| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
|
|
|
|||||||
|
|||||||||
Ann Thorac Surg 2002;73:587
© 2002 The Society of Thoracic Surgeons
a London, England, United Kingdom
e-mail: csaldanha{at}aol.com
A number of studies have demonstrated that glucose-insulin-potassium (GIK) solutions are beneficial in patients undergoing cardiac surgery. The mechanism by which they exert their beneficial effect, however, is not fully understood. In this study it was demonstrated that in diabetic sheep GIK improves left ventricular contractility and ventriculoarterial coupling, and decreases total mechanical work, without significantly affecting stroke work. This improvement in stroke work efficiency is a novel finding, and the authors postulate that it may explain the mechanism by which GIK solutions enhance tolerance to myocardial ischemia.
Although the results of this study are novel and valid, their extrapolation to the clinical situation is difficult. The sheep were only diabetic for 6 months, did not have coronary disease, and had normal ventricular function. The majority of diabetic patients undergoing cardiac surgery will have been diabetic for several years, have coronary disease, and may have impaired ventricular function. The study also did not include a control group of sheep without diabetes. The beneficial effects of GIK solutions are not confined to diabetics. Significantly higher postoperative cardiac indices and less requirements for inotropic support, have also been demonstrated in non diabetics who received GIK infusions and underwent coronary artery bypass grafting. The present study would therefore have been considerably enhanced if the authors had included a control group. This would have provided important information as to whether the improved stroke work efficiency also occurs in non-diabetic hearts.
It should also be borne in mind, that the beneficial effects seen with the clinical use of GIK solutions, may not be entirely due to a direct effect on the myocardium. It has been shown that GIK solutions reduce the elevation of serum free fatty acids in response to high-dose heparin. Elevated serum free fatty acids impair cardiac function in the hypoxic or ischemic myocardium. Consequently, if this is a significant mechanism by which GIK solutions exert their benefit, it would explain their beneficial effect in both diabetics and non diabetics undergoing cardiac surgery. It would also highlight, again, the difficulties with extrapolating the results of this study to the clinical situation.
Despite all these drawbacks, this study provides important new information. It will hopefully act as a stimulus, for further studies to evaluate the mechanisms and benefits of GIK solutions, both experimentally and clinically.
Related Article
Ann. Thorac. Surg. 2002 73: 582-587.
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
| HOME | HELP | FEEDBACK | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |
| ANN THORAC SURG | ASIAN CARDIOVASC THORAC ANN | EUR J CARDIOTHORAC SURG |
| J THORAC CARDIOVASC SURG | ICVTS | ALL CTSNet JOURNALS |
