Correspondence  |   September 2020
Blood Pressure Components and Organ Injury: Comment
Author Notes
  • Mie University Hospital, Mie, Japan. komekurahiroshi@gmail.com
  • (Accepted for publication June 9, 2020. Published online first on July 9, 2020.)
    (Accepted for publication June 9, 2020. Published online first on July 9, 2020.)×
Article Information
Correspondence
Correspondence   |   September 2020
Blood Pressure Components and Organ Injury: Comment
Anesthesiology 9 2020, Vol.133, 673-674. doi:https://doi.org/10.1097/ALN.0000000000003450
Anesthesiology 9 2020, Vol.133, 673-674. doi:https://doi.org/10.1097/ALN.0000000000003450
We read with great interest the article by Ahuja et al.1  on the association between various intraoperative blood pressure components and postoperative morbidity. They identified an association among the arterial systolic, mean, and pulse pressure hypotension with myocardial and renal injury. Although the main finding—a lower blood pressure can be associated with postoperative myocardial injury after noncardiac surgery and acute kidney injury—offers clinically valuable information, we believe that some inherent bias in the study design should be discussed and clarified.
First, compared with previously published studies, this study had an important difference in the definition of myocardial injury after noncardiac surgery.2  The outcome definition of myocardial injury in this study (i.e., elevation of troponin or creatinine kinase-myocardial bound during the first 7 postoperative days)1  was different from that approved by the consensus diagnostic criteria in 2014, which defined myocardial injury after noncardiac surgery as “elevated post-operative troponin measurement judged as resulting from myocardial ischemia during or within 30 days after non-cardiac surgery.”3,4  In addition, this study did not exclude nonischemic etiologies (sepsis, arrythmias, pulmonary embolism, etc.). A previous study showed that elevation of troponin levels in 11 to 14% cases after noncardiac surgery was due to nonischemic etiologies.3  Therefore, without an adequate outcome assessor, the results of Ahuja et al.1  tend to overestimate the actual incidence of myocardial injury by including nonischemic etiologies. Although this exclusion was not possible because of the retrospective study design using electronic medical records, the authors should discuss this aspect in the study limitations.