M. G. Calabrò

Cardiac protection by volatile anaesthetics: A multicentre randomized controlled study in patients undergoing coronary artery bypass grafting with cardiopulmonary bypass

Background and objectives: To evaluate the effects of total intravenous anaesthesia vs. volatile anaesthesia on cardiac troponin release in coronary artery bypass grafting with cardiopulmonary bypass, we performed a multicentre randomized controlled study to compare postoperative cardiac troponin release in patients receiving two different anaesthesia plans. Methods: We randomly assigned 75 patients to propofol (intravenous anaesthetic) and 75 patients to desflurane (volatile anaesthetic) in addition to an opiate‐based anaesthesia for coronary artery bypass grafting. Peak postoperative troponin I release was measured as a marker of myocardial necrosis. Results: There was a significant (P < 0.001) difference in the postoperative median (25th‐75th percentiles) peak of troponin I in patients receiving propofol 5,5 (2,3‐9,5) ng dL−1 when compared to patients receiving desflurane 2,5 (1,1‐5,3) ng dL−1. The median (interquartile) troponin I area under the curve analysis confirmed the results: 68 (30.5‐104.8) vs. 36.3 (17.9‐86.6) h ng dL−1 (P = 0.002). Patients receiving volatile anaesthetics had reduced need for postoperative inotropic support (24/75, 32.0% vs. 31/75, 41.3%, P = 0.04), and tends toward a reduction in number of Q‐wave myocardial infarction, time on mechanical ventilation, intensive care unit and overall hospital stay. Conclusions: Myocardial damage measured by cardiac troponin release could be reduced by volatile anaesthetics in coronary artery bypass surgery.

Long-term outcome of patients who require renal replacement therapy after cardiac surgery

Background and objective: Acute renal failure is a serious complication of cardiac surgery. We studied the long‐term survival and quality of life of patients requiring renal replacement therapy after cardiac surgery, since they represent a heavy burden on hospital resources and their outcome has never been adequately evaluated. Methods: Out of 7846 consecutive cardiac surgical patients, 126 (1.6%) required postoperative renal replacement therapy: their preoperative status and hospital course was compared with patients who had no need of postoperative renal replacement therapy. A multivariate analysis identified predictors of renal replacement therapy. Long‐term survival and quality of life was collected in patients who had renal replacement therapy and in case‐matched controls. Results: Hospital mortality in the study group was 84/126 (66.7%) vs. 118/7720 (1.5%) in the control population (P < 0.001). Patients who underwent renal replacement therapy and were discharged from the hospital (42 patients) had a reasonable long‐term outcome: at 42 ± 23 months, 30 out of 42 patients were alive, with only 3 patients complaining of limitations in daily activities. Predictors of in‐hospital renal replacement therapy were: emergency surgery, preoperative renal impairment, intra‐aortic balloon pumping, reoperation for bleeding, previous cardiac surgery, female gender, low ejection fraction, bleeding >1000 mL, chronic obstructive pulmonary disease and age. Conclusions: This study confirms that the in‐hospital mortality of patients requiring renal replacement therapy is high and shows a low long‐term mortality with reasonable quality of life in patients discharged from hospital alive.

A Bayesian network meta-analysis on the effect of inodilatory agents on mortality

BACKGROUND Inodilators are commonly used in critically ill patients, but their effect on survival has not been properly studied to date. The objective of this work was to conduct a network meta-analysis on the effects of inodilators on survival in adult cardiac surgery patients, and to compare and rank drugs that have not been adequately compared in head-to-head trials. METHODS Relevant studies were independently searched in BioMedCentral, MEDLINE/PubMed, Embase, and the Cochrane Central Register of clinical trials (updated on May 1, 2014). The criteria for inclusion were: random allocation to treatment with at least one group receiving dobutamine, enoximone, levosimendan, or milrinone and at least another group receiving the above inodilators or placebo, performed in cardiac surgical patients. The endpoint was to identify differences in mortality at longest follow-up available. RESULTS The 46 included trials were published between 1995 and 2014 and randomised 2647 patients. The Bayesian network meta-analysis found that only the use of levosimendan was associated with a decrease in mortality when compared with placebo (posterior mean of OR=0.48, 95% CrI 0.28 to 0.80). The posterior distribution of the probability for each inodilator to be the best and the worst drug showed that levosimendan is the best agent to improve survival after cardiac surgery. The sensitivity analyses performed did not produce different interpretative result. CONCLUSION Levosimendan seems to be the most efficacious inodilator to improve survival in cardiac surgery.

Mitral valve surgery and acute renal failure

Acute renal failure (ARF) is a serious complication following cardiac operations performed with cardiopulmonary bypass (CPB) and carries a high mortality rate [1]. Prior studies have attempted to identify predictors of ARF or to develop risk stratification algorithms. Valve operations are an independent predictor of ARF [2,3]. To our knowledge, no study has attempted yet to find an independent association between ARF and a specific type of valve operation (i.e. repair or replacement). The aim of this study is to define the incidence, predictors and mortality related to ARF after different types of mitral valve (MV) surgery. From January 1998 to January 2003, we studied 1276 consecutive adult patients who underwent isolated MV surgery with CPB. We excluded from our population patients with dialysis dependence and combined procedures. MV repair was mostly performed with the edge-to-edge technique with the positioning of a rigid ring while patients who had mitral replacement mostly had a mechanical valve implanted. All patients received a standard premedication and monitoring. Anaesthesia was induced in all patients with fentanyl–propofol–pancuronium, maintained with propofol, isoflurane, and additional doses of fentanyl. CPB was conducted with an institutional custom pack including a coated membrane oxygenator, with mild hypothermia (32–33°C). Non-pulsatile perfusion was used throughout the study, with perfusion maintained between 2 and 2.8 L min 1m 2. The pumps were primed with crystalloid solution, mannitol 18% 0.5 g kg 1 formulated to achieve a haematocrit of 18% or more during CPB. Packed red blood cells were added to achieve the desired haematocrit and as required by the clinical circumstance. Intermittent cold (4°C) blood cardioplegia was infused by means of heat exchanger and two roller pumps. Perioperative ventricular dysfunction occurring after cardiac surgery and CPB was managed with heart rate and rhythm control, preload and afterload optimization and, when these manoeuvres were ineffective, with inotropic drugs. Dopamine was the first sympathomimetic drug used and when it was unable to resolve the low-output syndrome it was coupled with epinephrine and/or enoximone and/or an intra-aortic balloon pump. Prophylactic use of a balloon pump was performed in patients with functional MV disease and with ejection fraction 30%. Prophylactic strategies such as hydration, dopamine, fenoldopam and mannitol were used according to anaesthesiologist’s preference. Loop diuretics have been administered early in the course of ARF to convert an oliguric to a nonoliguric state. ARF was defined as a postoperative 100% increase in serum creatinine (doubling from baseline values). Renal replacement therapy was initiated by the attending nephrologist and intensivist based on the clinical situation. Renal support was provided in all cases by continuous veno-venous haemofiltration (CVVH, Prisma CFM, Hospal Lyon, France) using high flux AN69 membranes with a membrane surface of 0.60 m2. Statistical analysis. Data were analysed using the SAS statistics package. Dichotomous variables were compared using 2-test with Yates correction. Continuous measures are expressed as mean SD unless otherwise indicated and were compared with a t-test for paired or unpaired data, as appropriate. A multivariate stepwise logistic regression was used to assess the independent correlates of ARF. Of 1276 patients included in the study, 32 (2.5%) developed postoperative ARF. The incidence of ARF for MV replacement and MV repair was 8% (25/312) and 0.7% (7/964) respectively (P 0.001). The overall population was 57 12.8-yr-old, 41% (528) female, 6.3% (81) with ejection fraction 40%. All perioperative clinical and patient characteristics are depicted in Table 1 together with a univariate analysis to study their association to ARF: patients who developed ARF had a higher incidence of preoperative comorbidities and perioperative complications. At a multivariate analysis that included all factors in Table 1 with entry and exit values P 0.05, MV replacement was an independent risk factor for the development of postoperative ARF (odd ratio (OR): 4.0, 95% confidence interval (CI): 1.49–10.59, P 0.01) together with low-output syndrome (OR: 13.7, 5.4–34.9, P 0.01), emergency surgery (OR: 8.5, 1.4–52.2, P 0.02, creatinine 124 μmol L 1 (OR: 7.9, 2.8–22, P 0.01), reopening for bleeding (OR: 4.5, 1.4–14.3, P 0.01), diabetes (OR: 4.4, 1.08–18.2, P 0.04) and age 100 Correspondence

Cardiac protection by volatile anaesthetics in high risk cardiac surgery patients: a randomized controlled study: O-15

with ischaemic heart disease (IHD). Alpha-2 agonists have beneficial effects on heart rate and provide adequate sedation in the perioperative period [1]. We investigated the effects of dexmedetomidine added to epidural anaesthesia on myocardial ischaemia and postoperative analgesic requirements in peripheral vascular surgery. Method: Twenty-eight patients with IHD undergoing peripheral vascular surgery were included in the study. Lumber epidural anaesthesia was initiated in all patients. In the first group (GD n 14) sedation was achieved with dexmedetomidine infusion, while the second (GM n 14) was sedated with midazolam. In the peroperative period we collected haemodynamic data and sedation scale. Holter ECG was performed during the first postoperative 24 hours. Dexmedetomidine infusion continued during 24 hours postoperatively. Troponin-T levels were determined preoperatively, and at postoperative 4th, 8th, 24th, 36th, 48th hours. Postoperative analgesic requirements according to patient-controlled analgesic pumps and visual analogue scale (VAS) were registered. Results: Demographic and operative data were similar between the two groups. There was no cardiac event in any group. Although heart rate was similar at the beginning of the study, it was slower at all times after dexmedetomidine infusion in GD. VAS were higher during postoperative 48 hours followup in GD. Analgesic requirements were higher in GM. Troponin-T levels decreased in GD during the study and were significatly lower at 8th, 24th, 36th hours in GD (0.036 vs. 0.15; 0.02 vs. 0.1 and 0.01 vs. 0.09 ng/mL respectively). Conclusion: Peripheral vascular surgery constitues a major risk for patients with IHD. Dexmedetomidine provides adequate sedation, decreases heart rate and also maintains haemodynamic stability. Dexmedetomidine is a safe alternative for peroperative sedation in ischaemic heart disease. Reference: 1 Talke P, Chen R, Thomas B, et al. The hemodynamic and adrenergic effects of perioperative dexmedetomidine infusion after vascular surgery. Anesth Analg 2000; 90: 834–839.