ABSTRACT
Abstract: This manuscript is an addendum to the positioning around the diagnosis and treatment of dyslipidemias of ANCAM and the joint group of associated medical societies, already published. It is the first part of a wider reflection aimed on refute several of the theses and arguments of a group of clinicians and researchers who question the validity of the "cholesterol hypothesis", the usefulness and safety of statins and the most modern inhibitors of proprotein convertase of subtilisin/kexin type 9 (iPCSK9,) and the role of saturated fatty acids consumed in the usual diet in the atherosclerotic risk. This iconoclastic point of view is dangerous insofar as it undermines the scaffolding that supports the primary and secondary prevention of atherosclerosis. In this section of the manuscript, only the cholesterol hypothesis is discussed. The data of comparative zoology are reviewed, and several experimental animal models are analyzed, both supporting the link between cholesterol and the appearance and evolution of atherosclerotic lesions. The methodology and the results of the Study of the 7 Countries are defended and are exposed the numerous epidemiological, pathological, clinical and interventional evidences, which in our opinion give a solid sustenance to the cholesterol hypothesis. Based on this knowledge it is criticized the LDL cholesterol values currently considered adequate. Furthermore, the so-called residual risk is considered, as well as the conflicting evidence about the usefulness of statins in elderly patients.
Resumen: Este manuscrito es un apéndice del posicionamiento en torno al diagnóstico y tratamiento de las dislipidemias de la ANCAM y el grupo de las sociedades médicas asociadas, previamente publicado. Es la primera parte de un trabajo más amplio enfocado a refutar varias de las tesis y argumentos de un grupo de clínicos e investigadores que ponen en duda la validez de la "hipótesis del colesterol", la utilidad y seguridad de las estatinas y los más modernos inhibidores de la proproteína convertasa de la subtilisina/kexina tipo 9 (iPCSK9) y el papel de los ácidos grasos saturados consumidos en la dieta habitual en el riesgo ateroscleroso. Este punto de vista iconoclástico es peligroso porque socava el andamiaje que soporta la prevención primaria y secundaria de la aterosclerosis. En esta primera sección del manuscrito, se discute sólo la hipótesis del colesterol. Se revisan los datos de zoología comparada y se analizan varios modelos animales de experimentación, que apoyan la liga entre el colesterol y la aparición y evolución de las lesiones aterosclerosa. Se defienden la metodología y los resultados del estudio de los 7 países y se exponen las numerosas evidencias epidemiológicas, patológicas, clínicas e intervencionistas, que a nuestro juicio dan un sustento sólido a la hipótesis del colesterol. Se critican también, en base a ese conocimiento, los valores de colesterol LDL actualmente considerados adecuados, a la vez que se discute el llamado riesgo residual y las evidencias conflictivas acerca de la utilidad de las estatinas en pacientes ancianos.
ABSTRACT
Abstract Background: Remote ischemic preconditioning (RIPC) represents an attractive therapy for myocardial protection, particularly when ischemic events can be anticipated. Although several hypothetic mechanisms have been proposed, no definite molecular pathways have been elucidated. Objective: We evaluated the effect of brachial circulation cuff occlusion on myocardial ischemic tolerance, necrosis, and nitric oxide (NO) in patients with ischemic heart disease undergoing elective percutaneous coronary interventions (PCI). Methods: 46 patients were randomly allocated into two groups: control and RIPC before PCI procedures. Electrocardiographic analysis, serum concentrations of troponin I (cTn-I) were measured at baseline and 24 hours after PCI. A blood sample from the atherosclerotic plaque was drawn to determine nitrate and nitrites. Results: RIPC increased the availability of NO in the stented coronary artery. Control patients presented a small but significant increase in cTn-I, whilst it remained unchanged in preconditioned group. The preconditioning maneuver not only preserved but also enhanced the sum of R waves. Conclusions: RIPC induced an intracoronary increase of NO levels associated with a decrease in myocardial damage (measured as no increase in cTn-I) with electrocardiographic increases in the sum of R waves, suggesting an improved myocardium after elective PCI.
Resumo Fundamento: Pré-condicionamento isquêmico remoto (PCIR) é uma terapia para proteção miocárdica, em particular quando é possível prever eventos isquêmicos. Embora vários mecanismos hipotéticos tenham sido propostos, nenhuma via molecular definitiva foi elucidada. Objetivo: Avaliar o efeito da oclusão da circulação braquial com manguito sobre a tolerância à isquemia miocárdica, a necrose miocárdica e a biodisponibilidade de óxido nítrico (NO) em pacientes com cardiopatia isquêmica submetidos a intervenção coronariana percutânea (ICP) eletiva. Métodos: 46 pacientes foram alocados aleatoriamente em dois grupos: controle e PCIR antes da ICP. Análise eletrocardiográfica e medidas da concentração sérica de troponina I (cTn-I) foram realizadas na condição basal e 24 horas após ICP. Coletou-se amostra de sangue da placa aterosclerótica para determinar os níveis de nitratos e nitritos. Resultados: O PCIR aumentou a disponibilidade de NO na artéria coronária que recebeu o stent. O grupo controle apresentou um aumento pequeno, mas significativo, da cTn-I, que permaneceu inalterada no grupo pré-condicionado. O pré-condicionamento não só preservou, como melhorou o somatório de ondas R no eletrocardiograma. Conclusões: O PCIR induziu aumento intracoronariano dos níveis de NO associado com redução do dano miocárdico (medido como aumento da cTn-I) e com aumento do somatório de ondas R, sugerindo melhora miocárdica após ICP eletiva.