Assessment of endothelial function by means of flow-mediated changes using pulse wave velocity.

Endothelial dysfunction is a leading cause of early development of cardiovascular diseases. Endothelial function can be assessed using ultrasound methods to watch the arterial flow-mediated dilation. It is also possible to find changes in pulse wave velocity (PWV) after induced ischemia related to the vessel diameter changes. Pre- and post-induced ischemia carotid-radial PWV was recorded in 226 hypertensive patients (150 women [63.5+/-12.4 years old] and 76 men [63.2+/-11.8 years old] and 55 healthy patients (38 women [63.1+/-12.6 years old] and 17 men [54.8+/-12.8 years old]). The authors considered normal endothelial function a PWV reduction of 5% from baseline. To assess nondependent endothelial dilation the authors performed carotid-radial PWV after sublingual administration of 5 mg of isosorbide dinitrate in a group of patients with abnormal flow-mediated dilation. A significant PWV reduction of 9.8% in normal patients and only 1.2% among hypertensive patients (P<.0005) was found. After sublingual isosorbide dinitrate intake the authors observed a greater fall in PWV (14%) than that observed in healthy people after induced ischemia. Carotid-radial PWV after induced ischemia decreased significantly in normal participants. No significant changes were observed in hypertensive patients. These results may offer a reliable tool to assess endothelial function in medium-size arteries.

La velocidad de la onda del pulso como método para evaluar la función endotelial / Evaluation of Endothelial Function through Pulse Wave Velocity

Introducción La disfunción endotelial está presente precozmente en la aterosclerosis y constituye la base fisiopatológica de ella y de la enfermedad cardiovascular (CV). La función endotelial puede estudiarse por ultrasonografía, que permite observar la vasodilatación mediada por flujo (VMF). También puede evaluarse por el cambio en la velocidad de la onda del pulso (VOP), que de acuerdo con la ecuación de Moens-Korteweg concuerda con los resultados obtenidos por otros métodos. Objetivos Investigar la función endotelial a través de las variaciones de la velocidad de la onda del pulso (VOP) carótido-radial preinducción y posinducción de isquemia braquial. Material y métodos La VOP carótido-radial se determinó en 248 pacientes hipertensos (160 mujeres, 63,6 ± 12,3 años y 88 hombres, 63,1 ± 11,6 años) y en 56 normotensos (38 mujeres, 63,1 ± 12,6 años y 18 hombres, 56,1 ± 13,7 años). Se consideró respuesta endotelial normal la reducción de la VOP > 5%. En pacientes con respuesta anormal se realizó la medición luego de la administración de 5 mg de dinitrato de isosorbide sublingual con el objeto de registrar la vasodilatación no dependiente del endotelio como forma de validación del método. Resultados La VOP se redujo el 9,3% en promedio en el grupo de sujetos sanos, mientras que en los pacientes esta reducción fue de sólo el 1,5% (p < 0,0005). La reducción de la VOP con dinitrato de isosorbide sublingual fue aún mayor que la de los individuos normales (18,2%) (p < 0,0001). Conclusiones La medición de la VOP carótido-radial preinducción y posinducción de isquemia discriminó el comportamiento endotelial entre personas normotensas e hipertensas. Este hallazgo consolida su utilidad para la medición de la función endotelial.

Background Endothelial dysfunction occurs early in the development of atherosclerosis and constitutes the physiopathologic basis of this condition and of cardiovascular disease (CVD). Ultrasound is useful to study endothelial function through the assessment of flow-mediated dilation (FMD). Endothelial function may also be evaluated by the change in pulse wave velocity (PWV) with results that are similar to those obtained by other methods according to the Moens-Korteweg equation. Objectives To evaluate endothelial function through the changes in the carotid-radial PWV before and after inducing ischemia at the level of the brachial artery. Material and Methods Carotid-radial PWV was determined in 24 hypertensive patients (160 women, 63.6±12.3 years and 88 men, 63.1±11.6 years) and in 56 controls (38 women, 63.1±12.6 years and 18 men, 56.1±13.7 years). A reduction in PWV <5% was considered a normal endothelial response. Patients with abnormal response received 5 mg of sublingual isosorbide dinitrate to evaluate endothelium-independent vasodilation for validation of the method. Results An average reduction by 9.3% was recorded in healthy subjects compared to a reduction by 1.5% in hypertensive patients (p<0.0005). The reduction in PWV after the administration of sublingual isosorbide dinitrate was even greater compared to normal subjects (18.2%) (p<0.0001). Conclusions The measurement of carotid-radial PWV before and after inducing ischemia is a reliable method to evaluate endothelial function.

Continuous improvement of arterial compliance beyond blood pressure decrease after 5 years of antihypertensive treatment.

Pulse wave velocity is a reliable marker of arterial compliance. Stiffness of large and elastic arteries leads to a faster propagation of pulse wave. The aim of this study was to evaluate changes in arterial distensibility using antihypertensive drugs. This treatment focused on the inhibition of the renin-angiotensin-aldosterone system and the changes produced in blood pressure. Measurements were taken at baseline and throughout 60 months in 66 previously untreated hypertensive patients (22 men and 44 women, aged 54 +/- 9.5 years, range 38-73 years at baseline). All patients received either angiotensin-converting enzyme inhibitors or, in case of adverse effects, angiotensin receptor blockers. To control blood pressure, diuretics, calcium channel blocking agents, or beta blockers were added when appropriate. Statistical analysis was performed by means of ANOVA with alpha = 0.05. Systolic and diastolic blood pressure decreased during the first year without significant changes thereafter. There were no significant changes in pulse pressure. Pulse wave velocity showed a continuous and significant decrease throughout the follow-up period, but its reduction since the third year was more evident than the decrease in systolic and diastolic blood pressure (p < 0.0001 for both). This observation could be related to changes in arterial remodeling probably due to angiotensin-converting enzyme inhibition or renin angiotensin system blockade. Further investigations are needed to establish this relationship.