Impaired endothelial function may underlie increased risk of cardiovascular events for patients with coronary heart disease and depression
Impaired endothelial function may explain
why individuals with coronary heart disease and elevated symptoms
of depression have an increased risk of cardiovascular events, according
to an article in the August 16 issue of the Journal of the American
College of Cardiology.
“Our study reiterates the association of
depression with poor vascular health. The findings suggest that
clinicians should evaluate patients with coronary disease for depressive
symptoms ? and give tentative support for referring those patients
for therapy,” said Alan Hinderliter, MD, a coauthor of the study.
The researchers, including lead author Andrew
Sherwood, PhD, studied 143 patients with documented coronary heart
disease to assess endothelial function and symptoms of depression.
In the patients (mean age, 63 years), endothelial function was assessed
through flow-mediated dilation. The depression assessment was conducted
by obtaining and scoring patients’ responses to the 21-item Beck
Depression Inventory (BDI).
Participants, two thirds of whom were male,
all indicated that they were sedentary at the time of enrollment,
and all had briefly discontinued anti-ischemic medications prior
to flow-mediated dilation assessment.
Although depression is relatively common
in patients with cardiovascular disease and coronary heart disease
and is associated with adverse outcomes, how depressive symptoms
contribute to elevated risk is unknown. The study found impaired
endothelial function in patients with high Depression scores compared
with those with relatively lower Depression Inventory scores. “Our
results suggest that the increased incidence of cardiovascular events
in depressed patients is mediated, in part, by endothelial function,”
Hinderliter said.
Other studies have found a link between depression
and impaired endothelial function in otherwise healthy individuals,
but this study is the first to document the association in a population
with coronary heart disease, the authors noted.
The researchers found that flow-mediated
dilation was significantly impaired in the 47 participants (33%)
whose Depression Inventory scores were greater than 10 (considered
an indication of clinically significant depressive symptoms), compared
with those who were not deemed depressed (0.75% vs. 7.46, p = 0.001).
The mean Inventory score was 16 in the depressed group and 4 in
the non-depressed patients.
Interestingly, flow-mediated dilation was
improved in patients who were taking antidepressant medication,
which may suggest that such medications lower cardiovascular risk
by favorably altering vascular endothelial function. To date, however,
there is no evidence that successful treatment of depression actually
reduces cardiovascular risk associated with depression, Hinderliter
noted.
In a commentary, Robert Carney, PhD, professor
of psychiatry at Washington University School of Medicine in St.
Louis, who was not connected with the study, said that despite the
lack of highly definitive findings, the study has important implications.
“The study adds another piece to the puzzle
of how depression may increase the risk for cardiac events, including
death. The results of this and similar studies suggest that this
risk may be reduced if depression is recognized and treated,” Carney
said. “Thus, treating clinicians need to do a better job of recognizing
depression in patients [with coronary heart disease], and either
offer treatment or refer to a specialist.”
The researchers acknowledged the study’s
limitations, primarily that it was an observational study involving
a relatively small sample, and that the Beck Depression Inventory
scoring is not a clinical measure of, nor a basis for, diagnosis
of clinical depression.
“Our study demonstrated a relationship between
depressive symptoms and endothelial dysfunction in patients with
coronary heart disease. It does not, however, establish a ‘cause-and-effect’
relationship between depression and endothelial dysfunction,” Hinderliter
said.
“The study was well conducted, but it will
be important to replicate it and to further investigate the finding
in a larger sample of patients,” Carney said.
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