Dynamic changes of excessive trabeculation in dilated cardiomyopathy: a longitudinal cardiovascular magnetic resonance study

Abstract Background A portion of dilated cardiomyopathy (DCM) patients present with left ventricular (LV) excessive trabeculation at diagnosis. It remains unknown if the extent of trabeculation would be reduced after guideline-directed medical therapy (GDMT). Purpose To investigate the dynamic change of excessive trabeculation after GDMT in patients with DCM, and its relationship with that in LV structure and function. Methods A group of DCM patients with baseline and follow-up cardiovascular magnetic resonance (CMR) examination after 1-2 years of GDMT were enrolled. Trabeculation was assessed by Petersen method as measuring the thickness of the most prominent non-compacted (NC) layer and the corresponding compacted (C) segment at the apical long-axis view at end-diastole. Excessive trabeculation was defined as the NC/C ratio > 2.3, and a regression was reached if it decreased to ≤ 2.3. Major adverse cardiovascular events (MACE) consisted of cardiovascular death, heart transplantation, and heart failure readmission. Results Among 218 DCM patients (45 ± 14 years, 67.4% male), 58 (26.6%) met the excessive trabeculation criteria at baseline. Despite a similar LV ejection fraction (LVEF), patients with excessive trabeculation had a higher LV end-diastolic dimension (73.3 ± 9.0 vs. 70.5 ± 8.0mm) and native T1 (1325.3 ± 71.2 vs. 1305.5 ± 65.9mm) (both p<0.05) with a trend of more late gadolinium enhancement (51.7% vs. 39.4% of patients). After 15 months of GDMT, patients with excessive trabeculation (n=58) showed a decreased NC layer (12.7 ± 3.4 vs. 11.3 ± 3.0 mm) and NC/C ratio (3.1 ± 0.9 vs. 2.7 ± 0.9) (both p < 0.05), 25.9% of whom showed a regression of trabeculation. Patients with the regression had a lower NC/C ratio (1.8 ± 0.4 vs. 3.0 ± 0.8, p < 0.001) and LV end-diastolic volume index (LVEDVi) (121.5 ± 40.5 ml/m2 vs. 165.9 ± 67.8ml/m2, p=0.004) compared with those without. The change of (△) NC/C ratio was associated with that of LVEDVi (r = 0.323), and LVEF as well (r = -0.254) (both p < 0.001). Excessive trabeculation at baseline did not differentiate patients with a higher risk of MACE by Kaplan-Meier survival curve (p= 0.208), but its persistent presence at follow-up did (p= 0.004). However, when put △NC/C ratio, △LVEDVi, △LVEF and In NT-proBNP into multivariate cox regression model, only the △LVEDVi (HR, 0.963; 95% CI: 0.942, 0.985; P = 0.001) and In NT-proBNP (HR, 2.016; 95% CI: 1.288, 3.157; P = 0.002) were independent predictors of MACE. Conclusions Regression of excessive trabeculation occurred after GDMT in DCM patients that was related somewhat to LV reverse remodeling and not an independent predictor of MACE. It may also indicate the interconnection between LV remodeling and trabeculation.