Comparison of different prophylactic myocardium saving measures during heart surgery. Effects on perioperative troponin-T levels.
OBJECTIVE
Different prophylactic myocardium saving strategies are often routine in open heart surgery. Even if theoretically well established, they must be critically reviewed in times of limited financial resources.


METHODS
Troponin-T (TnT) is a valuable tool to detect even minor myocardial damages independently from concomitant muscle injuries. We measured intra- and postoperative TnT-values and ST-wave deviations on the ECG in a control group and in patients receiving one of the following prophylactic


METHODS
hypothermia during cardiopulmonary bypass (CPB), nitroglycerine ([0.5 microgram/kg/min]) or nifedipine [0.1 microgram/kg/min] after aortic cross-clamping until end of operation, or perioperative Mg2+ per os.


METHODS
The study included 65 patients of a university hospital with preoperative good heart function scheduled for elective aorto-coronary bypass operation.


RESULTS
TnT values increased in all groups after CPB and peaked between end of operation and first post-operative day. TnT values above the critical border of 1.0 microgram/l in the early period after CPB were less often seen in the nitroglycerine and nifedipine group. No pronounced differences could be observed after the first postoperative day. Patients of the hypothermia group had most often TnT values above 1.0 microgram/l. Maximum TnT values of the control, the hypothermia and the Mg(2+)-group correlated with the duration of aortic-crossclamping. No correlation existed between ST-deviations and TnT-values.


CONCLUSIONS
The prophylactic measures failed to reduce myocardial damage as evidenced by the course of TnT values. They can therefore not be recommended as routine strategies in patients with good left heart function. Especially hypothermia should be considered carefully.
Knothe
C
C
Department of Anaesthesiology and Intensive Care Medicine, Justus-Liebig-University Giessen, Germany.
Boldt
J
J
Dehne
M
M
Zickmann
B
B
Porsch
S
S
Dapper
F
F
Hempelmann
G
G
D000368:Aged; D015415:Biomarkers / Q000097:blood; D002121:Calcium Channel Blockers / Q000008:administration & dosage; D002315:Cardiopulmonary Bypass; D001026:Coronary Artery Bypass; D004562:Electrocardiography; D006801:Humans; D007036:Hypothermia, Induced; D007432:Intraoperative Period; D008274:Magnesium / Q000008:administration & dosage; D008875:Middle Aged; D015428:Myocardial Reperfusion Injury / Q000097:blood / Q000175:diagnosis / Q000517:prevention & control*; D009543:Nifedipine / Q000008:administration & dosage; D005996:Nitroglycerin / Q000008:administration & dosage; D011184:Postoperative Period; D014336:Troponin / Q000097:blood*; D020107:Troponin T; D014665:Vasodilator Agents / Q000008:administration & dosage
D015415:Biomarkers; D002121:Calcium Channel Blockers; D014336:Troponin; D020107:Troponin T; D014665:Vasodilator Agents; D005996:Nitroglycerin; D008274:Magnesium; D009543:Nifedipine