An evaluation and comparison of metabolic and clinical changes in patients with acute coronary syndrome undergoing on-pump and off-pump coronary artery bypass surgery

Abstract

The best approach to surgical myocardil revascularization remains controversial. It is already known that an inflammatory response exists due to several factors related to the use of CPB. physiological stress response which leads to an increase in pro-inflammatory markers still remains during OPCAB surgery. surgery induces a wide haematological and hemodynamic changes. Hemodynamic and metabolic optimization is of daily importance in the hospital environment. morbidity and mortality. Lactate is also often used to predict clinical outcomes and complications but controversy remains about using this measure because of discrepancies in The aim of the study was to evaluate how metabolic and clinical changes relate to the incidence of complications and clinical outcomes in ACS patients undergoing on-pump and off-pump CABG Sixty patients diagnosed with ACS who received CABG surgery were recruited to participate in the study (30 patients on-pump and 30 patients off-pump). Patients not receiving isolated with reference to the intra-operative and post-operative metabolic data, intra-operative hemodynamic data and post-operative clinical outcomes/complications. lactate levels <5mmol/L or patients with lactate levels >5mmol/L. Comparisons between the two groups were made with reference to the intra-operative and post-operative metabolic data, Intra-operative metabolic data indicated 11 (37.0%) on-pump patients and 6 (20.0%) off-pump patients had peak lactate levels of >5mmol/L during cardiac surgery. The difference between the statistically comparison, the difference cannot be considered clinically relevant. differences (p<0.05) between the lactate < 5mmol/L group and the lactate > 5 mmol/L group. Intra-operative hemodynamic data showed statistically significant differences between the on- Post-operative metabolic data showed statistically significant differences (p<0.05) between the on-pump and off-pump groups for acid-base balance variables, pH, HCO3- and BE (B) from The metabolites, glucose and lactate, showed statistically significant differences (p<0.05) between the on-pump and off-pump groups from admission to ICU until 12 hours post- Despite the fact that elevated lactate levels have been described to be associated with adverse outcomes in paediatric- as well as general intensive care admission, no specific lactate level has surgery. Lactate values for the on-pump group were significantly higher during the immediate post- resulting in vasoconstriction and a redistribution of blood flow away from the peripheral tissue and the splanchnic circulation, creating an environment for increased lactate levels in the tissue. indication of a patient's likelihood of experiencing various complications. Both groups recovered to lactate levels of <2mmol/L by the 24th hour post-operatively. According to operatively this is associated with an increased 60-day mortality. The study did show a statistically significant difference between the on-pump and off-pump comparison, the difference cannot be considered conclusive and we can only make suggestions as to the trends seen in the data. Elevated lactate levels show that they may be poorly correlated with clinical outcomes and in order to see a more definite relationship between peak lactate levels and clinical outcomes, a larger study population will be required or perhaps a different lactate cut-off value should be considered. It may also be more useful to see if there is a positive correlation between the duration of time a patient is subjected to peak lactate levels of >5mmol/L and clinical outcomes. We recommend larger study population and change lactate cut-off value to >10mmol/L.