MMP9 and axial length measurement: MMP‐9 and TIMP‐1 levels have been associated with LV diastolic dysfunction in a small cohort of AL‐CMP patients.7 In vitro studies demonstrate that light chains induce increased ROS in cardiomyocytes.20–21 ROS in turn dysregulates MMP activities in cardiomyocytes.42 Furthermore, in isolated adult cardiomyocytes, spironolactone modulates ROS and MMP‐2 and MMP‐9 activities.42 Given these findings, spironolactone and other novel therapeutic interventions may modulate the ECM and LVH in AL‐CMP patients, and the present biomarker profile could be used as an indication of efficacy.