Objectives: The aim of this prospective study was to evaluate postoperative kinetics of four different biochemical ischaemic markers after elective aortic valve replacement (AVR). Additionally, pre-, peri- and postoperative data were analysed in order to identify factors with possible impact on the postoperative release of the selected enzymes.
Design: Forty patients (14 males, 26 females, aged 70 +/- 11 years; EF = 54 +/- 18% [mean +/- SD]) undergoing elective AVR were prospectively included in this study. For all patients, serum concentrations of cTnI, cTnT, and serum activities of CK-MB and CK were measured preoperatively as well as 0, 6, 12, 24, 48 and 120 hours after removal of the aortic cross-clamp. Clinical data were assessed in all patients and correlated with postoperative enzyme patterns.
Results: There were no major complications. Preoperatively, all patients showed enzyme values in the normal range whereas the four ischaemic markers reached higher values postoperatively. cTnI reached its maximum values 24 hours (XMed = 2.35 micrograms/L, 95%-CI [2.0, 3.3]) and cTnT 48 hours after the operation (XMed = 0.239 microgram/L, 95%-CI [0.174, 0.283]). Typical biphasic release kinetics could be demonstrated for cTnT. There was a high linear correlation between cTnI and cTnT at all sampling times. In contrast, a high linear correlation between cTnI, cTnT, and CK-MB-activity was only found 48 hours after aortic unclamping. cTnI nearly was in normal range 120 h postoperatively (XMed = 0.5 microgram/L, 95%-CI [0.2, 0.6]), whereas cTnT still remained pathologically elevated (XMed = 0.223 microgram/L, 95%-CI [0.137, 0.299]). No linear correlation was found between maximum values of the ischaemic markers postoperatively and age, gender, body surface area, ejection fraction, LV-hypertrophy, operating time, ECC time, time of cardiac arrest, lowest body temperature, perfusion pressure, cardioplegia volume, reperfusion time, postoperative septiformic circulatory instability, or ventilation time.
Conclusions: All four ischaemic markers showed individual peak characteristics and kinetics after uncomplicated AVR. In contrast to previous findings, aortic cross-clamping time had no detectable impact on postoperative peak patterns of any ischaemic marker.