BACKGROUND: Microvascular rarefaction due to hypertension has been linked to disease severity and end-organ complications. Optical coherence tomography angiography (OCTA) has been explored as a potential tool to evaluate the retinal microvascular network in hypertensive patients.
METHODS: PubMed, Scopus, Web of Science and Cochrane were systematically searched to 10th of September of 2021, along with a manual search. Studies that used OCTA as a primary diagnostic method to evaluate the macular microvasculature of hypertensive patients were included. Meta-analysis was performed using a random-effects model. Primary outcomes were macular vessel density and foveal avascular zone at the superficial and deep capillary plexus.
RESULTS: Of 947 screened articles, 9 were found eligible for qualitative and for quantitative analysis. Vessel density in hypertensive patients was reduced when compared to controls in the fovea (0.93, 95% CI 0.87 to 0.99, p=0.023) and the parafovea (0.95, 95% CI 0.93 to 0.97, p<0.001) of the superficial capillary plexus. Foveal avascular zone was larger in the deep plexus of hypertensive patients (1.10, 95% CI 1.03 to 1.18, p=0.003). Vessel density reduction was found in patients with worsening blood pressure control in three studies and prolonged disease in two studies.
CONCLUSIONS: Microvascular rarefaction of the macula is found in hypertensive patients with a reduction of foveal and parafoveal vessel density and an increase of foveal avascular zone area. Disease duration and severity might be related to a microvascular rarefaction. OCTA could offer a novel tool for the assessment and follow-up of hypertensive patients.