Background: Once surgical management is indicated, variation of Ebstein valve morphology affects surgical strategy. This study explored practical, easily measureable, cardiovascular magnetic resonance (CMR)-derived attributes that may contribute to the complexity and risk of cone reconstruction.
Methods: A retrospective assessment was performed of Ebstein anomaly patients older than 12 years age, with pre-operative CMR, undergoing cone surgical reconstruction by one surgeon. In addition to clinical data, the CMR-derived Ebstein valve rotation angle (EVRA), area ratios of chamber size, indexed functional RV (RVEDVi) and left ventricular (LV) volumes, tricuspid valve regurgitant fraction (TR%) and other valve attributes were related to early surgical outcome; including death, significant residual TR% or breakdown of repair.
Results: Of 26 operated patients older than 12 years age, since program start, 20 had pre-op CMR and underwent surgery at median (range) age 20 (14-57) years. TR% was improved in all patients. Four of the 20 CMR patients (20%) experienced early surgical dehiscence of the paravalve tissue, with cone-shaped tricuspid valve intact; one of whom died. A larger EVRA correlated with Carpentier category and was significantly related to dehiscence. If EVRA >60o, relative risk of dehiscence was 3.2 (CI 1.3-4.9, p = 0.03). Those with dehiscence had thickened, more tethered anterior leaflet edges (RR 17, CI 3-100, p < 0.01), smaller pre-operative functional RVEDVi; (132 vs 177 mL/m2, p = 0.04), and were older (median 38 vs 19 years, p = 0.01). TR %, chamber area ratios and LV parameters were not different.
Conclusions: Comprehensive CMR assessment characterizes patients prior to cone surgical reconstruction of Ebstein anomaly. Pragmatic observation of larger EVRA, smaller RVEDVi and leaflet thickening, suggests risk of repair tension and dehiscence, and may require specific modification of cone surgical technique, such as leaflet augmentation.
Keywords: Cardiovascular magnetic resonance imaging; Cone reconstruction; Congenital heart disease; Ebstein anomaly; Tricuspid valve.