Association between left ventricular function and paraprotein type in patients with multiplemyeloma

Background/Aims: Multiple myeloma (MM)-associated cardiac damage, particularly according to the type of monoclonal (M) protein has not been elucidated. We sought to investigate relationship between elevated serum M protein levels and echocardiographic indices of cardiac structure and function in patients with MM. Methods: We evaluated a total of 184 consecutive MM patients who underwent echocardiography for bone marrow pre-transplant screening. Serum levels of intact immunoglobulin M protein and free light chain kappa/lambda (FLC-/-) were measured. Results: One hundred thirty-nine patients were non-light chain MM (non-LCMM) and 45 patients belonged to LCMM. In patients with non-LCMM, significant correlations were found between serum M protein and left atrial volume index (LAVi; r = 0.720, p < 0.0001), E/e' (r = 0.511, p < 0.0001), and systolic pulmonary arterial pressure (r = 0.485, p < 0.0001). In patients with LCMM, log-transformed FLC- (log-) was correlated with left ventricular ejection fraction (LVEF, r = -0.536, p = 0.010), left ventricular (LV) end-systolic dimension (r = 0.500, p = 0.018), and LV end-systolic volume (r = 0.444, p = 0.038). On multivariate analyses, hematocrit and serum M protein were independent predictors of LAVi in patients with non-LC-MM. In patient with LCMM, FLC- isotype was only found to be an independent determinant of LVEF. Conclusions: An increase in serum M protein was associated with LV diastolic dysfunction, whereas an increase in serum FLC- concentration showed a negative correlation with the echocardiographic parameters of LV systolic function. These findings also suggest that serum M protein has different effects on LV function according to the type of paraproteins in patients with MM.