O49 Diabetes Is Associated to the Reduction of Carotid Body Volume in Resistant Hypertensive Patients

Background and Objective: Considering that carotid bodies (CB) are involved in the counterregulatory response to hypoglycemia and that their impact on blood pressure control still needs to be better clarified, the objective of this study was to characterize the volumetric reduction of CB in controlled and uncontrolled hypertensive patients. Methods: CT angiograms of hypertensive patients treated at the Heart Institute (University of São Paulo Medical School) were studied. The evaluated patients were separated into four groups: hypertensive (receiving 1 to 2 categories of antihypertensives) controlled (H-C, n=42) and uncontrolled (H-U, n=23), and resistant hypertensives (receiving 3 or more categories of antihypertensives) with controlled (HR-C, n=17) and uncontrolled (HR-U, n=23) blood pressure. CT angiograms (Aquilion ONE/PRISM–Canon) of the cervical arteries with iodinated contrast were evaluated. Artery reconstructions used 0.5 mm thick sections, with orthogonal measurements of CB to evaluate bilateral carotid diameters and bifurcations. Results The morphology of common, internal and external carotid arteries was very similar between the groups. The mean age between groups was not significantly different (H-C: 67±12; H-U: 63±16; HR-C:65±9; HR-U: 67±13 years). When evaluating the presence of atherosclerotic lesions, a similar proportion, approximately 50%, was found in all groups. On the other hand, the presence of diabetes in HR-U group was 52%, while in other groups it was 30%. Furthermore, CB volume (mm3) in the presence of diabetes, presented an important reduction, especially in resistant hypertensive patients (H-C: -4%; H-U: -27%; HR-C:-55%; HR-U: -64%). Conclusions: The reduction of CB volume may be associated with the loss of microvascularization, mediating a possible hyperactivity of CB, which consequently maintain the comorbidities observed in these patients. Experimental studies showed that bilateral resection of the carotid sinus nerve completely prevents insulin resistance and hypertension, reinforcing the strong effect of diabetes upon CB normal function found in the present study. Longitudinal studies will contribute to a better understanding of CB regulation and the impact of diabetic state on blood pressure control.