Beneficial impact of isoflurane during coronary bypass surgery on troponin I release.
BACKGROUND
Experimental studies indicate that isoflurane, a commonly used volatile anesthetic, mimics the cardioprotective effects of ischemic preconditioning, probably through ATP-sensitive K+ (KATP) channel activation. The aim of this study was to evaluate the impact of isoflurane during coronary bypass surgery (CABG) on troponin I release.


METHODS
Forty consecutive patients with chronic stable angina and multivessel disease undergoing isolated CABG were randomized to a control (16 men and 4 women, aged 51 to 73 years, mean 62) or isoflurane (15 men and 5 women, aged 51 to 77 years, mean 65) group before aortic cross-clamping and cardioplegia. Serum levels of troponin I and creatine kinase (CK)-MB, as markers of ischemic injury, were obtained at 24 hours after CABG. Regional wall motion score and left ventricular ejection fraction (LVEF) at transthoracic echocardiography were assessed 5 days postoperatively. Comparisons between groups were performed in the entire population and, subsequently, in those patients with preoperative LVEF < 50%.


RESULTS
There were no significant differences between isoflurane-treated patients and controls in cross-clamp time (49 +/- 14 vs 51 +/- 13 min, p = ns), peak values of troponin I (0.9 +/- 0.7 vs 1.4 +/- 1.3 ng/ml, p = ns) and CK-MB (62 +/- 27 vs 64 +/- 27 U/l, p = ns), or postoperative echocardiographic score (26 +/- 7 vs 22 +/- 5, p = ns) and LVEF (53 +/- 10 vs 55 +/- 7%, p = ns). When the comparisons were restricted to those patients with preoperative LVEF < 50%, at 24 hours the isoflurane-treated patients exhibited a smaller release of troponin I and of CK-MB than controls (1.1 +/- 0.7 vs 2.3 +/- 1.3 ng/ml, p = 0.03, and 39 +/- 10 vs 57 +/- 22 U/l, p = 0.04, respectively).


CONCLUSIONS
Isoflurane reduces myocardial injury in patients with impaired left ventricular function undergoing CABG; thus, it can be safely used as an additional cardioprotective tool during routine CABG in high-risk patients with poor left ventricular function.
Tomai
F
F
Divisione di Cardiochirurgia, Università di Roma Tor Vergata, European Hospital.
De Paulis
R
R
Penta de Peppo
A
A
Colagrande
L
L
Caprara
E
E
Polisca
P
P
De Matteis
G
G
Ghini
A S
AS
Forlani
S
S
Colella
D
D
Chiariello
L
L
D000368:Aged; D000704:Analysis of Variance; D018685:Anesthetics, Inhalation / Q000494:pharmacology*; D000787:Angina Pectoris / Q000601:surgery; D002908:Chronic Disease; D001026:Coronary Artery Bypass; D003327:Coronary Disease / Q000601:surgery; D003402:Creatine Kinase / Q000097:blood; D004452:Echocardiography; D005260:Female; D006439:Hemodynamics; D006801:Humans; D007124:Immunoenzyme Techniques; D007527:Isoenzymes; D007530:Isoflurane / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D009206:Myocardium / Q000201:enzymology; D013053:Spectrophotometry; D019210:Troponin I / Q000097:blood*; D016277:Ventricular Function, Left
D018685:Anesthetics, Inhalation; D007527:Isoenzymes; D019210:Troponin I; D007530:Isoflurane; D003402:Creatine Kinase