Analysis of serum troponin for the diagnosis of perioperative myocardial injury and dynamics of NT-proBNP in high cardiac risk patients after elective craniotomy for brain tumors

Background. Perioperative myocardial injury in noncardiac surgery (MINS) is an asymptomatic complication associated with increased postoperative mortality. In patients with brain tumors this pathology is underestimated. Potential risk factors for MINS in elective neurosurgery are hypercoagulation, cancelation of antiplatelet and anticoagulant therapy, and intraoperative hemodynamic fluctuations. Objective. To assess the frequency and identify risk factors for perioperative myocardial injury in patients with high cardiac risk in elective brain tumor surgery; to study the effect of perioperative myocardial injury on the postoperative NT-proBNP changes. Material and methods. 90 patients with brain tumors finally included (age 65 years and older or older than 45 years in the presence of one or more concomitant significant cardiovascular diseases), operated in the Burdenko National Medical Research Center of Neurosurgery of the Ministry of Health of the Russian Federation. Patients underwent serum hs-cTnI, NT-proBNP analysis and ECG recording before surgery, on the 1st and 2nd day after surgery. The features of patient’s somatic status and hemodynamic parameters in the perioperative period were also analyzed. Perioperative myocardial injury was considered: an increase hs-cTnI on 1 and/or 2 days after surgery by more than 99th percentile (URL), if the initial normal level of troponin; or a change of hs-cTnI on 1 and/or 2 days after surgery by 20% or more, if the initial elevated level of hs-cTnI. Clinical and laboratory characteristics were compared in 2 groups of patients: with MINS and without MINS. Results. In both groups of patients, an increase in the level of hs-cTnI was demonstrated on the first day after surgery (Wilcoxon test for the first group, p=0.04, for the second group, p=0.0002). No significant changes in the level of troponin on the second day, compared with the first, were detected. Perioperative myocardial injury developed in 14 of 90 patients. In the group with MINS, ASA class 3 and 4 patients were significantly more common than among patients without MINS: 13 of 14 vs. 47 of 76, p=0.03; OR 14.2 (95% CI 1.8—110.8), p=0.01. Patients operated on in the afternoon (after 12:00) prevailed in the group with MINS, compared with the group without MINS: 8 of 14 vs. 21 of 76, p=0.06; OR 3.49 (95% CI 1.08—1.27), p=0.0365. In the group with MINS, patients operated in a sitting position on the operating table were more common than in the group without MINS: 3 of 14 vs. 4 of 76, p=0.05; OR 4.9 (95% CI 0.97—24.95), p=0.055. Severe intraoperative hypotension (mean BP <55 mmHg) in patients with MINS was significantly more common than in patients without MINS: 8 of 14 vs. 19 of 76, p=0.025; OR 4.0 (95% CI 1.23—13), p=0.02. In both groups of patients was found a significant increase in the level of NT-proBNP on the first and second postoperative days compared with the preoperative level. The median level of NT-proBNP in patients with MINS after surgery was higher than in patients without MINS, there was no statistically significant difference between the groups. Conclusions. In our study, the frequency of perioperative myocardial injury in patients with high cardiac risk in elective surgery of brain tumors was 16%. The patient’s physical status 3—4 class by ASA, surgery in the afternoon and intraoperative decrease in mean blood pressure below 55 mmHg are risk factors for the development of perioperative myocardial damage. The relationship between the perioperative dynamics of hs-cTnI and NT-proBNP requires further study.