These findings are important because current analytical methods cannot reliably predict who will be likely to suffer from myocardial infarction (MI), or heart tissue death after cardiac surgery.
"We have identified six gene variants, or polymorphisms, that are significantly associated with the incidence of post-operative myocardial infarction following cardiac surgery," said Duke cardiothoracic anaesthesiolologist Mihai Podgoreanu, M.D. "Collectively, these variants can explain about 75 percent of the variability in heart damage in patients undergoing surgery."
The researchers began by identifying 48 known polymorphisms of 23 candidate genes that are all involved with the body's immune response. They then enrolled 432 patients undergoing cardiac surgery. Blood samples were taken 24 hours after surgery. Patients were considered to have suffered a post-operative MI if their CK-MB levels were at least ten times higher than the upper limit of normal. Of the patients, 52, or twelve percent, were considered to have suffered an MI.
Using a two-step genetic analysis, the researchers looked for genetic difference between those patients who suffered a post-operative MI and those who did not.
"We found it interesting that each of the six polymorphisms individually had only a modest effect, but when taken together, the combined effect was significant," Podgoreanu said. "If an individual is unfortunate enough to have this combination of genetic factors, they will likely experience an exaggerated and negative response to reperfusion."
Specifically, the deleterious polymorphisms were in genes that code for the production of four different proteins: interleukin-6 (IL-6), C-reactive protein (CRP), intercellular adhesion molecule-1 (ICAM1) and lipopolysaccharide-binding protein (LBP).
MEDICA.de; Source: Duke University Medical Center