Temporal endothelin dynamics of the myocardial interstitium and systemic circulation in cardiopulmonary bypass.
OBJECTIVE
Increased systemic levels of the bioactive peptide endothelin 1 during and after cardioplegic arrest and cardiopulmonary bypass have been well documented. However, endothelin 1 is synthesized locally, and therefore myocardial endothelin 1 production during and after cardiopulmonary bypass remains unknown.


METHODS
Pigs (n = 11) were instrumented for cardiopulmonary bypass, and cardioplegic arrest was initiated. Myocardial interstitial and systemic arterial levels of endothelin 1 were measured before cardiopulmonary bypass, throughout bypass and cardioplegic arrest (90 minutes), and up to 90 minutes after separation from bypass. Myocardial interstitial endothelin 1 was determined by microdialysis and radioimmunoassay.


RESULTS
Baseline myocardial endothelin 1 levels were higher than systemic endothelin 1 levels (25.6 +/- 6.7 vs 8.3 +/- 1.1 fmol/mL, P <.05). With the onset of bypass, myocardial endothelin 1 increased by 327% +/- 92% from baseline (P <.05), which preceded the increase in systemic endothelin 1 levels.


CONCLUSIONS
Myocardial compartmentalization of endothelin 1 exists in vivo. Cardiopulmonary bypass and cardioplegic arrest induce temporal differences in endothelin 1 levels within the myocardial interstitium and systemic circulation, which, in turn, may influence left ventricular function in the postbypass period.
Walker
C A
CA
Division of Cardiothoracic Surgery Research, Medical University of South Carolina, Charleston, SC, USA.
Baicu
S C
SC
Goldberg
A T
AT
Widener
C E
CE
Fary
D J
DJ
Almany
D K
DK
Ergul
A
A
Crawford
F A
FA
Spinale
F G
FG
D000704:Analysis of Variance; D000818:Animals; D002315:Cardiopulmonary Bypass; D019332:Endothelin-1 / Q000097:blood / Q000378:metabolism*; D006439:Hemodynamics; D016014:Linear Models; D017551:Microdialysis; D009206:Myocardium / Q000378:metabolism*; D011863:Radioimmunoassay; D013552:Swine; D013997:Time Factors; D016277:Ventricular Function, Left / Q000502:physiology
D019332:Endothelin-1