The relationship between intraoperative hypotension and high sensitivity troponin T level in hip and knee replacement surgeries

Myocardial injury is diagnosed by changes in high sensitivity troponin T (hsTnT). It is hypothesized that the injury may be caused by intraoperative hypotension (IOH). The aim of the study was to investigate the correlation between intraoperative hypotension and changes in high sensitivity troponin T levels. Totally, 33 orthopedic patients, 25 female, 8 male, with average age 67 ± 8.4 years were included in prospective observational study, 36.4% had hip replacement surgery (n=12) and 63.3% had knee replacement surgery (n=21).  Routine medication, co – morbidities, ECG changes were obtained. HsTnT was evaluated at two time points: T1 right before the surgery and T2 - on the first postoperative day.  IOH was defined as MAP ≤ 65 mm/Hg that lasts at least five minutes. Significantly increased hsTnT level was defined as ≥14 ng/L or > 20% from T1 measurement if it was ≥14 ng/L. Results from 33 patients demonstrates significantly increased levels of hsTnT postoperatively in 24.2%. The average surgery time for knee replacement was 84 ± 25.9 minutes and for hip replacemet was 79 ± 23.6 minutes without intergroup difference. Mean hsTnT level at T1 was 10.3 ng/L and at T2 12.62 ng/L without significant difference (p = 0.89). Eight patients had increased hsTnT  at T2 by 56,7 % compared to T1. There was no association between surgery type and hsTnT elevation. Elevated hsTnT levels postoperatively were found in 21.4% for those with IOH compared to 26.3% in those without IOH, p = 0.72. No cardiovascular emergencies were detected in postoperative period. There was not found significant correlation between IOH and postoperative hsTnT changes (p=0.77). After joint replacement surgery elevated hsTnT levels were found in both groups of patients with and without intraoperative hypotension. Intraoperative hypotension seems not to affect changes in hsTnT levels after joint replacement surgeries.