Abstract 3118: The MBL2 “LYQA Secretor” Haplotype is an Independent Predictor of Postoperative Myocardial Infarction (MI) in Caucasians Undergoing Coronary Artery Bypass Graft (CABG) Surgery
Background and Aim: Mannose binding-lectin (MBL) is an important component of innate immunity, and activator of the lectin complement pathway. Within the MBL2 gene are seven “secretor” haplotypes that code for altered serum MBL levels and complement activation. As complement is important in the pathophysiology of myocardial injury, we determined if MBL2 secretor haplotypes are independently associated with an increased risk of in-hospital, postoperative MI in patients undergoing CABG surgery.
Methods: Prospective, longitudinal multi-institutional study of 978 patients undergoing primary, elective CABG-only surgery with cardiopulmonary bypass between 8/2001 and 5/2005. Genotyping of 18 polymorphic sites within the MBL2 gene was performed at the National Cancer Institute using Sequenom MALDI-TOF. Multivariate, stepwise logistic regression was performed controlling for patient demographics, preoperative risk factors, medications and intraoperative variables to determine if MBL2 secretor haplotypes are independent predictors of in-hospital, postoperative MI (defined by clinician diagnosis of MI by ECG or enzyme criteria).
Results: The incidence of postoperative MI in Caucasians (n = 843) expressing the MBL2 LYQA secretor haplotype (CGTCGG) on the backbone of the extended haplotype CGTCGGCGGGT was significantly higher than Caucasians not expressing the haplotype (42% vs. 10%; P <0.007). Moreover, the MBL2 LYQA secretor haplotype was an independent predictor of postoperative MI in Caucasians following elective, primary CABG surgery after adjustment for other covariates (p<0.02; adjusted OR = 3.37; 95% CI 1.13 – 10.07). The MBL2 LYQA secretor haplotype in Caucasians was also an independent predictor of creatine kinase MB (CKMB) levels exceeding 60 ng/ml on postoperative day one (p<0.02; adjusted OR = 4.48; 95% CI 1.95 – 16.80). The MBL2 LYQA secretor haplotype in non-Caucasians (n = 135) was not independently associated with an increased risk of postoperative MI following elective, primary CABG surgery.
Conclusions: The MBL2 LYQA secretor haplotype is a novel independent predictor of postoperative MI in Caucasians undergoing primary, elective CABG surgery.