Systemic mastocytosis associates with cardiovascular events despite lower plasma lipid levels.

BACKGROUND AND AIMS: Mast cells have been implicated in the development and progression of atherosclerosis in animal models and human autopsy studies. However, it is unknown whether long-term exposure to excess of mast cells is associated with cardiovascular disease (CVD) in humans. Our objective was to compare the prevalence of CVD and cardiovascular risk factors in patients with systemic mastocytosis (SM) and controls.

METHODS: In 50 patients with SM and 50 age and sex matched controls, the history of CVD and presence of cardiovascular risk factors were assessed. Carotid ultrasound was performed to assess carotid intima-media thickness (C-IMT) and plaques presence.

RESULTS: CVD events were more prevalent in SM patients compared to controls (20% vs. 6%, p = 0.04). The prevalence of C-IMT and carotid plaques was similar between patients with SM and controls. In multivariate analysis, CVD events were significantly associated with SM (OR 7.0 (95% CI 1.3-37.6), p = 0.02) and hypertension (OR 9.5 (95% CI 1.9-48.7), p = 0.01). The prevalence of diabetes, hypertension, obesity and smoking was similar between the two groups. Total cholesterol and LDL-C levels were significantly lower in SM patients than in the control group. (5.1 ± 1.1 vs. 5.9 ± 0.9 mmol/l, p < 0.05 and 2.9 ± 0.8 vs. 3.5 ± 0.7 mmol/l, p < 0.05, respectively).

CONCLUSIONS: Despite lower plasma total cholesterol and LDL-C, the prevalence of CVD is higher in patients with SM compared to healthy controls. Beyond the setting of SM, this study can be considered as a proof of concept study, indicating the contribution of mast cells to CVD in humans.