Diagnóstico y alternativas terapéuticas en la isquemia miocárdica aguda perioperatoria en cirugía coronaria

Lipid emulsion enhances cardiac performance after ischemia-reperfusion in isolated hearts from summer-active arctic ground squirrels

Hibernating mammals, like the arctic ground squirrel (AGS), exhibit robust resistance to myocardial ischemia/reperfusion (IR) injury. Regulated preference for lipid over glucose to fuel metabolism may play an important role. We tested whether providing lipid in an emulsion protects hearts from summer-active AGS better than hearts from Brown Norway (BN) rats against normothermic IR injury. Langendorff-prepared AGS and BN rat hearts were perfused with Krebs solution containing 7.5 mM glucose with or without 1% Intralipid™. After stabilization and cardioplegia, hearts underwent 45-min global ischemia and 60-min reperfusion. Coronary flow, isovolumetric left ventricular pressure, and mitochondrial redox state were measured continuously; infarct size was measured at the end of the experiment. Glucose-only AGS hearts functioned significantly better on reperfusion than BN rat hearts. Intralipid™ administration resulted in additional functional improvement in AGS compared to glucose-only and BN rat hearts. Infarct size was not different among groups. Even under non-hibernating conditions, AGS hearts performed better after IR than the best-protected rat strain. This, however, appears to strongly depend on metabolic fuel: Intralipid™ led to a significant improvement in return of function in AGS, but not in BN rat hearts, suggesting that year-round endogenous mechanisms are involved in myocardial lipid utilization that contributes to improved cardiac performance, independent of the metabolic rate decrease during hibernation. Comparative lipid analysis revealed four candidates as possible cardioprotective lipid groups. The improved function in Intralipid™-perfused AGS hearts also challenges the current paradigm that increased glucose and decreased lipid metabolism are favorable during myocardial IR.

Cardioprotective Effects of Atorvastatin plus Trimetazidine in Percutaneous Coronary Intervention

Objective: To explore the effects of preoperative administration of conventional doses of atorvastatin plus trimetazidine on the myocardial injury of patients during the perioperative period of percutaneous coronary intervention (PCI).

Methodology: 475 cases of acute coronary syndrome patients before PCI were randomly divided into the control group (238 cases) and experimental group (237 cases).The control group was treated with conventional doses of atorvastatin calcium (20 mg each time, once a night), and the experimental group was treated with conventional doses of atorvastatin calcium plus trimetazidine hydrochloride (20 mg each time, tid) for 3 d. After PCI, preoperative and postoperative 24 h concentrations of serum creatine kinase MB isoenzyme (CK-MB), cardiac troponin I (cTnI) and high sensitivity C-reactive protein (hs-CRP) as well as activity of myeloperoxidase (MPO) were investigated. Left ventricular ejection fractions of the patients were then examined 4 weeks later.

Results: Postoperative 24 h cTnI concentration and elevated MPO activity of the experimental group were significantly lower than those of the control group (P <0 05). CK-MB activities and hs-CRP concentrations of the two groups did not differ significantly (P> 0 05).

Conclusion: The administration of conventional doses of atorvastatin plus trimetazidine three days before PCI is able to protect the perioperative patients from myocardial injury.

Early enteral nutrition in patients with hemodynamic failure following cardiac surgery

BACKGROUND

Enteral nutrition (EN) is controversial in patients with circulatory compromise. This study assesses the feasibility and safety of EN given early after cardiac surgery in patients with hemodynamic failure.

METHODS

Prospective observational study conducted in a surgical intensive care unit (ICU) of a tertiary hospital over 17 months.

INCLUSION CRITERIA

Cardiac surgery patients with hemodynamic failure (dependence on 2 or more vasoactive drugs and/or mechanical circulatory support) requiring more than 24 hours of mechanical ventilation. Variables Examined: Descriptive data, daily hemodynamic data, and variables related to the efficacy and safety of EN. EN was performed according to our EN protocol.

RESULTS

Of 642 patients admitted to the ICU, 37 (5.8%) met the inclusion criteria. Of these, 11 (29.7%) required mechanical circulatory support, and 25 (68.0%) met the criteria for early multiorgan dysfunction. Mortality was 13.5%. Mean EN duration was 12.3 days (95% confidence interval [CI], 9.6-15.0). The mean EN diet volume delivered/patient/d was 1199 mL (95% CI, 1118.7-1278.8), and mean EN energy delivered/patient/d was 1228.4 kcal (95% CI, 1145.8-1311). The set energy target was achieved in 15 patients (40.4%). The most common EN-related complication was constipation. No case of mesenteric ischemia was detected.

CONCLUSIONS

Our findings indicate that early EN is feasible in this type of patients and not associated with serious complications. However, it is difficult to attain an appropriate energy target by EN alone. These observations point to a need for monitoring of daily energy delivery and balance, as well as careful monitoring of warning signs of intestinal ischemia.