Materials and Methods
The institutional review board ensured ethics approval in accordance
with international recommendations. According to the decision of the
Ethics Committee, (protocol number 2016-01884) patient consent was
waived.
Patients were operated by two surgeons in 2016 and 2017. All major
cardiac interventions, except surgery for terminal heart failure (assist
devices, transplantation) or acute aortic disease (dissection), were
included. Follow-up focused on 30 days after surgery and documented
adverse events: Mortality, type 5 MI (which requires a significant
hs-cTnT increase by analogy with ESC guidelines, although the threshold
needs to be further defined), stroke, changes in ventricular function,
and new ECG modifications.
Other parameters that could have an impact on enzyme elevation were also
considered: Demographic and risk factors, i.e., preoperative MI,
European System for Surgical Cardiac Risk Evaluation (EuroSCORE II),
renal function, etc., direct surgery-related factors, i.e., type of
cardioplegia, cross-clamp and cardiopulmonary bypass time, blood
transfusions, intra-pericardial defibrillation, etc., and type of
surgery.
Cardiac enzymes, i.e. hs-cTnT and creatine kinase myocardial band
(CK-MB), were recorded before and 1, 6, 12, 24 to at least 48 hours
after surgery. The hs-cTnT assay used (Elecsys Troponin T high sensitive
by Roche, Basel, Switzerland) has the following specifications:
99th percentile URL is 14 nanogram per liter (ng/l)
with a precision value (coefficient of variation ≤ 10%) of 13 ng/l, a
limit of detection at 5ng/l and a blank at 3 ng/l [2]. CK-MB was
measured in international units and its concentration expressed in units
per liter (U/L).
Pre- and postoperative echocardiography was performed in all patients,
with a focus on new ventricular dysfunction (considered significant if
it had worsened by at least one grade according to the EuroSCORE
classification) or new regional wall motion abnormalities attributable
to coronary perfusion territories [3].