RESUMO
This aim of this study was to evaluate the presence of endothelial dysfunction in patients with primary hypertension and to determine the usefulness of nebivolol, a selective beta-adrenoceptor blocking agent, as a potential treatment for endothelial dysfunction. Of 176 patients with stage I hypertension, 36 patients (20%), the majority of whom were overweight/obese, were found to have abnormal results with myocardial perfusion single-photon emission computed tomography (MP-SPECT) under cold pressor test conditions. These 36 patients were treated for 28 days with 5 mg/d nebivolol, after which only 3 (8.3%) still had abnormal MP-SPECT results. The mean ischemia score was consistent with moderate risk and decreased significantly after treatment with nebivolol. All hemodynamic variables measured (systolic and diastolic blood pressure and heart rate) were also reduced significantly by treatment with nebivolol. Endothelial dysfunction plays a key role in the pathogenesis of atherosclerosis and its reversal has considerable implications for clinical outcomes in affected patients. The cold pressor testing results of this study suggest that nebivolol may have beneficial anti-ischemic effects in the coronary arteries of patients with hypertension. However, these findings need to be confirmed in larger randomized controlled trials, ideally comparing nebivolol with other blood pressure lowering agents or NO synthase inhibitors.
Assuntos
Antagonistas Adrenérgicos beta/uso terapêutico , Anti-Hipertensivos/uso terapêutico , Benzopiranos/uso terapêutico , Endotélio Vascular/efeitos dos fármacos , Etanolaminas/uso terapêutico , Hipertensão/tratamento farmacológico , Antagonistas Adrenérgicos beta/administração & dosagem , Adulto , Idoso , Benzopiranos/administração & dosagem , Endotélio Vascular/diagnóstico por imagem , Endotélio Vascular/fisiopatologia , Etanolaminas/administração & dosagem , Feminino , Hemodinâmica/efeitos dos fármacos , Humanos , Hipertensão/diagnóstico por imagem , Hipertensão/fisiopatologia , Masculino , Pessoa de Meia-Idade , Nebivolol , Sistema de Registros , Tomografia Computadorizada de Emissão de Fóton ÚnicoRESUMO
Introducción Estudios previos han publicado la correlación entre defectos de perfusión miocárdica (PM) SPECT durante la prueba de frío (PF) y la acetilcolina intracoronaria y su utilidad como marcador independiente de disfunción endotelial (DE). Objetivo Analizar la incidencia de positivización de los estudios de PM de esfuerzo en el seguimiento de pacientes asintomáticos con riesgo cardiovascular (CV) moderado y DE detectada con la PF. Material y métodos De 301 pacientes del Registro PARADIGMA (PM SPECT esfuerzo normal y probabilidad clínica < 20% de eventos a 10 años [riesgo moderado por índice de Framingham]), 55 tuvieron PF positiva (+) (18,3%). Se analizaron en forma prospectiva y consecutiva 15 pacientes asintomáticos con PF (+) y un grupo control (GC) de 15 pacientes con PF negativa (-), con apareamiento de sexo, edad y factores de riesgo coronario (FRC), que cumplieron un seguimiento de 12 ± 2 meses, en quienes se realizó una nueva PM SPECT de reposo y esfuerzo. Se utilizó un score de extensión de PM en un modelo de 17 segmentos. Se analizaron los FRC y la incidencia de isquemia en la PM de esfuerzo de seguimiento en cada grupo. Resultado Edad: PF (-) 57,3 ± 8,9 versus TF (+) 52,5 ± 7,5 (p = 0,09). Positivizaron la PM de esfuerzo: grupo PF (+) 5/15: 33,3% y 0 del GC (p = 0,04). Sin diferencias estadísticamente significativas en los FRC entre ambos grupos. Conclusiones Una PM SPECT anormal durante la PF en pacientes asintomáticos con riesgo CV moderado diferenció a aquellos pacientes que positivizaron los estudios de PM de esfuerzo a un año de seguimiento y no hubo estudios anormales en el grupo control.
Introduction Previous studies have published the correlation between myocardial perfusion SPECT (MP) during cold pressor test (CPT) and intracoronary acetylcholine and its usefulness as independent marker of endothelial dysfunction (ED). Objective To analyze the incidence of positivization of MP exercise studies in the follow up of asymptomatic patients with moderate cardiovascular risk (CV) and ED detected by PF. Material and Methods Of 301 patients of the PARADIGMA Registry (normal exercise MP SPECT and clinical probability < 20% of events at 10 years [moderate risk by Framingham index] 55 had positive PF (+) (18.3%). Prospectively and consecutively, 15 asymptomatic patients with PF (+), and a control group (CG) of 15 patients with negative PF, with paired sex, age and coronary risk factors (CRF), that accomplished a 12 ± 2 months follow up, and that underwent a new exercise and resting MP SPECT were analyzed. An MP extension score was used in a model of 17 segments. The CRF and the incidence of ischemia during follow up exercise MP of each group were assessed. Results Age: PF (-) 57.3 ± 8.9 versus TF (+) 52.5 ± 7.5 (p = 0,09). Positivized the exercise MP: PF group (+) 5/15: 33.3% and 0 in the CG (p=0.04). No statistically significant differences between CRF in both groups. Conclusions An abnormal MP SPECT during PF in asymptomatic patients with moderate CV risk differentiated those patients who positivized exercise MP studies at one year follow up and there were no abnormal studies in the control group.