In a new study, researchers found that recent active asthma in patients aged 50 years or older increased the risk for abdominal aortic aneurysms (AAA) and their rupture. The research article, “Asthma Associates with Human Abdominal Aortic Aneurysm and Rupture,” was published in the journal Arteriosclerosis, Thrombosis and Vascular Biology, an American Heart Association journal.
Both asthma and AAA involve inflammation. While asthma is characterized by increased IgE levels and accumulation of pro-inflammatory immune cells, such as eosinophils, macrophages and mast cells in the bronchi of patients, AAA patients have macrophages and neutrophils in their arterial walls.
Recent research indicates that human AAA lesions also present increased levels of mast cells and immunoglobulin E, or IgE, an inflammation-related protein made by the body in response to allergens. This suggests a possible link between allergy and asthma’s pathogenesis and AAA.
The research team hypothesized that asthma might promote the development of abdominal aortic aneurysms by inducing an increase of aortic wall pro-inflammatory cell accumulation and expansion. Researchers analyzed medical records from two studies done in Denmark. One study was done with 15,942 individuals age 50 or older with abdominal aortic aneurysms, using the Danish National Registry of Patients (DNRP). The second study was of 18,749 men ages 65 to 74, with both AAA and non-AAA controls, from the Viborg Vascular (VIVA) screening trial.
The results showed that patients with both AAA and asthma diagnosed within the past year had a more than 50 percent higher risk of a ruptured AAA than those without asthma. Patients diagnosed with asthma within the last six months were twice as likely, when compared to non-asthmatics, of developing aortic aneurysm rupture. Moreover, patients with a record of taking anti-asthmatic medication also had a significantly increased risk for AAA than those without anti-asthma records.
Although the study suggested that the increased IgE levels of asthma patients might activate inflammatory cells and lead to aneurysm and aortic rupture, further studies are necessary to understand the link between the two inflammatory events.
Lead author Guo-Ping Shi, DSc, a biochemist at Brigham and Women’s Hospital and Harvard Medical School in Boston, said in a press release, “Older patients, especially men, with a recent asthma diagnosis should be checked for signs of aortic aneurysm. In addition, patients with a diagnosed aneurysm who later develop asthma should also be monitored for changes in the size and strength of the aorta.”