Diagnostic approach to cardiac amyloidosis

Amyloidosis is a relatively rare disease that may be underdiagnosed and could affect the entire human body. Many organs may be affected, which could increase the morbidity and mortality. Cardiac involvement is the leading cause of poor prognosis. Patients with cardiac amyloidosis are usually admitted with heart failure. The clinical presentation varies greatly, and using the correct approach is important in identifying cardiac amyloidosis. A 51-year-old man was diagnosed with chronic heart failure. He had increased brain natriuretic peptide levels, a low ejection fraction, and left and right ventricular hypertrophy with granular sparkling as seen by echocardiography. These findings led us to perform a cardiac biopsy that confirmed the diagnosis of cardiac amyloidosis. Further investigation revealed that the patient had amyloid light-chain type amyloidosis due to multiple myeloma. He is now undergoing the 3rd phase of chemotherapy. Congo-red stain is usually used by physicians to histologically confirm amyloidosis, with which apple-green birefringence indicates amyloid deposits. Other stains such as direct fast scarlet (DFS) and hematoxylin-eosin (HE) can also confirm the presence of amyloid deposits. In the present case, DFS and HE were used, both of which suggested amyloid deposits surrounding myocardial cells. The use of a combination of stains can increase the diagnostic sensitivity and specificity of amyloidosis. However, the typical echocardiographic appearances would be enough to diagnose cardiac amyloidosis when it is impossible for the patient to undergo a cardiac biopsy, if an additional histological specimen from another tissue such as abdominal fat confirms amyloidosis.