ABSTRACT
Since peripheral vascular disease (PVD) is the forerunner of coronary heart disease (CHD), it is vital to detect PVD at an early stage. In the past, the non-invasive ankle arm index (AAI) has been successfully used to predict the susceptibility of PVD/CHD. However, different authors have used different permutations (i.e. highest, average and lowest) of ankle (ASBP) and arm (HSBP) systolic blood pressures to calculate AAI. This study aims to investigate the validity and applicability of different permutations of AAI formulae to predict sub-clinical PVD/CHD in young individuals. The study also investigated whether the use of AAI post-moderate exercise would enhance the predictability of PVD or CHD at an early stage. Individuals from different ethnic background within the UK took part in this study. Following 5min moderate cycle exercise using 50% of heart reserve, the AAI was significantly reduced (P<0.05). It was found that not all the permutations of AAI were acceptable and some over/under estimated AAI compared to currently accepted methodologies. According to the statistical analysis (ANOVA and 95% limits of agreement) calculation of AAI using values of (1) highest ASBP divided by highest HSBP, (2) highest ASBP divided by average HSBP, (3) average ASBP divided by highest HSBP and (4) lowest ASBP divided by average HSBP were within acceptable agreement with the standard method of calculating AAI. Inclusion of these permutations together with the standard method, would give a better predictions of PVD/CHD at an early age.
