Methods: Between January 1994 and December 2004, a total of 83 patients including 18 patients who were reoperated due to mechanical heart valve dysfunction (group 1), 15 patients with normal functions with lower international normalized ratio (INR) levels who underwent mechanical valve replacement (group 2), and 50 healthy individuals (group 3) were included. Factor V Leiden, prothrombin, interleukin (IL-6), and tumor necrosis factor alpha (TNF-a) polymorphisms were investigated for possible relationships between these factors and mechanical heart valve dysfunction.

Results: A significant difference in IL-6 polymorphism was found between group 1 and group 3 (p<0.05). Other polymorphisms were not significantly associated with mechanical heart valve dysfunction among the groups. The IL-6 G-174C polymorphism was found to be significantly associated with mechanical heart valve dysfunction.

Conclusion: Interleukin-6, the key inflammatory response cytokine, may play an effective role in mechanical heart valve dysfunction possibly through ongoing chronic inflammatory processes.