TTR and cardiac amyloidosis: Only if the index of suspicion is high would the patient next move to direct organ biopsy of the heart, liver, kidney, nerve, etc. Patients with echocardiographic evidence suggesting cardiac amyloidosis, usually demonstrating thickened ventricular walls, Doppler evidence of poor diastolic filling and abnormal longitudinal strain need to undergo a pyrophosphate scan which if positive should be considered TTR and not light chain amyloidosis.