ABSTRACT
RESUMEN Introducción: La utilidad de la resonancia magnética cardíaca (RMC) ha crecido ampliamente en los últimos años, en los cuales se han publicado distintos registros internacionales sobre su uso e impacto clínico. Sin embargo, no contamos con este tipo de información en Argentina. Objetivo: Evaluar indicaciones, protocolos utilizados, seguridad y consecuencias terapéuticas de la RMC en la República Argentina. Material y métodos: Se diseñó un registro prospectivo a nivel nacional con recolección de datos demográficos, indicaciones de RMC, complicaciones asociadas, diagnósticos y consecuencias terapéuticas. Resultados: Participaron 34 centros de 10 provincias de Argentina (85% centros privados, 59% centros con internación). Se incluyeron 1131 pacientes (edad 54 ± 18 años, 61% varones). Las principales indicaciones para el estudio de RMC fueron la miocardiopatía hipertrófica (13,9%) y la arritmia ventricular (12,3%). El 99,7% de los estudios fueron reportados sin complicaciones. Los resultados más frecuentes de la RMC fueron: normal (31,2%), miocardiopatía no isquémica (14,7%), miocardiopatía isquémico-necrótica (11,6%) y miocardiopatía hipertrófica (8,9%). La sospecha clínica fue confirmada en el 23,6% de los casos y la RMC generó un diagnóstico nuevo no sospechado en el 48,7% de los casos. Las consecuencias terapéuticas más frecuentes fueron el alta hospitalaria (31,6%) seguida por el cambio en la medicación (28,1%). Conclusiones: La RMC es un estudio ampliamente utilizado en Argentina, principalmente en centros privados, con un número muy bajo de complicaciones. Las principales indicaciones son las miocardiopatías (hipertrófica y dilatada) y la arritmia ventricular, y provee un diagnóstico nuevo no sospechado en casi la mitad de los casos. Se requieren de otros estudios en el futuro para evaluar las implicancias clínicas y terapéuticas.
ABSTRACT Background: The usefulness of cardiac magnetic resonance imaging (MRI) has greatly increased in the last years. Different international registries have been published on its use; however, there is no data available from Argentina. Objective: The aim of this study was to evaluate different indications, protocols, safety and therapeutic consequences of cardiac MRI in Argentina. Methods: A prospective national registry was designed with collection of demographic data, indications for cardiac MRI, associated complications, diagnoses and therapeutic consequences. Results: A total of 34 centers from 10 provinces of Argentina (85% private and 59% with inpatient capacity) participated in the study, including 1131 patients (mean age 54±18 years and 61% males). The main indications for cardiac MRI were hypertrophic cardiomyopathy (13.9%), and ventricular arrhythmia (12.3%). In 99.7% of cases, no study complications were reported. The most frequent results of cardiac MRI were: normal (31.2%), non-ischemic cardiomyopathy (14.7%), ischemic-necrotic cardiomyopathy (11.6%) and hypertrophic cardiomyopathy (8.9%). Clinical suspicion was confirmed in 23.6% of cases and cardiac MRI generated an unsuspected new diagnosis in 48.7% of cases. The main therapeutic consequences were hospital discharge (31.6%) followed by change in medication (28.1%). Conclusions: Cardiac MRI is widely used in Argentina, mainly in private centers with a very low incidence of complications. Cardiomyopathies (hypertrophic and dilated) and ventricular arrhythmia are its main indication, and it provides a new unsuspected diagnosis in almost half of the cases. Further studies are required to assess its clinical and therapeutic impact.
ABSTRACT
OBJECTIVES: Cardiovascular magnetic resonance (CMR) provides information on myocardial ischemia through stress perfusion studies. In clinical practice, the grading of induced perfusion defects is performed by visual estimation of their extension. The aim of our study is to devise a score of the degree of ischemia and to test its prognostic value. METHODS: Between 2009 and 2011, patients with diagnosed or suspected coronary artery disease underwent stress perfusion CMR. A score of ischemic burden was calculated on the basis of (1) stress-induced perfusion defect, (2) persistence, (3) transmurality, and (4) stress-induced contractile defect. Follow-up was censored after 4 years and primary end-point was defined by a composite of death, heart failure episode, acute coronary syndrome, and ventricular arrhythmias. Univariate and multivariate logistic regressions were used to assess the strength of the association between the CMR ischemic variables, and the composite outcome. RESULTS: Forty-four of the 128 patients (34%) presented with adverse events, while 84 (66%) did not. Sixty-one patients (48%) had negative perfusion studies while 67 (52%) showed perfusion defect. Patients with positive perfusion studies and adverse events (n = 39) had higher number of segments with persistent defect (3.3 vs 1.3, p = 0.001) and highest score (19.6 vs 13.3 p = 0.012) than patients with positive perfusion studies and absence of events (n = 28). The number of segments with persistent defect showed the strongest predictive value of adverse events (OR 1.54; CI 1.19-2.00; p < 0.001). CONCLUSIONS: The score of ischemic burden proposed herein has prognostic value. Persistence of a perfusion defect has the strongest impact on prognosis. KEY POINTS: ⢠Cardiovascular magnetic resonance provides information on myocardial ischemia by visual estimation of the presence of perfusion defects induced by stress. ⢠There is not a standardized method for grading perfusion defects which, in practice, is performed by visual estimation of their extension. ⢠As proven in this study, the integration of several parameters of perfusion defects (in addition to extension) into a semiquantitative score has prognostic value.
