Usefulness of postoperative high-sensitive troponin T measurement and implications for defining type 5 infarction

Abstract

Background and aim of the study Guidelines on myocardial revascularization indicate for type V myocardial infarction (MI) that postoperative troponin elevations need not be exclusively ischemic but may also be caused by direct epicardial injury. Additional complexity arises from the introduction of high-sensitive troponin markers. The present study attempts to contribute to the understanding of postoperative high-sensitive cardiac troponin T (hs-cTnT) increase. Methods Type of surgery, potential factors affecting the postoperative hs-cTnT increase, and possible thresholds indicative of type V MI were analyzed. Results Among 400 included patients, 2.8% had intervention-related ischemia analogous to the type V MI definition. Receiver-operating characteristics confirmed good discriminatory power for hs-cTnT and creatine kinase myocardial band (CK-MB), with ischemia indicating thresholds for hs-cTnT (1705.5 ng/l) and for CK-MB (113 U/l). The median postoperative hs-cTnT/CK-MB increase differed significantly depending on the type of surgery, with the highest increase after mitral valve and the lowest after off-pump coronary surgery. Regression analysis confirmed Maze procedure (p<0.001), cardiopulmonary bypass time (p=0.03), emergency indications (p= 0.01) and blood transfusion (p=0.02) as significant factors associated with hs-cTnT increase. In contrast, CK-MB increase was also associated with mortality (p=0.002). Intra-pericardial defibrillation was the only ischemia-independent factor additionally associated with proposed thresholds (p<0.001). Conclusions The present results confirm the influence of the type of surgery and other intervention-related parameters on the postoperative hs-cTnT increase. Type V MI-indicating thresholds may require reassessment, especially using high-sensitive markers.

Towards an improved definition of periprocedural myocardial infarction: The role of high‐sensitivity cardiac troponins

“… 14 Other ECG findings as definite ST‐elevation or new conduction abnormalities (left bundle branch block) reflect actual PMI, 8 but are relatively rare after CABG, and their absence certainly does not rule out PMI. In the current study by Niclauss et al, 7 the biomarker dynamics were weighed against the UDMI‐4, which actually incorporates the use of cTn, making the UDMI‐4 an imperfect gold standard for calibration of cTn concentrations. The cut‐off values for cTn proposed by the UDMI (>10 × URL with supporting evidence) and SCAI (>35 × URL with supporting evidence, >70 × URL for isolated rises) were somewhat arbitrarily chosen but mostly relied on studies using long‐term survival as a standard.…”

“…5 Two topics of utmost interest in these "rivaling" definitions are (1) the use of isolated biomarker concentration elevations 5 versus a biomarker rise accompanied by additional evidence (electrocardiographic, echocardiographic, or angiographic), 4 and (2) the preferred use of either the MB-isoenzyme of creatine kinase (CK-MB) 5 or cardiac troponins. 4,6 In this issue of the Journal of Cardiac Surgery, Niclauss et al 7 performed a retrospective analysis of CK-MB and high-sensitivity cardiac troponin T (hs-cTnT) dynamics and peak concentrations following different cardiac surgical interventions in 400 patients during a 2-year period in a single center. The majority of patients (42%) underwent coronary artery bypass grafting (CABG; on-pump in 71% of cases, off-pump [OPCAB] in 29%), other procedures included isolated aortic valve replacement (AVR; 25%), combined CABG + AVR (13%), mitral valve surgery (14%), and a concomitant rate of 18% for septal myectomies.…”

“…In this issue of the Journal of Cardiac Surgery , Niclauss et al 7 performed a retrospective analysis of CK‐MB and high‐sensitivity cardiac troponin T (hs‐cTnT) dynamics and peak concentrations following different cardiac surgical interventions in 400 patients during a 2‐year period in a single center. The majority of patients (42%) underwent coronary artery bypass grafting (CABG; on‐pump in 71% of cases, off‐pump [OPCAB] in 29%), other procedures included isolated aortic valve replacement (AVR; 25%), combined CABG + AVR (13%), mitral valve surgery (14%), and a concomitant rate of 18% for septal myectomies.…”