Long-term outcome of patients with perioperative myocardial infarction as diagnosed by troponin I after routine surgical coronary artery revascularization.
OBJECTIVE
Diagnosis of perioperative myocardial infarction (P-MI) after coronary artery bypass graft (CABG) surgery traditionally relied on a combination of electrocardiographic and enzyme assay changes. Patients with Q-wave P-MIs who survive to hospital discharge have a poorer long-term prognosis. Troponin assays are more sensitive and specific for detecting minor P-MI, with an increased incidence of P-MI being reported. This study investigated if P-MI after CABG surgery, as defined by troponin-I isozyme (cTn-I), correlated with long-term outcome.


METHODS
A prospective, observational study.


METHODS
A single-institution, cardiothoracic specialty hospital.


METHODS
Seventy patients undergoing elective CABG surgery.


METHODS
Patients (n = 70) were stratified into low-risk and high-risk groups according to the absence (cTn-I <15 microg/L) or presence (cTn-I >or=15 microg/L) of P-MI after CABG surgery. Patients with (n = 24) and without (n = 46) P-MI were then followed for 3 years after CABG surgery to determine the impact of cTn-I-defined P-MI on long-term outcome.


RESULTS
Most patients felt that their quality of life and activity index had improved and that their symptoms of angina had lessened at 12-month follow-up. However, cardiovascular event-free survival was significantly less in patients with P-MI (p = 0.01) 3 years postoperatively. The incidence for cardiovascular events was 0.24 versus 0.65 (p = 0.049) in those patients without and with P-MI, respectively. The hazard ratio (2.9; 95% confidence interval, 1.3-9.4) for cardiovascular incidents was also significantly greater in patients with P-MI. More specifically, the incidence of arrhythmia was 2.4% versus 26.1% (p < 0.01), and the incidence of vascular events was 4.9% versus 26.1% (p = 0.02) in patients without and with P-MI, respectively.


CONCLUSIONS
It was shown that P-MI as defined by cTn-I is associated with an increased long-term incidence of adverse cardiovascular events. An elevated peak cTn-I level (>or=15 microg/L) identified patients at increased risk but did not have a powerful positive predictive value for either cardiovascular (48%) or vascular (26%) complications. However, a peak cTn-I <15 microg/L was a negative predictor of adverse vascular outcome (95%). This may have implications for postoperative patient follow-up.
Riedel
Bernhard J
BJ
Division of Anesthesiology and Critical Care, University of Texas M.D. Anderson Cancer Center, Houston 77030, USA. briedel@mdanderson.org
Grattan
Amanda
A
Martin
C Bruce
CB
Gal
Janos
J
Shaw
Andrew D
AD
Royston
David
D
D015331:Cohort Studies; D001026:Coronary Artery Bypass / Q000009:adverse effects; D023921:Coronary Stenosis / Q000601:surgery*; D018572:Disease-Free Survival; D005500:Follow-Up Studies; D006801:Humans; D015994:Incidence; D009043:Motor Activity; D009203:Myocardial Infarction / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D011183:Postoperative Complications / Q000097:blood / Q000175:diagnosis* / Q000209:etiology; D011237:Predictive Value of Tests; D011379:Prognosis; D011446:Prospective Studies; D011788:Quality of Life; D018570:Risk Assessment; D012680:Sensitivity and Specificity; D013995:Time; D016896:Treatment Outcome; D019210:Troponin I / Q000097:blood*
D019210:Troponin I