Complete AVSD Repair — Two-Patch Technique

Repair of complete atrioventricular septal defect (cAVSD) restores atrial and ventricular septation and partitions the common AV valve into competent right- and left-sided orifices. The guiding principles are: preserve leaflet geometry, protect the conduction system, avoid left-sided stenosis or LV outflow tract obstruction (LVOTO), and achieve durable valve competence. Early definitive repair in early infancy is favored at many centers to limit pulmonary vascular disease and valve distortion [1].

1. Inspection and Orientation of the Common AV Valve

Begin with a deliberate survey of leaflet anatomy (superior and inferior bridging leaflets, right/left mural leaflets, right anterior leaflet) and subvalvar chords and papillary muscles. Place a small orienting stitch to maintain reference during septation. When sizing the two orifices, resist the temptation to “downsize” the left side—over-reduction invites postoperative LAVV stenosis. Rastelli type (A/B/C) and the cleft morphology help predict where tethering or LVOT encroachment might occur [2].

2. Inlet VSD Patch Closure

Close the ventricular component first. The conduction tissue runs adjacent to the posteroinferior rim of the VSD; therefore, keep the suture line slightly rightward onto the RV side along this margin. Near the AV node, many surgeons incorporate right-sided AV valve tissue rather than septal bites to avoid injury. Choose a supple patch (e.g., autologous pericardium or PTFE) tailored to avoid bulging into the LV inflow or RV cavity. Check that the patch does not tether the superior bridging leaflet toward the LVOT, a subtle cause of later obstruction [3].

3. Left AV Valve (LAVV) Cleft Closure

Close the left-sided cleft toward the primary chordae to restore a broad, central coaptation zone. Perform a meticulous saline test; add or remove stitches until the coaptation line is smooth without residual jets. Directly measure the left orifice to exclude stenosis; in tiny infants, partial cleft closure may be preferable to avoid high gradients. Re-evaluate chordal tension after the VSD patch—patch geometry can subtly alter leaflet reach [2].

4. Primum ASD Patch Closure and Protection of the Conduction System

When closing the primum ASD, route the suture line to shield the AV node: begin along the annulus of the left AV valve, continue onto the left atrial wall, and only then transition to the ASD edge to complete the atrial patch. This trajectory displaces sutures away from the nodal triangle and the penetrating bundle beneath the inferior bridging leaflet. Reassess both AV valves after atrial closure, as atrial geometry can alter leaflet coaptation [4].

Intraoperative Assessment

Transesophageal echocardiography confirms: absence of residual shunts (atrial and ventricular), LAVV/RAVV competence, acceptable LAVV mean gradient, preserved LVOT, and ventricular function. A low threshold to return to bypass is appropriate if there is significant AVVR, a high LAVV gradient, or evidence of LVOT impingement [1].

Technical Pearls and Pitfalls

• Hazard zone. The posteroinferior VSD rim near the inferior bridging leaflet is the conduction corridor; keep bites superficial and rightward here [3].
• LVOTO avoidance. A tall or stiff VSD patch, or excessive traction on the superior bridging leaflet, can narrow the LVOT. Shape the patch to follow the septal crest without creating a ridge [3,4].
• Valve competence vs stenosis. Aim for generous leaflet coaptation; in very small annuli, accept a tiny central jet rather than over-tightening the cleft [2].
• Right-sided balance. Over-partitioning that favors the right orifice risks LAVV stenosis; over-restricting the right side may provoke RAVV regurgitation. Adjust at the time of the saline test [2].
• Technique variants. Single-patch variants exist and may be chosen selectively; the principles of conduction protection and cleft management remain the same [8].

Early Postoperative Focus

Monitor rhythm continuously for AV block; junctional rhythms may respond to temporary AV sequential pacing. Follow valve performance with echocardiography—look for early AVVR or rising LAVV gradients—and screen the LVOT with Doppler. Outcomes series highlight low early mortality, attention to conduction protection, and the importance of addressing cleft-related regurgitation at index repair [5,6], with durable freedom from reoperation in most cohorts [7].

Summary

Two-patch repair of complete AVSD proceeds in four disciplined steps: orient the common valve, close the inlet VSD while protecting the conduction system, restore LAVV competence by cleft closure without inducing stenosis, and close the primum ASD along a conduction-sparing trajectory. Mastery lies in balancing complete septation with durable, non-stenotic AV valve function and an unobstructed LVOT, verified by systematic intraoperative testing and postoperative surveillance [1–7].

References

[1] Backer CL, Mavroudis CD, Alboliras E, et al. Repair of complete atrioventricular canal defects: two-patch technique and modifications to improve results. Annals of Thoracic Surgery. 1995.

[2] Mavroudis C, Backer C. Complete atrioventricular canal: anatomy, echocardiography, operative strategies, and technical considerations. Seminars in Thoracic and Cardiovascular Surgery – Pediatric Cardiac Surgery Annual. 1997.

[3] Alexi-Meskishvili V, Ishino K, Dähnert I, et al. Correction of complete atrioventricular septal defects with the two-patch technique. The Journal of Thoracic and Cardiovascular Surgery. 1996.

[4] Daebritz S. Repair of complete atrioventricular septal defect. The Annals of Thoracic Surgery. 2004.

[5] Xie O, Brizard C, d’Udekem Y, et al. Outcomes of complete atrioventricular septal defect repair in the current era: early and midterm results. European Journal of Cardio-Thoracic Surgery. 2014.

[6] Bakhtiary F, Takács J, Cho M, et al. Surgical repair of complete atrioventricular septal defect: early and long-term results. The Annals of Thoracic Surgery. 2010.

[7] Ong J, Brizard C, d’Udekem Y, et al. Repair of atrioventricular septal defect associated with tetralogy of Fallot or double-outlet right ventricle: 30 years of experience. The Annals of Thoracic Surgery. 2012.

[8] Crawford F. Repair of complete atrioventricular septal defect — single patch technique. The Annals of Thoracic Surgery. 2004.