P354 REMOVAL OF CARDIAC AL–AMYLOID LEADS TO CARDIOMYOCYTE POSITIVE REMODELING AND RESTRICTIVE PATTERN REVERSAL

Abstract

Abstract Background Properly treated AL cardiac amyloidosis can have a long survival. However, the mechanism involved in arresting or reversing cardiomyopathy, such as toxic suppression of the light chain or removal of the amyloid substance, is still unclear. We describe the case of a patient with AL amyloidosis treated with chemotherapy in whom serial endomyocardial biopsies were performed at diagnosis and after 17 years. Clinical case A 71–year–old lady onset with a hypertrophic phenotype cardiomyopathy (maximum thickness LV 18.2 mm, diastolic dysfunction with E/A ratio 2.45. preserved contractility (EF 55%) and NYHA class 3) received a diagnosis in 2004 of AL amyloidosis and underwent several cycles of chemotherapy. At clinical onset, cardiac amyloidosis was documented by endomyocardial biopsy. After 17 years, in 2021, the patient was hospitalized for palpitations and chest pain and documented intermittent phases of atrial fibrillation. The patient was reevaluated with immunoelectrophoresis, echocardiogram, cardiac magnetic resonance, coronary angiography, and left ventricular endomyocardial biopsy. Serum monoclonal chain AL–K was reduced from initial 233 mg/L to 18.2 mg/L, vn<19.4 mg/L. The echocardiogram showed reduction of the heart walls with reduction of the thickness to 14 mm, with regression of the restrictive pattern (E/A ratio from 2.45 to 0.5). Serum NT–proBNP decreased from 3188 pg/mL to 480 pg/mL (n.v.<334 pg/mL). Cardiac MRI revealed normal myocardial wall thickness, with preserved systolic function, in the absence of the typical late gadolinium enhancement pattern. Histology and electron microscopy showed no more hypo/atrophic cardiomyocytes and the interstitium was almost completely devoid of amyloid fibrils, which were distant from the cardiac cell allowing an improvement in oxygenation and trophism. Conclusions Remission of monoclonal gammopathy is associated with a removal of cardiac amyloid deposits and with a regression of cardiac hypertrophy and restrictive pattern. Histologically, the degradation of amyloid fibrils determines a better trophism of cardiomyocytes.