Prognostic implications of trabecular complexity measured by fractal analysis in left ventricular noncompaction

Abstract

Introduction Left ventricular non compaction (LVNC) is a heterogeneous entity characterized by prominent LV trabeculae. Fractal analysis, a semi-automatic method to quantify the degree of hypertrabeculation, has been described as a diagnostic criterion for LVNC. However, the prognostic implications of fractal analysis have not been investigated. Purpose Therefore, the aim of our study was to identify the relationship between the trabecular complexity measured by fractal analysis and the occurrence of cardiovascular events in LVNC patients. Methods We conducted a retrospective longitudinal multicenter cohort study of consecutive patients fulfilling LVNC criteria by cardiovascular magnetic resonance (CMR). The endpoints were heart failure (HF), ventricular arrythmias (VA), systemic embolism (SE) and all-cause mortality. Fractal analysis was performed on short-axis CMR cine images using CVI 42 software. The cohort was divided in two groups according to the maximal apical fractal dimension (FD). Results A total of 291 patients were included: age was 44±19 years and 56% were female. LV ejection fraction (LVEF) was 47% ± 14% and 26 patients (9%) presented late gadolinium enhancement (LGE). Mean global FD was 1.29±0.06 and maximal apical FD was 1.39±0.09. Baseline characteristics of patients with maximal apical FD 1.39 and 1.39, including functional LV parameters, were comparable (Table 1). After 3.8±2.5 years of follow-up, 37 patients (12.8%) presented HF, 30 (10.4%) had VA, SE occurred in 3 (1%) and 3 patients (1%) died. Maximal apical FD was not associated with the risk of HF or VA (both p ns), nor was mean global FD. There were no significant differences in the survival curves of both endpoints between the two groups: HR were 2.34 (95% CI 0.74–7.4, p 0.13) and 1.15 (95% CI 0.45–2.41, p 0.71) respectively for HF and VA (Image 1). LVEF and LGE remained consistent predictors of events. Conclusions In a large multicenter retrospective LVNC study, the degree of hypertrabeculation measured by fractal analysis was not associated with functional LV parameters and, most importantly, with the incidence of cardiovascular events. Therefore, our results suggest that diagnostic LVNC criteria should be refined to include parameters with actual prognostic implications. Funding Acknowledgement Type of funding sources: None.