Researchers Use OCT-A to Determine Association Between Ocular Features, ACS

Acute coronary syndrome (ACS) was associated with lower inner vessel length density, measured via optical coherence tomography angiography (OCT-A), and with higher concentrations of angiopoietin-2 and osteoprotegerin, according to study results published in Scientific Reports.

Cardiovascular risk factors like hypertension and diabetes lead to systemic inflammation and vascular stress, which in turn contribute to microvascular impairment and coronary macro and microvascular alterations. These alterations are closely associated, and together contribute to the pathophysiology of myocardial ischemia, researchers explained.

Because of these associations, the assessment of myocardial microvascularization is of major interest, so as to estimate a patient’s risk of acute coronary events. However, only invasive procedures are currently available.

In order to reinforce previous analyses of systemic microvascularization through biomarkers of angiogenesis and inflammation, researchers compared retinal microvascularization with OCT-A and systemic microvascularization biomarkers in patients with a high cardiovascular risk profile and controls.

A total of 62 eyes from patients with ACS who presented to cardiac intensive care units and 42 eyes of control patients from an ophthalmology department were included in the study. Thirty individuals in the high cardiovascular risk group exhibited hypertension (48%), 8 had diabetes (13%) and 24 were obese (39%). Researchers collected data from blood samples for each group and carried out OCT-A imaging on each patient.

Analyses revealed:

• Mean (SD) inner vessel length density in patients with ACS was lower than in control subjects (19.76 mm−1 [1.77] and 20.67 mm−1 [1.33] [P = .004]), respectively
• A significant difference was found for the inner perfusion density between those with ACS and control patients (mean 0.360 [0.027] and 0.373 [ 0.024] [P = .011]), respectively
• A ROC curve analysis showed an inner vessel length density value lower than 20.05 mm−1 was associated with the ACS cohort, with a specificity of 64% and a sensitivity of 55%
• Serum levels of angiopoietin-2 and osteoprotegerin were significantly higher in patients with ACS than controls with a mean at 2814 (912) pg/mL versus 1962 (618) pg/mL (P < .001), and 1060 (467) pg/mL versus 828 (308) pg/mL (P = .006), respectively
• Serum levels of ST2 tended to be higher in patients with ACS than controls with a mean at 25,359 (42,250) pg/mL versus 13,435 (7,632) pg/mL (P = .074), respectively
• No difference in TGF- β1 nor GDF-15 serum levels was found between patients with ACS and controls (P = .700 and P = .240, respectively)

In addition, researchers found age was significantly correlated with inner vessel length density and inner perfusion density. Overall, the results strengthen the hypothesis "that retinal vasculature status does not act independently and can reflect a systemic cardiovascular alteration.”

Patients with the most severe ACS who were unable to have a retinal examination were excluded from the study. This may have introduced selection bias, marking a limitation to the study. Future studies should also to take into account axial length in order to correct for magnification error.

“OCT-A could be a useful parameter to consider together with other pre-existing cardiovascular risk factors to assess high cardiovascular risk profiles and improve the screening of these patients in primary prevention,” authors concluded.

Reference

Hannappe M, Arnould L, Méloux A, et al. Vascular density with optical coherence tomography angiography and systemic biomarkers in low and high cardiovascular risk patients. Sci Rep. Published online October 7, 2020. doi:10.1038/s41598-020-73861-z