By Annette M. Boyle
SAN FRANCISCO — The relationship between post-traumatic stress disorder (PTSD) and elevated risk for cardiovascular disease and mortality has been well documented in recent years. How PTSD specifically affects heart health, however, has been less clear.
A study at the San Francisco VA sought to add to that information and found that one mechanism might be an impairment in the ability of blood vessel to dilate in response to stimulus or endothelia dysfunction.
Using flow-mediated brachial artery vasodilation (FMD), researchers measured how well an artery responds to changes in pressure as a blood pressure cuff expands and contracts. They found that, in veterans with PTSD, the arteries were unable to expand normally, which increases the risk of heart attack and stroke.
In an article about the study in the Journal of the American Heart Association, the researchers noted that “it has been estimated that a 1% decrease in FMD is predictive of a 10% absolute increase in future cardiovascular events and mortality.”
The San Francisco VA study found that veterans with PTSD have a 2.4% reduction in FMD, which would increase their risk of cardiovascular events and mortality by nearly 25%, according to co-author Mary Whooley, MD, an investigator at NCIRE, the Veterans Health Research Institute, as well as a physician at the San Francisco VAMC and professor of medicine, epidemiology and biostatistics at the University of California, San Francisco.1
The study measured FMD in 67 veterans with PTSD and 147 veterans without the disorder. Veterans with PTSD had a dilation of 5.8% compared to 7.5% in veterans without PTSD, a sign of impaired endothelia function. Researchers also found a strong correlation between declining FMD response and deteriorating renal function, hypertension and age, but multivariate analysis confirmed the association of PTSD and impaired vasodilation.
“Traditional risk factors such as high blood pressure, diabetes, high cholesterol and smoking, have not fully explained why people with PTSD seem to be at higher heart disease risk. Our study suggests that chronic stress may directly impact the health of the blood vessels,” explained lead author Marlene Grenon, MD, vascular surgeon at the San Francisco VAMC and associate professor of surgery at the University of California San Francisco.
The researchers hypothesized that repeated provocation of endothelial stress reactivity, which PTSD may cause, could increase the formation of fatty plaques in the arteries and reduce their responsiveness over time. Among the possible mechanism are impairments of the nitric oxide pathways, increased inflammation, and “a perturbation in major stress systems such as the hypothalamic-pituitary-adrenal axis and autonomic nervous system,” they suggest.
Researchers noted that patients with PTSD have lower peripheral cortisol levels, which might contribute to inflammation. In addition, psychological stress can increase oxidative stress or release vasoconstrictors.
PTSD could also increase the risk of cardiovascular disease through a self-perpetuating cycle similar to that seen in depression, Whooley told U.S. Medicine. Depression reduces interest in physical activity and increases both medication nonadherence and smoking. About half of veterans with PTSD are also depressed, and it is likely that the stress and anxiety of PTSD could increase the risk of unhealthy behavioral choices.
Those behaviors contribute to increased inflammation, heart rate variability and release of stress hormones such as epinephrine, dopamine and norepinephrine, which are known to increase the risk of cardiovascular disease. The symptom burden, emotional distress and functional limitations associated with heart disease then increase stress, anxiety and depression.
That cycle offers opportunities to intervene, however. While the authors noted that “it is currently unknown whether treatment of PTSD would improve vascular function or future cardiovascular risk,” counseling and support could encourage patients to take steps to improve their health.
“I think behavioral factors play the most critical role,” Whooley said. To mitigate the impact of PTSD on cardiovascular health, she offered some simple advice: “Exercise more!”
The VA suggests exercises such as walking, jogging, swimming and weight-lifting to reduce stress and physical tension and help veterans cope with the difficult emotions associated with PTSD. Exercise can also build self-esteem and increase feelings of personal control that encourage patients to take additional steps to improve and protect their health.
Other steps physicians can recommend to reduce stress and short-circuit the cycle that leads to cardiovascular disease in patients with PTSD include connecting with other trauma survivors, moving to a safe area, volunteering and strengthening personal relationships, according to the VA.
Those measures can help veterans protect their heart health, but more remains to be done.
“We need to determine better ways we can help people manage PTSD and other types of stress to reduce the negative impact of chronic stress on blood vessels,” Grenon emphasized. “At the Veterans Administration in San Francisco, we are in the process of starting a multidisciplinary vascular rehabilitation clinic to try to better manage traditional and nontraditional risk factors including stress, to improve cardiovascular health.”
- Marlene Grenon, Christopher D. Owens, Hugh Alley, Sandra Perez, Mary A. Whooley, Thomas C. Neylan, Kirstin Aschbacher, Warren J. Gasper, Joan F. Hilton, Beth E. Cohen. Posttraumatic Stress Disorder Is Associated With Worse Endothelial Function Among Veterans. Journal of the American Heart Association. 2016;5(3):e003010