Serum lipids act as inverse acute phase reactants and are falsely low in patients with critical limb ischemia

Background: Lipid levels generally fall after an acute myocardial infarction. This study was conducted to see what trends lipid levels had in patients who underwent operation for critical limb ischemia. Methods: The study was prospective and included 30 patients who underwent operation for critical limb ischemia. Serum lipid profiles and C-reactive protein were analyzed before surgery and 3 months after peripheral bypass surgery. In addition, comparison of lipid levels after surgery was made with 287 healthy and 283 ischemic heart disease controls from The Copenhagen City Heart Study. Results: Total, low density lipoprotein, and high density lipoprotein cholesterol levels were found to be significantly lower before surgery than 3 months after surgery (P < .001). In contrast, C-reactive protein was higher before surgery and decreased after 3 months (P < .0001). An inverse linear correlation was found between total cholesterol/low density lipoprotein cholesterol and C-reactive protein (P < .001 and P < .04, respectively). Comparison with controls showed that cholesterol levels 3 months after surgery were significantly lower (P < .009). Conclusion: Serum cholesterol levels are not reliable in the preoperative period and should therefore be measured at least 3 months after surgery when they seem to approach a more representative level.