Original articlePrognostic significance of interventricular septal thickness in patients with AL amyloidosis

- Cardiac involvement is the major prognostic determinant of AL amyloidosis.
- Interventricular septal thickness (IVST) >15 mm was an important prognostic factor.
- IVST >15 mm was also adversely prognostic in advanced stage patients.
- IVST might be used as a useful prognostic indicator in AL amyloidosis.

The major prognostic determinant of immunoglobulin light chain (AL) amyloidosis is cardiac involvement. However, the role of interventricular septal thickness (IVST), which reflects the extent of cardiac involvement, remains unclear. Therefore, we analyzed 77 patients with newly diagnosed AL amyloidosis and evaluated the prognostic role of IVST. Fifty patients (64.9%) had cardiac involvement and 17 patients (22.1%) showed IVST >15 mm. Among all patients, the revised Mayo Clinic Stage III-IV and IVST >15 mm were independently associated with inferior overall survival (OS) in a multivariable analysis. IVST >15 mm was also adversely prognostic for OS in a subgroup of advanced-stage (revised Mayo Clinic stage III-IV) patients in a multivariable analysis (P < 0.001). Furthermore, advanced-stage patients with IVST >15 mm did not show survival benefit from treatment with bortezomib-based regimens and/or autologous stem-cell transplantation (ASCT). Our study demonstrated that IVST >15 mm is adversely prognostic independent of the revised Mayo Clinic staging system in patients with AL amyloidosis. In addition, the degree of IVST might be used as a useful prognostic indicator that can guide the management of patients with AL amyloidosis especially at an advanced stage.

Differences in overall survival (OS) according to the interventricular septal thickness (IVST) and the new four-factor model, incorporating IVST into the revised Mayo Clinic staging system; patients are grouped by the presence of 0-1 (low-risk), 2-3 (intermediate-risk), or 4 (high-risk) of the following risk factors: IVST > 15 mm, troponin-T ≥ 0.025 ng/mL, N-terminal pro-brain natriuretic peptide ≥1800 pg/mL, and difference between involved and uninvolved free light chains ≥ 18 mg/dL.158