Amyloidosis-related echo features and mortality in patients with multiple myeloma

Abstract

Abstract Background/Introduction Patients with multiple myeloma (MM) are at increased risk of developing AL amyloidosis. It was determined by screening fat pad and bone marrow biopsy that 38% MM patients had amyloidosis at time of diagnosis and the majority were asymptomatic (1). However, whether amyloidosis-related echo features in MM affect survival remains unknown (1, 2). Purpose The goals of our study are to: 1) characterize prevalence of amyloidosis-related echo features in patients with multiple myeloma, 2) investigate whether decrease in longitudinal strain affect survival outcomes. Methods Patients diagnosed with MM between Jan 1, 2000 and Dec 31, 2017 at our institution were identified through Clinical Looking Glass. Those with echo within 1 year after myeloma diagnosis and left ventricular ejection fraction (LVEF) greater than 40% were included. Global longitudinal strain (GLS) and LVEF measurements were done using EchoGo (Ultromics, Oxford, UK). The average of GLS obtained from apical 4-chamber and apical 2-chamber views was used for analysis, with decreased GLS defined as absolute value less than 18%. Statistical analysis was conducted with STATA13, using Chi square test and Kruskal-Wallis for univariable analysis and Cox regression model for survival analysis. Results From a total cohort of 909 patients, 252 met inclusion criteria, of which 59 (23.4%) patients had decreased average GLS (see Table 1). Patients' mean age was 63±11 years, 44.8% were male and most were Black (42.7%) and the rest Hispanic (33.3%) and White (7.9%). Median follow up time was 4.25 years. The group with decreased GLS had lower percentage of females (22% vs 51.8%, p<0.01), higher percentage of previous MI (11.9% vs 1.6%, p<0.01) and more prior diagnosis of heart failure (20.3% vs 1.6%, p<0.01). Among patients with decreased GLS, five-year mortality rate was 63.3% compared to 46.0% in those with preserved GLS (p<0.036). Median survival time was 3.9 years among those with reduced GLS and 4.3 years in those without (see Figure 1; p<0.01). Reduced GLS correlated with decreased survival (HR 1.6, p=0.03) even after adjusting for demographic variables (age, gender, race), history of MI, history of CHF, Charlson comorbidity index, myeloma RISS stage, and LVEF (≥50% vs 40–50%). Forty-seven (18.6%) patients had end diastolic inter-ventricular septum (IVSd) thickness ≥1.2cm. Median GLS in patients with increased IVSd thickness was 19% compared to 21% in those without (p=0.01). Nine patients had the apical sparing strain pattern for amyloidosis. Total of 158 patients had bone marrow specimen stained with Congo-red with 7 (4.4%) testing positive. Median GLS was 19% in the group staining positive for Congo-red compared 21% in the group with negative stain (p=0.03). Conclusions Decrease in GLS on baseline echo correlates with increased mortality in patients with MM and may be due to subclinical cardiac amyloidosis. Funding Acknowledgement Type of funding sources: None.