Left atrioventricular valve incompetence after repair of common atrioventricular canal defects.

BACKGROUND: Reoperation rate for residual atrioventricular (AV) valve regurgitation after repair of common atrioventricular canal defect (AVCD) is currently between 5% and 10%. This retrospective analysis evaluates the impact of AV valve anatomy, age at repair, and surgical technique on postoperative AV valve incompetence.
METHODS: Between January 1982 and July 1994, 205 patients with common AVCD underwent surgical repair at our institution. A complete form with common atrioventricular orifice (CCAVCD) was present in 81 patients. One hundred twenty-four had separate AV valves and orifices; 22 of these had a restrictive ventricular septal defect component. Preoperative moderate to severe AV valve regurgitation (AVVR) was present in 74 (36%), with a lower incidence in the CCAVCD group (20/81, 25%) versus the transitional (8/22, 36%) or the partial forms (46/102, 45%) (p = 0.02). The incidence was 12.5% (3/24) for CCAVCD patients less than 4 months of age (p = 0.02). Repair of the left AV valve was performed according to the trifoliate approach in most cases (142/205, 70%). Follow-up was 98% complete.
RESULTS: By Kaplan-Meier analysis, survival at 12.3 years was 97.8% +/- 1% in partial AVCD, 95.4% +/- 4% in transitional AVCD, and 73.2% +/- 5% in CCAVCD (median follow-up, 60 months). Freedom from reoperation at 12.3 years was 93.5% +/- 2% for partial AVCD, 76.9 +/- 9% for the transitional form, and 68.3% +/- 5% for CCAVCD: Postoperative moderate to severe AVVR occurred in 42 patients (21%), with lower incidence for CCAVCD (10/81, 12.5%) versus transitional AVCD (8/22, 36%) and partial AVCD (24/102, 24%) (p = 0.02). Postoperative moderate AVVR was found in only 1 patient with CCAVCD less than 4 months of age (p < 0.01). Nine patients (5%) underwent reoperation for residual postoperative AVVR Valve repair was performed in all with no operative death. By Cox proportional risk multivariate analysis, preoperative AVVR and double orifice "mitral" valve were associated with increased risk of postoperative left AVVR (p < 0.01), whereas a bifoliate approach appeared to reduce the risk of this event in partial AVCD (p = 0.03).
CONCLUSIONS: Postoperative AVVR is related to the type of anatomy of the AV valve, to the age at repair, and to the surgical technique employed. Residual AVVR can still be corrected with conservative techniques at low mortality rates. Early repair of common AVCD is associated with a lower incidence of preoperative and postoperative AVVR in CCAVCD and seems to prevent progression of annular dilation and preoperative AVVR in partial AVCD.