Variation of method for measurement of brachial artery pressure significantly affects ankle-brachial pressure index values

Background: measurement of ankle brachial pressure indices (ABPI) is important in the assessment of patients with peripheral vascular disease. Methods: thirty-one hospitals with a vascular surgeon were selected at radom. A telephone questionnaire was completed to assess the method used for the measurement of ABPI. Following the survey, 14 patients with peripheral vascular disease had their ABPI measurement done by two observers, a pre-registration house officer and a clinical nurse practitionar. Observers were blinded to their own and each others results. Brachial systolic pressures were obtained using a DINAMAP(TM) (Critikon, Tampa, U.S.A.) automated blood pressure mointor, the Korotkoff method (12cm cuff, parallel wrap) and an 8 MHz Doppler probe (Huntleigh) and sphygmomanometer. Ankle systolic pressures were obtained using the Doppler probe. The results were analysed using the Wilcoxon signed rank test. Results: the survey demonstrated that at the majority of centres with vascular laboratories the brachial artery systolic pressures were measured using a Doppler probe. In contrast, at centres where the house officers performed the routine measurements, over 60% used the Korotkoff method to obtain this reading. One in four nurse practitioners used the Korotkoff method. When the ABPI values were calculated, the DINAMAP produced significantly higher median values than the Korotkoff (0.76 vs 0.72, p = 0.003) and Doppler methods (0.79 vs 0.70, p<0.0001). The nurse had a higher median ABPI value of 0.76 compared with the doctor (0.71, p = 0.01). Conclusion: this study shows that measurement of ABPI varies in different vascular units. The technique for ABPI measurement should be standardised.