COHgb levels predict the long-term development of acute myocardial infarction in CO poisoning

Abstract

Background: There are several studies evaluating the cardiac effects of carbon monoxide (CO) poisoning during the acute period; however, the number of studies evaluating the long-term cardiac effects is limited. Objective: The present study aimed to evaluate the effects of blood carboxyhemoglobin (COHb) levels, elevated due to CO poisoning on the long-term development of acute myocardial infarction (AMI). Methods: This cross-sectional cohort study included a total of 1013 consecutive patients who presented to the emergency department (ED) due to CO poisoning, between January 2005 and December 2007. The diagnosis of CO poisoning was made according to the medical history and a COHb level of greater than 5%. In terms of AMI development, the patients were followed up for an average of 56 months. Results: At the end of follow-up, 100 (10%) of 1013 patients experienced AMI. Carboxyhemoglobin levels at the time of poisoning were higher among those who were diagnosed with AMI compared to those who were not (55% +/- 6% vs 30% +/- 7%; P < .001). Using a multivariate Cox proportional hazards model with forward stepwise method, age, COHb level, CO exposure time, and smoking remained associated with an increased risk of AMI after adjustment for the variables found to be statistically significant in a univariate analysis. According to a receiver operating characteristic curve analysis, the optimal cutoff value of COHb used to predict the development of AMI was found to be greater than 45%, with 98% sensitivity and 94.1% specificity. Conclusion: In patients presenting to the ED with CO poisoning, COHb levels can be helpful for risk stratification in the long-term development of AMI. (C) 2016 Elsevier Inc. All rights reserved.