Cutting into the Unknown—Does Resection of Endocardial Fibroelastosis in Patients with Borderline Left Ventricle and Hypertrabeculation Restore Ventricular Function?

Background: Patients with borderline left ventricles (LVs) and endocardial fibroelastosis (EFE) often present with left ventricular hypertrabeculation/non-compaction (LVHT), a rare myocardial phenotype associated with various congenital heart defects. EFE, a subendocardial thickening restricting the LV, can infiltrate into the underlying myocardium leading to diastolic dysfunction. While surgical resection of EFE in these patients aims to improve LV diastolic dysfunction, the efficacy and long-term effects on the underlying myocardium with LVHT are underexplored.

Methods: We conducted a retrospective, single-center cohort study at Boston Children’s Hospital, including patients with borderline LVs, EFE, and LVHT from January 2009 to June 2023. We analyzed patient characteristics, surgical EFE resections, and hemodynamic outcomes. The primary outcome was whether patients could maintain the LV as the systemic ventricle. Secondary outcomes included changes in LV diastolic function and postoperative complications.

Results: Of 24 patients (median age at diagnosis: 0.8 months for LVHT, 4 months for EFE), 16 (67%) underwent primary EFE resection shortly after diagnosis (median age: 5.5 months). Associated cardiac anomalies are shown in [Table 1]. Post-resection, 4 (25%) showed improved LV diastolic function, 9 (56%) still had EFE at follow-up, and 6 (38%) also had EFE at discharge. Ten (63%) maintained systemic LV function. In contrast, of eight patients who did not undergo resection, only three (38%) had a systemic LV at follow-up. The overall survival rate was 88%, 3/24 (13%) underwent heart transplantation, and 4/24 (17%) required assisted circulation.

Table 1 Associated cardiac anomalies

Associated cardiac anomaly, n (%)	Total n = 24
Hypoplastic left heart syndrome/complex	18 (75)
Atrial septal defect/ventricular septal defect	17 (71)/1 (4)
Annulo-leaflet mitral ring	2 (8)
Mitral valve anomalies	23 (96)
Left ventricular outflow tract obstruction/subaortic membrane	11 (46)/9 (38)
Aortic valve anomalies	24 (100)
Coarctation of the aorta	6 (25)

Conclusion: EFE resection can enhance LV diastolic function in patients with borderline LVs and LVHT, although complete resection often remains elusive. The progressive nature of EFE’s infiltration into the trabecular myocardium requires individualized surgical approaches and adjunctive therapies to optimize the outcomes of this unique patient cohort.

Publication History

Article published online:
11 February 2025