ABSTRACT
The retinal vasculature is a unique site where the microcirculation can be noninvasively imaged in vivo. This presents an opportunity to study otherwise inaccessible structural features of the microcirculation. Recently, a number of population-based studies have developed quantitative methods of measuring these retinal signs, and investigated how these signs relate to metabolic disorders such as diabetes, hypertension, obesity, and metabolic syndrome. These studies have reported fairly consistent associations of retinopathy lesions, arteriolar narrowing and venular dilation with these metabolic disorders, suggesting a microvascular component in either the pathogenesis or manifestation of these disorders. Further, several of these signs have been associated with future risk of cardiovascular outcomes, such as coronary heart disease and stroke, independently of traditional risk factors. This review will examine in detail the evidence linking retinal vascular signs with metabolic disorders and discuss their implications for research and clinical practice.
A vasculatura retiniana apresenta uma oportunidade única de observação não-invasiva da microcirculação e de suas estruturas in vivo. Recentemente, uma série de estudos populacionais desenvolveu métodos quantitativos de observação destes sinais retinianos e suas relações com distúrbios metabólicos, tais como diabetes, obesidade, hipertensão arterial e síndrome metabólica. Esses estudos demonstraram associações das lesões retinianas, entre elas estreitamento arteriolar e dilatação venular, com essas alterações metabólicas, sugerindo um componente microvascular na patogênese ou na manifestação destes distúrbios. Ainda, vários destes sinais foram associados com risco de doença cardiovascular, tais como doença arterial coronariana e acidente vascular cerebral independente dos fatores de risco clássicos. Esta revisão discute em detalhes as evidências entre os sinais retinianos e os distúrbios metabólicos e suas possíveis implicações na pesquisa e na prática clínica.
Subject(s)
Humans , Diabetic Retinopathy/pathology , Hypertension/complications , Retinal Artery Occlusion/pathology , Retinal Artery/pathology , Arterioles/pathology , Cardiovascular Diseases/complications , Diabetic Retinopathy/etiology , Hypertension/pathology , Microcirculation , Metabolic Syndrome/complications , Obesity/complications , Retinal Artery Occlusion/etiologyABSTRACT
La importancia de la disfunción microvascular en la cardiopatía coronaria está cobrando cada vez más peso. Se sabe poco sobre este aspecto de la cardiopatía coronaria debido a las dificultades para estudiar la microcirculación coronaria directamente. La retina es el único sitio donde se puede obtener imágenes de los capilares directamente, lo que nos da la oportunidad de estudiar in vivo la estructura y la patología de la circulación humana, así como la posibilidad de detectar cambios microvasculares relacionados con el desarrollo de enfermedades cardiovasculares. Esta revisión abarca los últimos avances en investigación, que vinculan las manifestaciones vasculares retinianas con la cardiopatía coronaria, y pone de manifiesto la abundante evidencia científica encontrada de que las manifestaciones vasculares retinianas pueden reflejar el estado de la microvasculatura coronaria. Es probable que las manifestaciones más estudiadas, el estrechamiento de las arteriolas y, más recientemente, la dilatación de las vénulas, estén relacionadas, independientemente de los factores de riesgo tradicionales, con un elevado riesgo de cardiopatía coronaria en las mujeres. Hasta ahora se han visto frustrados los intentos por mejorar la predicción del riesgo de cardiopatía coronaria, que se centraban en la incorporación, como complemento de algoritmos tradicionales como el de Framingham, del calibre de los vasos de la retina a los sistemas de puntuación de predicción del riesgo. Sin embargo, actualmente se están realizando investigaciones sobre el valor predictivo de otras manifestaciones vasculares de la retina. Las fotografías de la retina nos ofrecen registros duraderos que permiten controlar los cambios longitudinales de estas manifestaciones y de la salud vascular (AU)
There is increasing recognition that coronary microvascular dysfunction also plays an important role in coronary heart disease. Little is known about this aspect of coronary heart disease due to difficulties in studying the coronary microcirculation directly. The retina is a unique site where the microcirculation can be imaged directly, providing an opportunity to study in vivo the structure and pathology of the human circulation and the possibility of detecting changes in microvasculature relating to the development of cardiovascular disease. This review covers the recent progress in research linking retinal vascular signs to coronary heart disease, and finds accumulating evidence that retinal vascular signs may provide a window into the health of the coronary microvasculature. The most widely studied signs, arteriolar narrowing, and more recently, venular dilation, are likely associated with increased risk of coronary heart disease in women, independent of traditional risk factors. Attempts to improve coronary heart disease risk prediction by incorporating retinal vessel caliber size into risk prediction scores complementing traditional algorithms such as the Framingham risk scores have so far been disappointing. Research is ongoing into the predictive utility of other retinal vascular signs. Retinal photography provides long-lasting records that enable monitoring of longitudinal changes in these retinal signs and vascular health (AU)