Real-life evaluation of an algorithm for the diagnosis of cardiac amyloidosis

The French referral centre Henri-Mondor Amyloidosis Network, France, used algorithm of Gillmore et al., to diagnose cardiac amyloidosis (CA) with bone scintigraphy (BS), gammopathy testing (GT), biopsies (extracardiac and cardiac), and genetic testing to diagnosis CA. To evaluate the real-life use of a modified Gillmore algorithm for the diagnosis of cardiac amyloidosis (CA) at the French National Reference Centre for Cardiac Amyloidosis (Henri Mondor Hospital, Créteil, France). In a “one-stop shop” approach, bone scintigraphy (BS), a monoclonal gammopathy test (GT), a salivary gland biopsy (SGB), and genetic testing were performed at the same time. This retrospective cohort study was conducted from June 2008 to May 2019. All patients having undergone BS and GT after referral to the Henri-Mondor reference centre for suspected amyloidosis were included in the study. A total of 1222 patients were included: 349 had no cardiac uptake on BS and negative GT (BS−/GT−), 276 were BS-/GTpositive (GT+), 420 patients were BS+/GT−, and 177 were BS+/GT+. Our “one-stop shop” amyloidosis check-up enabled us to diagnose 892 (73%) patients; only 330 (27%) patients required additional examinations, such as mass spectrometry and/or a cardiac biopsy. This subset notably included 112 patients with amyloid light chain (AL) amyloidosis. Over 64% of the patients with transthyretin (TTR) amyloidosis (ATTR-CA) or another type of amyloidosis were diagnosed during the “one-stop shop” visit. BS had a sensitivity of 99% and a specificity of 96% for the diagnosis of ATTR-CA. GT had a sensitivity of 100% and a specificity of 76% and SGB had a sensitivity of 54% and a specificity or 100% for the diagnosis of AL amyloidosis. 205 (17%) of the 910 TTR genetic tests detected TTR mutations – most of which were found in patients aged between 55 and 84. The results of our real-life cohort study confirmed the ability of a “one-stop shop” approach with a modified Gillmore algorithm to diagnose CA and thus emphasized the importance of simultaneous testing for earlier diagnosis. The SGB has diagnostic value because it is easy, quick and less invasive than a cardiac biopsy. We also found that the diagnostic yield for a TTR mutation test was low in patients aged 85 or more.