The role of B−type natriuretic peptide in the evaluation of left atrioventricular valve regurgitation following surgical repair of partial atrioventricular canal

Abstract

Background: Left atrioventricular valve (LAVV) regurgitation usually follows surgical repair of partial atrioventricular canal (PAVC). Although measurements of B-type natriuretic peptide (BNP) levels are useful for the monitoring and prediction of outcomes in chronic mitral regurgitation, no data are available on the role of BNP measurements in the assessment of LAVV regurgitation in patients after surgical correction of PAVC.
Aim: To determine the role of plasma BNP determination in the assessment of LAVV regurgitation in patients after surgical repair of PAVC.
Methods: We evaluated 41 patients who had undergone surgery for PAVC between 1968 and 2005 with preserved left ventricular ejection fraction (LVEF, mean age at follow-up: 39.2 ± 14.0 years, mean age at the time of surgery: 31.3 ± 15.6 years, 32 females) and 13 healthy controls (mean age: 38.9 ± 13.2 years, 9 females). All the subjects had undergone transthoracic echocardiography and had their plasma BNP levels determined. LAVV regurgitation was assessed qualitatively on 1+ to 4+ grading scale and quantitatively by calculating the effective regurgitant orifice area (EROA).
Results: LAVV regurgitation was present in 40 (97.6%) patients. Compared to patients with mild-to-moderate LAVV regurgitation (grade 1+ to 2+/EROA < 0.4 cm²) evaluated qualitatively and quantitatively, the group with severe regurgitation (grade 3+ to 4+/EROA ≥ 0.4 cm²) had higher values of left atrial volume (LAvol) and right ventricular (RV) systolic pressure, although there was no significant difference in plasma BNP levels. There were significant correlations between BNP levels and LAvol (r = 0.54, p = 0.0001), age at follow-up (r = 0.61, p=0.0001), age at the time of surgery (r = 0.58, p = 0.0001), RV diastolic diameter (r = 0.38, p = 0.02) and RV systolic pressure (r = 0.48, p = 0.002). Multivariate logistic regression analysis showed that only LAvol and age at the time of surgery but not the degree of LAVV regurgitation were independently associated with elevated plasma BNP levels.
Conclusions: In patients late after surgical repair of the PAVC with preserved LVEF, plasma BNP levels reflect the consequences of the shunt at atrial level and LAVV regurgitation expressed by LAvol but it does not allow to estimate the severity of regurgitation.