Glycaemic control in critically ill patients with cardiovascular disease

Change in the perioperative blood glucose and blood lactate levels of non-diabetic patients undergoing coronary bypass surgery

In the present study, a retrospective analysis of the trends and factors affecting blood glucose and blood lactate levels was carried out for non-diabetic adult patients who had undergone coronary artery bypass graft (CABG) surgery. Between October 2009 and October 2011, 200 non-diabetic adult patients undergoing CABG surgery were examined. Glucose and lactic acid levels were observed successively during surgery [following the induction of anesthesia, cardio-pulmonary bypass (CPB), aortic cross-clamping and aortic stop flow infusion], at the end of surgery and after surgery [1, 6, 12, 24 and 48 h after admission to the intensive care unit (ICU)]. The results of blood gas analyses and other related indicators for trend analysis were investigated. The peak blood glucose and blood lactate levels during CPB, as well as other CPB factors, were also analyzed. Following aortic cross-clamping, intraoperative blood glucose and blood lactate levels increased gradually with increasing operative time. Postoperatively, blood glucose and blood lactate levels continued to rise. Blood glucose and blood lactic acid levels during CPB were positively correlated. The blood glucose and blood lactate levels of non-diabetic adult patients undergoing CABG increased gradually with operative time following aortic cross-clamping. Moreover, blood glucose and blood lactate levels were positively correlated with the duration of CPB and duration of aortic cross-clamping.

Improved resistance to ischemia and reperfusion, but impaired protection by ischemic preconditioning in patients with type 1 diabetes mellitus: a pilot study

Background

In patients with type 1 diabetes mellitus (T1DM), cardiovascular events are more common, and the outcome following a myocardial infarction is worse than in nondiabetic subjects. Ischemic or pharmacological preconditioning are powerful interventions to reduce ischemia reperfusion (IR)-injury. However, animal studies have shown that the presence of T1DM can limit these protective effects. Therefore, we aimed to study the protective effect of ischemic preconditioning in patients with T1DM, and to explore the role of plasma insulin and glucose on this effect.

Methods

^99mTechnetium-annexin A5 scintigraphy was used to detect IR-injury. IR-injury was induced by unilateral forearm ischemic exercise. At reperfusion, Tc-annexin A5 was administered, and IR-injury was expressed as the percentage difference in radioactivity in the thenar muscle between the experimental and control arm 4 hours after reperfusion. 15 patients with T1DM were compared to 21 nondiabetic controls. The patients were studied twice, with or without ischemic preconditioning (10 minutes of forearm ischemia and reperfusion). Patients were studied in either normoglycemic hyperinsulinemic conditions (n = 8) or during hyperglycemic normoinsulinemia (n = 7). The controls were studied once either with (n = 8) or without (n = 13) ischemic preconditioning.

Results

Patients with diabetes were less vulnerable to IR-injury than nondiabetic healthy controls (12.8 ± 2.4 and 11.0 ± 5.1% versus 27.5 ± 4.5% in controls; p < 0.05). The efficacy of ischemic preconditioning to reduce IR-injury, however, was lower in the patients and was even completely abolished during hyperglycemia.

Conclusions

Patients with T1DM are more tolerant to forearm IR than healthy controls in our experimental model. The efficacy of ischemic preconditioning to limit IR-injury, however, is reduced by acute hyperglycemia.

Trial Registration

The study is registered at www.clinicaltrials.gov (NCT00184821)

Gene polymorphisms of superoxide dismutases and catalase in diabetes mellitus

Background

Reactive oxygen species generated by hyperglycaemia modify structure and function of lipids, proteins and other molecules taking part in chronic vascular changes in diabetes mellitus (DM). Low activity of scavenger enzymes has been observed in patients with DM. Protective role of scavenger enzymes may be deteriorated by oxidative stress. This study was undertaken to investigate the association between gene polymorphisms of selected antioxidant enzymes and vascular complications of DM.

Results

Significant differences in allele and genotype distribution among T1DM, T2DM and control persons were found in SOD1 and SOD2 genes but not in CAT gene (p < 0,01). Serum SOD activity was significantly decreased in T1DM and T2DM subjects compared to the control subjects (p < 0,05). SOD1 and SOD2 polymorphisms may affect SOD activity. Serum SOD activity was higher in CC than in TT genotype of SOD2 gene (p < 0,05) and higher in AA than in CC genotype of SOD1 gene (p < 0,05). Better diabetes control was found in patients with CC than with TT genotype of SOD2 gene. Significantly different allele and genotype frequencies of SOD2 gene polymorphism were found among diabetic patients with macroangiopathy and those without it. No difference was associated with microangiopathy in all studied genes.

Conclusion

The results of our study demonstrate that oxidative stress in DM can be accelerated not only due to increased production of ROS caused by hyperglycaemia but also by reduced ability of antioxidant defense system caused at least partly by SNPs of some scavenger enzymes.