Role of Nutrition Support in Adult Cardiac Surgery

A Consensus Statement From an International Multidisciplinary Expert Group on Nutrition in Cardiac Surgery

Christian Stoppe; Andreas Goetzenich; Glenn Whitman; Rika Ohkuma; Trish Brown; Roupen Hatzakorzian; Arnold Kristof; Patrick Meybohm; Jefferey Mechanick; Adam Evans; Daniel Yeh; Bernard McDonald; Michael Chourdakis; Philip Jones; Richard Barton; Ravi Tripathi; Gunnar Elke; Oliver Liakopoulos; Ravi Agarwala; Vladimir Lomivorotov; Ekaterina Nesterova; Gernot Marx; Carina Benstoem; Margot Lemieux; Daren K. Heyland

Disclosures

Crit Care. 2017;21(131) 

In This Article

Counteracting the Inflammatory Response - The Role of Key Nutrients

Cardiac surgery with myocardial ischemia/reperfusion and use of CPB is known to be associated with deleterious consequences, resulting from the inflammatory response during cardiac surgery. The duration of CPB time correlates with the extent of the inflammatory response. Furthermore, surgical trauma, ischemia/reperfusion, and contact activation with the CPB circuit result in the release of mainly pro-inflammatory markers, reactive oxygen species, and reactive nitrogen species that contribute to the development of organ dysfunction.[35] In this setting, the use of pharmaco-nutrients, which may exert specific effects on metabolism, the inflammatory response, markers of oxidative stress, and immune cell activity, are of considerable interest. The amino acids glutamine and arginine, lipids such as omega-3 fatty acids, micronutrients such as selenium and zinc, or vitamins A, C, D, and E, are examples of such key nutrients. Despite theoretical promise, several large-scale clinical trials involving these nutrients had disappointing results in the general ICU patient population.[22,36–38] However, in a small randomized trial in 177 patients, Leong et al. demonstrated that perioperative metabolic therapy with coenzyme Q10, magnesium, lipoic acid, omega-3 fatty acids, and selenium was feasible, safe, and associated with improved redox status, reduced myocardial damage, and shorter length of postoperative hospital stay after cardiac surgery.[39] Although by no means generalizable, the results of that study support the hypothesis that key nutrients can mitigate perioperative oxidative stress and improve cardiac surgical outcomes. Similarly, recent results from a non-randomized open-label study indicate a beneficial effect of perioperative sodium selenite supplementation, whereas the supplementation strategy was still insufficient to compensate for a second decrease in selenium levels during the postoperative course. Given these data, a large-scale multi-center trial was recently launched to study the clinical significance of high-dose (2000 μg) perioperative sodium selenite supplementation in patients at high risk after cardiac surgery.[40]

In a recent clinical trial, perioperative nutritional therapy was administered in the cardiac surgery ICU in order to increase myocardial and plasma arginine/asymmetric dimethylarginine ratio and other amino acids.[41] The investigators demonstrated an increase in inflammatory cells in cardiac tissue at the start and end of cardiac surgery, whereas perioperative supplementation during surgery did not affect the myocardial inflammatory response.[41] Similarly, Tepaske et al. performed a double-blind, three-arm clinical trial to determine whether the addition of glycine to oral nutrition may improve the patients' outcomes after cardiac surgery. It was demonstrated that oral immune-enhancing nutrition reduced postoperative complications, whereas the addition of glycine did not result in any additional beneficial effect.[42] Taken together, recent data do not show a clinical relevant benefit after supplementation of arginine or glycine in patients undergoing cardiac surgery.

So far, preliminary results from small phase II trials on fish oil (FO)-containing emulsions have demonstrated that preoperative FO application is a promising strategy to modulate the biological and clinical response to cardiac surgery.[43] Berger et al. demonstrated that perioperative FO infusions significantly decreased biological and clinical signs of inflammation, in a rather low-risk population of cardiac surgery patients, as reflected by a low mean Euroscore (5), which is routinely used for the preoperative risk stratification in cardiac surgery patients. Furthermore, mainly uncomplicated coronary artery bypass surgery was performed.[44] Given these findings, supplementation of FO may be of particular relevance in patients with more complex procedures with more prolonged CPB time and subsequent pronounced inflammatory response. Manzanares et al. recently conducted a systematic review and included 10 randomized controlled trials (RCTs), in which researchers evaluated FO-containing emulsions in PN or EN in the ICU. The researchers found that FO-containing emulsions may significantly reduce the rate of infections. In addition, FO-containing emulsions were associated with clinically important reductions in duration of mechanical ventilation and hospital length of stay.[45] Further research is encouraged and is needed in cardiac surgery patients to clarify the role of FO.

Pharmaco-nutrition offers a promising approach to enhance the body's defense mechanisms and to attenuate the deleterious effects of SIRS and improve outcomes. This may be of particular relevance for high-risk patients undergoing complex procedures with prolonged CPB duration and an overwhelming release of pro-inflammatory mediators.

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