Impact of Diabetic Retinopathy on Vulnerability of Atherosclerotic Coronary Plaque and Incidence of Acute Coronary Syndrome

Although an association has been reported between the microvascular complications of diabetic patients and their poor prognosis after cardiovascular events related to advanced atherosclerosis, it is not clear whether there is a relation between diabetic retinopathy (DR) and the severity of plaque vulnerability. Fifty-seven diabetic patients with coronary artery disease, classified as non-DR (n = 42) or DR (n = 15), underwent angioscopic observation of at least 1 entire coronary artery. The number of yellow plaques (NYP) through the observed coronary artery was counted and their color grades, defined as 1 (light yellow), 2 (yellow), or 3 (intense yellow), were evaluated. The NYP per vessel and the maximum yellow grade were determined. The association between the presence of DR and incidences of acute coronary syndrome (ACS) was analyzed during the follow-up period (mean 7.1 ± 3.3 years; range, 0.83 to 11.75 years). Mean NYP per vessel and maximum yellow grade were significantly greater in DR than in non-DR patients (2.08 ± 1.01 vs 1.26 ± 0.77, p = 0.002, and 2.40 ± 0.74 vs 1.90 ± 0.82, p = 0.044, respectively). The cumulative incidences of ACS were higher in the DR group (p = 0.004), and the age-adjusted hazard ratio for ACS was 6.943 (95% CI 1.267 to 38.054; p = 0.026) for DR compared with non-DR patients. Our findings indicate that coronary atherosclerosis and plaque vulnerability are more severe in patients with DR. DR as a microvascular complication may be directly linked with macrovascular plaque vulnerability and fatal cardiovascular events such as ACS.