Cardiac amyloidosis determines the prognosis of systemic amyloidosis; roles and responsibilities of cardiologist.

Refer to the page 752-760

Cardiac amyloidosis is a prognostically critical condition, since it is a frequent cause of death in patients with systemic amyloidosis.1)2) Lee et al.3) reported, for the first time, describing systemic amyloidosis in Korea from the perspective of cardiologists. In this paper, the authors enrolled 129 systemic amyloidosis patients retrospectively from 1999 to 2011. They showed that cardiac involve was the major prognostic factor, and old age, elevation of cardiac troponin I (cTNI), left ventricular (LV) systolic dysfunction and diastolic dysfunction were independent prognostic factors in survival. All cardiac amyloidosis were confirmed to have cardiac involvement by well-established and uncontroversial criteria including mean left ventricular thickness over 12 mm and low voltage in electrocardiogram or pathologically-confirmed amyloid deposit in endomyocardial biopsy. These diagnostic criteria were closely related to poor outcome in systemic amyloidosis.3)

The diagnosis and prognosis of cardiac amyloidosis still remains to be clarified, despite the development of more sensitive tools, such as delayed gadolinium enhancement (DGE) in cardiac magnetic resonance imaging (MRI) and cardiac biomarkers. In previous studies, when cardiac MRI was performed in all AL amyloidosis patients, DGE was found in 47% of the patients with normal LV wall thickness in echocardiography.4) Moreover, the level of NT-proBNP proved to be a better discriminating factor than the LV thickness (>12 mm) in echocardiography.5-8) But, it is still not clear whether we should suspect cardiac amyloidosis in patients with normal LV thickness in echocardiography or whether early diagnosis of cardiac amyloidosis improves the prognosis of the patients.

Since AL type is the most common type of systemic amyloidosis, chemotherapy and autologous stem cell transplantation are the therapies of choice. As shown,3) the hematologic response in AL amyloidosis is important in improving survival.9) Without hematologic response, it is difficult to obtain the responses in other organs. Likewise, in this paper, cardiac amyloidosis patients with better response to chemotherapy showed better survival compared to the patients with a lesser response.3) Many AL amyloidosis patients achieve hematologic response with high dose of melphalan and dexamethasone therapy or autologous hematologic stem cell transplantation.10) Additionally, bortezomib-based chemotherapy can be applied to achieve hematologic response in patients without hematologic response through melphan-based chemotherapy or autologous stem cell transplantation. Therefore, there is a significant limitation in this retrospective study. The authors did not show data regarding the benefit of additional chemotherapy in patients who had no hematologic response. In the meantime, active assessment of chemotherapy response and effort to achieve hematologic response cannot be overemphasized in the treatment of AL cardiac amyloidosis.

To accurately assess multi-organ involvement and treat systemic amyloidosis, an interdisciplinary approach of cardiology, hematooncology, nephrology, pathology, and laboratory medicine and more is needed. Considering that cardiac involvement is a major prognostic factor in systemic amyloidosis, cardiologists have a great responsibility and may play a pivotal role.