Prognostic Impact of Hypertrabeculation and Noncompaction Phenotype in Dilated Cardiomyopathy: A CMR Study

The purpose of this study was to evaluate the impact of hypertrabeculation and left ventricular (LV) myocardial noncompaction phenotype by cardiac magnetic resonance (CMR) on outcomes of patients with nonischemic dilated cardiomyopathy (DCM).

Myocardial trabeculations and noncompaction are increasingly observed in patients with DCM, but their prognostic impact remains unknown.

We prospectively evaluated outcomes of 162 consecutive patients (102 men; age 55 ± 15 years; ejection fraction [EF] 25 ± 8%) with DCM undergoing CMR. The amount of noncompaction was quantified as noncompacted/compacted (NC/C) length in the long-axis view and as the ratio of NC/C mass in the short-axis view and compared against 48 healthy control subjects (age 60 ± 10 years).

Fifty-eight DCM patients (36%) had NC/C length ≥2.3, and 71 (44%) had NC/C mass greater than the 95% confidence interval (CI) of control subjects. NC/C length and NC/C mass did not correlate with any clinical, echocardiographic, or CMR parameters. Over a 3.4-year median follow-up, 29 patients experienced major adverse cardiovascular events (MACE) (12 cardiovascular deaths, 8 heart transplantations, 4 LV assist device implantations, and 5 resuscitated cardiac arrests or appropriate device shocks). Cox univariate analysis identified smoking, New York Heart Association functional class, blood pressure, LV and right ventricular end-diastolic and end-systolic volumes, LV EF, right ventricular EF, and late gadolinium enhancement as predictors of MACE. In multivariate analysis, only LV EF and late gadolinium enhancement were independent predictors of MACE-free survival (hazard ratio: 0.922, 95% CI: 0.878 to 0.967, p = 0.001 and HR: 1.096, 95% CI: 1.004 to 1.197, p = 0.04, respectively). Neither NC/C length nor NC/C mass had significant predictive value for MACE-free survival, either unadjusted or after adjustment for baseline variables. Also, there was no difference in cardioembolic event rate between groups with high and low NC/C length or mass.

Cardiovascular outcomes of adult patients with nonischemic DCM do not appear to be influenced by the degree of trabeculation. This argues against a noncompaction phenotype designating a more severe form of DCM.