The Importance of Lipoprotein(A) in Pathogenesis of the High Risk Unstable Angina

Abstract

Objectives: The aim of this study is to compare lipoprotein (a) [Lp(a)] levels in patients with low and high risk unstable angina pectoris which is defined according to the cardiac troponin-I (Tn-I) levels and to investigate their relation with myocardial damage. Methods: From patients with chest pain; venous blood samples were collected for measuring serum Lp(a) and CRP (C-reactive protein) levels on admission and serum cTn-I levels 12 and 24 hours after admission. Fifty-nine patients with serum cTn-I levels <1.0 ng/ml were assigned as negative unstable angina group and 53 patients with serum cTn-I levels ≥1.0 ng/ml were assigned as positive unstable angina groups, respectively. Severity of coronary artery disease was determined by angiography in all patients. Results: Compared with cTn-I negative group, Lp(a) levels were significantly higher in cTn-I positive group (52.9±6.0 mg/dl vs 15.7±2.5 mg/dl, p<0.0001). There was a significant correlation between Lp(a) and cTn-I levels (r=0.870, p=0,0001). We could not establish any correlation between Lp(a) levels and Gensini score or between multiple vessel disease and LDL cholesterol levels (p>0.05). Also, there was no significant difference between cTn-I positive and negative groups with respect to Gensini score (p>0.05). Conclusion: Increased Lp(a) levels and significant relation between Lp(a) and cTn-I levels support that Lp(a) can be a risk factor for plaque destabilization and thrombosis rather than severity of coronary artery disease in patients with high risk unstable angina. Furthermore, high levels of Lp(a) may be related with myocardial injury patients with unstable angina.