Ankle-arm index as a predictor of cardiovascular disease and mortality in the cardiovascular health study

Peripheral arterial disease (PAD) in the legs, measured noninvasively by th e ankle-arm index (AAI) is associated with clinically manifest cardiovascul ar disease (CVD) and its risk factors. To determine risk of total mortality , coronary heart disease, or stroke mortality and incident versus recurrent CVD associated with a low AAI, we examined the relationship of the AAT to subsequent CVD events in 5888 older adults with and without CVD. The AAT wa s measured in 5888 participants greater than or equal to 65 years old at th e baseline examination of the Cardiovascular Health Study. All participants had a detailed assessment of prevalent CVD and were contacted every 6 mont hs for total mortality and CVD events (including CVD mortality, fatal and n onfatal myocardial infarction, congestive heart failure, angina, stroke, an d hospitalized PAD). The crude mortality rate at 6 years was highest (32.3% ) in those participants with prevalent CVD and a low AAI (P<0.9), and it wa s lowest in those with neither of these findings (8.7%, P<0.01), Similar pa tterns emerged from analysis of recurrent CVD and incident CVD. The risk fo r incident congestive heart failure (relative risk [RR]=1.61) and for total mortality (RR=1.62) in those without CVD at baseline but with a low AAI re mained significantly elevated after adjustment for cardiovascular risk fact ors. Hospitalized PAD events occurred months to years after the AAI was mea sured, with an adjusted RR of 5.55 (95% CI, 3.08 to 9.98) in those at risk for incident events. A statistically significant decline in survival was se en at each 0.1 decrement in the AAI. An AAI of <0.9 is an independent risk factor for incident CVD, recurrent CVD, and mortality in this group of olde r adults in the Cardiovascular Health Study.