medial arterial calcification on TSBP and TBPI is not obvious ,while the influence on ASBP and ABPI is significant.Conclusion: In the majority of patients with type 2 diabetes, assessment of TBPI conveys no advantage over ABPI in determining perfusion pressure of the lower limbs. As long as ABPI is not obviously falsely elevated (i.e.> 1.3), it gives as much information as TBPI and can be relied upon to make clinical decisions. Only in those patients with overt calcification(ABPI> 1.3), are toe pressure measurements superior for less influence having been laid on it. Measurement of TSBP and TBPI can help to reduce the rate of missed diagnosis on diabetic foot caused by ABPI.