Perioperative myocardial ischemia contributes to postoperative morbidity and mortality. Remote intermittent ischemia (RI) has been shown to benefit patients undergoing coronary artery bypass graft (CABG) surgery by decreasing postoperative cardiac troponin levels. In addition, there is evidence that volatile anesthetics may provide myocardial protection. In this prospective randomized controlled trial we tested the hypothesis that RI is cardioprotective under a strict anesthetic regime with volatile anesthesia until cardiopulmonary bypass (CPB). We also assessed whether RI modulates postoperative cytokine and growth factor concentrations. Fifty-four patients referred for elective CABG surgery without concomitant valve or aortic surgery were randomized to three 5-min cycles of left upper limb ischemia by cuff inflation (RI) or placebo without cuff inflation (Plac). All patients received the volatile anesthetic isoflurane (1.15-1.5 vol%) before CPB and the intravenous anesthetic propofol (3-4 mg/kg/h) thereafter until the end of surgery. Cardiac arrest during CPB was induced by intermittent cross-clamp fibrillation, or by blood cardioplegia. We excluded patients older than 85 years, with unstable angina, significant renal disease, and those taking sulfonylureas. Troponin I (cTnI) was measured preoperatively and after 6, 12, 24 and 48 h. In addition, brain natriuretic peptide (BNP), creatine kinase (CKMB) and a panel of cytokines and growth factors were analyzed perioperatively. Although cTnI, BNP and CKMB all increased post-CABG, there were no significant differences between RI and Plac groups; area under the curve for cTnI 189.4 (183.6) ng/mL/48 h and 183.0 (155.2) ng/mL/48 h mean (SD), p = 0.90, respectively, despite a tendency to a shorter (p < 0.07) cross-clamp time in the treatment group. Similarly, there were no differences between groups in the central venous concentrations of numerous cytokines and growth factors. In patients undergoing CABG surgery RI does not provide myocardial protection under a strict anesthetic regime with volatile anesthesia until CPB, and RI was not associated with changes in cytokines.

Leptin is a vasoactive peptide in human SV and internal mammary artery. Its action is not nitric oxide or endothelial-dependent. Markers of body fat did not correlate with leptin-mediated vasodilatation, raising the intriguing possibility of selective resistance to leptin's actions.

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ObjectiveCyclosporin-A (CsA) has been reported to reduce myocardial infarct size in both the experimental and clinical settings. This protective effect is dependent on its ability to prevent the opening of the mitochondrial permeability transition pore, a critical determinant of cell death in the setting of acute ischaemia-reperfusion injury. Whether CsA can reduce the extent of peri-operative myocardial injury (PMI) in patients undergoing coronary artery bypass graft (CABG) surgery is unknown, and is investigated in this randomised controlled clinical trial.Methods78 adult patients undergoing elective CABG surgery were randomised to receive either an intravenous bolus of CsA (2.5 mg/kg) or placebo administered after induction of anaesthesia and prior to sternotomy. PMI was assessed by measuring serum cardiac enzymes, troponin T (cTnT) and CK-MB at 0, 6, 12, 24, 48 and 72 h after surgery.ResultsThere was no significant difference in mean peak cTnT levels between control (n=43) and CsA treatment (n=40) patients (0.56±0.06 ng/mL with control vs 0.35±0.05 ng/mL with CsA; p=0.07). However, in higher-risk patients with longer cardiopulmonary bypass times, there was a significant reduction in PMI with CsA therapy (p=0.049), with a reduced postoperative cTnT rise by 0.03 ng/mL for every 10 min, when compared with control.ConclusionsIn patients with longer cardiopulmonary bypass times, a single intravenous bolus of CsA administered prior to CABG surgery reduced the extent of PMI.

It has been suggested that maintaining ventilation during bypass might reduce lung injury, which is a common complication of cardiac surgery. In order to assess this, a study is being undertaken to examine the effect upon a number of parameters that may be indicative of lung injury, of continued ventilation compared with discontinued ventilation whilst on bypass. The following parameters have been assessed: extravascular lung water, static and dynamic compliance, ratio of left atrial/right atrial white blood count, alveolar arterial oxygen gradient and the respiratory index together with clinical end points. Provisional results are reported. Twenty-three elective patients for coronary artery surgery have to date been randomised to either ventilation (VB) (n=12) or non-ventilation on bypass (NVB) (n=11). The post-bypass extravascular lung water was significantly smaller in the VB group compared to the NVB group (530+/-50 ml vs. 672+/-32 ml; P=0.028). Extubation time was also significantly shorter in the VB group (3.6+/-0.3 h vs. 4.8+/-0.4 h; P=0.038). The provisional results of this work in progress are suggestive that continued ventilation during bypass may reduce lung injury.

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BNP is a valuable biochemical marker, which is easy to measure and can be beneficial in predicting the operative outcome.

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