Toe Brachial Index query

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Can anyone help with information of their experience evaluating toe/brachial index results eg; what is regarded as normal vs below normal and/or any other advice ?

 

Hi Andrew, I conducted a Lit Review/study last year on TBI. Generally found that the 'normal range' discussed in research varies greatly.

One tip..doppler is very hard to use as physically it is hard to position the probe. A digital clamp is much easier.

See an excerpt from my lit review below. I Found past studies on reliability and validity very ambiguous also.

Hope this helps.

TBI is used to evaluate the blood flow through the small arteries of the toe. The TBI compares the systolic pressure of the hallux (1st toe) arteries, to the systolic pressure of the brachial artery. The equation for the TBI is similar to that of the ABI, with the toe pressure reading replacing the ankle pressure as the numerator.
E.g. a toe pressure of 75mmHg, and a brachial pressure of 100mmHg
75/100 = TBI of 0.75
A normal TBI differs to that of the ABI, as the normal blood flow and pressure to the hallux is expected to be less than that at the ankle and arm. The normal range is considered to be an index greater 0.65 (Carter, 1993; Huntleigh-Healthcare, 2007; Nicolaides, 1985; Williams, Harding, & Price, 2005). If a TBI is below 0.65, this indicates reduced blood flow to the small vessels supplying the hallux (Williams et al., 2005).
How TBI is established
As with procedure of taking an ABI, it is important the participant is supine with the ankles at an equal level to the heart. It is also recommended that socks or footwear remain on until immediately before the measurement is taken, to reduce a drop in temperature and the possible effect of vasospastic disorders. The toe pressure is obtained, along with a brachial pressure measurement (refer to section 3.8 for details of obtaining individual measurements). The TBI is then obtained using the formula discussed in the last paragraph. A digital pressure cuff applied around the hallux and an APPG clamp will be utilized in this study (see figure 3.2 of a foot set up for taking a TBI).

3.7.1.4 Reliability and validity of TBI

The TBI is reported as a very reliable parameter, being shown to be twice as reproducible as the ABI (Bird et al., 1999). TBI has been shown to be a reliable indicator of small arterial vessel changes when people with impaired ABI are excluded, as shown by a longitudinal study, over 4 years (Aboyans et al., 2006).

 

Hi Melbpod,
Thats a great help thank you ..

 

Hi MelbPod,

Is there any chance of getting a copy of your lit review? I am in the process of looking into the TBI and other non-invasive vascular tests.

Rebecca

 

Hi Rebecca,
Im in the process of editing it for submission. Im happy to provide you with the reference list if this helps? Otherwise, hopefully it will be published in not too long

Sally Belcher

 

Hi Sally,

A reference list would be brilliant - thanks so much!!

Rebecca