Retinal Microvascular Signs and Incident Cardiovascular Event in Asians

Abstract

Purpose: Retinal microvascular signs may provide insights into the structure and function of systemic small vessels that are associated with cardiovascular diseases (CVD). Previous studies were conducted in Western populations who have different CVD risk factor profile as Asians. We investigated whether retinal microvascular signs are predictive of CVD events in a multi-ethnic Asian cohort.

Methods: We conducted a prospective, population-based study in a multi-ethnic Asian cohort (Malay, Chinese and Indian) aged ≥40 years at baseline using data from the Singapore Malay Eye Study and the Singapore Prospective Study. Retinal microvascular signs were assessed from baseline retinal photographs. Retinopathy was graded using the modified Airlie House classification system. Retinal vascular parameters (arteriolar caliber, venular caliber and fractal dimension) were measured using computer-assisted programs to quantify the retinal vessels widths and global geometric complexity of the retinal vasculature. Incident CVD event was defined as newly diagnosed clinical stroke or acute myocardial infarction (AMI) or CVD death documented by National Registry of Diseases Office after the baseline examination.

Results: A total of 5,644 participants were free of prevalent stroke and AMI at baseline. During the follow-up (median 4.24 years), 250 (4.4%) and 124 (2.2%) participants developed a stroke/AMI and CVD death, respectively. In Cox proportional-hazards models adjusting for established risk factors (age, sex, race, systolic blood pressure, diabetes, smoking, cholesterol and C-reactive protein), presence of retinopathy (hazard ratio [HR] 1.70, [95% confidence interval 1.19, 2.44]), narrower retinal arteriolar caliber (HR 1.14, [1.00, 1.30], per standard deviation [SD] decrease), and wider retinal venular caliber (HR 0.88, [0.77, 1.00], per SD decrease) were independently associated with risk of CVD event. The C statistic was not changed when these retinal signs were incorporated into the model (C statistic 0.829 vs. 0.820, p=0.315). Retinal fractal dimension was not associated with risk of CVD event.

Conclusions: Retinopathy, narrower retinal arteriolar caliber and wider retinal venular caliber predict the risk of CVD events in Asians, consistent with studies in Western countries, supporting a role of microvascular pathology in CVD development. These retinal signs, however, did not improve the discrimination of CVD risk models significantly.

Keywords: 688 retina • 464 clinical (human) or epidemiologic studies: risk factor assessment • 550 imaging/image analysis: clinical