Association of severity of coronary artery disease by SYNTAX score (SS) and lower extremity arterial disease by duplex ultrasound (DUS) study-an Indian perspective.

Coronary artery disease (CAD) and lower extremity artery disease (LEAD) often coexist. Ankle brachial index (ABI) has been shown to be an independent predictor of CAD. Studies have reported correlation of CAD and LEAD on the basis of ABI and also invasive angiography. But rigorous searching did not reveal any similar research where severity of LEAD was assessed by duplex ultrasound (DUS). In this study, we assessed the association of severity and localisation of LEAD by DUS with SYNTAX score (SS). A total of 637 subjects above 45 years of age with coronary angiographic confirmation of CAD were studied in this single centre cross-sectional, descriptive and analytical research. High SS was significantly more common in subjects with LEAD (p = 0.04). In the femoro-popliteal segment, total occlusion of arteries was found in significantly more proportion of subjects with high SS. A progressive increase in mean SS was noted across the grades of arterial disease in the femoro-popliteal segment (p = 0.007). 85.2% of the LEAD was in the femoro-popliteal segment, while below-knee arterial disease was present in 98.5% of subjects with LEAD. Hypertension, smoking, history of CVE and presentation with ACS independently increased the risk of LEAD. High prevalence of asymptomatic LEAD and association of high SS with LEAD as a whole as well as femoro-popliteal involvement suggests the need for a point of care DUS study (POCUS) since treatment varies with location and extent of disease which cannot be fathomed by ABI alone. Being the largest study on association of CAD and LEAD from Indian subcontinent till date and also the first study to use non-invasive tool as DUS for LEAD assessment while studying its association with CAD makes this a landmark experience.