Analysis of diagnostic and therapeutic strategies in advanced cardiac light-chain amyloidosis

Abstract

Background: Prognosis of advanced cardiac light-chain amyloidosis (ACAL) is ominous. Diagnosis of ACAL is frequently preceded by several biopsies of non-clinically affected tissues, which can result in dangerous treatment delays. Combinations of alkylators and steroids have a limited role in its therapy. Definitive efficacy of bortezomib in ACAL is not widely described. In this study we analyze the diagnostic yield of biopsies and compare the effect of bortezomib with other therapeutic strategies in ACAL patients.

Methods: This study is a retrospective analysis of 40 consecutive ACAL patients treated at our hospital (2005 to 2015). For comparison purposes, the cohort was divided into 2 groups: patients treated with bortezomib (n = 23) and those treated with other therapeutic approaches (non-bortezomib, n = 8).

Results: Sensitivity of biopsies of non-clinically affected organs was 23%, as compared with 97% for affected organ biopsies (p < 0.0001). The need for >2 biopsies resulted in an average delay in diagnosis of 4.1 months (p = 0.007). Hematologic response was observed in 96% of patients in the bortezomib group compared with 25% in the non-bortezomib group (relative risk = 3.8; 95% confidence interval 1.14 to 12.75; p = 0.0002). Cardiac response criteria were met by 60% of patients in the bortezomib group as compared with none in the non-bortezomib group (p = 0.005). Survival at 6 months and 1 and 2 years for bortezomib patients was 91%, 91% and 73%, as compared with 58%, 15% and 0% for non-bortezomib patients (log rank, p < 0.0001), respectively.

Conclusion: In our experience, the sensitivity of biopsies from non-affected organs in ACAL is poor and could result in diagnostic delay. Bortezomib was associated with higher hematologic and cardiac response rates as well as survival when compared with other therapies.

Keywords: NT-proBNP; biopsy; bortezomib; cardiac amyloidosis; light-chain amyloidosis.