A prospective, randomised, single‐blind pilot study to determine the effect of anaesthetic technique on troponin T release after off‐pump coronary artery surgery

Abstract

SummaryIschaemic damage to the myocardium inevitably occurs during coronary artery surgery. However, the extent of the damage may be influenced by the anaesthetic technique used. The most sensitive and reliable marker of myocardial damage is currently thought to be troponin T. We conducted a prospective, randomised, single-blind pilot study to determine the baseline values of troponin T release after off-pump coronary artery bypass surgery in 30 patients randomly allocated to receive either propofol, isoflurane or isoflurane and high thoracic epidural analgesia. All other treatment was standardised. Patients undergoing emergency surgery and those with unstable angina were excluded. Blood samples were taken at 0, 3, 6, 12, 24 and 48 h after surgery for troponin T analysis. Mean troponin T levels at 24 h were not significantly different between the groups (p = 0.41). These data allows appropriate power calculations for further, large-scale studies to determine the anaesthetic technique that provides optimal myocardial protection.

Comparison of haemodynamics and myocardial injury markers under desflurane vs. propofol anaesthesia for off-pump coronary surgery. A prospective randomised trial

“…We did not observe a significant effect of desflurane on blood concentrations of markers of myocardial ischaemia: troponin I and CK-MB. Earlier studies demonstrated conflicting results: a decreased concentration after volatile anaesthesia [12,14], or no effect [10,[15][16][17][18]. In two studies published recently, late postconditioning with sevoflurane used for sedation after coronary surgery also did not provide reduction of troponin release [19,20].…”

Treating myocardial stunning randomly, with either propofol or isoflurane following transient coronary occlusion and reperfusion in pigs

“…[4,14,15,47,48] A recent randomized study demonstrated that isoflurane, administered in low minimum alveolar concentration through the precardiopulmonary bypass reduces postoperative catecholamine requirements of cardiac surgery patients. [49] There are at least three different mechanisms in the cellular or sub cellular levels involved in this volatile anesthetic protection, and all of them were out of the scope of our present study:…”

“…A review of the medical literature reveals that the effects of propofol on myocardial stunning after transient ischemia have not been properly investigated, and that in vivo it was far from being advantageous, [8,9,11,12,14,[16][17][18]32] even though there is some evidence (mostly in in vitro studies) for its potential to protect the ischemic myocardium. [13,15,[33][34][35][36][37][38] The purpose of this study was to compare the effects of propofol vs isoflurane in a porcine model of acute coronary occlusion, imitating postischemic reversible contractile dysfunction conditions that may appear in off-pump cardiac surgery. We investigated the hypothesis that volatile anesthetic isoflurane improves global myocardial function, following transient coronary occlusion and reperfusion when compared to the short-acting intravenous anesthetic, propofol.…”

“…[1][2][3][4][5][6] However, the application of propofol to the patients of coronary artery disease is controversial. [7][8][9][10][11][12][13][14][15][16][17][18] Propofol is commonly used during fast track anesthesia for off-pump bypass where transient ischemia is common. [26][27][28][29][30] Currently, an intravenous technique with propofol in conjunction with opioids is commonly used in cardiac anesthesia.…”

All that glisters…How to assess the ‘value’ of a scientific paper

“…One emerging problem is that some researchers (or their critics) are placing far too much emphasis upon power analysis [28]. One example demonstrates the type of misplaced faith in power analysis: ‘…at least 400 patients would be required to prove there is no statistically significant difference between the groups…’[29] (our emphasis). Such statements reveal a poor understanding of the scientific method and of the concept of scientific proof.…”