Versatile Toe-Brachial Index (TBI) assessment

Diagnosis of peripheral artery disease (PAD) can be a tricky undertaking, even with the use of modern diagnostic tools. We are referring specifically to those for ABI assessment, which all have one significant drawback—they are unusable in patients with incompressible arteries. Fortunately, there is an alternative.

To be fair, the main problem in the field PAD diagnosis is not the (un)suitability of one method or the other in specific cases, but the underutilisation of any diagnostic method. Namely, despite the growing prevalence of PAD, there is a significant number of potential patients who are still undiagnosed [1, 2]. Unfortunately, this is true even for at-risk individuals.

A comprehensive study on the quality of wound care in the UK found that 40% of patients with leg ulcers had not yet been given an ABI assessment.

Late or no diagnosis can have similar outcomes, although that greatly depends on the complex interaction of various risk factors that may be affecting the patient. The most prominent risk factor is diabetes mellitus, which is responsible for both greater incidence of the disease and severity of its many complications [4]. Tobacco smoking comes in a close second, even though it could share first place with diabetes [5]. Female smokers are particularly at risk, an astonishing 20 times more than women who have never smoked [6]. Even more, whereas smoking cessation and continuous abstinence have many positive health benefits and eliminate or at least greatly mitigate the risk of development of variety of diseases, the same cannot be said for PAD [7, 8, 9, 10, 11]. Former smokers are at a 2.6 times greater risk than non-smokers [12].

Risk factors also include a history of prior CVDs and associated conditions, especially coronary artery disease (CAD), which is indicative of atherosclerosis, myocardial infarction (MI), transient ischaemic attacks (TIA) and stroke [13, 14, 15, 16, 17, 18]. Last but not least are typical cardiovascular risk factors like hypertension, hyperlipidaemia, unhealthy weight, chronic obstructive pulmonary disease (COPD) and a family history of PAD [19, 20, 21, 22, 23].

Still, they are hardly comparable to diabetes due to its complex and harmful effects on those with PAD. There is also another risk factor, which isn’t mentioned with those already listed, mirroring its conspicuous absence in many diagnostic and treatment guidelines for PAD. We are, of course, talking about chronic kidney disease (CKD): estimates of prevalence rates of PAD in patients with CKD vary greatly, from around 23% and 25% and all the way up to 35% [24, 25, 26]. The numbers behind the increased risk of a patient with renal insufficiency having a low ABI, defined as < 0.9, are otherwise well-researched [27].

Renal insufficiency and diabetes go unfortunately hand in hand as the latter is the most common cause of the former [28]. From the perspective of PAD though, they have another thing in common—both can cause calcification of the arteries (incompressible arteries) [29, 30, 31]. This excludes the use of ABI assessment, but does not demand the use of more complex and expensive methods such as angiography since there is another, similarly simple and convenient method—the Toe-Brachial Index (TBI) assessment.

The MESI mTABLET TBI diagnostic tool

The ABI assessment, whether with a Doppler probe and a sphygmomanometer or with an oscillometric-plethysmographic device, in those with incompressible arteries will always show an abnormally high score (generally in the ≥ 1.30 range), which is unusable for diagnosing PAD or its severity. It has limited and specific diagnostic value (an ABI ≥ 1.4 is associated with increased risk for MI in at-risk population), but little else [32]. The TBI, on the other hand, is not subject to such limitations as toe arteries are rarely incompressible (33).

The TBI has other advantages in comparison with the ABI. It is more suitable for patients with excruciating pain in the lower extremities and those with end-stage renal disease and is even regarded as an informal predictor of mortality in dialysis patients [34, 35, 36, 37]. Similar diagnostic utility was likewise observed in patients with type 2 diabetes: low TBI is associated with increased risk of recurrent CVD and progression of diabetic nephropathy [38, 39].

However, this greater versatility of TBI assessment for specific patients only really comes to prominence if performed by a diagnostic device that offers more than many comparable ones on the market, like the MESI mTABLET TBI. The MESI mTABLET TBI is a complete diagnostic tool for measuring blood pressure on one or both toes simultaneously. The MESI mTABLET and TBI diagnostic module are wirelessly connected to each other and, given that they are battery powered, can be used without connection cables.

Watch how to perform a fully automated, quick, simple, and reliable measurement of toe-brachial index using MESI mTABLET TBI.

Another significant feature of the MESI mTABLET TBI not found in other diagnostic devices is the integrated support for electronic health records (EHR), which involves creation, management, automatic result saving and sharing with other healthcare professionals. Users can consequently send diagnostic data to another specialist before he or she even receives the referred patient(s), or easily request a second opinion. This is possible even if the recipient is not a user of the MESI mTABLET as MESI mRECORDS supports data sharing on other devices (PC, tablets, mobile phones, etc.).

Incompressible arteries in patients with potential PAD exclude the use of otherwise versatile ABI assessment and favour the use of TBI measurement. There are several diagnostic devices on the market for performing the latter, but none as simple and intuitive to use as the MESI mTABLET TBI, which is designed with the digital future in mind.