Post-traumatic stress disorder (PTSD) in veterans is associated with worse vascular function, which can increase their risk for cardiovascular disease (CVD) and death, according to researchers at UC San Francisco and the affiliated San Francisco VA Health Care System.
The study, which appears in the March 2016 issue of the Journal of the American Heart Association, found that veterans with PTSD were more likely to have worse endothelial vascular function, which controls the flow of nutrients and toxins from the blood stream to the brain and body, and plays a key role in blood vessel dilation, blood pressure, clotting and inflammation.
“If other studies confirm that patients with PTSD have worse endothelial function, this could be an important target in our efforts to prevent CVD and improve the health of veterans with PTSD,” said senior author Beth Cohen, MD, associate professor of medicine at UCSF Health and SFVAHCS.
An estimated 7.7 million Americans suffer from PTSD. Many veterans returning from tours are affected by PTSD and, over time, the effects may be physical as well as mental.
It is believed that the cumulative effects of stress negatively impact the nervous, cardiovascular, metabolic and immune systems. Previous studies have indicated that psychosocial factors such as PTSD result in increased risk for cardiovascular disease and mortality over other risk factors such as diabetes, hypertension and obesity. Despite this association, the underlying mechanisms are not well understood.
For their study, Cohen and her research team recruited 214 outpatients at the SFVAHCS between June 2011 and August 2015 for CVD testing. The tests involved flow-mediated brachial artery vasodilation (FMD) – the gold standard measurement of endothelial function – and an established symptom checklist for diagnosis of PTSD. Endothelial dysfunction is a potential mechanism in the development and progression of cardiovascular disease.
Overall, 31 percent (64) of the 214 patients were found to have PTSD. These patients also were more likely to suffer from depression and had worse endothelial function, as measured by a significantly lower FMD.
Adjusting for demographic, comorbidity and treatment characteristics, PTSD was associated with worse endothelial function. Possible reasons include impairment of pathways for nitric oxide, a key mediator; lower peripheral cortisol levels that can result in endothelial cell inflammation; or the release of vessel constricting agents.
“To our knowledge, this represents the largest cohort measuring endothelial function with flow-mediated vasodilation in patients with PTSD,” said lead author Marlene Grenon, MDCM, associate professor of surgery at UCSF Health and SFVAHCS and investigator in the Vascular Integrated Physiology and Experimental Therapeutics (VIPERx) lab in San Francisco. “The data provide evidence of a clear association between PTSD and vascular function among veterans and illustrate the need to determine the optimal multidisciplinary strategies to treat patients with comorbid PTSD and CVD risk.”
The researchers note that more study in a broader population group is needed to determine whether poor endothelial function contributes to excess risk of CVD in these patients.
Co-authors on the paper included Christopher Owens, MD; Hugh Alley; Sandra Perez; and Warren Gasper, MD, all of UCSF, the SFVAHCS and VIPERx. Additional authors included Mary Whooley, MD, and Thomas Neylan, MD, of UCSF and SFVAHCS; and Kristin Aschbacher, PhD, and Joan Hilton, MD, of UCSF.