Coronary artery bypass grafting in patients with type 2 diabetes mellitus: a comparison between minimized and conventional extracorporeal circulation

Minimized extracorporeal circulation is improving outcome of coronary artery bypass surgery in the elderly

Advanced age is a known risk factor for morbidity and mortality after coronary artery bypass grafting (CABG). Minimized extracorporeal circulation (MECC) has been shown to reduce the negative effects associated with conventional extracorporeal circulation (CECC). This trial assesses the impact of MECC on the outcome of elderly patients undergoing CABG. Eight hundred and seventy-five patients (mean age 78.35 years) underwent isolated CABG using CECC (n=345) or MECC (n=530). The MECC group had a significantly shorter extracorporeal circulation time (ECCT), cross-clamp time and reperfusion time and lower transfusion needs. Postoperatively, these patients required significantly less inotropic support, fewer blood transfusions, less postoperative hemodialysis and developed less delirium compared to CECC patients. In the MECC group, intensive care unit (ICU) stay was significantly shorter and 30-day mortality was significantly reduced [2.6% versus 7.8%; p<0.001]. In conclusion, MECC improves outcome in elderly patients undergoing CABG surgery.

Insulin infusion on postoperative complications of coronary artery bypass graft in patients with diabetes mellitus

Background:

Cardiovascular events are common in patients with diabetes mellitus (DM), which make coronary artery bypass graft (CABG) a highly demanded surgery in this population. Tight control of blood glucose in patients with DM is beneficial in reducing postoperative complications; however, the adequate range has not been determined yet.

Objectives:

This study aimed to investigate the effect of semi-tight (moderate) control of DM on complications and serum glucose levels during and after CABG.

Patients and Methods:

In this prospective clinical trial, 18 and 31 patients with and without DM, respectively, who were referred to Shahid Chamran Hospital, Isfahan, Iran, for elective CABG surgery, were enrolled. For DM group, patients with controlled DM (i.e. glycosylated hemoglobin levels [HgA1C] ≤ 7%) were recruited. Blood glucose level (blood sugar, BS) was measured after anesthesia, during pumping, warming, off pumping, six and 12 hours after Intensive Care Unit (ICU) admission, and at discharging from the hospital. The hemodynamic state of the patients, bleeding, need of blood transfusion, infection, and duration of hospitalization were also monitored and recorded.

Results:

None of the BS measurements (FBS, after anesthesia, on-pump, warming, off pump, six and 12 hours after ICU admission, and at discharge) were significantly different between study groups (P > 0.05). Frequency of surgery site bleeding and blood transfusion need were not significantly different between these groups (P > 0.05).

Conclusions:

Semi-tight control of DM with insulin infusion during operation did not led to any difference in the type and rate of CABG complications between patients with well-controlled and those without DM; however, BS levels in patients with well-controlled DM could be more easily controlled.

Impact of age on early outcome after coronary bypass graft surgery using minimized versus conventional extracorporeal circulation

Background

Objective of this study was to evaluate the impact of age on comparative early outcomes after coronary artery bypass graft surgery (CABG) with minimized (MECC) and conventional extracorporeal circulation (CECC).

Methods

A retrospective age-, gender- and operation-matched cohort analysis between January 2005 and December 2010 with a total of 2274 patients undergoing CABG with MECC (n = 1137; 50%) or CECC was performed. Patients were stratified into 4 groups according to age: <59 years, 60–69 years, 70–79 years, and 80 years of age or older. Outcomes were compared within each age group. Patients with preoperative dialysis were excluded from analysis. Primary endpoint was 30-day mortality.

Results

Patients treated with CECC had a significantly higher mean logistic EuroSCORE (6.3% vs. 5.0%; p < 0.001), a slightly lower rate of preoperative myocardial infarction (46% vs. 51%; p = 0.01) and a higher rate of impaired renal function (eGFR < 60 mL/min/1.73 m2: 24% vs. 20%; p = 0.01) compared to MECC-patients. Left internal mammary artery was significantly used more often in MECC patients (93% vs. 86%; p < 0.001). Cardiopulmonary bypass and aortic-cross clamping time were significantly lower in the MECC group (p < 0.001). Overall 30-day mortality was significantly higher in patients treated with CECC (4.4% vs. 2.2%; p = 0.002). Within the different age groups mortality rates were not significantly different except for patients aged 60–69 years (4.5% vs. 1.8%; p = 0.03). Postoperative requirement of renal replacement therapy (4% vs. 2.2%; p = 0.01), respiratory insufficiency (9.9% vs. 6.6%; P = 0.004) and incidence of low cardiac output syndrome (3% vs. 1.2%; p = 0.003) were significantly increased in patients with CECC. Multivariate analysis identified age (p = 0.005; 95% CI 1.01 to 1.08; OR 1.05) among other parameters as an independent risk factor, whereas conventional extracorporeal circulation itself did not present as an independent risk factor for 30-day mortality.

Conclusions

In this matched study sample early outcome was significantly better in patients with MECC compared to CECC, irrespective of age. Prior myocardial infarction estimated GFR < 60 mL and waiving the use of LIMA were independent risk factors for 30-day mortality, which were more present in the CECC group.

Effects of Moderate Glycemic Control in Type II Diabetes With Insulin on Arterial Blood Gas Parameters Following Coronary Artery Bypass Graft Surgery

Background:

Coronary artery bypass grafting (CABG) is one of the common surgeries in patients with coronary artery disease (CAD). It is more probable for patients with diabetes to undergo surgeries due to CAD and they have a higher mortality rate compared to the others

Objectives:

The aim of the present study was to assess the effects of insulin infusion therapy on blood gas parameters in two groups of patients, eligible for CABG, defined as A: well controlled diabetes (HbA1C < 7%) and B: non-diabetic patients.

Patients and Methods:

We followed two groups of patients, defined as patients with and without diabetes who were candidates for CABG, between March 2010 and March 2012. Patients with diabetes underwent moderate or semi-tight glycemic control, using continuous intravenous insulin infusion.

Results:

There were 13 male and 18 female subjects in the on-diabetic group and 11 male and 7 female patients in the controlled diabetic group. There was no significant difference between the studied participants regarding age, cardiac ejection fraction, blood pH and PO₂ and PCO₂ levels.

Conclusions:

CABG surgery adversely affects arterial blood gas (ABG) determinations. On the other hand, findings showed there is no significant difference in the ABG parameters between patients with well controlled diabetes and the ones without.

Impact of minimized extracorporeal circulation on outcome in patients with preoperative anemia undergoing coronary artery bypass surgery

Preoperative anemia and low hematocrit during cardiopulmonary bypass have been associated with worse outcome in patients undergoing cardiac surgery. The minimized extracorporeal circulation (MECC) allows a reduction of the negative effects associated with conventional extracorporeal circulation (CECC). In this study, the impact of the MECC on outcome of anemic patients after coronary artery bypass grafting (CABG) was assessed. Between January 2004 and December 2011, 1,945 consecutive patients with preoperative anemia underwent isolated CABG using CECC (44.8%) or MECC (55.2%). The cutoff point for anemia was 13 g/dl for men and 12 g/dl for women. The postoperative creatine kinase and lactate levels were significantly lower in the MECC group (p < 0.001). There was no difference in postoperative blood loss between the groups. However, the intraoperative and postoperative transfusion requirements were significantly lower in the MECC group (p < 0.05). Furthermore, MECC patients had lower incidences of postoperative acute renal failure, and low cardiac output syndrome, shorter intensive care unit lengths of stay and reduced 30-day mortality (p < 0.05). In conclusion, a reduced postoperative mortality, lower transfusion requirements, and less renal and myocardial damage encourage the use of MECC for CABG, especially in the specific high-risk subgroup of patients with anemia.