Biphasic temporal pattern of plasmatic N-terminal pro-brain natriuretic peptide ( Nt-proBNP) in children and adolescent undergoing surgical repair of ostium secundum atrial septal defect (ASD)
Background : Nt-proBNP is a circulating marker of ventricular function produced
within cardiomyocites in response to pressure and volume overload.
Methods: Plasmatic Nt-proBNP levels were measured before surgery and after 1,
8, 16, 24, 48 , 72, 96, 120, 144, 168 hours in 45 pts ( median age 5.1
( 0.5-15.8 ) years ) submitted to ASD surgical repair.
Results:
Pre and post-operative peak values of Nt-proBNP are shown in tab 1 .
Nt-proBNP level reached the peak of 3799 (546-21239) pg/mL 24 hours after surgery.
The level decreased and then again increased forming the second smaller peak of
779 (535-2940) pg/mL on the fifth day.
Right/left ventricle end-diastolic dimension ratio measured by echocardiography
on the second peak time was significantly lower than the first peak
( 0.85 +/- 0.10 vs 1.25 +/- 0.12 , P < 0.05 ).
On multivariate regression analysis using age, postoperative peak Tn I, preoperative, , first peak, second
peak Nt-proBNP as variables the only determinant of the postoperative length of stay
( LOS ) was the second peak value of Nt-proBNP ( R2= 0.46 , p < 0.05 )
Conclusion: A biphasic pattern of plasma Nt-proBNP is seen after surgical closure
of ASD. The second peak values of Nt-proBNP may reflect the amount of the left ventricle
overload after L-R shunt closure.
Secondary elevation of Nt-proBNP is a strong determinant of postoperative LOS.
| Tab 1. Pre and postoperative peak values of Nt-proBNP | |
|---|---|
| Nt-proBNP ( pg/mL) | |
| Time | Median (range) |
| Preoperative | 147 (27-1096) |
| Postoperative first peak ( 24 h ) | 3799** (546-21239) |
| Postoperative second peak ( 144 h ) | 779* (535-2940) |
| * P <0.05 and ** P < 0.001 vs preoperative | |