03 Mar NEJM Study Evaluates Levels of hs Troponin after Cardiac Surgery and Risk of Death
MedicalResearch.com Interview with:
PJ Devereaux MD PhD
Professor of Medicine, and
of Health Research Methods, Evidence and Impact
President of the Society of Perioperative Research and Care
MedicalResearch.com: What is the background for this study?
Response: More than 1 million patients undergo cardiac surgery in the United States and Europe annually. Although cardiac surgery has the potential to improve and prolong a patient’s quality and duration of life, it is associated with complications. Prognostically important heart injury – detected by an elevated blood concentration of either cardiac troponin or creatine kinase myocardial MB isoform (CK-MB) – is one of the most common complications after cardiac surgery and is associated with increased mortality.
Although elevated CK-MB was historically used to define heart injury after cardiac surgery, this assay is no longer available in many hospitals worldwide, and consensus statements have recommended high-sensitivity cardiac troponin assays as the preferred biomarker. Based on expert opinion, the Fourth Universal Definition of Myocardial Infarction suggested that a cardiac troponin concentration >10 times the upper reference limit, in patients with a normal baseline measurement, should be the threshold used in the diagnosis of heart attack along with evidence of ischemia (e.g., ischemic ST changes on an ECG) in the first 48 hours after coronary artery bypass grafting (CABG). Although the Academic Research Consortium-2 Consensus stated there was no evidence-based threshold for cardiac troponin after CABG, they endorsed a threshold for the diagnosis of heart attack of ≥35 times the upper reference limit together with new evidence of ischemia, based on expert opinion. They also defined a threshold of ≥70 times the upper reference limit as a stand-alone criterion for clinically important periprocedural myocardial injury.
Globally, many hospitals now use high-sensitivity cardiac troponin assays; however, limited data are available to define a prognostically important degree of myocardial injury after cardiac surgery based on these assays. We undertook the Vascular Events in Surgery Patients Cohort Evaluation (VISION) Cardiac Surgery Study to examine clinical outcomes after cardiac surgery.
A primary objective was to determine the relationship between postoperative levels of high-sensitivity cardiac troponin I and the risk of death 30 days after cardiac surgery.
MedicalResearch.com: What are the main findings?
Response: Amongst patients who had isolated coronary artery bypass grafting / aortic valve replacement or repair (CABG/AVR), we demonstrated that the prognostically important threshold troponin value was 5670 ng/L (218 times the upper reference limit) within 1 day of surgery and 1522 ng/L (59 times the upper reference limit) on day 2 or 3 after surgery. Among patients who underwent other cardiac surgery, we estimated that the prognostically important threshold troponin value was 12,981 ng/L (499 times the upper reference limit) within 1 day of surgery and 2503 ng/L (96 times the upper reference limit) on day 2 or 3 after surgery.
We observed that the lowest troponin thresholds associated with an increased risk of death at 30 days after cardiac surgery were substantially higher than the levels that are currently recommended as the basis for diagnosis of perioperative heart attack or clinically important perioperative heart injury in consensus statements. The recommended troponin thresholds in these consensus statements (>10, ≥35, and ≥70 times the upper reference limit) were exceeded by 97.5%, 89.4%, and 74.7% of patients, respectively, within the first day after surgery.
MedicalResearch.com: How might these findings improve patient care?
Response: These findings can help to ensure we are not over diagnosing heart attacks after heart surgery and that randomized controlled trials evaluating interventions to prevent heart attacks after heart surgery are providing accurate results. This can have a big impact on the results of clinical trials.
MedicalResearch.com: What recommendations do you have for future research as a result of this work?
Response: Further studies evaluating other high-sensitivity troponin assays in patients having heart surgery would be valuable.
Disclosures: Although most funding came from peer reviewed funding bodies, we did receive the assays and some funding from Abbott Diagnostics.
High-Sensitivity Troponin I after Cardiac Surgery and 30-Day Mortality
P.J. Devereaux et al for the VISION Cardiac Surgery Investigators
N Engl J Med 2022;386:827-836
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