Estudo comparativo da reatividade vascular em tabagistas, diabeticos e hipertensos

AUTOR(ES)
DATA DE PUBLICAÇÃO

2000

RESUMO

Cigarette smoking, non-insulin-dependent diabetes mellitus and essential hypertension are stablished risk factors for atherosclerosis and premature cardiovascular disease. Heavy smokers, uncompensated diabetics and patients with uncontrolled essential hypertension show impaired arterial vasodilatation which results ftom endothelial dysfunction, a key factor in early atherogenesis.We evaluated the brachial artery diameter and flow in response to mechanical (endothelium-dependent) and pharmacological (endothelium-independent) stimuli in healthy subjects and in groups with smoking, noninsulin-dependent diabetes mellitus (NIDDM) and essential hypertension. Nitrite/nitrate, cGMP and thromboxane B2 levelswere quantified. sixty patients (34M and 26F) aged 22-65 years old (x =48.3) were classified into four groups: 1) Controls-n=15, 2) Heavy smokers-n=15, 3) Uncompensated diabeticsn= 15 (glycemia>140rng/dl and glycosylated haemoglobin >8.0 %), and 4) Patients with uncontrolled essential hypertension - n=15. Brachial artery diameter was measured by a high resolution ultrasound technique before and afier reactive hyperemia and glyceryl trinitrate (Nitrostat, 0.4 mg) administration. Heavy smokers, uncompensated diabetics and uncontrolled hypertensive patients showed impaired flow-dependent vasodilatation (8.0 ± 2.5%, 5.7 ± 2.5% and 7.2 ± 3.3%,respectively) compared to the controls (12.0 ± 3.3%)(p<0.001). Smokers had a normal endothelium-independent response compared to the controls (25.0 ± 78.3% vs 25.5 ± 9.2%). Uncompensated diabetics and patients with uncontrolled essential hypertension had an impaired endothelium independent response (17.2 ± 6.8% and 16.9 ± 6.9%, respectively) compared to the controls (25.5 ± 9.2%)(P<0.005). The levels of cGMP and thromboxane B2 were not different in the four groups, but nitrite/nitrate concentrations also were increased in diabetics compared to the controls (266 ± 47 ? M vs 125 ± 22 ? M) (P<0.005). Smokers, uncompensated diabetics and uncontrolled hypertensive patients showed a similar endothelium-dependent response, but only smokers had unimpaired endothelium-independent functions.

ASSUNTO(S)

endotelio oxido nitrico hipertensão

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