Role of β-type natriuretic peptide as predictor of early post-operative outcomes in Chinese patients undergoing anesthesia

Dear Editor-in-Chief,

I read an article published in the December 2017 issue of Bangladesh Journal of Pharmacology (Chen and Lin, 2017) with great interest. The authors had studied whether the levels of pre-operative and post-operative B-type natriuretic peptide (BNP) could play a role as the predictor of post-operative complications in Chinese patients. I wish to make some comments on that article.

In the “Introduction” section of that article, the authors had written the following sentence: “Few studies demonstrated that the levels of BNF predicted the post-operative complication in terms of mortality and morbidity after cardiac surgery (Mair et al., 1999; Struthers, 1994; Morrison et al., 2002; Harrison et al., 2002)”.

However, none of the four references cited for this sentence is supporting it. Harrison et al. (2002) had investigated the levels of BNP and concluded that it highly predicted the cardiac events in the subsequent six months in patients presented to the emergency department with dyspnea. Mair et al. (2002), did not study about the impact of BNP in cardiac surgery (Mair et al., 1999). Morrison et al. (2002) concluded that assessing the levels of BNP would help in differentiating the cause of dyspnea from pulmonary or cardiac origin. This study has nothing to do with cardiac surgeries (Morrison et al., 2002). The article by Struthers (1994) is also not relevant for that sentence (Struthers, 1994).

Chen and Lin, (2017), had failed to quote references for the subsequent sentence i.e. “ In contrast to this, there are few studies which reported variation in response of BNP, possibly due to the age factor or severity factor of cardiac diseases.”

The authors mentioned in the “Discussion” section that the incidence of mortality was significantly higher in patients who had higher pre-operative BNP while comparing it to those who had lesser pre-operative BNP (Chen and Lin, 2017). However, the Table III depicts the p-values as >0.05 for both mortality parameters i.e. within 30 days and within one year.

Although the authors had mentioned that their study was the first pilot study that assessed the role of pre-operative BNP levels as predictor of early postoperative outcomes in Chinese population undergoing anesthesia, there is one study available in the literature that had indeed analyzed it already. Of course, there are some differences between these two studies (Chen and Lin, 2017, Ma et al. 2015). Ma et al had studied the impact of N-terminal probrain natriuretic peptide (NT-pro-BNP) and cardiac troponin I (cTnI) levels in patients aged over 60 years undergoing emergent non-cardiac surgery. They concluded that both pre-operative plasma NT-proBNP and cTnI are independently associated with an increased risk of MACE [major adverse cardiac events] in elderly patients after non-cardiac surgery performed on an emergency basis. In addition, they also observed that the combination than using either biomarker separately provides better prognostic information. This study was conducted between December 2007 and December 2013 on Chinese population, and published in March 2015 (Ma et al. 2015).

I also feel that it would have been better if the authors (Chen and Lin, 2017) had used a specific cut-off value for BNP in their patients.

M. S. Raghuraman

Department of Anesthesiology, Shri Sathya Sai Medical College and Research Institute, Sri Balaji Vidyapeeth University, Chennai, India. drraghuram70@gmail.com ; ORCID iD