**2. Brief overview on** *H. pylori* **infection and cardiovascular diseases**

The role of *H. pylori* infection in the development and progression of CVDs has been established for the past two decades. Early epidemiology studies have suggested an association between *H. pylori* infection and increased prevalence of atherosclerosis [27] An early study that included 96 patients with CAD and 96 patients without CAD has revealed the followings: 1) there is a significant link between CAD and infection with *H. pylori*, especially the one expressing the virulence factor cytotoxin-associated gene A (CagA) proteins, 2) patients infected with CagA-positive *H. pylori* show significantly greater coronary artery lumen loss and arterial re-stenosis after percutaneous transluminal coronary angioplasty (PTCA) with stent implantation, 3) *H. pylori* eradication significantly attenuates the reduction in coronary artery lumen in CAD patients after PTCA [28]. Diabetic subjects with *H. pylori* infection have more severe peripheral arterial stiffness compared with those without *H. pylori* infection, and a higher cardiovascular risk score and 10-year cardiovascular risk stratification [29, 30]. After adjusting for traditional CVD risk factors, *H. pylori* infection is found to be the only independent predictor of incident carotid plaque with the multivariate odds ratio (OR) of 2.3, and incident acute stroke (with multivariate OR of 3.6) [31]. *H. pylori* infection was positively associated with the prevalence of HTN among Chinese adults [25, 26].

Helicobacter pylori *Infection and Endothelial Dysfunction DOI: http://dx.doi.org/10.5772/intechopen.97260*

Recently, a study using cardio-ankle vascular index reported that subjects with positive *H. pylori* serology were significantly associated with increased arterial stiffness [32].

A recent study, using a large database with a total of 208,196 patients diagnosed with peptic ulcer diseases, compared the cardiovascular outcome for subjects with and without *H. pylori* eradication. A total of 3,713 patients with *H. pylori* eradication treatment within 365 days of the index date were included in the study with randomly selected same number of patients using propensity scores as cohort of non-eradication patients for comparison. The study demonstrated that there was a significant decrease in composite end-points for CHD and death in the early eradication group. The cumulative CHD rate was significantly lower in younger patients (< 65 years old) with *H. pylori* eradication therapy started <1 year of the index date compared to those patients without eradication at all. Interestingly, the study also showed that eradication treatment did not appear to have a significant effect in older patients (≥ 65 years old). Multivariate analysis shows that HTN and renal diseases are risk factors for CHD in patients without eradication, while younger age (< 65 years old) was a protective factor for CHD for the patients with *H. pylori* therapy [33]. Thus, there is little doubt that *H. pylori* infection is indeed associated with significant CVDs including atherosclerosis, HTN, CHD, cerebrovascular disease, and peripheral arterial diseases, as well as their clinical outcomes especially in younger patients (< 65 years old).
