K. S. Shrestha1, A. A. Gullick2, T. S. Wahl2, R. H. Hollis2, J. Richman2, J. K. Kirklin2, M. S. Morris2 1University Of Alabama at Birmingham,School Of Medicine,Birmingham, Alabama, USA 2University Of Alabama at Birmingham,Department Of Surgery,Birmingham, Alabama, USA
Introduction: The American College of Surgeons National Surgical Quality Improvement Program (NSQIP) provides benchmarking quality standards designed to improve quality of care and surgical outcomes. We explore NSQIP’s current definition (2007 Universal Definition) of myocardial infarctions (MI) and compare to an updated definition, the 2012 Universal Definition of MI.
Methods: All NSQIP assessed post-operative cardiac events in 2013-2015 from a single institution were examined as part of a quality improvement project. The current NSQIP definition (2007 Universal definition) classifies an MI by one of the following: a troponin elevation 3-times the upper limit of normal (ULN), ischemic EKG changes, or any charted physician diagnosis. The 2012 Universal definition is defined by a troponin elevation of 5-times the ULN and at least one of the following: ischemic symptoms, ischemic EKG changes, wall motion abnormalities on imaging studies, or an intraluminal thrombus detected on an angiogram. The study group included all patients who met the NSQIP definition for postoperative MI. The 2012 Universal definition was then applied to the group with patient- and procedure-specific characteristics compared by MI definition (NSQIP vs. 2012) using Chi-Square tests.
Results: Eighty-one patients were identified. Only 27 (33.3%) of patients meeting the NSQIP definition also met the 2012 Universal definition of MI. Overall, the average patient was a 68.1 (SD 12.2) year old white (69.1%) male (54.3%) with a BMI of 28.2 (SD 7.8). There were no significant differences between definition groups (NSQIP vs. 2012) regarding patient demographics or perioperative complications. Only 22.2% of the NSQIP defined group had a troponin level 5-times the ULN meeting the 2012 Universal defined group (p<0.0001). Patients classified using the 2012 Universal definition had significantly more ischemic EKG changes compared to the NSQIP definition (ST-elevation: 25.9% vs 3.7%, respectively, p=0.01; Q wave: 22.2% vs. 0%, respectively, p= 0.001). NSQIP defined MI occurrences were more likely to be NSTEMI type II events compared to the 2012 Universal group (85.2% vs. 51.9%, p = 0.003). Patients with MI meeting 2012 definition were more likely to have Ischemic symptoms (70.4% vs 37%, p=0.005) and abnormal imaging changes (33.3% vs 13%, p=0.03) compared to the current NSQIP definition.
Conclusion: Only one-third of patients with a MI defined by the current NSQIP definition met the 2012 universal MI definition. Compared to the current NSQIP MI definition, the 2012 Universal definition captures patients with more ischemic symptoms, ischemic EKG changes, abnormal changes on imaging studies, and higher troponin levels during an MI with fewer NSTEMI Type II events. The current NSQIP definition may over-estimate true coronary events. Further consideration to update and reclassify NSQIP’s MI definition may be warranted.
The project described was supported by Awards Numbered T32DK062710 and P30DK079626 from the National Institute of Diabetes and Digestive and Kidney Diseases. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institute of Diabetes and Digestive and Kidney Diseases or the National Institutes of Health.