Intraoperative release of troponin T in coronary venous and arterial blood and its relation to recovery of left ventricular function and oxidative metabolism following coronary artery surgery

Abstract

Objective-To investigate the intraoperative release of troponin T during uncomplicated coronary artery surgery and to determine its relation to ischaemic time and to recovery of left ventricular function and oxidative metabolism. Design-A prospective observational study. Setting-Cardiac surgical unit in a tertiary referral centre. Methods-Troponin T, creatine kinase, and lactate were analysed from arterial and coronary sinus samples taken before operation, and 1, 4, 6, 10, 20, 35, and 45 minutes after cross clamp release. Net myocardial troponin T release and lactate extraction were derived from their respective arteriovenous diVerences. Haemodynamic measurements were made using a thermodilution pulmonary artery catheter. Patients-45 patients, mean (SD) age 62 (9) years, with two or three vessel coronary artery disease and chronic stable angina undergoing routine coronary artery surgery. Results-Before operation, troponin T concentrations were not raised, but within one minute of cross clamp release they increased progressively in both coronary sinus and arterial blood for the entire 45 minutes of reperfusion studied. Coronary sinus troponin T concentrations were consistently higher than arterial concentrations at all time points (p < 0. Conclusions-Troponin T concentrations increased in every patient after cross clamp release, and were consistently higher in coronary sinus blood than in arterial blood, indicating net myocardial release of troponin T during the period of reperfusion. Intraoperative net troponin T release has functional significance, as it is closely related to ischaemic time and reflects delayed recovery of left ventricular function and oxidative metabolism; therefore, its measurement may contribute to the perioperative assessment of myocardial injury sustained during coronary artery surgery. (Heart 1998;80:341-348)

Myocardial Conditioning

“…Nonetheless, the proportion of patients exhibiting postprocedural release of cardiac enzymes-a variable associated with poor short-term and long-term outcomes-has been estimated at 30% after elective PCI and 40% to 90% after CABG surgery, with 12% to 19% of CABG patients developing Q-wave or non-Q-wave infarction. [107][108][109][110][111][112] These data demonstrate that, as with STEMI, there remains considerable scope for augmenting cardioprotection in clinical instances of planned ischemia-reperfusion.…”

Das atriale natriuretische Peptid als Indikator einer milden postoperativen kardialen Dysfunktion nach unkomplizierter Bypasschirurgie

“…TnT als signifikantem Marker bei myokarddialer Ischämie, kommt in der Bypasschirurgie eine zentrale Rolle bei der Abschätzung der funktionellen Beeinträch-tigung des linken Ventrikels zu (12,13,25). Quantitative Konzentrationsbestimmungen von TnT, scheinen Rückschlüsse auf die Schwere des ischämischen Schadens und einer verzögerten Erholung der linksventrikulären Funktion und des oxidativen Metabolismus in einem kurzfristigen Zeitfenster zuzulassen (12,13).…”

“…Quantitative Konzentrationsbestimmungen von TnT, scheinen Rückschlüsse auf die Schwere des ischämischen Schadens und einer verzögerten Erholung der linksventrikulären Funktion und des oxidativen Metabolismus in einem kurzfristigen Zeitfenster zuzulassen (12,13). ANP sollte dagegen eher als mittel-bis langfristiger Funktionsparameter dienen.…”

“…Mehrere international veröffentlichte Studien beschäftigen sich mit der Rolle des ANPs im Zusammenhang mit ischämischen Ereignissen am Myokard und der Frage, ob die Konzentrationsverläufe dieses Hormons zur Einschätzung der kardialen Funktion herangezogen werden können (1,5,7,19,21,22,27,28). Auch die Rolle des TnTs in der Bypasschirurgie zur Abschätzung des myokardialen Schadens und als Verlaufsmarker für die Beeinträchtigung der Funktion des linken Ventrikels und des oxidativen Metabolismus wurden mehrfach untersucht (12,13,25).…”

Predicting the outcome of revascularization in ischaemic left ventricular dysfunction

“…The presence of hibernation alone does not guarantee recovery of function after revascularization and a number of other factors are important, including the severity of pre-operative dysfunction, previous or peri-operative myocardial infarction, myocardial preservation during surgery, and the nature of the surgical procedure itself -traditional bypass surgery vs beating heart surgery [7] . However, advances in anaesthesia, revascularization techniques and postoperative pharmacological support have lessened the associated risks, and have increased the importance of hibernation.…”