Abstract
Background
In patients with suspected amyloid cardiomyopathy (CM) and a monoclonal protein, tissue biopsy is mandatory to exclude amyloid light–chain CM (AL–CM), the subtype requiring urgent therapy. We aimed to develop a pragmatic approach to estimate the most likely final diagnosis before biopsy.
Methods
We studied a multicenter cohort of adults referred for biopsy because of suspected amyloid CM. Clinical, laboratory, ECG/echocardiographic and bone–tracer scintigraphy data were collected at initial suspicion. In patients with a monoclonal protein, we derived age cut–offs overall and by carpal tunnel syndrome (CTS), defined an age–based “grey zone” (74–83 years), and evaluated risk modifiers for AL–CM and transthyretin CM (ATTR–CM). We built a points–based algorithm for “grey–zone” patients. Clinical utility was assessed using decision–curve analysis.