Retinal microvascular changes in microvascular angina: Findings from the Australian Heart Eye Study.

OBJECTIVE: Microvascular changes in microvascular angina are poorly understood due to difficulties in imaging the coronary microcirculation in vivo. The retinal microvasculature may reflect changes in coronary microcirculation. We assessed microvascular changes in the retina in patients with microvascular angina and compared them with patients with angiographically proven coronary artery disease. METHODS: We performed retinal photography and coronary angiography on 915 patients. Retinal vessel calibers were measured using a validated computer-assisted method; coronary artery disease was graded from coronary angiograms. Microvascular angina was defined as angina with <25% stenosis in all coronary epicardial arteries. RESULTS: A total of 139 patients (15.2%) had microvascular angina, while 776 (84.8%) had coronary artery disease. Participants with microvascular angina and coronary artery disease had similar retinal arteriolar and venular calibers. After adjustment for age, ethnicity, mean arterial pressure, diabetes, current smoking, body mass index, and fellow vessel caliber, women with smaller venules were threefold more likely to have microvascular angina than women with larger venules (multivariable-adjusted odds ratio 3.54, 95% confidence interval 1.35 to 9.24, P < 0.01). This difference was not observed in men. CONCLUSIONS: Microvascular angina in women was associated with microvascular changes distinct from those in coronary artery disease.

Metabolic syndrome and retinal microvascular calibre in a high cardiovascular disease risk cohort.

AIMS: To investigate the independent associations between metabolic syndrome and retinal vessel calibre in a high cardiovascular risk cohort, and to determine whether these associations also exist in patients without diabetes, hypertension or coronary artery disease (CAD). METHODS: The Australian Heart Eye Study is an observational study that surveyed 1680 participants who presented to a tertiary referral hospital for the evaluation of potential CAD by coronary angiography. Metabolic syndrome was defined according to the Third Report of the National Cholesterol Education Program. Retinal arteriolar calibre narrowing and retinal venular calibre widening were measured from retinal photographs. CAD was quantified using severity (Gensini) and extent scores. Diabetes and hypertension were defined from clinical investigation (fasting plasma glucose >7.0 mmol/L and blood pressure >130/85 mm Hg) or from self-reported clinical diagnosis, including the use of medications. RESULTS: A total of 979 participants had complete information on metabolic syndrome components and were included in cross-sectional analyses. After adjusting for age, sex, smoking status and fellow vessel calibre, persons with metabolic syndrome (compared with persons without metabolic syndrome) had narrower retinal arteriolar calibre (mean difference 4.3 µm, p<0.0001). No significant difference in venular calibre was observed (p=0.05). This association persisted in persons without diabetes (mean arteriolar calibre difference 4.4 µm, p=0.0006) but not in participants without CAD and those without hypertension. CONCLUSIONS: Metabolic syndrome is independently associated with narrower retinal arterioles but not wider retinal venules among those at high risk of CAD. The association between metabolic syndrome and narrower retinal arterioles is likely due to the presence of CAD or hypertension in individuals with this syndrome, as the association is not significant in individuals without hypertension or without CAD.

Gender differences in the severity and extent of coronary artery disease.

OBJECTIVE: To investigate whether women presenting with suspected angina would show less severe coronary artery disease in than men as determined by the extent score. METHODS: We examined 994 participants of the Australian Heart Eye Study presenting for coronary angiography in the investigation of chest pain from June 2009 to February 2012. People were excluded if there was a history of coronary artery bypass surgery, previous stenting procedure or incomplete angiogram scoring. An extent and vessel score was calculated using invasive coronary angiography. Normal coronary arteries were defined as having no luminal irregularity (Extent score = 0). Obstructive coronary artery disease was defined as a luminal narrowing of greater than 50%. RESULTS: Women compared to men without infarction had a lower burden of CAD with up to 50% having normal coronary arteries in the 30-44 year group and 40% in the 45-59 year group. Compared to men, women with chest pain had lower mean extent scores (19.6 vs 36.8; P < 0.0001) and lower vessel scores (0.7 v 1.3; P < 0.0001). Although the mean extent score was lower in women than men with myocardial infarction, this was not statistically significant (34.8 vs 41.6 respectively; P = 0.18). CONCLUSION: There is a marked difference in coronary artery disease severity and burden between females and males presenting for the investigation of suspected angina. Women are more likely to have normal coronary arteries or less severe disease than age-matched men, particularly if they do not present with myocardial infarction.