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Partial defect of atrioventricular canal — Clinical Guidelines

Overview

Partial defect of atrioventricular canal (AVC) involves anomalies in the AV valves and septation, often presenting as unbalanced defects with varying degrees of right and left ventricular involvement. Surgical management focuses on biventricular repair when feasible, though univentricular palliation may be necessary in severe cases.

Diagnosis

Key Diagnostic Criteria: Fragmentation of the interventricular septum, anterior displacement of the mitral annulus, and visualization of a common AV valve leaflet in the left ventricular outflow tract 11.

Recommended Tests: Echocardiography (M-mode, two-dimensional, and biplane cineangiography) for detailed anatomical assessment 1 11 13 14.

Grading: Ventricular hypoplasia can be assessed by echocardiographic ventricular size ratios (e.g., RVED/LVED ratio) 12.

Management

First-Line Treatment: Biventricular repair is preferred when feasible, especially in less unbalanced defects 3.

Adjunctive Treatments: Careful surgical technique for interatrial patch placement to avoid conduction disturbances 4.

Surgical Considerations: Avoid suturing the cleft of the mitral valve in cases of potentially parachute mitral valve to prevent iatrogenic mitral stenosis 10.

Postoperative Monitoring: Close follow-up for residual AV valve incompetence, with reoperation rates ranging from 5% to 10% 5.

Special Populations

Down Syndrome: Surgical correction is appropriate despite potential higher morbidity; postoperative survival rates are comparable to non-Down syndrome patients 8.

Pediatric Considerations: Early surgical intervention is crucial to prevent progressive pulmonary vascular disease, especially in infancy 6 15.

Key Recommendations

Utilize echocardiography, particularly M-mode and two-dimensional imaging, for accurate preoperative assessment of AVC anatomy 1 11 13. (Evidence: Moderate)

Consider biventricular repair in unbalanced AVC defects when feasible, based on preoperative imaging and anatomical suitability 3. (Evidence: Moderate)

Avoid suturing the mitral valve cleft in cases of potentially parachute mitral valve to prevent postoperative mitral stenosis 10. (Evidence: Weak)

Monitor patients closely for residual AV valve incompetence post-repair, given the risk of reoperation 5. (Evidence: Moderate)

Perform early surgical intervention in infants with AVC to mitigate the risk of developing severe pulmonary vascular disease 6 15. (Evidence: Moderate)

References

1 Jones AL, White BR, Ghosh RM, Mondal A, Ampah S, Ho DY et al.. Cardiac magnetic resonance predictors for successful primary biventricular repair of unbalanced complete common atrioventricular canal. Cardiology in the young 2024. link 2 Nam HH, Dinh PV, Lasso A, Herz C, Huang J, Posada A et al.. Dynamic Annular Modeling of the Unrepaired Complete Atrioventricular Canal Annulus. The Annals of thoracic surgery 2022. link 3 Vida VL, Sanders SP, Milanesi O, Stellin G. Biventricular repair of right-dominant complete atrioventricular canal defect. Pediatric cardiology 2006. link 4 Aeba R, Katogi T, Kashima I, Mitsumaru A, Takeuchi S, Kawada S. Placement of interatrial patch suture lines in atrioventricular canal defect repair. The Journal of cardiovascular surgery 2000. link 5 Michielon G, Stellin G, Rizzoli G, Milanesi O, Rubino M, Moreolo GS et al.. Left atrioventricular valve incompetence after repair of common atrioventricular canal defects. The Annals of thoracic surgery 1995. link00851-9) 6 Yamaki S, Yasui H, Kado H, Yonenaga K, Nakamura Y, Kikuchi T et al.. Pulmonary vascular disease and operative indications in complete atrioventricular canal defect in early infancy. The Journal of thoracic and cardiovascular surgery 1993. link 7 Higashidate M, Tamiya K, Kurosawa H, Imai Y. Role of the septal leaflet in tricuspid valve closure. Consideration for treatment of complete atrioventricular canal. The Journal of thoracic and cardiovascular surgery 1992. link 8 Rizzoli G, Mazzucco A, Maizza F, Daliento L, Rubino M, Tursi V et al.. Does Down syndrome affect prognosis of surgically managed atrioventricular canal defects?. The Journal of thoracic and cardiovascular surgery 1992. link 9 Marino B, Digilio MC, Giannotti A, Dallapiccola B. Atrioventricular canal associated with trisomy 9. Chest 1989. link 10 David I, Castaneda AR, Van Praagh R. Potentially parachute mitral valve in common atrioventricular canal: pathological anatomy and surgical importance. The Journal of thoracic and cardiovascular surgery 1982. link 11 Johnson GL, Twyman RE, Todd EP, Cottrill CM, Noonan JA. Echocardiographic classification of complete atrioventricular canal defects. American heart journal 1981. link90228-3) 12 Mehta S, Hirschfeld S, Riggs T, Liebman J. Echocardiographic estimation of ventricular hypoplasia in complete atrioventricular canal. Circulation 1979. link 13 Draulans-Noë HA, Voogd PJ, Ligtvoet CM, Ridder J, Wenink AC. Two-dimensional echocardiography in atrioventricular canal malformation: a diagnostic approach. Acta medica Scandinavica. Supplementum 1979. link 14 Thanopoulos BD, Fisher EA, DuBrow IW, Hastreiter AR. Right and left ventricular volume characteristics in common atrioventricular canal. Circulation 1978. link 15 Newfeld EA, Sher M, Paul MH, Nikaidoh H. Pulmonary vascular disease in complete atrioventricular canal defect. The American journal of cardiology 1977. link80135-5) 16 Pieroni DR, Homcy E, Freedom RM. Echocardiography in atrioventricular canal defect: a clinical spectrum. The American journal of cardiology 1975. link90558-5)

Partial defect of atrioventricular canal