C-reactive protein (CRP) elevation in patients with abdominal aortic aneurysm is independent of the most important CRP genetic polymorphism

ObjectiveC-reactive protein (CRP) is a marker of cardiovascular disease. The objective was to determine if abdominal aortic aneurysm (AAA) and CRP serum concentration and its CRP gene are associated.Methods and ResultsAAA patients and AAA negative controls were recruited. CRP concentration was measured and the single nucleotide polymorphism (SNP), rs3091244, assessed. AAA cases were divided into those measuring 30-55 mm and >55 mm in diameter, to assess correlation of CRP with AAA size. A total of 248 (227 male) cases and 400 (388 male) controls were included. CRP concentration was higher in cases (385.0 μl/dL [310.4-442.8] vs 180.3 μl/dL [168.1-196.9]; P < .0001). It was higher in large aneurysms (685.7 μl/dL [511.8-1083.0] vs 291.0 μl/dL [223.6-349.6]; P < .0001), with significant correlation observed to size (r = 0.37, P < .0001). CC was the most common SNP genotype with no difference in distribution (P = .43) between cases and controls. No difference existed in CRP for each genotype in the overall cohort (P = .17), cases (P = .18) and controls (P = .19).ConclusionThe results demonstrate that CRP production may be related to the presence of AAA, especially in advanced disease. The serum concentration of CRP does not appear to be influenced by the functional SNP of the CRP gene, which also appears to have no association with AAA formation.

Clinical RelevanceElucidation of the aetiology of AAA will provide a basis for future management, such as anti-inflammatory treatments. The role of C-reactive protein in AAA patients as a marker and possible promoter of disease progression is strengthened by this study. However, this appears to be independent of the CRP gene suggesting a local production phenomenon. Future use of the serum protein may include prediction of surgical candidates, in view of the increased concentration with larger aneurysms.