Subjects with a clinical history of asthma had lower endothelial function than healthy controls, regardless of whether participants had normal confirmation of the disease. The study results, which were published in Respiratory Medicine, also showed that participants with asthma who regularly used short-acting beta-agonist (SABA) medications had increased arterial stiffness than those who did not use SABAs. The researchers aimed to compare markers of cardiovascular risk, specifically endothelial function, arterial stiffness and systemic inflammation, between those with confirmed asthma, unconfirmed asthma and healthy controls. The researchers also aimed to investigate the effect of SABA use on these vascular outcomes. This cross-sectional study included 26 patients with confirmed asthma, 15 patients with unconfirmed asthma, and 26 healthy controls all recruited from the Edmonton metropolitan area, Canada. All study participants were between the ages of 18 and 45 and current non-smokers. Participants completed a pulmonary function test and asthma assessment. Physiological signs of asthma were defined as the clinical history of symptoms such as recurrent wheezing, coughing and/or chest tightness. Physiological features also include reversibility of forced expiratory volume in 1 second (FEV1) ≥12% and 200 mL, a ≥20% decrease in FEV1 after a methacholine challenge, or a ≥10% decrease in FEV1 after an exercise challenge. Participants were labeled with confirmed asthma if they had a clinical history and physiological signs of asthma. Those labeled with unconfirmed asthma had a clinical history but no physiologic evidence of asthma. Healthy controls had no evidence of asthma. The researchers compared endothelial function, arterial stiffness and systemic inflammation between these three groups of participants. The researchers assessed participants’ endothelial function as flow-mediated dilatation (FMD) after 5 minutes of hypersystolic forearm occlusion away from the imaging site. A 1% reduction in FMD is associated with a 7% increase in cardiovascular risk. Arterial stiffness of participants was assessed using pulse wave velocity (PWV). PWV was measured between the carotid and radial arteries. A 1 m/s increase in PWV corresponds to an approximately 16% increase in cardiovascular risk. Systemic inflammation was assessed by serum C-reactive protein (CRP) levels after venous blood collection from participants. CRP levels have been linked to cardiovascular risk, even for those without underlying cardiovascular morbidity. Endothelial function was significantly lower in both confirmed and unconfirmed asthma groups compared to healthy controls. There was no significant difference in FMD between the confirmed and unconfirmed asthma groups. No significant difference was found in arterial stiffness and systemic inflammation between both asthma and control groups. Participants with confirmed and unconfirmed asthma were grouped and then stratified based on SABA use. SABA was used by 19 participants and not used by 22 participants in the last year. There was no significant difference between endothelial function and systemic inflammation between these two groups. However, SABA users had significantly higher arterial stiffness by an average of 1.5 m/s than non-SABA users. Limitations of this study include the small sample size and the inability to account for seasonal variations in asthma symptoms due to the cross-sectional design. Also, this study did not adjust for other variables that may influence vascular outcomes. Reduced vascular function was observed in participants with asthma regardless of physiological confirmation of asthma, suggesting that the relationship between asthma and cardiovascular risk may be due to factors other than asthma pathophysiology and perhaps due to asthma symptomatology, the researchers noted. . The researchers also noted that this study highlights the need for proper asthma management to avoid inappropriate use of SABA in patients with unconfirmed normal asthma. Report Henry SL, Moore LE, Brotto AR, Rowland S, Fuhr D, Stickland MK. Systemic vascular health is included in both confirmed and unconfirmed asthma. Respir Med. 2022? 200. doi:10.1016/j.rmed.2022.106932
