Peri-operative myocardial injury in patients undergoing surgery for critical limb ischaemia.
BACKGROUND
Although up to a half of patients undergoing abdominal aortic aneurysm (AAA) repair suffer myocardial injury, as indicated by a rise in cardiac troponin I (cTnI), this is infrequently accompanied by a rise in creatine kinase (CK)-MB fraction or electrocardiogram (ECG) changes. This study compares for the first time peri-operative cTnI, CK-MB and ECG changes in patients undergoing surgery for critical lower limb ischaemia (CLI).


METHODS
Twenty-nine patients (20 men, median age 75 [range, 57-95] years) were studied prospectively. cTnI, CK/CK-MB ratio and ECG were performed pre-operatively and on post-operative days 1, 2 and 3.


RESULTS
Eleven (38%) patients had an elevated cTnI >0.5 ng/ml. Five (17%) patients had an elevated CK-MB fraction >4% and all of these patients had an elevated cTnI. Eleven (38%) patients had ischaemic changes on ECG including seven of 11 (64%) patients with elevated cTnI and all five patients with elevated CK-MB fraction. There was no relationship between pre-operative cardiac status, antiplatelet use or type of anaesthesia and post-operative cTnI rise. Patients with a cTnI rise were younger (p=0.01), and were more likely to have presented with gangrene (p=0.04) and have a longer operation time (p=0.01) than patients who did not demonstrate a cTnI rise. Four patients developed clinically apparent cardiac complications: cardio-pulmonary arrest (n=1), cardiogenic shock (n=1), acute CCF (n=1) and rapid atrial fibrillation (n=1). Survival at 6 months was 26 of 29 (90%) patients.


CONCLUSIONS
These data demonstrate that over a third of patients operated for CLI sustain peri-operative myocardial injury, many of which are not clinically apparent. Pre-operative medical optimisation may improve prognosis in this group of patients.
Hobbs
S D
SD
University Department of Vascular Surgery, Birmingham Heartlands Hospital, Birmingham, UK.
Yapanis
M
M
Burns
P J
PJ
Wilmink
A B
AB
Bradbury
A W
AW
Adam
D J
DJ
D000368:Aged; D000369:Aged, 80 and over; D019917:Blood Vessel Prosthesis Implantation / Q000009:adverse effects*; D003402:Creatine Kinase / Q000097:blood; D052279:Creatine Kinase, MB Form; D004562:Electrocardiography; D005260:Female; D006801:Humans; D007431:Intraoperative Complications / Q000175:diagnosis*; D007511:Ischemia / Q000601:surgery*; D007527:Isoenzymes / Q000097:blood; D035002:Lower Extremity / Q000098:blood supply*; D008297:Male; D008875:Middle Aged; D009203:Myocardial Infarction / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D011183:Postoperative Complications / Q000175:diagnosis*; D011446:Prospective Studies; D016896:Treatment Outcome; D019210:Troponin I / Q000097:blood
D007527:Isoenzymes; D019210:Troponin I; D003402:Creatine Kinase; D052279:Creatine Kinase, MB Form