When a condition such as the Ebstein anomaly displays significant heterogeneity in its presentation (ranging from manifestations in the neonatal period to those in adulthood) and its low prevalence limits surgical groups’ experience with these patients, multicenter studies become essential. However, while these studies help improve decision-making for managing these patients, they are not always easy to interpret or apply in clinical practice.
Various surgical techniques have been described for correcting this condition, which extends beyond a mere tricuspid valve anomaly. As highlighted in the article under review, this anomaly is considered a right ventricular myopathy, of which tricuspid regurgitation is just one manifestation. Therefore, this anomaly must be studied and conceptualized from this perspective. Essentially, Ebstein anomaly is a myopathy caused by the variable delamination failure of the tricuspid valve leaflets. Myocytes in these patients have a reduced number of myofibrils compared to healthy individuals, a feature that shares genetic abnormalities with noncompaction cardiomyopathy.
The combination of varying degrees of tricuspid valve delamination failure and the underlying myopathy creates a broad spectrum of clinical presentations. This heterogeneity, together with the condition’s low prevalence, makes it difficult to draw robust conclusions about its management. Personally, I believe that neonatal presentations of the anomaly should be analyzed separately from those presenting during school-age or later. A large proportion of neonatal patients require univentricular repair due to the severity of the lesion during this period.
The article discussed in this commentary examines the outcomes of surgical management for Ebstein anomaly patients treated at six hospitals in Australia and New Zealand over 34 years, from 1985 to 2019.
A total of 125 patients aged over 15 years were analyzed, with a mean patient age of 35 years. The number of cases managed varied by center, ranging from nine in the center with the lowest volume to 40 in the one with the highest. Most patients presented in NYHA functional class I-II, while 30% were in class III-IV.
More than half of the patients underwent tricuspid valve repair using different techniques, while 40% required tricuspid valve replacement. Among the latter, 19% required permanent pacemaker implantation due to post-surgical heart block, with a higher prevalence in the replacement group.
The 30-day mortality rate was 2%, with an average follow-up period of nine years (range: 3.4–20 years). Notably, only eight patients completed the 10-year follow-up. Total mortality was 6%, and the need for reoperation during follow-up was 17%. After 10 years of follow-up, there were no significant differences in reoperation rates between repair and replacement patients.
COMMENTARY:
As seen, despite the long timeframe of the study (34 years) and the inclusion of data from six centers across two countries, only 125 patients older than 15 years were analyzed due to the low prevalence of the condition. Consequently, most centers manage fewer than one case per year on average.
There is limited clarity regarding the specific repair techniques used in patients who underwent tricuspid valve preservation. Only a small percentage underwent the repair described by Da Silva, while the techniques applied to the remaining patients are not specified. It is reasonable to assume that repair techniques evolved as their efficacy became better understood. Likely, various surgical techniques were employed throughout the study period, beginning with Danielson’s method described in 1979, which was later refined by Carpentier in 1988 with anterior leaflet mobilization and reorientation of the plication. Subsequently, Da Silva perfected this approach in 2007 by mobilizing all leaflets and reorienting them clockwise. Additionally, simple but effective maneuvers such as those by Wu, Hetzer, and the Sebening stitch provided solutions in challenging cases.
Similarly, a subgroup of patients (13% of the total sample) underwent a bidirectional cavopulmonary shunt (BCPS). The authors noted that this procedure was added in cases of right ventricular dysfunction, cyanosis, anticipated tricuspid stenosis after repair, or difficulty separating the patient from cardiopulmonary bypass. Based on the authors’ data, it is challenging for readers to establish clear criteria for selecting patients eligible for BCPS. Nearly all patients exhibited right ventricular dysfunction, and the authors did not provide objective data or cutoff points for deciding on this intervention.
Most patients also presented atrial septal defects which, combined with severe tricuspid regurgitation, suggest that cyanosis is not attributable to a single factor. Furthermore, the decision to perform BCPS due to challenges in separating patients from cardiopulmonary bypass reflects a lack of preoperative planning and clear criteria, leading to intraoperative decisions under critical conditions. Unfortunately, even the most experienced surgeons in Ebstein anomaly cannot definitively determine when BCPS should be initially performed or if the azygos vein should always be ligated in these cases, nor when to close the atrial septal defect.
Although mortality and reoperation outcomes are similar to those reported in other studies, it is worth noting the limited follow-up, as only a small percentage of patients completed the full follow-up period. Interestingly, the long-term outcomes were comparable between patients undergoing repair versus replacement. This observation must be considered alongside the average age of the patients in this series (35 years). When patients present at this age, it is likely that repair and replacement yield similar outcomes. However, the scenario may differ for younger patients, especially school-aged children, in whom the accelerated degeneration of bioprostheses requires that repair be prioritized whenever possible.
Finally, I would like to add that although repair or replacement should ideally be pursued in these patients, there is a subgroup with severe ventricular dysfunction—not only of the right ventricle but also the left—caused by significant displacement and dilation of the right chambers. For this subgroup, where treatment success is unlikely, heart transplantation should be considered as a definitive therapeutic option.
REFERENCE:
Doig F, Finucane K, Skillington P, Jones S, Sharma V, Daley M, et al. Surgical Management of Ebstein Anomaly: The Australia and New Zealand Experience. World J Pediatr Congenit Heart Surg. 2024 Mar;15(2):155-159. doi: 10.1177/21501351231189279.
