Degree of Left ventricular myocardial trabeculation and non-compaction phenotype do not influence the prognosis of non-ischemic dilated cardiomyopathy

Amzulescu, Mihaela Silvia [UCL] Rousseau, Michel [UCL] Ahn [UCL] de Meester de Ravenstein, Christophe [UCL] Vancraeynest, David [UCL] Pasquet, Agnes [UCL] Vanoverschelde, Jean-Louis [UCL] Pouleur, Anne-Catherine [UCL] Gerber, Bernhard [UCL]

Background: Increased left ventricular (LV) myocardial trabeculation has been described in several cardiomyopathies, and particularly in non-compaction cardiomyopathy. Yet its prognostic impact remains unknown. Therefore we investigated whether the degree of LV trabeculated myocardium (Trab), assessed by cardiac magnetic resonance (CMR), influences the prognosis of patients with non-ischemic dilated cardiomyopathy (DCM). Methods: 158 patients (53±14 years, 99 males) with DCM, LV ejection fraction (EF)<40% and without coronary artery disease by angiography or multidector CT, underwent cine and delayed-enhancement (DE) CMR. The amount of Trab was assessed in end-diastole, by 2 methods: 1) as the maximum ratio of Trab/nonTrab myocardium measured on long axis cine images and 2) as Trab/nonTrab mass measured on short axis cine stacks. Patients were followed for a composite end-point of cardiovascular death, heart transplantation, left ventricular assist device implantation, resuscitated cardiac arrest and appropriate device choc (MACE). Kaplan-Meier survival and Cox proportional hazards analysis were used to assess the relationship between the degree of trabeculation and MACE. Results: Mean indexed LV end-diastolic (EDV) and end-systolic (ESV) volumes were 162±51 ml/m2 and 125±50 ml/m2 respectively. Mean LV EF was 24±8%. 36% of patients had DE. The mean±SD Trab/nonTrab ratio was 1.95±1.0. Trab/non Trab mass was 23±8%. Trab mass was significantly correlated to Trab/non Trab ratio (r=.60, p<.001). 70 patients had a end-diastolic Trab/non trab ratio>2.3 suggesting non-compaction. Over a median follow-up of 3.2 years, 26 patients had MACE. Univariate Cox analysis identified NYHA class (p=.046), smoking (p=.009) diastolic blood pressure (p=.03), LVEDVi (p=.003), LVESVi (p=.002), RVEDVi (p=.004), RVESVi (p=.001), LVEF (p=.005) and RVEF (p=.001) as independent predictors of MACE. By contrast, the degree of trabeculation, either assessed by Trab/NonTrab ratio or by Trab mass, was not related to outcome. In multivariable analysis, RVEF was the only independent predictor of event free survival [HR=0.95, 95% CI [0.93-0.98], p=0.006]. Conclusion: The strongest predictor of outcome in our patients with dilated cardiomyopathy was right ventricular ejection fraction. In contrast, prognosis was not influenced by the degree of left ventricular myocardial trabeculation. This argues against non-compaction phenotype being a more severe form of dilated cardiomyopathy.