PTSD & Heart Disease: A Vicious Cycle

For men and women living with post-traumatic stress disorder (PTSD), their bodies may be as profoundly affected as their minds. In addition to persistent nightmares, negative thoughts and hyper-arousal, the illness is linked to other chronic medical conditions, most notably cardiovascular disease.

PTSD may be a risk factor for heart disease as well as the result of heart disease. In a study of male twins who were on active military duty during the Vietnam War, researchers found that the incidence of coronary heart disease (CHD) in twins with PTSD was more than twice that of twins with no history of PTSD (22.6 percent vs. 8.9 percent) after adjusting for heart disease risk factors (J Am Coll Cardiol 2013; 62[11]:970-978).

They also found PTSD was associated with significantly lower myocardial perfusion and coronary flow reserve based on positron emission tomography. At least one twin in each of the 281 pairs suffered from PTSD, and in the discordant pairs, the odds of developing CHD in the twin with PTSD was 90 percent higher than for his brother. 

“We used objective measures of heart disease—myocardial perfusion imaging—and found evidence that those with PTSD had indications of worse perfusion,” says lead researcher Viola Vaccarino, MD, PhD, of Emory University’s Rollins School of Public Health in Atlanta.

Vaccarino adds that there was no evidence that twins with PTSD had risk factors for heart disease, such as obesity or high cholesterol, so those variables could not explain the differences in disease risk. Instead, she believes that the relationship is likely due to biological changes brought on by exposure to high levels of stress.

The stress response is exaggerated in PTSD, she adds, which leads to higher levels of stress hormones in the body.

“We think that repeated activation of the stress system with reminders of trauma in everyday life in people with PTSD may in the long term damage heart and the blood vessels,” she says. “There are multiple potential mechanisms through which hormones may damage or injure the vessels and predispose people with PTSD to ischemic heart disease.”

Stress & harm

Donald Edmondson, PhD, MPH, of Columbia University Medical Center in New York City, says that stress increases autonomic nervous system activity, which can lead to inflammation. “When we think about the cardiovascular system and particularly the coronary arteries, we think about plaque, which becomes large due to this inflammation over time,” he says. “The heart beats faster, blood pressure goes up, the blood vessels constrict and the plaque is more likely to rupture.”

Another possible explanation, he adds, may be lack of sleep. One of the manifestations of PTSD is difficulty sleeping due to hyper-arousal and nightmares related to the traumatic event, and people who get less than six hours of sleep a night are at increased risk for cardiovascular events. 

A study published recently found an association between PTSD and a lack of oxygen to the heart (Biol Psychiatry 2013; 74[11]:861-866). The authors, led by Jesse H. Turner, MD, of the University of California, San Francisco, found that patients with PTSD were significantly more likely to have MI measured by exercise treadmill tests.

The researchers enrolled 663 patients from two Veterans Affairs Medical Centers between 2008 and 2010 and identified PTSD using the Clinician Administered PTSD Scale. Participants underwent exercise treadmill testing to detect MI.

Seventeen percent of patients with PTSD showed ischemic changes based on their treadmill tests compared with 10 percent of patients without PTSD.

Cardiovascular risk also may be elevated in PTSD patients because of nonadherence to treatment for hypertension. Edmondson and colleagues found PTSD to be an independent risk factor for nonadherence to blood pressure treatment (JAMA Intern Med online Dec. 2, 2013).

The researchers studied 98 patients with uncontrolled hypertension from a primary care clinic in New York City. They determined the presence of PTSD symptoms using a screening tool and assessed medication adherence during the time between two later clinic visits. Patients who stuck to their medication regimen less than 80 percent of the time (based on the percentage of days the prescribed dose was taken) were considered nonadherent.

Average adherence was 86 percent, and 41 percent of the patients were nonadherent. Before adjustment, analysis found that 68 percent of patients with PTSD as defined by the screening tool were nonadherent. In comparison, only 26 percent of patients who had a negative PTSD screen were nonadherent. After adjustment, the researchers found that those with positive PTSD screens were more than five times as likely to be nonadherent.

Heart attack as trigger

Edmondson’s other research has suggested that the relationship between heart disease and PTSD is what he calls a vicious cycle. A life-threatening medical event such as a heart attack or a stroke can ultimately bring about the manifestations of PTSD, which can increase the risk of another cardiovascular event.

“People who suffer a heart attack or stroke may have intrusive thoughts about the event, try to avoid thinking about it. They have persistent changes in how they think, their moods become negative, they experience hyper-arousal and they have a hard time sleeping,” he explains.

In a 2012 meta-analysis, Edmondson and colleagues found an association between clinically meaningful PTSD symptoms brought on by acute coronary syndrome (ACS) and a higher risk for other cardiac events or death (PLoS ONE 2012; 7[6]:1-10). They analyzed 24 observational cohort studies that evaluated PTSD related to an ACS event. They determined that ACS-induced PTSD symptoms are about 12 percent prevalent and associated with about a doubling of risk for later cardiac events or mortality.

One year later, Edmondson and his co-investigators found a similar relationship between PTSD symptoms and stroke or transient ischemic attack (TIA) (PLoS 2013; 8[6]:1-6). A meta-analysis of nine studies found that PTSD symptoms develop in about 25 percent of stroke or TIA survivors.

Recognize & treat early

Vaccarino and Edmondson say while their study findings add to the understanding of the association between PTSD and heart disease, their data do not suggest causation and the mechanisms behind the relationship are not fully understood. However, they argue that acknowledging the link can potentially save lives and money.

“There may be opportunities to lower the risk of cardiovascular disease, which is the number one cause of death in the population,” Vaccarino says. “Prevention is the best approach for patients and society.  It is better for patients’ health and much more economical to treat risk factors than to treat heart disease when it manifests itself and people actually have to go to the hospital—and many people do not even make it to the hospital.”

“About 7 percent of people in the U.S. have PTSD, and they’re at about 50 percent increased risk for incident cardiovascular disease than the rest of the country,” Edmondson says. “If those 7 percent of people are having cardiovascular events at an increased rate, then we’re talking millions of dollars a year.”

And he adds that if these same patients are at increased risk for a second heart attack or stroke triggered by PTSD, then that could be a substantial increase in recurrence rates.

“A second heart attack costs just as much as the first one did,” he says.

Still some unknowns

But Stephen Sidney, MD, MPH, of Kaiser Permanente Northern California in Oakland, Calif., says that he is a bit more cautious in his interpretation of the research data. In an editorial accompanying Vaccarino et al’s study, he wrote that while the evidence supporting a causative relationship between PTSD and heart disease is strong, he would be more convinced with more rigorous research. The disease trajectory and the duration of exposure to risk factors are unknowns that need to be determined.

“One thing we don’t know is the course of this particular disorder,” he says. “It’s a clinical disorder that is manifested by psychiatric symptoms and some people may have it for a short while or others for most of their entire lives. But I didn’t see much in the available research that determined how long a person had the disorder. In general, for most risk factors, the duration of exposure is important.”

He adds that the available studies have measured PTSD using different tools and because of that variability and not fully understanding the course of the disease, there is not enough information to establish causality or a risk score similar to the Framingham risk score for coronary heart disease.
Regardless of his desire for better designed research, Sidney agrees that the findings thus far deserve consideration.

“Clinicians should take PTSD seriously and screen for it when appropriate. If it’s diagnosed, they should provide treatment or refer patients for treatment,” Sidney says.