A Lower Aorto-iliac Bifurcation Position and Incident Cardiovascular Disease: The Multi-Ethnic Study of Atherosclerosis (MESA)

The aorto-iliac bifurcation distance (AIBD, distance from the aorto-iliac bifurcation to the L5/S1 disc space) identifies the position of the bifurcation along the spine. The prognostic significance of a lower bifurcation position and for CVD events and total mortality is unknown. In a multi-ethnic cohort of community living, healthy, older adults, we determined the independent hazard of a smaller AIBD (lower bifurcation position) for incident coronary heart disease (CHD, defined as myocardial infarction, resuscitated cardiac arrest, and sudden cardiac death), CVD (defined as hard CHD plus stroke and stroke death), and total mortality. In 1711 participants (51% men), the mean AIBD was 26 + 15 mm. After a median follow-up of 10 years 63 (3.7%) developed CHD, 100 (5.8%) developed CVD, and 129 (7.5%) were deceased. In unadjusted models, compared to the fourth AIBD quartile (highest bifurcation position), the first quartile was associated with increased hazard for CHD (HR = 1.5, 95% CI: 0.8 to 3.0), CVD (HR = 1.6, 95% CI: 0.9 to 2.7), and total mortality (HR = 2.2, 95% CI: 1.3 to 3.6). After adjustments for age, gender, ethnicity, smoking, diabetes, systolic blood pressure, hypertension medications, total and HDL cholesterol, hazard ratios for CHD (HR = 0.8, 95% CI: 0.4 to 1.7), CVD (HR = 0.9, 95% CI: 0.5 to 1.7), and total mortality (HR = 1.1, 95% CI: 0.6 to 1.8) were non-significant. Despite being an independent marker for adverse vascular changes in the aorta, the aorto-iliac bifurcation position was not independently associated with future CVD events.