Incidence of Abnormal Ankle-Brachial Index in Diabetic Patients Asymptomatic of Arteriosclerotic Vascular disease Brintha Vasagar, MD, MPH, Katee Castleman, MD, Jonathan Eichorn, DO, Adam Rajoulh, MD, and Jeffery Swartz, MD

Introduction Diabetes affects 9.3% of the American population had diabetes in 2012: 29.1 million people 73,000 non-traumatic lower-limb amputations in diabetics in 2010: 60% of the non-traumatic lower-limb amputations Risk factors include smoking, hypertension, hypercholesterolemia, type 2 diabetes Seen in 75% of PAD 96% of men with PAD have at least one of these No specific screening recommendation for these risk factors USPSTF Recommendations: Insufficient evidence in asymptomatic patients

Ankle-Brachial Index (ABI) Recognized as an important indicator of peripheral artery disease (PAD), a common manifestation of atherosclerosis and crucial risk factor for coronary artery and cerebrovascular disease

Aims To determine the incidence of abnormal ABI in adult diabetics asymptomatic of arteriosclerotic vascular disease

Study Population

Study Population Inclusion criteria: Exclusion criteria: Diabetes Age 20 to 80 years Exclusion criteria: Documented history of cerebrovascular disease Coronary artery disease Intermittent claudication Subjective history of chest pain Systolic blood pressure >160 mm Hg Diastolic blood pressure >100 mm Hg

Materials & Methods ABIs were calculated using Stanford 25 Protocol Brachial, dorsalis pedis, and posterior tibialis blood pressures were measured bilaterally Appropriately sized manual blood pressure cuff Doppler ultrasound ABI Calculation: Patients were notified of their results within two weeks of study completion Appropriate follow-up designated by primary care provider Highest pressure in right foot Right ABI = Highest pressure of both arms

Demographics 46 participants, mean age 57 years (Median 56.5 years) 20 men (43%), 26 women (57%) 12 smokers (26%), 34 non-smokers (74%)

Results Normal ABIs (ABI 0.9 -1.3): 63% Abnormal ABIs showing elevated values (ABI >1.3): 28% Abnormal ABIs showing mild disease (ABI 0.7-0.9): 9% 33% of smokers had abnormal ABIs, while 38% of non-smokers had abnormal ABIs 75% of men had abnormal ABIs, while 8% of women had abnormal ABIs

DISCUSSION 63% with Normal ABIs Is MAC obscuring PAD? 28% of abnormal ABIs were elevated, only 9% with abnormal ABIs showing mild disease Supports assertion of MAC in diabetic population limiting utility of ABIs Female gender correlated with more abnormal ABIs Not supported by large scale studies May be due to small sample size No correlation with smoking status Opposed by large scale studies Does not account for participants who might have smoked for many years previously Age correlation No clear correlation, despite several large studies showing increased risk of PAD with age

Alternative Methods of Diagnosing PAD In screening diabetic patients for PAD, other studies show higher sensitivity with CWD (72.2%) and TBI (63.6%) compared to ABI (45.2%)

Conclusions 37% of diabetics screened had abnormal ABIs, suggesting screening may be beneficial even in asymptomatic patients MAC may elevate ABIs into the normal range despite PAD - large number of false negatives TBI and CWD may be considered as alternatives to ABI screening in the diabetic population asymptomatic for PAD