[Isoflurane preconditioning decreases the plasma concentration of matrix metalloproteinase-9 and protects myocardium against cardiopulmonary bypass in cardiac valve replacement].
OBJECTIVE
To explore the effect of isoflurane preconditioning on the plasma concentration of matrix metalloproteinase (MMP)-9 and myocardial ultramicrostructure in patients undergoing cardiac valve replacement.


METHODS
Thirty patients undergoing elective cardiac valve replacement with cardiopulmonary bypass (CPB) were randomly assigned to a control group (ný15) and an isoflurane group (ný15). In the isoflurane group, isoflurane of 1.0 minimum alveolar concentration end-tidal( 1.1% approximately 1.2%) was administered for 30 min followed by a 15 min washout period before the CPB. The control group did not inhale isofurane, and there was no difference in the other drugs in the 2 groups. Blood samples for MMP-9 were obtained before incision(T(0)) and at 30 min (T(1)),6 h (T(2)),12 h (T(3)), and 24 h (T(4)) after the reperfusion. Right atrial biopsies were collected before and after the CPB to observe the myocardial ultramicrostructure.


RESULTS
Compared with T(0), the mean MMP-9 level significantly increased at T(1), T(2) and T(3) in the control group(P<0.01), while the MMP-9 level only at T(1) significantly increased in the isoflurane group (P<0.01). The mean MMP-9 level was significantly reduced in the isoflurane group at T(2) compared with each time point in the control group. The difference in MMP-9 levels between T(1), T(2), T(3) and T(0) was significantly lower in the isoflurane group than that in the control group (P<0.01). The ultramicrostructure injury of myocardium under electron microscope in the control group was worse than that in the isoflurane group.


CONCLUSIONS
The plasma concentration of MMP-9 is inhibited by isoflurane preconditioning in patients undergoing cardiac valve replacement after CPB, which might be part of its protective mechanism against myocardium injury after CPB.
Ruan
Wenyan
W
Department of Anesthesiology, Central South University, Changsha 410011, China. ruanwy33@hotmail.com
Xu
Junmei
J
Li
Zhijian
Z
Tan
Miao
M
Ran
Ke
K
D000293:Adolescent; D000328:Adult; D002315:Cardiopulmonary Bypass; D002316:Cardiotonic Agents / Q000627:therapeutic use*; D005260:Female; D019918:Heart Valve Prosthesis Implantation / Q000379:methods*; D006801:Humans; D019157:Ischemic Preconditioning, Myocardial / Q000379:methods*; D007530:Isoflurane / Q000627:therapeutic use*; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000097:blood*; D008875:Middle Aged; D009206:Myocardium / Q000648:ultrastructure; D055815:Young Adult
D002316:Cardiotonic Agents; D007530:Isoflurane; D020780:Matrix Metalloproteinase 9