[Predictive value of multi-sliced computed tomography to evaluate obstructive coronary vessel, in the preoperative assessment of non-coronary cardiac surgery]. / Valor predictivo de la tomografía multicorte para evaluar lesiones obstructivas coronarias, en el preoperatorio de cirugía cardiaca no coronaria.

INTRODUCTION: Significant Coronary Artery Disease (CAD>50%) it can easily detected with Multislice Computed Tomography (MSCT), nevertheless if MSCT may replace Invasive Coronary Angiography (ICA) in the preoperative assessment of the patient undergoing to non-coronary cardiac surgery is not well defined. The objective of this study was to know if the MSCT can replace ICA in the preoperative valuation of patients who go to cardiac surgery METHOD: 64 consecutive patients in Class I recommendation of American College of Cardiology / American Heart Association (ACC/AHA) guidelines for preoperative ICA were evaluated. Patients with angina, contrast medium allergy, serum creatinine up to 2.0 mg/dL, previous coronary cardiac surgery or coronary angioplasty and supraventricular arrhythmias were excluded. Both, Coronary artery calcium (CAC) and coronary angiography were evaluated. RESULTS: The prevalence of significant (>50%) CAD was 12.5%. The Sensitivity of MSCT to detect significant CAD was 87.5%, its Specificity of 92.8%, Predictive Negative Value was 98.1% and Area Under the Curve (ROC analysis) = 0.90. Anyone with Rheumatic Valvular Disease had significant CAD or CAC>400 UA (RR = 0.80, IC95% 0.69-0.94). Degenerative Aortic Valve Stenosis had a major probability of significant CAD (RR of 9.0; IC 95% 1.64-49.80). Logistic Regression Analysis showed than CAC>400 UA (Coef ß 0,351, t = 4.402 p = 0.000) and male gender (Coef ß 0,179, t = 2.445, p = 0.017), were the best predicting variables of CAD. This study shows different populations in patients undergoing to non-coronary cardiac surgery. CONCLUSIONS: Gender, CAC> 400 UA and type of cardiac disease previously surgery may be useful for triage to MSCT or ICA in the preoperative assessment. This study shows that ICA may be necessarily indicated in some patients in assessment of non-coronary cardiac surgery but not absolutely indicated in all patients that Guidelines of ACC/AHA have recommended.

Valor predictivo de la tomografía multicorte para evaluar lesiones obstructivas coronarias, en el preoperatorio de cirugía cardiaca no coronaria / Predictive value of multi-sliced computed tomography to evaluate obstructive coronary vessel, in the preoperative assessment of non-coronary cardiac surgery

Introducción: En la actualidad la enfermedad coronaria obstructiva (obstrucción mayor de 50%) puede ser fácilmente evaluada por medio de la tomografía coronaria multicorte. Sin embargo, aún no se define si ésta puede reemplazar a la angiografía coronaria invasiva, en pacientes que van a cirugía cardiaca no coronaria. Objetivo: Conocer si la tomografía coronaria multicorte puede sustituir a la angiografía coronaria invasiva en la detección de enfermedad coronaria en pacientes que van a ser operados de cirugía cardiaca no coronaria; comparando entre si la sensibilidad y especificidad de ambos métodos en la detección de enfermedad coronaria. Método: Se incluyeron consecutivamente 64 pacientes con edades de 55.17 ± 12.73 años, en Clase I de las guías del Colegio Americano de Cardiología/Asociación Americana de Corazón para realizar angiografía coronaria en el preoperatorio de cirugía cardiaca no coronaria. Se excluyeron enfermos con angina de pecho, alergia al medio de contraste, creatinina sérica por arriba de 2.0 mg/dL, que tuvieran previamente cirugía cardiaca o angioplastia coronaria y arritmias supra-ventriculares. Se analizó la anatomía coronaria y se cuantificó la cantidad de calcio coronario. Resultados: La prevalencia de obstrucción coronaria mayor de 50% fue 12.5%. La tomografía coronaria multicorte mostró sensibilidad de 87.5%, especificidad de 92.8%, valor predictivo negativo de 98.1% y área bajo la curva de 0.90, para predecir obstrucción coronaria. Ningún paciente con valvulopatía reumática tuvo obstrucción coronaria mayor de 50% o score de calcio > 400 U A (RR = 0.80, IC 95% 0.69-0.94). La estenosis valvular aórtica degenerativa tuvo mayor probabilidad de obstrucción coronaria mayor de 50% (RR = 9.0: IC 95% 1.64-49.8). Con análisis multivariado usando regresión logística, el score de calcio mayor de 400 UA (Coef ß 0.342, t = 4.297, p = 0.000) y sexo masculino (Coef ß 0.174, t = 2.214, p = 0.031), fueron las variables predictoras de más peso. Este estudio muestra poblaciones diferentes en el grupo de pacientes que van a cirugía cardiaca no coronaria. Conclusiones: El género masculino, el calcio coronario mayor de 400 UA y el tipo de enfermedad cardiaca previa a la cirugía cardiaca no coronaria pueden ser variables útiles para realizar la selección de pacientes que pueden evaluarse con tomografía coronaria multicorte o con angiografía coronaria invasiva. La angiografía coronaria invasiva puede indicarse necesariamente en algunos pacientes que van a cirugía cardiaca no coronaria, pero no es absolutamente necesaria en todos los enfermos como hasta hoy se recomienda en las guías del Colegio Americano de Cardiología y la Asociación Americana de Corazón.

Introduction: Significant Coronary Artery Disease (CAD>50%) it can easily detected with Multislice Computed Tomography (MSCT), nevertheless if MSCT may replace Invasive Coronary Angiography (ICA) in the preoperative assessment of the patient undergoing to non-coronary cardiac surgery is not well defined. The objective of this study was to know if the MSCT can replace ICA in the preoperative valuation of patients who go to cardiac surgery Method: 64 consecutive patients in Class I recommendation of American College of Cardiology / American Heart Association (ACC/AHA) guidelines for preoperative ICA were evaluated. Patients with angina, contrast medium allergy, serum creatinine up to 2.0 mg/dL, previous coronary cardiac surgery or coronary angioplasty and supraventricular arrhythmias were excluded. Both, Coronary artery calcium (CAC) and coronary angiography were evaluated. Results: The prevalence of significant (>50%) CAD was 12.5%. The Sensitivity of MSCT to detect significant CAD was 87.5%, its Specificity of 92.8%, Predictive Negative Value was 98.1% and Area Under the Curve (ROC analysis) = 0.90. Anyone with Rheumatic Valvular Disease had significant CAD or CAC>400 UA (RR = 0.80, IC95% 0.69-0.94). Degenerative Aortic Valve Stenosis had a major probability of significant CAD (RR of 9.0; IC 95% 1.64-49.80). Logistic Regression Analysis showed than CAC>400 UA (Coef ß 0,351, t = 4.402 p = 0.000) and male gender (Coef ß 0,179, t = 2.445, p = 0.017), were the best predicting variables of CAD. This study shows different populations in patients undergoing to non-coronary cardiac surgery. Conclusions: Gender, CAC> 400 UA and type of cardiac disease previously surgery may be useful for triage to MSCT or ICA in the preoperative assessment. This study shows that ICA may be necessarily indicated in some patients in assessment of non-coronary cardiac surgery but not absolutely indicated in all patients that Guidelines of ACC/AHA have recommended.

Effect of ezetimibe-simvastatine over endothelial dysfunction in dyslipidemic patients: assessment by 13N-ammonia positron emission tomography.

BACKGROUND: Dyslipidemias constitute an independent risk factor for the development of atherogenesis and they also predispose to the development of endothelial dysfunction (ED). Using PET with (13)N-ammonia, it is possible to quantify myocardial blood flow (MBF) in mL/min/g and to quantitatively evaluate ED. With the use of lipid lowering therapy it is possible to reduce ED and increase the MBF and the endothelial-dependent vasodilation index (ENDEVI). In this study, we aimed to evaluate with (13)N-ammonia PET the benefic effects of the combined treatment ezetimibe/simvastatine on the endothelial function of dyslipidemic patients after 8 weeks of treatment. MATERIAL AND METHODS: Fourteen consecutive patients with dyslipidemia diagnosis and 17 healthy volunteers were studied with a three phase [rest, Cold Pressor Test (CPT), and adenosine-induced hyperemia] (13)N-ammonia PET for MBF quantification assessment. A second PET study was performed in the dyslipidemic group after 8 weeks of treatment with ezetimibe/simvastatine (10/40 mg). Myocardial flow reserve (MFR), ENDEVI, and %ΔMBF were calculated. RESULTS: Total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides concentrations were markedly altered in the dyslipidemic group and after 8 weeks of treatment these values improved. Dyslipidemic patients showed endothelial dysfunction when compared with the control group, (MFR 2.79 ± 0.94 vs 3.15 ± 0.48, P < 0.05 ; ENDEVI 1.28 ± 0.25 vs 1.53 ± 0.24, P < 0.05; and %ΔMBF 29.08 ± 24.62 vs 53 ± 24.60%, P < 0.05, respectively). After 8 weeks of treatment, we found a significant increase in all the endothelial function markers (MFR: 3.14 ± 0.86, P < 0.05, ENDEVI 1.65 ± 0.23, P < 0.05; %ΔMBF: 65.21 ± 23.43, P < 0.05). CONCLUSIONS: Dyslipidemic patients show endothelial dysfunction measured with (13)N-ammonia PET. Treatment with ezetimibe/simvastatine was effective improving the lipid profile as well as the endothelial function of these patients. PET may be a useful tool to monitor vascular reactivity and regression/progression of coronary atherosclerosis after pharmacologic interventions.

Comparison of 18FDG PET with thallium SPECT in the assessment of myocardial viability. A segmental model analysis.

BACKGROUND: In patients with myocardial infarction and left ventricular dysfunction, the evidence of myocardial viability is primordial. There are some methods to detect the presence of myocardial viability, 201 thallium reinjection SPECT protocol represents the most common radioisotopic technique to evaluate it. Positron emission tomography (PET) using FDG is considered the gold standard. The aim of this study was to compare globally and by segments the value of both techniques in the detection of viable myocardium. METHODS: Twenty-three consecutive patients with previous myocardial infarction and left ventricular dysfunction were studied. All of them underwent into a SPECT perfusion scan and a FDG PET study to asses myocardial viability. Each study was performed in less than one week between the other. For the analysis, the myocardium was divided into 17 segments. A visual semi-quantitative analysis was carried out according to the following score indicating radiotracer uptake: O = normal to 4 = absent. Myocardial viability was defined as the presence of normal, mildly or moderately reduced radiotracer uptake. The scores obtained by PET were compared to those obtained in SPECT. A statistical analysis was performed using the SPSS v. 10. RESULTS: 391 segments were analyzed. PET detected viability in 130 segments that had been defined as non-viable by SPECT. No differences in the analysis by vascular territories were found. Thirty percent of the segments that were defined as non viable by SPECT were viable by PET, meanwhile only 1% of the segments detected viable by SPECT were considered non viable with PET. CONCLUSIONS: FDG PET study represents a better technique to detect myocardial viability, compared to thallium reinjection SPECT protocol. By this study we have demonstrated that more of 3 of each 10 studies may be diagnosed as non viable where viability is present.

Comparison of 18FDG PET with thallium SPECT in the assessment of myocardial viability. A segmental model analysis

BACKGROUND: In patients with myocardial infarction and left ventricular dysfunction, the evidence of myocardial viability is primordial. There are some methods to detect the presence of myocardial viability, 201 thallium reinjection SPECT protocol represents the most common radioisotopic technique to evaluate it. Positron emission tomography (PET) using FDG is considered the gold standard. The aim of this study was to compare globally and by segments the value of both techniques in the detection of viable myocardium. METHODS: Twenty-three consecutive patients with previous myocardial infarction and left ventricular dysfunction were studied. All of them underwent into a SPECT perfusion scan and a FDG PET study to asses myocardial viability. Each study was performed in less than one week between the other. For the analysis, the myocardium was divided into 17 segments. A visual semi-quantitative analysis was carried out according to the following score indicating radiotracer uptake: O = normal to 4 = absent. Myocardial viability was defined as the presence of normal, mildly or moderately reduced radiotracer uptake. The scores obtained by PET were compared to those obtained in SPECT. A statistical analysis was performed using the SPSS v. 10. RESULTS: 391 segments were analyzed. PET detected viability in 130 segments that had been defined as non-viable by SPECT. No differences in the analysis by vascular territories were found. Thirty percent of the segments that were defined as non viable by SPECT were viable by PET, meanwhile only 1% of the segments detected viable by SPECT were considered non viable with PET. CONCLUSIONS: FDG PET study represents a better technique to detect myocardial viability, compared to thallium reinjection SPECT protocol. By this study we have demonstrated that more of 3 of each 10 studies may be diagnosed as non viable where viability is present.

[Evaluation of coronary flow by means of PET in the Mexican population without coronary artery disease]. / Valoración del flujo coronario mediante PET en lapoblación mexicana sin enfermedad arterial coronaria.

UNLABELLED: Coronary artery disease (CAD) represents the principal cause of morbidity and mortality in our environment. Positron emission tomography (PET) is a new technique in our country that allows the assessment of myocardial perfusion and the absolute quantification of the coronary blood flow (CBF) through the utilization of radiotracers using the same criteria employed in conventional nuclear cardiology. CBF normal values have been determined in other populations around the world. No studies in our country assessing in a non-invasive way the CBF have been published before. The quantification of CBF in healthy population is important to establish a standard measure and determine through it, the effects of the many diseases that change the coronary blood flow. The quantification of the CBF, the calculation of coronary blood flow reserve (CFR) and the endothelium dependent vasodilatation index (EDVI) through PET is possible performing three different acquisition stages: rest, cold pressor test (CPT) and pharmacologic stress using Ammonia as radiotracer. The aim of this study was to evaluate the CBF, the CFR and the EDVI in healthy Mexican volunteers. RESULTS: Global basal CBF was 0.34 (+/- 0.09) mL/g/min, during CPT increased to 0.55 (+/- 0.17) mL/g/min and during the stress increased to 1.18 (+/- 0.25). CFR was 3.5 (+/- 0.65) and EDVI was 1.55 (+/- 0.33). CONCLUSIONS: CFR and EDVI values obtained in Mexican healthy population correlates very well with those reported in the literature. This values represents a reference to further research that use this technology.

Valoración del flujo coronario mediante PET en la población mexicana sin enfermedad arterial coronaria / Evaluation of coronary flow by means of PET in the Mexican population without coronary artery disease

La enfermedad arterial coronaria (EAC) representa la primera causa de morbi mortalidad en nuestro medio. La tomografía por emisión de positrones (PET) es una técnica novedosa en nuestro país mediante la cual es posible valorar la perfusión miocárdica a través de radiotrazadores, lo que permite detectar defectos de perfusión utilizando los mismos criterios que en cardiología nuclear. A su vez, a través del estudio del flujo coronario (FC) es posible detectar la EAC en sus etapas más tempranas. El FC ha sido determinado en otras poblaciones a nivel mundial, sin embargo, hasta el momento no existen estudios en nuestro país que lo hayan valorado de manera no invasiva. La importancia de determinar el FC en voluntarios sanos radica en establecer una base para poder comparar estos resultados con los encontrados en pacientes con diferente patología que afecte el flujo coronario. Para la determinación del FC y la reserva de flujo coronario (RFC) y del índice de vasodilatación dependiente de endotelio (IVED) mediante PET se realizan 3 mediciones en 3 fases distintas: reposo, estimulación con frío (CPT) y esfuerzo farmacológico, con la utilización de amonio. Objetivo: Determinar el FC en las tres fases en población sana con la utilización de amonio-PET. Resultados: El FC global basal fue de 0.34 (±0.09) mL/g/min, durante el CPT incrementó a 0.55 (±0.17) mL/g/min y con el estrés llegó a 1.18 (±0.25). La RFC fue de 3.5 (±0.65) y el IVED de 1.55 (±0.33). Conclusiones: Los valores obtenidos de RFC y de IVED en población mexicana sana coincide con los reportados en la literatura. Estos valores representan una base de referencia para las investigaciones futuras con esta tecnología en nuestro país.

Coronary artery disease (CAD) represents the principal cause of morbidity and mortality in our environment. Positron emission tomography (PET) is a new technique in our country that allows the assessment of myocardial perfusion and the absolute quantification of the coronary blood flow (CBF) through the utilization of radiotracers using the same criteria employed in conventional nuclear cardiology. CBF normal values have been determined in other populations around the world. No studies in our country assessing in a non-invasive way the CBF have been published before. The quantification of CBF in healthy population is important to establish a standard measure and determine through it, the effects of the many diseases that change the coronary blood flow. The quantification of the CBF, the calculation of coronary blood flow reserve (CFR) and the endothelium dependent vasodilatation index (EDVI) through PET is possible performing three different acquisition stages: rest, cold pressor test (CPT) and pharmacologic stress using Ammonia as radiotracer. The aim of this study was to evaluate the CBF, the CFR and the EDVI in healthy Mexican volunteers. Results: Global basal CBF was 0.34 (±0.09) mL/g/min, during CPT increased to 0.55 (±0.17) mL/g/min and during the stress increased to 1.18 (±0.25). CFR was 3.5 (±0.65) and EDVI was 1.55 (±0.33). Conclusions: CFR and EDVI values obtained in Mexican healthy population correlates very well with those reported in the literature. This values represents a reference to further research that use this technology.

[Positron emission tomography (PET): a useful tool for the assessment of cardiac metabolism]. / Tomografía por emisión de positrones (PET): Una herramienta util para el estudio del metabolismo cardiaco.

Under normal conditions, myocardial metabolism is based on the oxidation of fatty acids and in a lesser extent carbohydrates. Cardiac function depends upon an adequate supplement of adenosine triphosphate (ATP) by these substrates. However, the main source of energy is susceptible to change upon a various physiologic (exercise) as well as pathologic (ischemia-reperfusion) conditions. Recently, carnitine has gained attention as a modulator of fatty acids and carbohydrates metabolism by means of modifying intramitochondrial Acetyl-CoA/CoA ratio. Disturbances in fatty acids and carbohydrates metabolism in the myocardium have been associated with cardiovascular diseases (chronic ischemic disease, ventricular hypertrophy and dilated cardiomyopathy). The evaluation of cardiac metabolism attains great value regarding diagnosis, treatment and prognosis of these diseases. Currently, positron emission tomography (PET) is one of the preferred methods to evaluate cardiac energy metabolism in clinical practice. In PET images the tracers most commonly used are 11C-palmitate, 11C-acetate y 18Fluoro-2-deoxyglucose (FDG), the first two are employed to assess fatty acids oxidation and FDG is used to evaluate carbohydrates metabolism.

Tomografía por emisión de positrones (PET): Una herramienta útil para el estudio del metabolismo cardiaco / Positron emission tomography (PET): A useful tool for the assessment of cardiac metabolism

En condiciones normales el metabolismo energético del corazón se basa en la oxidación de ácidos grasos y en menor proporción de carbohidratos. La función cardiaca depende del suplemento adecuado de trifosfato de adenosina (ATP) proveniente de dichos sustratos. Sin embargo, la fuente principal de energía está sujeta a modificación porfactorestanto fisiológicos (ejercicio) como patológicos (isquemia-reperfusión). Recientemente, se ha puesto gran atención al papel de la carnitina como regulador del metabolismo de ácidos grasos y carbohidratos mediante la modulación de la relación intramitocondrial de acetil-CoA/CoA. Las alteraciones en el metabolismo de carbohidratos y ácidos grasos a nivel miocárdico se han asociado al desarrollo de diversas patologías cardiovasculares (cardiopatía isquémica, hipertrofia ventricular, y miocardiopatía dilatada) por lo cual el estudio del metabolismo cardiaco cobra gran relevancia para el diagnóstico, y pronóstico de estas patologías. Dentro de la práctica clínica, la tomografía por emisión de positrones (PET) es una de las técnicas más empleadas para la evaluación del metabolismo cardiaco. Los radiotrazadores más ampliamente empleados en imagen PET son "C-palmitato, "C-acetato y 18Fluoro-2-desoxiglucosa (FDG), los dos primeros se emplean para el estudio del metabolismo oxidativo de los ácidos grasos y la FDG nos permite estudiar el metabolismo de carbohidratos.

Under normal conditions, myocardial metabolism is based on the oxidation of fatty acids and in a lesser extent carbohydrates. Cardiac function depends upon an adequate supplement of adenosine triphosphate(ATP) by these substrates. However, the main source of energy is susceptible to change upon a various physiologic (exercise) as well as pathologic (ischemia-reperfusion) conditions. Recently, carnitine has gained attention as a modulator of fatty acids and carbohydrates metabolism by means of modifying intramitochondrial Acetyl-CoA/CoA ratio. Disturbances in fatty acids and carbohydrates metabolism in the myocardium have been associated with cardiovascular diseases (chronic ischemic disease, ventricular hypertrophy and dilated cardiomyopathy). The evaluation of cardiac metabolism attains great value regarding diagnosis, treatment and prognosis of these diseases. Currently, positron emission tomography (PET) is one of the preferred methods to evaluate cardiac energy metabolism in clinical practice. In PET images the tracers most commonly used are "C-palmitate, "C-acetate y 18Fluoro-2-deoxyglucose (FDG), the first two are employed to assess fatty acids oxidation and FDG is used to evaluate carbohydrates metabolism.