Background: Due to demographic change and increased risk for conventional surgery frailty is gaining importance in cardiac surgery as a decisive parameter for selection of conventional or interventional surgery. Nutritional laboratory markers are known to be altered in frail patients.
Method: In this prospective observational study, all elective patients presenting for cardiac surgery were included and screened for frailty according to fried criteria. With routine blood withdrawal before surgery and on the 6th postoperative day in house laboratory analysis was done and one sample of serum was analyzed for plasma redox and frailty biomarkers.
Results: A total of 250 patients were included preoperatively; mean age was 67 ± 9 years, and 78.1% were male. Frail patients had altered levels of cryptoxanthin (presurgery: 0.37 ± 0.35 frail vs. 0.22 ± 0.15 µmol/L, non-frail, p = 0.003, pre/post p = 0.008), carotene-α (presurgery 0.16 ± 0.08 frail vs. 0.13 ± 0.08 µmol/L nonfrail, p = 0.006, pre/post p = 0.03) and -β (presurgery 0.62 ± 0.28 frail vs. 0.48 ± 0.25 µmol/L nonfrail, p < 0.001, pre/post p < 0.001), tocopherol-α (presurgery 27.84 ± 9.81 frail vs. 23.23 ± 7.5 µmol/L nonfrail p < 0.001, pre/post p < 0.001) and -γ (presurgery 1.66 ± 0.73 frail vs. 1.34 ± 0.85 µmol nonfrail, p < 0.001, pre/post p < 0.001) before and after the operation. Other plasma redox biomarkers (3-nitrotyrosine, protein carbonyls, malondialdehyde, 3-methylhistidine) showed no differences between groups but postoperative results of increased protein carbonyls and malondialdehyde and decreased 3-nitrotyrosine. Age and BMI are positively associated with plasma 3-methylhistidine, suggesting increased muscular protein breakdown in old, obese patients.
Tocopherol gamma measured after the operation shows a correlation with the length of intensive-care stay. Still, we could not see an effect on mortality, in-hospital stay or other adverse events.
Conclusion: Further analysis needs to be done to evaluate predictive value of plasma biomarkers like fat soluble micronutrients. Depletion of fat-soluble micronutrients in frail and prefrail patients according to fried cannot be explained only by decreased food intake. Considering strong antioxidant activity of Lycopin, β-carotin and retinol, oxidative stress seems to play a role in depletion of the fat-soluble-micronutrients stores after the surgery. This suggests that oxidative stress might be secondary to cellular damage during the Cardiac surgery.
