Prosthesis-Free Repair of Partial Atrioventricular Septal Defect in Down Syndrome: A Valve-Sparing Technique

Introduction

Atrioventricular septal defects (AVSDs) are among the most common congenital heart anomalies associated with Down syndrome (trisomy 21), resulting from abnormal development of the endocardial cushions [1]. In patients with Down syndrome, the complete form of AVSD is more frequent; however, partial AVSD with a mitral cleft, with or without tricuspid valve involvement, are also observed [1–3].

When a partial AVSD presents in adulthood with severe mitral and tricuspid regurgitation, it poses a distinct surgical challenge [1,3]. Chamber dilation, impaired ventricular function, and complex valve pathology make repair technically demanding [1,3]. Furthermore, the management strategy must consider the patient’s long-term quality of life. The use of prosthetic rings, while providing stable annuloplasty, commits patients – particularly those with intellectual disabilities and caregiver dependency – to lifelong anticoagulation with its associated risks and compliance burdens [3,4].

While valve-sparing repair techniques for partial AVSD are well established in pediatric populations, reports describing prosthesis-free repair of dual atrioventricular valve regurgitation in adults with Down syndrome are rare [4,5]. Previous case reports have documented successful AVSD repairs in pediatric patients with Down syndrome, but few have addressed the specific challenges of delayed adult presentation with severe dual valve involvement [1,4,5].

Therefore, a tailored surgical approach is required for this unique clinical scenario. This report describes the case of a 21-year-old man with Down syndrome, partial AVSD, and severe mitral and tricuspid regurgitation managed with a prosthesis-free, valve-sparing surgical repair and reconstruction. We detail the operative technique and rationale, highlighting its utility in avoiding prosthetic material and long-term anticoagulation, thereby addressing a critical management need in this vulnerable population.

Case Report

OPERATIVE TECHNIQUE:

The procedure was performed through a median sternotomy with standard cardiopulmonary bypass, bicaval cannulation, cardioplegic arrest, and mild systemic hypothermia (32–34°C). Right atriotomy revealed a partial AVSD. A three-step repair was undertaken. The mitral valve was repaired by continuous closure of the cleft at the A2 segment using 5-0 polypropylene sutures, followed by a modified suture annuloplasty with 2-0 polifilament suture on Teflon pledgets to achieve annular reduction (Figure 1). The tricuspid valve was reconstructed by direct suture closure of the septal leaflet cleft combined with a modified De Vega annuloplasty (Figure 2). Finally, the AVSD was closed with a modified single-patch technique using a 4×5 cm autologous pericardial patch secured by a continuous 5-0 polypropylene suture [2]. The postoperative course was uneventful, and the patient remained clinically stable with preserved valve competence and no residual shunts 1 year after surgery.

Discussion

This case report demonstrates that a prosthesis-free, valve-sparing repair can be successfully performed in an adult with Down syndrome presenting with a complex partial AVSD and severe dual valve regurgitation, offering a valuable surgical alternative that avoids the need for lifelong anticoagulation.

AVSDs are frequent in Down syndrome, with the complete form being more common than partial AVSD [1]. Involvement of both atrioventricular valves complicates surgical repair, particularly when severe regurgitation has developed in adulthood [1,3]. Early repair in infancy has been shown to prevent pulmonary vascular disease and progressive valve dysfunction, with single- and double-patch techniques providing excellent long-term results [2,4]. In contrast, delayed repair is technically demanding due to chamber dilation, impaired ventricular function, and complex valve pathology [1,3].

Our case illustrates this challenging scenario of delayed presentation. As noted in the literature, adults with unrepaired or residual AVSD often present with atrioventricular valve regurgitation as the dominant lesion, frequently necessitating reoperation [1,5]. The surgical management in such cases must address not only the septal defects but also the often-advanced pathology of the valves themselves. While prosthetic ring annuloplasty is a standard and effective method for addressing annular dilation and providing long-term stability in many settings [3], its application in the context of a partial AVSD adjacent to a primum ASD presents specific technical constraints. The fibrous skeleton in this region is often deficient, providing a paucity of secure, deep suture sites necessary for reliable ring implantation without risking injury to the conduction system or creating residual leaks [3].

In our patient, preoperative assessment revealed significant annular dilation of both valves (mitral annulus 42 mm, tricuspid annulus 43 mm in diastole) contributing to central regurgitation, justifying the need for annuloplasty beyond simple cleft closure. No other significant valvular pathology, such as leaflet restriction or major chordal abnormalities, was identified, making the valves suitable for a reparative approach. The specific intraoperative challenge was to achieve a stable reduction of both annuli without prosthetic material. For the mitral valve, this was accomplished by a modified suture annuloplasty using pledgeted running sutures to reduce the posterior annulus (Figure 1). For the tricuspid valve, an extended De Vega annuloplasty was performed. The modification allowed for a tailored, semicircular annular remodeling and reduction that included the anterior, posterior, and postero-septal segments, thereby addressing the predominant areas of dilation while maintaining a safety margin from the critical conduction system at the anteroseptal commissure (Figure 2). This technique provides effective annular remodeling and reduction while preserving a degree of physiologic, three-dimensional annular motion, which facilitates improved leaflet coaptation. By avoiding the rigidity associated with a prosthetic ring, this direct, suture-based approach circumvented the difficulties of ring placement in this anatomic context.

Comparison with previously reported cases reveals the uniqueness of our approach. Ginde et al [4] reported excellent long-term outcomes after surgical repair of complete AVSD in childhood, but their series focused on pediatric populations with primarily prosthetic ring annuloplasty. Similarly, Jain et al [5] described clinical features and outcomes in adults with childhood repair of partial AVSD, but their cohort study did not address de novo adult presentation with severe dual valve regurgitation requiring prosthesis-free repair. To the best of our knowledge, this is the first detailed report of a deliberate, complete prosthesis-free approach for both atrioventricular valves in an adult with Down syndrome and unrepaired partial AVSD.

Although prosthetic ring annuloplasty is documented to provide superior long-term stability in some series [3], the specific valvular pathology in this case allowed for effective repair with suture techniques alone [3,5]. Crucially, this strategy eliminated the need for prosthetic material and the associated requirement for prolonged anticoagulation therapy. For patients with Down syndrome, who often have limited compliance with complex medical regimens and depend on caregiver support, this presents a significant advantage in long-term management [4].

Post-repair transesophageal echocardiography confirmed a competent repair with no residual shunts. The final mitral annular diameter was reduced to 32 mm, and the tricuspid annular diameter to 32 mm, with negligible transvalvular gradients (mean mitral gradient 2 mmHg, mean tricuspid gradient 1 mmHg). These measurements confirm the effectiveness of the suture annuloplasty technique in achieving adequate annular reduction and competency.

At 1-year follow-up, valve competence was preserved, ventricular function was stable, and no residual shunts were present, supporting the feasibility of this technique. This case demonstrates that even in complex adult presentations of partial AVSD with dual atrioventricular valve insufficiency in Down syndrome, autologous, prosthesis-free repair is a safe and effective option, balancing operative feasibility with long-term patient safety and quality of life.

This case report contributes to the surgical literature by demonstrating that in select patients with suitable valve morphology, a tailored suture-based strategy can be a viable alternative to prosthetic rings, particularly when the avoidance of lifelong anticoagulation is a paramount concern [3].

Conclusions

This report demonstrates that a tailored, prosthesis-free repair is a safe and effective strategy for managing partial AVSD with significant mitral and tricuspid regurgitation in adults with Down syndrome. By utilizing autologous tissue and suture-based annuloplasty techniques, this approach successfully corrects the complex defect while eliminating the need for prosthetic material and lifelong anticoagulation, providing a significant advantage in the long-term management of this patient population.

To build upon this experience, future studies should focus on evaluating the long-term durability and hemodynamic outcomes of prosthesis-free repairs in larger cohorts of patients with Down syndrome and similar congenital pathologies. Additionally, research aimed at developing clear preoperative echocardiographic and clinical criteria to guide the selection of suture-based versus prosthetic ring annuloplasty in individual patients would be invaluable. Establishing such guidelines would help standardize surgical decision-making, optimize patient-specific outcomes, and further improve the quality of life for individuals with intellectual disabilities who require complex cardiac care.