[Progress in the knowledge on endothelial dysfunction and its application in clinical practice]

Factores que predisponen a la elevación de la tensión arterial en pacientes normotensos operados en cirugía electiva

La estabilidad circulatoria es uno de los propósitos principales durante el acto anestésico-quirúrgico. Por eso, el objetivo propuesto fue determinar la relación de los factores de riesgo identificados, con la elevación de la tensión arterial en pacientes normotensos operados en cirugía electiva, bajo anestesia general orotraqueal. Se realizó un estudio de caso-control con n=88 normotensos que fueron operados en el transcurso del año 2018, distribuidos normalmente (p=0,000) en compensados (n=44) y descompensados (n=44). Se analizaron variables: anestésico-quirúrgicas, factores de riesgo (independientes) y variable dependiente: descompensación hemodinámica (dicotómica). Se realizaron pruebas de hipótesis: Kolmogorov–Smirnov (normalidad), ONEWAY (diferencias tensionales entre grupos) y de asociación: Ji-cuadrado, Fisher y Regresión logística (p<0,05) y Odds Ratio (OR>1). Los resultados fueron representados en tablas y gráficos estadísticos y a través del método de análisis y síntesis fueron expresados textualmente. Se concluye que los antecedentes patológicos personales y familiares, el tabaquismo, cafeísmo, sedentarismo y el hipercolesterolemia constituyen factores de riesgo de hipertensión arterial, que en la medida que se conjugan se produce una potenciación de sus efectos y se elevan considerablemente los riesgos de los pacientes operados en cirugía electiva, aun cuando estos sean considerados como normotensos en la evaluación preoperatoria y al entrar al salón

[Cardiovascular syndrome X and endothelial dysfunction]

Up to 30% of patients with chest pain who undergo coronary arteriography, have completely normal coronary angiograms. The subgroup with typical angina and a positive response to stress testing is generally included under the diagnosis of cardiovascular syndrome X. Several causes and mechanisms have been investigated in the past twenty years, to explain both chest pain and ischemic angina-like ST segment depression that are commonly observed in these patients. Clinical and pathogenic heterogeneity appears to be the main features of the syndrome. Among the suggested pathophysiological mechanisms, endothelial dysfunction of the coronary microcirculation features prominently. In this review, we present the available evidence regarding endothelial dysfunction in cardiovascular syndrome X.

[Endothelial dysfunction in cardiologists after 24 hours on call]

The objective was to determine if the stress caused by 24 hours on call in a cardiology emergency room alters endothelial function assessed by high-resolution ultrasonography in the brachial artery. Fifteen young physicians were studied in a crossover design: a) after a normal night of sleep at home, and b) after 24 hours on call without sleeping in an emergency room. Both studies were made at rest, 5 minutes after forearm occlusion and 3 minutes after administration of sublingual nitroglycerin. High-resolution ultrasonography and a 7.5-MHz linear array transducer were used to measure the brachial artery lumen. After 24 hours on call, physicians had significantly higher resting systolic and diastolic blood pressure. They also had a non-significant increase in heart rate and a lower brachial artery diameter. Brachial artery dilatation caused by hyperemia was only 3.35%, while it increased to 11.34% after normal sleep (p < 0.001). Only 2 physicians showed more than 4.4% dilatation, which was considered a normal response, while 13 had more than 4.4% after a normal night of sleep at home (p < 0.01). The response to nitroglycerin was similar under control conditions and after 24 hours of duty oncall.In conclusion, stress caused by 24 hours on call in a cardiology emergency room depresses or abolishes endothelial function.

[Brachial artery flow-mediated dilation in healthy men, men with risk factors, and men with acute myocardial infarction. Importance of occlusion-cuff position]

INTRODUCTION AND OBJECTIVES

Flow-mediated dilation (FMD) is endothelium-dependent and can be assessed by ultrasound in the brachial artery. We sought to determine the most suitable position for the occlusion cuff for the study of FMD in three groups of adult men.

SUBJECTS AND METHODS

We included 160 subjects, mean age 58.5 7.8 years: 40 healthy subjects, 80 with cardiovascular risk factors, and 40 patients with AMI. In a subgroup of 60 subjects, the first 10, 30, and 20 of each group, respectively, FMD was evaluated twice, after upper arm occlusion and forearm occlusion to induce hyperemia.

RESULTS

In the initial substudy, the FMD after upper arm occlusion was 7.6 2.4% in healthy subjects, 5.1 2.2% in men with risk factors (p < 0.0001), and 3.5 2.2% in AMI patients (p < 0.041, with respect to the risk-factor group). FMD after forearm occlusion was 4.6 1.5%, 2.3 2.1% (p < 0.006), and 2.2 1.9%, respectively, with no significant statistical differences between the risk-factor and AMI groups. Only upper arm occlusion was performed in the remaining participants, as planned, because it provided the most accurate information. Overall, the FMD was, respectively, 7.8 3.1%, 5 2.6% (p < 0.0001) and 3.3 3% (p < 0.004, with respect to the risk-factor group). FMD was directly related to HDL cholesterol and inversely related to resting diameter and number of risk factors.

CONCLUSION

The best approach to studying FMD is proximal occlusion since it allows for a better stratification of the with endothelial dysfunction. With this technique, a worsening of endothelial function in acute myocardial infarction can be demonstrated.

[Interleukin-10 and coronary disease]

Understanding of the pathophysiology of atherosclerosis has changed markedly over the past few decades. It is now widely accepted that inflammation plays a fundamental role in the genesis and development of atherosclerosis. Inflammatory mechanisms also appear to determine clinical presentation and disease outcome. Atherosclerotic lesions have high concentrations of inflammatory cells (T lymphocytes and activated macrophages) as well as an abundance of pro-inflammatory cytokines [interleukin (IL)-1, IL-6, IL-8, interferon-gamma, tumor necrosis factor-alpha, etc.] that modulate local inflammatory responses. These may also alter plaque stability and facilitate the development of acute cardiovascular events. The role of anti-inflammatory cytokines in this context remains to be studied. IL-10 is an anti-inflammatory cytokine synthesised by T-lymphocytes and macrophages and has other anti-inflammatory effects. IL-10 expression within human atherosclerotic plaques has been demonstrated and animal experiments have shown that low levels of IL-10 lead to the development of extensive and unstable atherosclerotic lesions. Currently available evidence suggests a potential protective role for IL-10 in atherosclerosis. This new perspective on coronary disease as a chronic inflammatory process may open new avenues for the management of ischemic heart disease.