C. N. Holcomb1, L. A. Graham2, T. M. Maddox4, K. M. Itani3, M. T. Hawn1,2 1University Of Alabama At Birmingham,Department Of Gastrointestinal Surgery,Birmingham, AL, USA 2Birmingham VA Medical Center,The Center For Surgical, Medical Acute Care Research And Transitions (C-SMART,Birmingham, AL, USA 3Boston University And Harvard Medical School,Department Of Surgery,Boston, MA, USA 4University Of Colorado School Of Medicine,Cardiology,Denver, COLORADO, USA
Introduction: Patients with coronary stents undergoing non-cardiac surgery are at an increased risk of adverse cardiac events. Knowledge of this risk may increase the number of troponin tests and influence interventions performed in the early post-operative period.
Methods: The VA Patient Treatment File was used to identify coronary stents implanted in the VA system from October 1, 1999 through September 30, 2010. Patients undergoing non-cardiac surgery within 24 months of coronary stent were identified using VA Surgical Quality Improvement Program data. Each stented patient was matched to two non-stented patients undergoing non-cardiac surgery. Matching variables included age, race, surgical specialty, fiscal year of the operation, work RVU, and components of the revised cardiac risk index. Cardiac troponin (cTroponin) levels drawn in the first 72 hours following surgery were assessed and a cTroponin >0.04ng/ml was considered a positive test. The outcomes of interest were MI, cardiac catheterization, and death. Bivariate frequencies were compared using chi-square test.
Results: Over the 11 year study period, 5,855 stented patients and 11,371 non-stented patients with similar cardiac risk underwent an inpatient surgery. Within the first 72 hours of surgery, patients with coronary stents had higher rates of cTroponin testing (25.5% vs 18.7%, p<0.001) with more positive tests (56.4% vs. 52.9%, p=0.04) compared to non-stented patients. Among those tested, stented patients experienced higher rates of MI (9.8% vs 6.3%, p<0.001). Myocardial infarctions were diagnosed at lower maximum cTroponin values in stented patients versus non-stented patients (Figure). Following a diagnosis of MI, patients with stents were more likely to undergo cardiac catheterization (31.2% vs 19.9%, p<0.01) with no difference in cardiac mortality (17.2% vs 20.9%, p=0.34) between the two cohorts.
Conclusions: Post-operative cTroponin testing among patients with coronary stents was associated with higher observed MI rates and cardiac catheterizations at lower maximum troponin levels but no observed difference in mortality following MI compared to non-stented patients. Further studies should be done to determine factors predicting improved outcomes with cardiac interventions following surgery.
