Evaluación de la infiltración micocárdica en amiloidosis mediante cardiorresonancia magnética

Abstract

La amiloidosis cardiaca (AC) es una enfermedad infiltrativa causada por el depósito de fibrillas anormales insolubles en el espacio intersticial del miocardio. A pesar de que la forma de cadenas ligeras (AL) es el tipo más común de amiloidosis sistémica con afectación cardiaca, las formas familiar de transtiretina (TTR) y senil pueden también involucrar al corazón. La AC debe ser considerada en el diagnóstico diferencial de la insuficiencia cardiaca con función sistólica de ventrículo izquierdo (VI) preservada, especialmente cuando se detecta un patrón de llenado restrictivo, e incluso en ausencia de afectación conocida de otros órganos. En este sentido, los signos clásicos electrocardiográficos (ECG) y ecocardiográficos han sido extensamente utilizados para su diagnóstico. Sin embargo, aunque presentan una excelente especificidad adolecen de suficiente sensibilidad para detectar la enfermedad en fases iniciales. Por otro lado, el diagnóstico definitivo con biopsia endomiocárdica (BEM) no está extensamente disponible y tampoco está exento de potenciales complicaciones...

Cardiac amyloidosis (CA) is an infiltrative disease caused by the deposition of insoluble abnormal fibrils in the myocardial interstitial space. Although light chain (AL) form is the most common type of systemic amyloidosis with cardiac involvement, familial transthyretin (TTR) and senile forms, can also involve the heart. CA must be considered in the differential diagnosis of heart failure with preserved left ventricular (LV) systolic function, especially when restrictive filling is detected, and even when no other organ involvement is known. In this regard, classical electrocardiographic (ECG) and echocardiographic features have been extensively used on diagnosis. However, in spite of their excellent specificity they may lack enough sensitivity to detect early stages of disease. On the other hand, the definitive diagnosis with endomyocardial biopsy (EMB) is not widely available and not free from potential complications. In this clinical scenario, cardiac magnetic resonance (CMR) emerged as a valuable non-invasive diagnostic tool through the ability of late gadolinium enhancement (LGE) to detect extracellular space expansion. Firstly, a subendocardial global hyperenhancement pattern and abnormal contrast kinetics were described in association with CA diagnosis. Nonetheless, given the diffuse deposition of amyloid a direct quantitative estimation of infiltration would be preferable over the qualitative detection of macroscopic deposition with LGE. Hereof, the evaluation of diffuse interstitial involvement with CMR T1 mapping techniques have raised interest in the study of cardiomyopathies. Several sequences and protocols have been tested to achieve this goal. Among them, equilibrium or bolus contrast CMR evaluation with Modified Look Locker Inversion-recovery (MOLLI), and its shortened version shMOLLI, appear to be the most precise methods for extracellular volume (ECV) quantification...