The eye, the kidney, and cardiovascular disease: old concepts, better tools, and new horizons

Abstract

Chronic kidney disease (CKD) is common, with hypertension and diabetes mellitus acting as major risk factors for its development. Cardiovascular disease is the leading cause of death worldwide and the most frequent end point of CKD. There is an urgent need for more precise methods to identify patients at risk of CKD and cardiovascular disease. Alterations in microvascular structure and function contribute to the development of hypertension, diabetes, CKD, and their associated cardiovascular disease. Homology between the eye and the kidney suggests that noninvasive imaging of the retinal vessels can detect these microvascular alterations to improve targeting of at-risk patients. Retinal vessel–derived metrics predict incident hypertension, diabetes, CKD, and cardiovascular disease and add to the current renal and cardiovascular risk stratification tools. The advent of optical coherence tomography (OCT) has transformed retinal imaging by capturing the chorioretinal microcirculation and its dependent tissue with near-histological resolution. In hypertension, diabetes, and CKD, OCT has revealed vessel remodeling and chorioretinal thinning. Clinical and preclinical OCT has linked retinal microvascular pathology to circulating and histological markers of injury in the kidney. The advent of OCT angiography allows contrast-free visualization of intraretinal capillary networks to potentially detect early incipient microvascular disease. Combining OCT’s deep imaging with the analytical power of deep learning represents the next frontier in defining what the eye can reveal about the kidney and broader cardiovascular health.

Choriocapillaris microvasculature dysfunction in systemic hypertension

“…We report changes in the choriocapillaris microvasculature that is associated with kidney function (eGFR and urine MCR levels). The arrangement of the choriocapillaris and kidney glomerular microvasculature have several structural and organizational similarities that support the concept that choriocapillaris microvascular network might reflect changes in kidney microvasculature associated with renal disease 32 . We can therefore hypothesize that the presence of large CFD, signifying microvascular rarefaction, may mirror similar alterations in the renal microcirculation.…”

The Eye as a Non-Invasive Window to the Microcirculation in Liver Cirrhosis: A Prospective Pilot Study

“…Examination of the microvasculature in this way has been used extensively in the research of both retinal and neurological disorders [ 17 , 18 ]. Moreover, retinal microvascular changes have been linked to increased cardiovascular risk [ 19 , 20 ], including the incidence of stroke [ 21 ] and coronary heart disease [ 22 ], suggesting that these abnormalities may reflect systemic microcirculatory dysfunction, and could represent an early, non-invasive technique to detect subclinical vascular pathology [ 22 ]. Cirrhosis is associated with widespread microcirculatory dysfunction and haemodynamic abnormalities.…”

Relationships Between Retinal Vascular Characteristics and Renal Function in Patients With Type 2 Diabetes Mellitus

“…The eye and kidney have several structural, developmental, and organizational similarities 6 ; current studies suggest that DN and DR share common microvascular pathophysiologic mechanisms, including inflammation, endothelial dysfunction, oxidative stress, and thickening of the basement membrane. 7 Several epidemiologic studies suggested DR and DN usually progress parallelly and share close relationship 8 ; thus, it is reasonable to assume that the severity of DR is a predictor of renal function.…”