Identifier: TDX:1250
Authors: Montero Jaime, Manuel
Abstract:
Diabetes mellitus (DM) is a disease that has acquired the status of 'pandemic' in the XXI century. Currently about 366 million people worldwide suffer from this disease. According to the Health Survey of Catalonia (ESCA 2002) the estimated prevalence of type 2 diabetes mellitus (T2DM) in the population aged 30-69 years is 6.1% and in the range of population between 30-89 years can lead to exceed 10%. At the time of the diagnosis of type 2 DM, 5% of patients have retinopathy. This percentage increases to 40-50% after 10 years and 90%after 20 years. It is the leading cause of blindness in developed countries. Numerous studies show the decline in the incidence of blindness by RD with early treatment. Therefore, the detection of the RD must be a priority. The color Doppler ultrasound is a noninvasive diagnostic method that allows the study of retrobulbar vessels. Among the parameters studied, the most reproducible is the index of resistance, which can be defined as the resistance to blood flow in the distal vascular bed to the point of insonation. Since in diabetes vascular involvement occurs, this diagnostic method would provide us information about the evolutionary status of diabetic retinopathy. Furthermore, diabetic patients show great variability in the expression of vascular disease mainly dominated by diabetic macular edema and diabetic ischemic retinopathy. It has been suggested that these forms may have a genetic background. Our results allow us to differentiate between these two groups, since the hemodynamic alterations differ in the type of the retrobulbar vessel affected. Besides, correlation between hemodynamic and metabolic alterations exists, mainly the poor control of diabetes and LDL cholesterol and other risk factors, the main arterial hypertension. These results allow us to conclude that color Doppler ultrasound is a useful diagnostic method for the diagnosis and management of diabetic patients in relation to early diagnosis and prediction of the evolution towards forms of macular edema or ischemic retinopathy. - Contributions and new knowledge that the thesis gives: As I mentioned earlier, diabetic retinopathy is characterized by a great variability in its development and clinical expression. Currently the classification of diabetic retinopathy is based on ophthalmoscopic findings that do not address the evolutionary complexity of this disease. The study of retrobulbar vasculature, evaluating the resistance index in the different vessels allows us to group patients into two broad categories: those with a predominance of ischemic phenomena and other with a predominance of exudative phenomena and development of diabetic macular edema, being a early marker for the development of the disease. The first will show elevated resistance index in the central retinal artery and the second in the posterior ciliary. Furthermore, each of the two groups shows a different behavior in macrovascular involvement. The systematic use of Doppler ultrasound in diabetic patients would know its evolution taking therapeutic implications. It is very likely that there is a genetic background, especially in patients with a predominance of exudative phenomena. This possibility should be confirmed in future studies. - Methods and relevant conclusions: Cross-sectional study of a clinical series of patients representative of the studied population. Comparative study of the results of Doppler ultrasonography of the ophthalmic artery, central retinal and posterior ciliary regarding the presence of retinopathywith a predominance of ischemic or diabetic macular edema, and retinal and choroid thickness measured by OCT (Coherence Tomography Optics). Univariate statistical analysis by applying Student's t or Chi Square and multivariate by applying logistic regression analysis of each of the risk factors for the development of diabetic retinopathy or macular edema ischemic regarding resistance indices of the vascular tree studied. After analyzing the results we conclude that the ischemic diabetic retinopathy is associated with a high rate of resistance in the central artery of the retina and with a loss of retinal thickness as measured by OCT. Also is associated with an intima-media complex thickening in the unilateralcarotid and with higher incidence of arterial hypertension. The cases of diabetic macular edema present an increase of the resistance index in the posterior ciliary as well as higher incidence of plaques in the unilateral carotid, and cholesterol elevation- LDL. Choroidal thickness was decreased when measured by OCT. In all cases poorly controlled, i.e. showing elevated levels of glycosylated hemoglobin, an elevation of resistanceindex was observed in all retrobulbar vessels. - Tangible results of the investigation: Books, articles, .. Pending publication. - Presence of the Doctoral candidate in other research groups: Section of Vascular Medicine. Lipids Unit. Professor Lluis Masana.
Repositori URV