Comparison of various non-invasive tools for diagnosing AL cardiac amyloidosis

Cardiac involvement is the most important cause of death in light chain amyloidosis (AL) and its early diagnosis is a major issue for therapeutic strategy. Gold diagnostic standards are either invasive (cardiac biopsy) or not widely available (cardiac MRI). We aim to compare diagnostic value of various diagnostic tools in this setting. Methods Following diagnostic, tests were performed after first diagnosis of AL amyloidogenic disorder: clinical examination, blood testing of BNP and troponin I, EKG, echocardiography, 24-hours EKG Holter, cardiac MRI, cardiopulmonary test. Cutoffs were chosen from literature for parameters with continuous values. Final diagnosis of cardiac amyloidosis (CA) was done either by MRI if diffuse late enhancement was present or by endomyocardial biopsy. Diagnostic values of tests as well as their combination were calculated. Results Among sixty-seven consecutive patients (64 ± 10 years, 21 with multiple myeloma and 46 with MGUS), final diagnosis of CA was done in 45 patients. Renal, digestive and neurologic AL involvements were present in 44%, 15% and 20% respectively of patients with CA. The table shows diagnostic values of EKG, BNP and echography as well as their combinations. Usefulness of troponin, Holter or stress test was less relevant ( Table 1 ). Conclusion Combining EKG, biomarkers and echocardiography result in nearly optimal diagnosis of AL CA.