COULD THE CAROTID BODY REDUCTION BE RELATED TO RESISTANT AND UNCONTROLLED HYPERTENSION?

Abstract

Objective: Considering that the carotid bodies act on autonomic regulation and their impact on blood pressure control still needs to be better clarified, the objective of the study was to characterize the carotid body of patients with controlled and uncontrolled hypertension through a retrospective study of angiotomography. Design and method: For this, CT angiograms of hypertensive patients treated and evaluated at Heart Institute (USP, São Paulo, Brazil) were studied. The evaluated patients were separated into three groups: controlled hypertensive (C-Hyp, receiving up to 2 categories of antihypertensive drugs), resistant hypertensive (receiving 3 or more categories of antihypertensive drugs), with controlled blood pressure (CR-Hyp) and uncontrolled (UnCR -Hyp). CT angiography (Aquilion ONE/PRISM – Canon) of patients undergoing evaluation of cervical arteries with iodinated contrast were evaluated. The reconstructions of the arteries used slices of 0.5mm thickness, with orthogonal measurements of the carotid body to assess the diameters and bilateral carotid bifurcations. Results: The morphology of the common, internal and external carotid arteries was very similar between groups. The mean age of the assessed groups was not significantly different (C-Hyp: 59±14; CR-Hyp: 66±8; UnCR-Hyp: 52±13 years). In the C-Hyp group (n = 29), 24% had uncontrolled blood pressure, perhaps associated with the treatment adjustment process. When assessing the presence of atherosclerotic lesions, the C-Hyp and CR-Hyp groups showed a higher proportion (34% and 40%, respectively), when compared to uncontrolled resistant hypertensive patients (8.3%); however, this lower precentage must be due to the duration of treatment and the control of comorbidities that these patients must undergo. On the other hand, the UnCR-Hyp group showed a reduction in the axial and sagittal measures of the carotid body (1.9±0.3 and 2.8±0.7mm, respectively, -14% and -12%). Conclusions: This reduction observed in the carotid body may be related to a loss of microvascularization (making it difficult to measure on tomography) and interfering with blood pressure control in the UnCR-Hyp group. Further studies, including more patients and normotensive individuals, will be important to define which pattern of changes in the carotid body may be related to the loss of response to antihypertensive treatment.