Endomyocardial biopsy confirmed AL amyloidosis in a 58-year-old woman with undifferentiated shock and preserved ejection fraction (60-65%) after initial noninvasive tests were inconclusive.
Case Report (n=1)
A high index of suspicion and definitive tissue biopsy are crucial for diagnosing AL amyloidosis in heart failure patients presenting with restrictive cardiomyopathy and undifferentiated shock when noninvasive tests are inconclusive.
Abstract Introduction Light chain (AL) amyloidosis, a systemic disorder, causes misfolded light chains to deposit as insoluble amyloid fibrils in various organs. Cardiac involvement is the strongest predictor of mortality. Early diagnosis is crucial, as 5-year survival when diagnosed within 6 months of cardiac symptoms is 79%, but this declines to 19% if diagnosis is delayed beyond 19 months. Description A 58-year-old African American woman presented with progressively worsening dyspnea, abdominal distention, and leg swelling. She had recurrent ascites, CKD Stage 3a, hypertension, and atrial fibrillation. On admission, she was hypotensive with signs of fluid overload. Labs revealed BNP of 142 pg/mL, rising creatinine (1.56 to 2.2 mg/dL), and mildly elevated troponin. CT scan revealed emphysema with bilateral effusion, ascites, and nodular liver. Echocardiogram revealed a preserved left ventricular (LV) ejection fraction (60-65%), concentric LV hypertrophy, and elevated bilateral filling pressures. Multiple thoracenteses and paracenteses yielded exudative effusions with negative infectious and autoimmune studies. Initial amyloidosis workup was misleading, with inconclusive global longitudinal strain imaging on echocardiogram, normal kappa/lambda ratio, and negative serum/urine protein electrophoresis and immunofixation. The fat pad biopsy was negative for Congo red staining. Diuretic resistance and progressive vasopressor dependence complicated her course, ultimately requiring continuous renal replacement therapy. Right heart catheterization (RHC) revealed markedly elevated biventricular filling pressures and low cardiac index, consistent with restrictive cardiomyopathy. Given high clinical suspicion, she was referred for endomyocardial biopsy, which confirmed AL amyloidosis. Despite maximal hemodynamic support, she developed refractory cardiogenic shock and multiorgan failure, and care was transitioned to comfort measures. Discussion A high index of suspicion for amyloidosis is warranted in heart failure patients presenting with disproportionate LV wall thickening (often without antecedent hypertension, or even with hypotension), particularly when associated with restrictive cardiomyopathy, right ventricular wall thickening, or unexplained systemic signs. In this case, RHC revealed a low cardiac index despite hypervolemia, underscoring the paradox of restrictive physiology where increased preload fails to augment stroke volume; hence, managing this challenging form of cardiogenic shock requires continuous hemodynamic monitoring to achieve the delicate balance between inotrope titration and preload optimization. Initial noninvasive tests, including echocardiography, protein electrophoresis, light chain assays, and immunofixation, may be inconclusive. Cardiac MRI with late gadolinium enhancement and T1 mapping offers superior tissue characterization (70-80% accuracy). Definitive diagnosis requires tissue biopsy showing Congo red-positive amyloid deposits (cardiac/renal biopsy approaching 100% sensitivity). Early diagnosis facilitates prompt, targeted chemotherapy, improving outcomes in this high-mortality disease. This abstract is funded by: None
Maheshwari et al. (Fri,) conducted a case report in AL amyloidosis (n=1). Endomyocardial biopsy confirmed AL amyloidosis in a 58-year-old woman with undifferentiated shock and preserved ejection fraction (60-65%) after initial noninvasive tests were inconclusive.