Nigerian Journal of Cardiology

: 2013  |  Volume : 10  |  Issue : 1  |  Page : 1--2

The role of ankle brachial index in the diagnosis of peripheral artery disease in hypertensive subjects in a Nigerian Health Centre

Kamilu M Karaye 
 Department of Medicine, Bayero University and Aminu Kano Teaching Hospital, Kano, Nigeria

Correspondence Address:
Kamilu M Karaye
Department of Medicine, Bayero University and Aminu Kano Teaching Hospital, PO Box 4445, Kano

How to cite this article:
Karaye KM. The role of ankle brachial index in the diagnosis of peripheral artery disease in hypertensive subjects in a Nigerian Health Centre.Nig J Cardiol 2013;10:1-2

How to cite this URL:
Karaye KM. The role of ankle brachial index in the diagnosis of peripheral artery disease in hypertensive subjects in a Nigerian Health Centre. Nig J Cardiol [serial online] 2013 [cited 2023 Mar 23 ];10:1-2
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Full Text

The epidemiology of Lower Extremity Arterial Disease (LEAD) has been investigated in many Countries including Nigeria, where it was previously reported to be very rare. Yakubu et al. had earlier reported that over a period of 10 years, a total of 320 limb amputations were performed on adults at the Ahmadu Bello University Hospital, Nigeria, but there was no case of peripheral vascular disease in the patients other than diabetic ulcers. [1] More recently, lower extremity peripheral artery disease (LEAD) was also found to be absent among hypertensive subjects at very high absolute cardiovascular risk. [2] These two studies relied exclusively on the symptoms and signs of LEAD, which are grossly inadequate for its diagnosis.

The primary non-invasive test for the diagnosis of LEAD is the ankle-brachial index (ABI). In healthy persons, the ABI is >1.0. Usually an ABI <0.90 is used to define LEAD. The actual sensitivity and specificity have been estimated, respectively, at 79% and 96%. [3] The level of ABI also correlates with LEAD severity, with high-risk of amputation when the ABI is <0.50. An ABI change of >0.15 is generally required to consider worsening of limb perfusion over time, or improving after revascularization. [4] In addition, the ABI is a strong marker of cardiovascular diseases (CVD), and is predictive of cardiovascular events and mortality. Low ABI values (<0.90) are predictive of atherosclerosis, such as coronary and carotid arterial diseases. [5]

In the study by Umuerri et al., ABI was used in a cross-sectional study to assess the prevalence of LEAD and its association with some CVD risk factors. [6] Patients were recruited consecutively, while excluding those with pedal edema, regardless of the presence or absence of intermittent claudication (IC). They got a prevalence of 41.8% using ABI among 153 hypertensive subjects, while a history of IC was obtained in only 7.8% of the subjects, and combining ABI with IC did not improve on the diagnostic sensitivity of the former. In this study, there was no significant statistical relationship between LEAD and its key traditional risk factors, namely increased age, smoking, male sex, and dyslipidemia. The use of ABI to assess for LEAD is novel in Nigerian settings, which makes the Umuerri study commendable. Ikem et al. had previously reported using ABI to assess for LEAD in diabetic subjects in Ile-Ife, Nigeria, which is another commendable effort. [7]

The Umueri study has raised an important question: is atherosclerosis as common in Nigerian hypertensive patients as suggested by the study, given the high prevalence of LEAD? Unfortunately, the study has not provided us with enough details to answer the question because of the lack of some important information, including:

No detailed clinical information such as findings on examination of the cardiovascular system, including auscultation of the femoral arteries at the groin level; palpation of the femoral, popliteal, dorsalis pedis, and posterior tibial sites; examination of the skin for the color, temperature, and integrity of the skin including calf hair loss. This is because beyond their diagnostic importance, clinical signs could have a prognostic value. [8] Electrocardiogram, serum creatinine and urinalysis were not carried out to screen for ischemic heart disease and kidney disease, which are important associated clinical conditions that can worsen prognosis.No matched control group, without which the odds ratio of having LEAD in the presence of hypertension cannot be estimated.Overall, it could be said that the contribution of the Umuerri study to our understanding of the morbidity of Nigerian hypertensive subjects is not very clear. However, the study is among the first to use a novel tool (ABI) to assess for LEAD among hypertensive subjects in Nigeria.


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