Decreased Cardiac Ejection Fraction Is Associated with Worse Survival in Patients with Light Chain Amyloidosis Treated with Autologous Stem Cell Transplantation

Introduction:

Cardiac involvement is one of the main predictors for survival in patients with light chain (AL) amyloidosis. Biomarkers such as Troponin T and N-terminal pro b-type natriuretic peptide (NT-proBNP) are used routinely for detecting cardiac involvement. In addition echocardiogram (ECHO) is used to determine septal and left ventricular wall thickness and strain. Most patients with AL present with preserved ejection fraction (EF) however, the outcomes of AL patients undergoing autologous stem cell transplantation (ASCT) with decreased EF are not very well described.

Methods:

We retrospectively reviewed patients who had a diagnosis of AL amyloidosis and received ASCT between March 1996 and September 2017. All patients had an ECHO done before ASCT and the EF was documented. In our practice, the threshold for performing ASCT is an EF >40%. We evaluated the outcomes of patients who had an EF <55% compared to patients with an EF ≥55%. The baseline characteristics were compared between patients with high and low EF. Progression-free survival (PFS) was defined as time from ASCT to disease progression, relapse, or death of any cause. Overall survival (OS) was calculated from time of ASCT to death of any cause. Univariate and multivariate analysis for PFS and OS were done using the following variables: age>65 vs. ≤65 years, Mayo 2012 stage 3/4 vs. 1/2, bone marrow plasma cell percentage (BMPC) ≥ 10% vs. <10%, organs involved >2 vs. ≤2, melphalan conditioning 200mg/m² vs. 140 mg/m² ,ASCT year >2010 vs. ≤2010, and EF <55% vs. ≥55%.

Results:

We identified 716 patients and 69 (10%) had an EF<55%, with most (n=63, 91%)having cardiac involvement . Compared to patients with EF ≥55%, patients with EF <55% were more likely to have Mayo 2012 stage 3/4 (58% vs. 22%, P<0.0001) and more likely to have thicker interventricular septum (median 14 vs. 12 mm, P<0.0001). The day 100 transplant related mortality (TRM) was higher in patients with EF <55% compared to EF ≥55% (19% vs. 6%, P=0.0006). In patients with Mayo 2012 stage 3/4, the day 100 TRM was higher in patients with an EF<55% compared to EF ≥55% (27% vs. 7%, P=0.004).

Overall, PFS and OS were significantly shorter in patients with EF <55% compared to patients with EF ≥55% (Figure 1 A,B ). Evaluating PFS and OS according to EF specifically in Mayo 2012 stage 3/4 patients is displayed in Figure 1 (C,D). Predictors for PFS included Mayo 2012 stage 3/4 vs. 1/2 (hazard ratio (HR): 1.4, P=0.006), BMPC ≥ 10% vs. <10% (HR: 1.5,P=0.0005), melphalan conditioning 200mg/m² vs. 140 mg/m² (HR:0.7, P=0.01), ASCT year >2010 vs. ≤2010 (HR: 0.7, P=0.01), and EF <55% vs. ≥55% (HR: 1.5, P=0.02). For OS, age >65 vs. ≤65 years ( HR:1.4, P=0.04), Mayo 2012 stage 3/4 vs. 1/2 (HR: 1.96, P<0.0001), melphalan conditioning 200mg/m² vs. 140 mg/m² (HR:0.5, P<0.0001), BMPC ≥ 10% vs. <10% (HR: 1.8, P=0.03), ASCT year >2010 vs. ≤2010 (HR: 0.5, P<0.0001), and EF <55% vs. ≥55%(HR:1.9, P=0.003) were predictive.

Conclusion:

Having an EF <55% is associated with a higher day 100 TRM and is an independent predictor for PFS and OS in patients with AL amyloidosis undergoing ASCT.