Markers of Chlamydia pneumoniae and human cytomegalovirus infection in patients with chronic peripheral vascular disease and their relation to inflammation, endothelial dysfunction and changes in lipid metabolism

Is there an association between central vein stenosis and line infection in patients with tunnelled central venous catheters (TCVCs)?

PURPOSE

Central vein stenosis (CVS) and line infection are well-recognized complications of tunnelled central venous catheters (TCVCs) in patients on haemodialysis. The aim of this study was to evaluate any relationship between CVS and line infection.

METHODS

Analysis of 500 consecutive patients undergoing TCVC insertion was undertaken. Data were collected on patient demographics, details of line insertion and duration, culture-proven bacteraemia and presence of symptomatic CVS. Logistic regression analysis was used to determine risk factors for CVS and bacteraemia.

RESULTS

Mean patient age was 59.0 years (range: 17-93). Mean number of catheter days was 961.1 ± 57.6 per TCVC; 39.4% of TCVCs were associated with culture-proven bacteraemia and 23.6% developed symptomatic CVS. Bacteraemia and CVS were inevitable complications of all TCVCs. The time to symptomatic CVS was longer in patients with bacteraemia than without (1230.91 ± 101.29 vs. 677.49 ± 61.59 days, p<0.001). Patients who had early infection within 90 days of TCVC insertion were less likely to develop CVS (5.9% vs. 22.8%, p<0.001). There was no difference in the bacteraemia rate per 1,000 catheter days between patients with and without CVS (2.62 ± 1.41 vs. 2.35 ± 0.51; p = 0.98). Number of line days (odds ratio (OR) 1.02, p = 0.003), age (OR 1.04, p = 0.04) and culture-proven line infection (OR 0.59, p = 0.014) were all independently associated with CVS.

CONCLUSIONS

Our results suggest that early line infection may be protective against CVS. Alternatively, there may be two distinct predisposition states for CVS and line infection. Further studies are needed to confirm our association and investigate causation.

Pathogens and atherosclerosis: update on the potential contribution of multiple infectious organisms to the pathogenesis of atherosclerosis

It is currently unclear what causes the chronic inflammation within atherosclerotic plaques. One emerging paradigm suggests that infection with bacteria and/or viruses can contribute to the pathogenesis of atherosclerosis either via direct infection of vascular cells or via the indirect effects of cytokines or acute phase proteins induced by infection at non-vascular sites. This paradigm has been supported by multiple epidemiological studies that have established positive associations between the risk of cardiovascular disease morbidity and mortality and markers of infection. It has also been supported by experimental studies showing an acceleration of the development of atherosclerosis following infection of hyperlipidaemic animal models. There are now a large number of different infectious agents that have been linked with an increased risk of cardiovascular disease. These include: Chlamydia pneumoniae, Porphyromonas gingivalis, Helicobacter pylori , influenza A virus, hepatitis C virus, cytomegalovirus, and human immunodeficiency virus. However, there are significant differences in the strength of the data supporting their association with cardiovascular disease pathogenesis. In some cases, the infectious agents are found within the plaques and viable organisms can be isolated suggesting a direct effect. In other cases, the association is entirely based on biomarkers. In the following review, we evaluate the strength of the data for individual or groups of pathogens with regard to atherosclerosis pathogenesis and their potential contribution by direct or indirect mechanisms and discuss whether the established associations are supportive of the infectious disease paradigm. We also discuss the failure of antibiotic trials and the question of persistent infection.