The Effect of Insulin on Protein Metabolism After Cardiac Surgery

Cardiac Surgery Clinical Trial

Official title:

The Effect of Insulin on Protein Metabolism After Cardiac Surgery

Clinical Trial Details — Status: Recruiting

Administrative data

• NCT number: NCT01601561
• Other study ID #: 09-105-SDR
• Status: Recruiting
• Phase: N/A
• First received: March 9, 2012
• Last updated: May 17, 2012
• Start date: June 2010

Study information

• Verified date: May 2012
• Source: McGill University Health Center
• Contact: n/a
• Is FDA regulated: No
• Health authority: Canada: Canadian Institutes of Health Research
• Study type: Interventional

Clinical Trial Summary

Background: The hyperinsulinemic-normoglycaemic clamp technique is a precise method of providing insulin and glucose while maintaining normoglycemia. High-dose insulin has profound effects on glucose and protein metabolism. It has been demonstrated in coronary artery bypass graft (CABG) surgery patients that high-dose insulin causes hypoaminoacidaemia. The investigators hypothesize that the reduction of plasma amino acids (AAs) levels as seen in patients undergoing CABG surgery and receiving high-dose insulin is a consequence of an inhibition of whole body proteolysis as assessed by L-[1-13C]leucine tracer kinetics.

Objective: The present study aims to investigate the effect of high-dose insulin therapy on whole body protein, glucose and end-organ metabolism in patients undergoing CABG surgery using stable isotope tracers [6,6-2H2]glucose, L-[1-13C]-leucine and L-[2H5]phenylalanine. The changes in the metabolic-endocrine milieu will also be evaluated by plasma concentrations of glucose, lactate, free fatty acids, prealbumin, albumin, fibrinogen, insulin, glucagon, and cortisol.

Methods: With the approval of local institution's ethical committee, 30 patients scheduled for elective will be enrolled. The patients will be divided randomly into two groups. The control group will receive a standard IV insulin protocol with the aim of keeping blood glucose < 10 mmol/L. The treatment group will be administered a high dose insulin infusion of 5 mU/kg/min coupled with a variable infusion of glucose to maintain normoglycemia (4-6 mmol/L). Insulin infusion will be continued until the end of the study period approximately 8 hours after surgery. L-[1-13C]leucine and [6,6-2H2]glucose kinetics will be used to assess changes in whole body protein and glucose kinetics. Hepatic albumin synthesis will be determined by using primed continuous infusion of L-[2H5]phenylalanine. The preoperative measurements will be performed on the morning before the surgery. Postoperative studies will be conducted two hours after arrival in the intensive care unit. Tracer kinetics between the two groups will be analyzed using ANOVA for repeated measurements.

Significance: High-dose-insulin results in a significant reduction in plasma AAs in cardiac surgery. This study should address if this drop in plasma AA levels is secondary to a decrease in breakdown, an increase in synthesis or both during high-dose insulin therapy in open heart surgery.

Recruitment information / eligibility

• Status: Recruiting
• Enrollment: 30
• Est. primary completion date: December 2012
• Accepts healthy volunteers: No
• Gender: Both
• Age group: 18 Years to 90 Years

Eligibility

Inclusion Criteria:

• ability to give informed consent

Exclusion Criteria:

• signs of severe malnutrition or obesity: body mass index (BMI) < 20 or > 30 kg.m-2, more than 10% involuntary body weight loss over the preceding six months, serum albumin < 35 g.L-1

• chronic liver failure

Study Design

Allocation: Randomized, Endpoint Classification: Efficacy Study, Intervention Model: Parallel Assignment, Masking: Double Blind (Subject, Outcomes Assessor), Primary Purpose: Prevention

Related Conditions & MeSH terms

• Cardiac Surgery

Intervention

Drug:
• Regular human insulin injection
Hyperinsulinemic normoglycemic clamp from beginning of surgery until 8 hours after surgery. Humulin R 5 mU/kg/min and a variable infusion of glucose.

Locations

Country	Name	City	State
Canada	Royal Victoria Hospital, McGill University Health Centre	Montreal	Quebec

Sponsors (1)

Lead Sponsor	Collaborator
McGill University Health Center

Country where clinical trial is conducted

Canada, 

Outcome

Type	Measure	Description	Time frame	Safety issue
Primary	Protein breakdown	Protein breakdown as measured by 13C leucine	Eight hours after the end of surgery	No