Revista Colombiana de Cardiología
Print version ISSN 0120-5633
PAEZ E, Astrid N et al. Validation of oscillometric measurement of ankle-brachial index compared with arterial lower limb echo-doppler for arterial disease. Rev. Colom. Cardiol. [online]. 2010, vol.17, n.4, pp. 157-166. ISSN 0120-5633.
INTRODUCTION: previous studies reported validation and/or correspondence of ankle-brachial index measured by OMRON (ABIO) versus an ABI measured by Doppler, but the latter is not the gold standard. Objective: to determine the criterion validity of ABIO versus arterial duplex ultrasonography of lower extremities (ADULE) in detecting peripheral arterial disease (PAD). METHODS: evaluation study of diagnostic technologies by cross sampling. One hundred one persons with at least one cardiovascular risk factor were recruited consecutively from the Heart Institute in Bucaramanga. The ABIO was measured with the OMRON® HEM 780 equipment, and the ADULE was measured as gold standard; evaluators were blinded. RESULTS: repeated measurements of blood pressure in each extremity showed almost perfect reproducibility, as their correlation coefficients were above 0.86 and the agreement of the method was adequate ±15 mm Hg, for most measurements. According to ROC curve analysis, the cutoff for ABIO < 1.1 had high sensitivity (96.3%), low specificity (< 23.81%) and moderate quality of sensitivity (0.67); cutoff points lower than 0.9 have high specificity (> 90.48%), moderate sensibility (<70.37%), moderate predictive positive and negative values and efficiency (> 70.37%), positive likelihood ratio close to or above the ideal (7-10), moderate quality of sensibility (0.58), substantial quality of specificity (0.66-0.78) and efficiency or discriminatory ability (0.62-0.67). CONCLUSIONS: these findings enable to recommend measurement of ABIO in people with cardiovascular risk factors as a routine test, either for screening (cutoff point £ 1.1 or £ 1.2) or for diagnosis (cutoff point £ 0.9); the latter cutoff being of greater importance given the high specificity of the test, +LR and quality of specificity. Moreover, since ABI measurement by oscillometric methods is of low cost, requires a simple training of nurses and doctors, and is brief in its application, it could be easily used in primary health care in people with cardiovascular risk factors.
Keywords : ankle brachial index; peripheral arterial disease; diagnostic test; specificity; sensitivity.