A) CagA-positive cytotoxic H. pylori strains as a link between plaque instability and atherosclerotic stroke.

AIMS: Previous studies suggested an association between infection by cytotoxic CagA-positive Helicobacter pylori strains and atherosclerotic stroke. It has been hypothesized that CagA strains could increase the risk for stroke by affecting carotid plaque irregularity. Our aims were: (1) to confirm the association between CagA strains and atherosclerotic stroke, and (2) to assess the association between CagA strains and carotid plaque irregularity. METHODS AND RESULTS: We enrolled 105 consecutive patients affected by atherosclerotic stroke and 130 sex, age, social background-matched controls without relevant vascular diseases. Risk factors for atherosclerotic stroke, H. pylori infection and CagA status were evaluated in all subjects. The presence of plaque instability was evaluated by colour Doppler ultrasound. The prevalence of CagA-positive strains was significantly higher in patients than in controls (adjusted OR 2.99, 95% CI 1.52-5.88, P=0.002). The CagA seropositivity was the only factor independently associated with carotid plaque irregularity (adjusted OR 8.42, 95% CI 1.58-44.64, P=0.004). CONCLUSION: The evidence of significant associations between CagA-positive H. pylori strains and the presence of carotid plaque instability support their possible involvement in the pathophysiology of atherosclerotic stroke.