Abstract 17102: Establishing Outcome-Based Severity Partitions for LV Dilation

Abstract

Background: The 2015 American Society of Echocardiography chamber quantification guideline 1 included healthy population-based normal controls for left ventricular (LV) size, but not severity partitions due to the lack of data to support mild, moderate, and severe categories. In this study, we propose using adverse outcomes to define “severe” in non-ischemic dilated cardiomyopathy (DCM). Methods: 778 adults with DCM were enrolled prospectively and underwent CMR from June 2012 to August 2020 at West China Hospital and followed for a median of 49 months 2 . 72 healthy Chinese adults served as controls. We evaluated “severe” increase in LV end-diastolic volume indexed to body surface area (EDVi), LVEDV/right ventricular (RV) EDV, and “severe” decrease in LV ejection fraction (EF) using receiver operator characteristic (ROC) and area under the curve (AUC) analysis based on cardiovascular outcome. We defined “moderate” as control mean +½ the standard deviation (SD) distance between control mean and “severe” and “mild” as between control mean +2 SD and “moderate”. Results: Of 778 participants, 190 experienced heart failure death, sudden cardiac death, or heart transplant. For LVEDVi, the “severe” dilation cut point was 184 mL/m 2 , 10.9 SD from control mean (71 ml/m 2 ). Thus, “moderate” dilation starts at 128 ml/m 2 (control mean +5.4 SD) and “mild” starts at 92 ml/m 2 (control mean +2 SD). The LVEDV/RVEDV ratio partitions are similar to RVEDV/LVEDV partitions for pulmonary arterial hypertension 3 . It is well known that LVEDVi and LVEF have sex-based differences with females having smaller hearts and higher EF 4 . the volume ratio is slightly lower in females as compared to the males (Table 1). Conclusion: Severity of LV dilation and dysfunction based on LVEDVi, LVEF, and LVEDV/RVEDV can be determined by finding upper limits of normal, using outcomes to determine “severe” category, and using the SD distance between severe and control mean to determine mild and moderate categories.