Value of postoperative blood glucose in predicting complications and length of stay after coronary artery bypass grafting☆

Guideline directed medical therapy (GDMT) following coronary artery bypass graft (CABG) surgery has been shown to prolong survival and decrease major adverse cardiovascular events (MACE) and the need for repeat revascularization. Unfortunately, compliance with GDMT in CABG patients may be as low as 50%, thus negating the beneficial long-term effects of CABG surgery.

This chapter will review those GDMT interventions that have been shown to prolong survival and minimize MACE following CABG. Strategies will be provided by which GDMT can be instituted, and compliance maintained, to achieve the best long-term outcomes in CABG patients.

About 40–50% of patients undergoing coronary artery bypass graft (CABG) surgery have diabetes. The prevalence of impaired glucose tolerance (IGT) is also high in this group, however, incidence of new diabetes following CABG surgery is unknown. Objectives: To determine incidence of new diabetes and the impact on ICU and hospital stay in patients undergoing CABG surgery in India, we performed a registry-based study.

Prospectively collected data among consecutive adult cardiac surgical patients who underwent CABG surgery at a single hospital were analyzed. Descriptive statistics are reported.

We recruited 1559 consecutive patients (men 1355, women 204) and analyzed data among 933 non-diabetic patients. Patients with known diabetes (n = 626, 40%) were excluded. 57 (6.1%) of the 933 non-diabetic patients developed persistently high glucose levels at discharge with incidence rate of 61 + 5/1000. Patients who developed diabetes had similar age and body mass index vs those who did not, but had greater preoperative IGT (44.6 vs 13.7%) and more time-period in intensive care unit (102.0 + 75 vs 80.2 + 29 hours) as well as in hospital (11.7 + 5.7 vs 9.6 + 2.4 days) (p < 0.001).

In a significant proportion of non-diabetic patients diabetes is unmasked after CABG. This is more likely in those with impaired glucose tolerance and prolonged period in intensive care and hospital.

Perioperative hyperglycaemia (> 1.80 g/L or 10 mmol/L) increases morbidity (particularly due to infection) and mortality. Hypoglycaemia can be managed in the perioperative period by decreasing blood sugar levels with insulin between 0.90 and 1.80 g/L but it may occur more frequently when the goal is strict normoglycaemia. We propose continuous administration of insulin therapy via an electronic syringe (IVES) in type-1 diabetes (T1D) and type-2 diabetes (T2D) patients if required or in cases of stress hyperglycaemia. Stopping a personal insulin pump requires immediate follow on with IVES insulin. We recommend 4 mg dexamethasone for the prophylaxis of nausea and vomiting, rather than 8 mg, combined with another antiemetic drug. The use of regional anaesthesia (RA), when possible, allows for better control of postoperative pain and should be prioritised. Analgesic requirements are higher in patients with poorly controlled blood sugar levels than in those with HbA1c < 6.5%. The struggle to prevent hypothermia, the use of RA and multimodal analgesia (which allow for a more rapid recovery of bowel movements), limitation of blood loss, early ambulation and minimally invasive surgery are the preferred measures to regulate perioperative insulin resistance. Finally, diabetes does not change the usual rules of fasting or of antibiotic prophylaxis.