Gustavo de León

Nuclear magnetic resonance‐based metabolomics predicts exercise‐induced ischemia in patients with suspected coronary artery disease

The purpose of this study was to develop a 1H‐nuclear magnetic resonance metabolomic approach capable of predicting the occurrence of exercise‐induced ischemia in patients with suspected coronary artery disease and to identify the metabolite patterns that contribute most importantly to the prediction. In 31 patients with suspected effort angina and without previous myocardial infarction, serum was obtained just prior to a stress single‐photon emission computed tomography. Serum NMR spectra were acquired with pulse‐and‐acquire and T2‐edited sequences. The region between 0.50 and 4.25 ppm was used for analysis. Twenty‐two patients had reversible myocardial perfusion defects and nine did not. Both groups had similar age and clinical profile, except for more smokers and diabetics in the ischemia group, and attained a similar peak heart rate. The best separation was achieved with long T2‐edited spectra, 84% of patients being correctly classified based on the partial least square discriminant analysis. The main contributors to discrimination were lactate, glucose, as well as methyl and methylene moieties of lipids and long‐chain amino acids. Metabolomic analysis of serum can predict exercise‐inducible ischemia in patients with suspected coronary artery disease. This capability could be useful in screening and risk stratification of patients with coronary risk factors. Magn Reson Med 60:27–32, 2008.

Silent myocardial ischemia in patients with symptomatic intracranial atherosclerosis: associated factors.

Background and Purpose— Optimization of coronary risk evaluation in stroke patients has been encouraged. The relationship between symptomatic intracranial atherosclerosis and occult coronary artery disease (CAD) has not been evaluated sufficiently. We aimed to investigate the prevalence of silent myocardial ischemia in patients with symptomatic intracranial atherosclerosis and to identify factors associated with its presence. Methods— From 186 first-ever transient ischemic attack or ischemic stroke patients with intracranial stenoses, 65 fulfilled selection criteria, including angiographic confirmation of a symptomatic atherosclerotic stenosis and absence of known CAD. All patients underwent a maximal-stress myocardial perfusion single-photon emission computed tomography (SPECT). Lipoprotein(a) [Lp(a)], C-reactive protein, and homocysteine (Hcy) levels were determined before SPECT. Results— Stress-rest SPECT detected reversible myocardial perfusion defects in 34 (52%) patients. Vascular risk factors associated with a pathologic SPECT were hypercholesterolemia (P=0.045), presence of >2 risk factors (P=0.004) and high Lp(a) (P=0.023) and Hcy levels (P=0.018). Ninety percent of patients with high Lp(a) and Hcy levels had a positive SPECT. Existence of a stenosed intracranial internal carotid artery (ICA; odds ratio [OR], 7.22, 2.07 to 25.23; P=0.002) and location of the symptomatic stenosis in vertebrobasilar arteries (OR, 4.89, 1.19 to 20.12; P=0.027) were independently associated with silent myocardial ischemia after adjustment by age, sex, and risk factors. Conclusions— More than 50% of the patients with symptomatic intracranial atherosclerosis and not overt CAD show myocardial perfusion defects on stress-rest SPECT. Stenosed intracranial ICA, symptomatic vertebrobasilar stenosis and presence of high Lp(a) and Hcy levels may characterize the patients at a higher risk for occult CAD.

Usefulness of Exercise Test and Myocardial Perfusion–Gated Single Photon Emission Computed Tomography to Improve the Prediction of Major Events

Background—The incremental prognostic value of myocardial perfusion–gated single photon emission computed tomography (MPGS) compared with exercise test has not yet been properly evaluated. Methods and Results—Five thousand six hundred seventy-two consecutive patients with known or suspected coronary disease undergoing exercise MPGS between 1997 and 2007 were included. Three-year predictive models for total death and death from cardiovascular causes or acute myocardial infarction (ie, major cardiovascular events [MCE]) were built using Cox-regression modeling, including only the clinical information. Then the exercise and MPGS information was sequentially added. The added discriminative ability of exercise test information and MPGS was assessed by net reclassification improvement and integrated discrimination improvement. The increase in predictive ability of exercise information for death and MCE was high as assessed by net reclassification improvement (0.199 and 0.263) and integrated discrimination improvement (0.042 and 0.021). The only variable of MPGS associated with total death was ejection fraction (hazard ratio, 0.84; 95% confidence interval, 0.79–0.89; P<0.001). Global stress ischemic score emerged as an additional variable associated with MCE (hazard ratio, 1.07; 95% confidence interval, 1.02–1.12; P=0.007). Adding MPGS information barely improved the prognostic value for total death (net reclassification improvement, 0.017; integrated discrimination improvement, 0.013), but it increased for MCE (net reclassification improvement, 0.122; integrated discrimination improvement, 0.033). Conclusions—Adding MPGS information to exercise information does not improve prediction of total death, although it allows a more accurate prediction of MCE.

Variables predictoras de mejoría de la función sistólica ventricular izquierda después de la cirugía de revascularización coronaria en pacientes con miocardiopatía isquémica

INTRODUCTION AND OBJECTIVES Although it is known that the presence of myocardial viability predicts an increase in ejection fraction after revascularization in patients with ischemic cardiomyopathy, little is known about other predictive factors. The aim of this study was to identify variables that can predict an increase in ejection fraction after coronary revascularization surgery in patients with ischemic cardiomyopathy and a viable myocardium. METHODS The study included 30 patients (mean age 61.6 [11] years, one female) with ischemic cardiomyopathy (ejection fraction <or=40%) who fulfilled criteria for myocardial viability. All underwent ECG-gated single-photon emission computed tomography before and after surgery. RESULTS An increase in ejection fraction >or=5% occurred after surgery in 17 of the 30 patients (56.6%). These patients were characterized by the presence of left main coronary artery disease (P< .004), a large number of grafts (P< .03), a high perfusion summed difference score (P< .012), a low end-diastolic volume (P< .013), and a low end-systolic volume (P< .01). An end-systolic volume <148 mL and a summed difference score >or=4 gave the best predictive model (P=.001, R2=0.73) for an increase in ejection fraction. CONCLUSIONS In patients with ischemic cardiomyopathy and a viable myocardium, the main determinants of an increase in ejection fraction after revascularization surgery were low levels of left ventricular remodeling and myocardial ischemia.

Analysis of apical remodeling in gated myocardial perfusion SPECT imaging in ischemic cardiomyopathy

BackgroundA divergent pattern (DP) of the left ventricle (LV) is an expression of apical remodeling in myocardial perfusion gated single-photon emission computed tomography (SPECT) of patients with ischemic cardiomyopathy (ICM).Methods and ResultsWe consecutively studied 156 patients (mean age, 63 years; 24 women) with ICM (LV ejection fraction, ≤40%) using gated SPECT and technetium-labeled agents. Apical remodeling was considered to exist when a DP was observed. Apical remodeling was noted in 30% of patients, all of whom had a history of anterior myocardial infarction. A divergent pattern was observed more frequently in younger patients and in those with ST-segment elevation on their electrocardiograms. The longer the interval between the infarction and the performance of gated SPECT, the more prevalent were the LV dilatation and DP. A divergent pattern was associated with cardiac death and heart failure only in patients with scintigraphic criteria for myocardial viability.ConclusionsA divergent pattern in gated SPECT, as an expression of apical remodeling, can be observed in up to a third of patients with ICM, all with a history of anterior infarction. The longer the time between the infarction and the gated SPECT, the more prevalent the LV dilatation becomes. Apical remodeling is a variable predicts mortality in patients with scintigraphic criteria for viability.

Prevalencia y significado angiográfico de la SPECT de perfusión miocárdica normal con electrocardiograma de esfuerzo positivo

De una serie consecutiva de 7.350 estudios con tomografia computarizada por emision de fotones simples (SPECT) de perfusion miocardica, 66 pacientes (0,9%) con un electrocardiograma (ECG) de base normal y no revascularizados presentaron un estudio gammagrafico normal junto con un ECG positivo en la prueba de esfuerzo. En este estudio analizamos retrospectivamente a los 33 enfermos con estudio coronariografico, de los cuales 26 eran mujeres (p

Prueba de esfuerzo submáxima y atropina en la SPECT de perfusión miocárdica

Introduccion y objetivos El objetivo de este estudio es evaluar la eficacia diagnostica de la tomografia computarizada por emision monofotonica (SPECT) de perfusion miocardica con la administracion de atropina intravenosa al final de una prueba de esfuerzo con insuficiente taquicardizacion. Metodos A 172 pacientes que, a pesar de realizar una prueba ergometrica limitada por sintomas, no alcanzaron un 80% de taquicardizacion, sin presentar angina ni descenso del segmento ST ≥ 1 mm, se les administro 1 mg de atropina intravenosa al final del esfuerzo. A 23 de estos pacientes con criterios de isquemia gammagrafica en la SPECT con atropina, y en el curso de 1 semana, se les practico una segunda SPECT sin la administracion de atropina con la finalidad de comparar la presencia y la gravedad de la isquemia gammagrafica entre los dos estudios (suma puntuacion diferencial [SPD]). Resultados De los 172 pacientes, 75 (43,6%) presentaron angina (n = 56) o descenso del segmento ST (n = 30) con la administracion de atropina. De los 23 pacientes en los que se hicieron ambas pruebas, 8 (35%) tuvieron isquemia (SPD ≥ 2) unicamente en la prueba con atropina. Ademas, la SPD fue significativamente superior en las imagenes de SPECT con atropina (5,6 ± 4,5 frente a 3,1 ± 2,8; p = 0,0001). Conclusiones La administracion de atropina al final de una prueba de esfuerzo insuficiente permite obtener criterios gammagraficos de isquemia en una tercera parte de los casos en que no se habria obtenido sin la administracion del farmaco.

Acute Myocardial Infarction: Estimation of At-Risk and Salvaged Myocardium at Myocardial Perfusion SPECT 1 Month after Infarction

PURPOSE To estimate at-risk and salvaged myocardium by using gated single photon emission computed tomography (SPECT) myocardial perfusion imaging after acute myocardial infarction (AMI). MATERIALS AND METHODS The study was approved by the hospitals Ethical Committee on Clinical Trials (trial register number, PR(HG)36/2000), and all patients gave informed consent. Forty patients (mean age, 61.78 years; eight women) with a first AMI underwent two gated SPECT examinations--one before percutaneous coronary intervention (PCI) and one 4-5 weeks after PCI. Myocardium at risk was estimated by assessing the perfusion defect at the first gated SPECT examination, and salvaged myocardium was estimated by assessing the risk area minus necrosis at the second examination. Myocardium at risk was estimated by determining the discordance between the areas of left ventricular (LV) wall motion and perfusion at the second examination. Concordance between tests was analyzed by means of linear regression analysis, the Pearson correlation, the intraclass correlation coefficient, and Bland-Altman analysis. RESULTS An improvement in perfusion, wall motion, wall thickening, and LV ejection fraction (P < .001) was observed at 1 month. At 1 month, the area with abnormal wall motion was greater than the area of altered perfusion (35.47 vs 23.1 cm(2); P = .007). The extent of myocardium at risk estimated from this discordance correlated well with myocardium at risk measured at the first gated SPECT examination and with salvaged myocardium between both studies (Pearson correlation: 0.78 and 0.6, respectively). Concordance for correct classification of patients with salvaged myocardium of 50% or greater was 83% (κ = 0.65). CONCLUSION Myocardial perfusion gated SPECT performed 1 month after early PCI in a first AMI provides potentially useful information on at-risk and salvaged myocardium. SUPPLEMENTAL MATERIAL http://radiology.rsna.org/lookup/suppl/doi:10.1148/radiol.13122324/-/DC1.

Recomendaciones sobre las maniobras de provocación de isquemia, protocolos de adquisición, interpretación de las imágenes y elaboración de los informes

Las posibilidades actuales de la cardiologia nuclear hacen posible elegir entre multiples opciones de tecnicas y protocolos de esfuerzo o estres farmacologico, adquisicion y procesamiento de las imagenes, en el campo del diagnostico y pronostico de la cardiopatia isquemica y en la valoracion de la viabilidad miocardica. En el presente capitulo se presenta una descripcion de dichas tecnicas y protocolos, y se realizan una serie de recomendaciones sobre la presentacion de los informes, adaptados a nuestro medio.

Recomendaciones sobre las indicaciones clínicas de la gated-SPECT de perfusión miocárdica

Desde 1999 no se habia realizado ninguna revision de las Guias de actuacion clinica de la Sociedad Espanola de Cardiologia en Cardiologia Nuclear, por lo que en este articulo exponemos las indicaciones clase I y IIa de la American College of Cardiology/American Heart Association/American Society of Nuclear Cardiology (ACC/AHA/ASNC) con nivel de evidencia A o B, junto con las 27 indicaciones consideradas adecuadas por el Comite de expertos de la American College of Cardiology Foundation/American Society of Nuclear Cardiology (ACCF/ASNC) y los comentarios que hemos considerado oportuno anadir los firmantes de este articulo.