RESUMO
The importance of cardiac autonomic neuropathy (CAN) derives from its remarkable frequency and its clinical impact. The clinical features are postural hypotension and resting tachycardia, these abnormalities may be overlooked in a high number of patients asymptomatic. Although rarely life threatening, CAN causes considerable morbidity, which can be ameliorated by its identification and appropriate treatment. Circulatory reflexes were studied in 48 diabetic patients and 14 normal control subjects. Twenty-six of the diabetic patients had normal response. The remaining 22 had evidence of neuropathy and abnormal cardiac response during these tests. Only one patient had postural syncope but he had severe orthostatic hypotension. The others remained asymptomatic. All the control subjects had normal reflexes. Beat-to-beat variation with deep breathing (sinus arrhythmia), carotid body massage and mental stress, were important for the detection of CAN (86, 90 and 90% sensitivity respectively). The Valsalva maneuver and sinus arrhythmia showed 82 and 92% of specificity for the diagnosis of CAN. Our findings suggest that CAN in diabetic patients can be detected by these relatively simple test. We propose a rational approach to the diagnosis. Our method is applicable as a clinical routine examination for cardiac neuropathy.
Assuntos
Neuropatias Diabéticas/diagnóstico , Hipotensão Ortostática/diagnóstico , Taquicardia/diagnóstico , Adulto , Idoso , Arritmia Sinusal/diagnóstico , Arritmia Sinusal/etiologia , Pressão Sanguínea , Corpo Carotídeo/fisiopatologia , Teste de Esforço , Feminino , Frequência Cardíaca , Humanos , Hipotensão Ortostática/etiologia , Masculino , Pessoa de Meia-Idade , Estresse Psicológico/fisiopatologia , Taquicardia/etiologia , Manobra de ValsalvaRESUMO
Surgical correction of renovascular hypertension was studied in 16 patients. In all the patients severe high blood pressure and stenosis of at least one renal artery was demonstrated; in 14 patients plasma renin activity (PRA) in renal veins and peripheral blood was measured. All cases were followed for 36 to 48 months after surgical treatment. Blood pressure was normalized after surgical treatment (2 aortorenal bypasses, 2 nephrectomies and 7 autotransplants) in 7 patients, all of them had hyperreninemia, hypersecretion from the stenotic kidney and suppression of the contralateral kidney. In one patient with stenosis of one renal artery, blood pressure was normalized after surgery, even though no alterations in renin secretion was demonstrated. Surgery (1 bypass, 2 nephrectomies, 1 autotransplant and 1 aortorenal anastomosis) induced a decrease in blood pressure in five patients, all had normal PRA in peripheral blood and hypersecretion from the stenotic kidney. Three patients remained hypertensive in spite of nephrectomy of the stenotic kidney all had hyperreninemia without lateralization. In two patients renal failure was evident from the time they entered the study; both had hyperreninemia, lateralization and suppression of the contralateral kidney, one improved with nephrectomy of stenotic kidney and hemi-nephrectomy of the contralateral and the other remained hypertensive after nephrectomy. The initial status of renin secretion has prognostic value for the response to surgical treatment of renovascular hypertension.