Are Retinal Microvascular Caliber Changes Associated with Severity of Coronary Artery Disease in Symptomatic Cardiac Patients?

Abstract

Recent population-based studies have shown that retinal vascular caliber may predict the risk of clinical coronary artery disease (CAD) events. Whether this association is related to macro- or microvascular mechanisms remains unknown. We investigated the relationship of retinal vascular caliber with severity and extent of CAD in symptomatic cardiac patients. Overall, 98 patients attending diagnostic coronary angiography were recruited. Coronary angiography was used to assess for the severity and extent of CAD. Digital retinal photography was performed immediately prior to cardiac catheterization, and retinal vascular caliber was measured from these photographs by using a computer program and summarized as central retinal arteriolar (CRAE) and venular (CRVE) equivalents. Retinal arteriolar and venular calibers were not associated with increasing severity of CAD, as assessed by Leaman scores (CRAE/CRVE: P for trend=0.17/0.57), presence of clinically significant CAD (CRAE/CRVE: P=0.35/0.32), or number of diseased vessels (CRAE/CRVE: P for trend=0.18/0.69). Retinal vascular caliber changes are not associated with the severity of obstructive CAD in symptomatic patients. These data suggest that the association of retinal vascular caliber with clinical CAD seen in epidemiological studies may not be applicable to clinical symptomatic patients and may be related to microvascular, rather than macrovascular, mechanisms.