Coronary and Peripheral Vasomotor Responses to
Mental Stress
Muhammad Hammadah, Emory University
Jeong Hwan Kim, Emory University
Ibhar Al Mheid, Emory University
Ayman Samman Tahhan, Emory University
Kobina Wilmot, Emory University
Ronnie Ramadan, Emory University
Ayman Alkhoder, Emory University
Mohamed Khayata, Emory University
Girum Mekonnen, Emory University
Oleksiy Levantsevych, Emory University
Only first 10 authors above; see publication for full author list.
Journal Title: Journal of the American Heart Association
Volume: Volume 7, Number 10
Publisher: Wiley Open Access: Creative Commons Attribution
Non-Commercial | 2018-05-15
Type of Work: Article | Final Publisher PDF
Publisher DOI: 10.1161/JAHA.118.008532
Permanent URL: https://pid.emory.edu/ark:/25593/spg7k
Final published version: http://dx.doi.org/10.1161/JAHA.118.008532
Copyright information:
© 2018 The Authors.
This is an Open Access work distributed under the terms of the Creative
Commons Attribution-NonCommercial-NoDerivatives 4.0 International License
(http://creativecommons.org/licenses/by-nc-nd/4.0/).
Accessed April 9, 2019 11:48 AM EDT
ORIGINAL RESEARCH
Coronary and Peripheral Vasomotor Responses to Mental Stress
Muhammad Hammadah, MD; Jeong Hwan Kim, MD; Ibhar Al Mheid, MD; Ayman Samman Tahhan, MD; Kobina Wilmot, MD;
Ronnie Ramadan, MD; Ayman Alkhoder, MD; Mohamed Khayata, MD; Girum Mekonnen, MD; Oleksiy Levantsevych, MD; Yasir Bouchi, MS;
Belal Kaseer, MD; Fahad Choudhary, MD; Mohamad M. Gafeer, MD; Frank E. Corrigan III MD; Amit J. Shah, MD; Laura Ward, MPH;
Michael Kutner, PhD; J. Douglas Bremner, MD; David S. Sheps, MD; Paolo Raggi, MD; Viola Vaccarino, MD, PhD; Habib Samady, MD;
Kreton Mavromatis, MD; Arshed A. Quyyumi, MD
Background-—Coronary microvascular dysfunction may contribute to myocardial ischemia during mental stress (MS). However, the
role of coronary epicardial and microvascular function in regulating coronary blood flow (CBF) responses during MS remains
understudied. We hypothesized that coronary vasomotion during MS is dependent on the coronary microvascular endothelial
function and will be reflected in the peripheral microvascular circulation.
Methods and Results-—In 38 patients aged 598 years undergoing coronary angiography, endothelium-dependent and
endothelium-independent coronary epicardial and microvascular responses were measured using intracoronary acetylcholine and
nitroprusside, respectively, and after MS induced by mental arithmetic testing. Peripheral microvascular tone during MS was
measured using peripheral arterial tonometry (Itamar Inc, Caesarea, Israel) as the ratio of digital pulse wave amplitude compared to
rest (peripheral arterial tonometry ratio). MS increased the rate-pressure product by 22% (23%) and constricted epicardial
coronary arteries by 5.9% ( 10.5%, 2.6%) (median [interquartile range]), P=0.001, without changing CBF. Acetylcholine
increased CBF by 38.5% (8.1%, 91.3%), P=0.001, without epicardial coronary diameter change (0.1% [ 10.9%, 8.2%], P=not
significant). The MS-induced CBF response correlated with endothelium-dependent CBF changes with acetylcholine (r=0.38,
P=0.03) but not with the response to nitroprusside. The peripheral arterial tonometry ratio also correlated with the demandadjusted change in CBF during MS (r= 0.60, P=0.004), indicating similarity between the microcirculatory responses to MS in the
coronary and peripheral microcirculation.
Conclusions-—The coronary microvascular response to MS is determined by endothelium-dependent, but not endotheliumindependent, coronary microvascular function. Moreover, the coronary microvascular responses to MS are reflected in the
peripheral microvascular circulation. ( J Am Heart Assoc. 2018;7:e008532. DOI: 10.1161/JAHA.118.008532.)
Key Words: endothelial function • epicardial • flow • mental stress • microvascular • resistance
ental stress (MS) has been linked to increased risk of
cardiovascular diseases and adverse cardiovascular
outcomes.1-3 Acute MS results in transient pathological
hemodynamic and neuroendocrine activation.4 Vasomotor
changes in the coronary conductance and resistance vessels
modulate coronary blood flow (CBF) during physiologic and
psychological stress.5,6 For example, vasodilation of the
M
epicardial and coronary microvasculature during maximal
exercise can increase CBF by 4- to 5-fold, with the greatest
contribution coming from dilation of the resistance or
microvessels.7 In the normal coronary circulation, acute MS
results in dilation of both epicardial arteries and microvessels,
increasing CBF to match the increase in demand imposed by
the MS-induced increases in blood pressure, heart rate, and
From the Division of Cardiology, Departments of Medicine (M.H., J.H.K., I.A.M., A.S.T., K.W., R.R., A.A., M. Khayata, G.M., O.L., Y.B., B.K., F.C., M.M.G., F.E.C., A.J.S.,
V.V., H.S., K.M., A.A.Q.) and Psychiatry and Behavioral Sciences (J.D.B.), Emory University School of Medicine, Atlanta, GA; Departments of Epidemiology (A.J.S., L.W.,
P.R., V.V.) and Biostatistics and Bioinformatics (M. Kutner), Rollins School of Public Health, Emory University, Atlanta, GA; Atlanta VA Medical Center, Decatur, GA
(A.J.S., J.D.B., K.M.); Department of Epidemiology, University of Florida College of Medicine, Gainesville, FL (D.S.S.); Mazankowski Alberta Heart Institute, University of
Alberta, Edmonton, Alberta, Canada (P.R.).
Accompanying Table S1 and Figures S1 through S5 are available at http://jaha.ahajournals.org/content/7/10/e008532/DC1/embed/inline-supplementarymaterial-1.pdf
Correspondence to: Arshed A. Quyyumi, MD, Division of Cardiology, Department of Medicine, Emory University School of Medicine, 1462 Clifton Road NE, Suite
507, Atlanta, GA 30322. E-mail: aquyyum@emory.edu
Received January 3, 2018; accepted March 28, 2018.
ª 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley. This is an open access article under the terms of the Creative Commons
Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is
non-commercial and no modifications or adaptations are made.
DOI: 10.1161/JAHA.118.008532
Journal of the American Heart Association
1
Coronary and Peripheral Vasomotion in Mental Stress
Hammadah et al
What Is New?
• This study demonstrates for the first time that microvascular vasomotor changes during mental stress in the digital
circulation reflect changes in the coronary circulation.
• Microvascular endothelium-dependent, but not -independent, function predicts coronary microvascular responses
during mental stress in patients with coronary artery
disease.
What Are the Clinical Implications?
• Endothelial dysfunction results in impaired vasomotion
during mental stress and thus contributes to development
of mental stress–induced myocardial ischemia in patients
with coronary artery disease.
• Whether improvement of endothelial function will improve
coronary vascular responses to mental stress and reduce
mental stress–induced myocardial ischemia needs further
investigation.
contractility.5,8,9 In the presence of coronary artery disease
(CAD), epicardial coronary arteries paradoxically constrict,
and resistance vessel dilation is markedly impaired,5,10
resulting in diminished vasodilation that, if severe enough,
can lead to myocardial ischemia.5,8-12 Other studies, however,
have not confirmed this finding.9,12
The underlying mechanisms for these responses remain
understudied. Coronary vasodilation is modulated by both
endothelial and nonendothelial mechanisms. Vascular
responses to endothelium-dependent agonists such as acetylcholine estimate endothelial function and responses to
endothelium-independent agents including sodium nitroprusside reflect smooth muscle and other nonendothelial vasodilatory function; and responses to adenosine largely estimate
maximal endothelium-independent microvascular function or
flow reserve. One study showed that the magnitude of
coronary epicardial endothelial dysfunction significantly correlated with epicardial vasoconstriction during MS.10 To our
knowledge, no study has assessed the relationship between
the epicardial and microvascular responses to MS and
coronary vascular endothelium-dependent and -independent
function, or with coronary flow reserve. A comprehensive
assessment of these responses with MS was 1 goal of our
investigation.
Several studies have assessed peripheral vascular changes
by measuring digital vasoconstriction in response to MS, by
utilizing a noninvasive peripheral arterial tonometry (PAT)
device.4,13,14 The degree of peripheral microvascular constriction measured with this device has been related to the
propensity toward MS-induced myocardial ischemia (MSIMI)
DOI: 10.1161/JAHA.118.008532
in patients with CAD.4,13,14 Whether there is any relationship
between peripheral and coronary vasomotion during MS has
not been previously studied and is a goal of our
investigation.4
In this study we aimed to examine the relationship
between coronary vascular responses to MS and (1) endothelium-dependent epicardial (coronary diameter response) and
microvascular function (acetylcholine-mediated CBF and
resistance responses), (2) endothelium-independent epicardial and microvascular function (sodium nitroprusside–mediated responses), and (3) endothelium-independent coronary
flow reserve (response to adenosine), in patients with stable
CAD. We further examined the association between the
peripheral and coronary vascular responses during MS. Our
hypothesis was that MS-induced coronary vascular responses
are associated with endothelium-dependent but not endothelium-independent coronary epicardial and microvascular function. Second, we hypothesized that the coronary
microcirculatory responses to MS will correlate with the
digital peripheral microvascular reactivity.
Methods
The data, analytic methods, and study materials will not be
made available to other researchers for purpose of reproducing the results or replicating the procedure.
Study Population
Forty-six people were enrolled from the Mental Stress
Ischemia Prognosis Study,15 a prospective study that
recruited patients with stable CAD between June 2011 and
August 2014 at Emory University–affiliated hospitals. Presence of CAD was defined by an abnormal coronary angiogram
demonstrating angiographic evidence of atherosclerosis with
at least luminal irregularities. Patients with an acute coronary
syndrome or with decompensated heart failure during the
previous 2 months, end-stage renal disease, or unstable
psychiatric conditions were excluded. Clinical information
including previous CAD events, CAD risk factors, coronary
angiography results, and current medications were documented using standardized questionnaires and chart reviews.
Patients were tested in the morning after a 12-hour fast.
Antianginal medications (b-blockers, calcium-channel blockers, and long-acting nitrates), xanthine derivatives, and
caffeine-containing products were withheld for 24 hours
before stress testing. Sedation was not given before catheterization in order to exclude the potential effects of these
medications on reactivity during MS testing. The research
protocol was approved by the Institutional Review Board, and
all participants provided informed consent.
Journal of the American Heart Association
2
ORIGINAL RESEARCH
Clinical Perspective
Coronary and Peripheral Vasomotion in Mental Stress
Hammadah et al
ORIGINAL RESEARCH
Study Flow
Measurements
Diagnostic coronary angiogram
(10 min of equilibration)
Baseline measurement
BP, HR, APV and vessel diameter
Acetylcholine (15ug/min for 3 min)
BP, HR, APV and vessel diameter
(5-10 min of equilibration)
Adenosine (2.2mg/min for 2 min)
BP, HR, APV and vessel diameter
(15 min of equilibration)
PAT
T
g MS / 3 min before MS))
PAT ratio ((during
Mental Stress Testing (5 min)
BP, HR, APV and vessel diameter
(15 min of equilibration)
Acetylcholine (15ug/min for 3 min)
BP, HR, APV and vessel diameter
(5 min of equilibration)
Nitroprusside
Nitropr sside (20
(20ug/min
g/min for 3 min)
BP, HR, APV and vessel diameter
Figure 1. Schematic flowchart of the study protocol and respective measurements. APV indicates
average peak velocity; BP, blood pressure; HR, heart rate; MS, mental stress test; PAT, peripheral arterial
tonometry.
Cardiac Catheterization
After insertion of a 7F femoral vascular sheath under local
anesthesia and administration of 5000 U of heparin, routine
coronary angiography was performed. Patients were not
premedicated beforehand with analgesics or sedatives to
avoid the effects of these medications on the responses to
MS. All measurements were made in unobstructed coronary
arteries (<20% stenosis). A 0.014-inch Doppler wire (Flowire,
Volcano Corp, Rancho Cordova, CA) was advanced into a
nondiseased segment of either the left anterior descending or
the circumflex coronary artery through a 7F guide and a 3F
infusion catheter and placed in a straight unoverlapped
segment of the epicardial coronary artery without any side
branches, which allowed measurement of a stable flowvelocity signal.
Dextrose 5% was continuously infused through the infusion
catheter at a rate of 1 mL/min. The coronary diameter for
calculating CBF was measured in a segment 0.25 to 0.5 cm
beyond the tip of the Doppler wire. CBF (mL/min) was
estimated as p9average peak velocity (cm/s)90.1259vessel
DOI: 10.1161/JAHA.118.008532
diameter (mm). Coronary vascular resistance (CVR) was
calculated as mean arterial pressureCBF. To measure
epicardial changes during the drug infusions and MS, coronary
diameter was also measured in a long (>1 cm) distal segment
of the study coronary artery where the effects of the infused
drugs would be evident. Coronary artery diameter changes
were measured off-line in the Emory cardiovascular imaging
and biomechanical core laboratory using a computerized
edge-detection system (PIE Medical Imaging, Maastricht, The
Netherlands) by investigators blinded to the patients’ demographic and clinical data.16 Rate-pressure product was
calculated as mean arterial blood pressure9heart rate.
Study Protocol
After completion of the diagnostic coronary angiogram and
placement of the Doppler Flowire, there was a 10-minute
resting period before measurement of resting blood pressure,
heart rate, and average peak velocity and performance of a
coronary angiogram (Figure 1, Figures S1 and S2). This was
followed by measurement of endothelium-dependent
Journal of the American Heart Association
3
Coronary and Peripheral Vasomotion in Mental Stress
Hammadah et al
Digital Blood Flow Measurement Using Finger
Plethysmography
During the aforementioned study, digital pulse wave amplitude was continuously measured at rest and during MS using
PAT (Itamar Medical, Caesarea, Israel) as previously
described.13,14 Analyzable data free of artifact were available
in 24 patients. Briefly, the device, which uses a modified form
of plethysmography, was applied to the index finger on the
side opposite to the operator. Registered pressure changes
were fed into a personal computer where the signal was
filtered, amplified, stored, and analyzed in an operatorindependent manner. The baseline pulse wave amplitude
was determined by averaging the last 3 minutes of recording
that preceded MS testing. The amplitude during MS was
determined as the lowest pulse wave amplitude during the
arithmetic test. The PAT ratio was calculated as the ratio of
the minimum pulse wave amplitude during MS to the baseline,
with a ratio <1 signifying a vasoconstrictive response.4
Statistical Analysis
Baseline data are reported as meanSD, median (interquartile
range), or percentage. Linear regression with repeated measures was employed to test the change in coronary epicardial
diameter, CBF, and CVR with each intervention. The median
percentage changes are reported with 95% confidence intervals, which were computed based on order statistics using an
incomplete b distribution. The Spearman rank correlation was
utilized to test associations between the responses during MS
and during coronary and peripheral vascular testing. Patients
were grouped based on their CBF responses to acetylcholine
and nitroprusside using median cutoff values and using a
cutoff of 2.5 for coronary flow reserve.17 The Mann-Whitney U
test was used to test differences between groups in response
DOI: 10.1161/JAHA.118.008532
to MS. Statistical analyses were conducted using SPSS (v
23.0, IBM Corp, Armonk, NY).
Results
Of the 46 enrolled subjects, 8 patients could not complete the
study either for symptomatic reasons or because the CAD
was not suitable for insertion of the Flowire and administration of acetylcholine. Thus, 38 subjects, mean age
598 years, were included in the analysis (Table 1).
Coronary Vascular Responses During MS
MS testing, performed after 15 minutes of equilibration
following preceding intracoronary vasomotor challenges,
resulted in a significant increase in heart rate (meanSD)
(1817 beats/min), mean arterial pressure (1411 mm Hg),
and rate-pressure product (22%23%), P<0.001 for all (Figure 2, Table S1). Overall, there was significant epicardial
coronary arterial constriction (median interquartile range
5.9% [ 10.5, 2.6]; P=0.001) during MS, but the responses
were heterogeneous; 8 patients had epicardial vasodilation,
whereas 30 had constriction during MS (Figure 2, Table S1,
Figure S3). Overall, there was no change in the CBF 2.6%
( 13.3%, 15.7%) or CVR 12.0% ( 9.0%, 18.6%), but the
responses were heterogeneous (Figure 2, Table S1, Figure S3).
Endothelium-Dependent Function and Response
to MS
Acetylcholine (10 6 mol/L) infusion, performed after the
baseline measurements and before any other pharmacologic
testing, caused a significant increase in CBF (38.5% [8.1%,
91.3%], P=0.001) and decrease in CVR ( 29.1% [ 49.0%,
3.4%], P=0.001), but no overall change in coronary epicardial diameter (0.1% [ 10.9%, 8.2%], P=not significant)
(Table S1). The responses were heterogeneous (Figures S4A
and S5A).
There was a significant correlation between the microvascular vasodilator responses, measured as changes in CBF
during MS and the CBF changes with the endotheliumdependent dilator acetylcholine (r=0.38, P=0.03) (Figure 3A).
The correlation between coronary epicardial diameter
changes during MS and during acetylcholine infusion was
not significant (r=0.15, P=0.40) (Figure 3B). However, all
patients who had vasoconstriction in response to acetylcholine had vasoconstriction during MS, whereas the
response in those who dilated during acetylcholine infusion
was more heterogeneous (Figure 3B). Last, the correlation
between the CVR changes during MS and with acetylcholine
did not reach statistical significance (r=0.26, P=0.17).
Journal of the American Heart Association
4
ORIGINAL RESEARCH
vasodilation during infusion of intracoronary acetylcholine at a
rate of 15 lg/min for 3 minutes to obtain an estimated
10 6 mol/L intracoronary concentration (n=36). After a 5- to
10-minute period to allow for equilibration, coronary flow
reserve was measured after a 2-minute infusion of intracoronary adenosine at 2.2 mg/min (n=31). After a 15-minute
period to allow for equilibration, patients underwent mental
arithmetic stress testing (n=38). At the end of 5 minutes of
MS testing, the aforementioned measurements were
repeated. Fifteen minutes after completion of the MS test,
endothelium-dependent vasodilation was remeasured with
repeat infusion of intracoronary acetylcholine followed by
measurement of endothelium-independent function after
infusion of sodium nitroprusside at 20 lg/min for 3 minutes
(n=24). Coronary flow and diameter measurements were
repeated at the end of each intervention.
Coronary and Peripheral Vasomotion in Mental Stress
Hammadah et al
ORIGINAL RESEARCH
Table 1. Patient Characteristics
Mean (SD),
Median [IQR], or %
Clinical variables
Number
38
Age, y
598
Male, %
84
Black, %
Body mass index, kg/m
49
2
307
Diabetes mellitus, %
30
Hypertension, %
71
Hyperlipidemia, %
81
Ever smoking, %
68
Myocardial infarction, %
14
Ejection fraction, %
5710
Previous history
Percutaneous coronary intervention, %
19
Heart failure, %
13
Depression, %
19
PTSD, %
5
Medications
Aspirin, %
65
Clopidogrel, %
16
Statins, %
61
b-Blockers, %
45
ACE inhibitors, %
30
Resting hemodynamics
Heart rate, bpm
7712
Mean arterial blood pressure, mm Hg
11215
RPP, mm Hgbpm
75681892
Figure 2. Hemodynamic and coronary vascular responses during mental stress (MS). Bars and error bars represent the median
change and 95% confidence interval, respectively. CBF indicates
coronary blood flow; CI, confidence interval; CVR, coronary
vascular resistance; HR, heart rate; MAP, mean arterial pressure.
to acetylcholine, the respective responses during MS were
significantly lower than those in subjects with healthier
endothelial function (>median response to acetylcholine)
(Figure 4A). However, there were no differences between
the epicardial responses to acetylcholine and the epicardial
responses to MS.
We also compared the coronary vascular responses to
acetylcholine in 20 subjects before and 15 minutes after MS.
There were no differences between the epicardial and
microvascular responses before and after MS testing; postMS, CBF +45.3% (16.7%, 150.4%), CVR 34.9% ( 56.6%,
15.1%), and epicardial coronary changes +1.4% ( 7.4%,
7.6%) were similar to pre-MS testing values (Table S1).
Cardiac catheterization results
Primary diagnosis of diagnostic angiogram
Obstructive CAD, %
26
Nonobstructive CAD, %
71
Vasospastic angina, %
3
Gensini score
7.0 [2.5, 15.5]
Percentage stenosis of the study vessel
10% [10%, 20%]
ACE indicates angiotensin-converting enzyme; bpm, beats per minute; CAD, coronary
artery disease; IQR, interquartile range; PTSD, posttraumatic stress disorder; RPP, ratepressure product.
We grouped patients based on their coronary microvascular responses to acetylcholine using a median cutoff of CBF
response into those with “less healthy” endothelial function
(<median response) and those with “healthier” endothelium
(≥median response). In patients with <median CBF response
DOI: 10.1161/JAHA.118.008532
Endothelium-Independent Function and Response
to MS
Sodium nitroprusside administration, following post-MS
acetylcholine challenge, dilated the coronary epicardial arteries (11.9% [7.8%, 22.3%], P<0.001) and microcirculation (CBF
increased 97.3% [58.2%, 147.4%] and CVR decreased 55.1%
[ 67.2%, 47.7%], both P<0.001) (Table S1, Figures S4B and
S5B). There was no correlation between the coronary flow or
diameter responses to nitroprusside and the responses to MS
(Spearman rank correlation of 0.07, P=0.74). We then
grouped patients based on their microvascular response to
nitroprusside into those with high versus low response using a
median cutoff. There was also no significant difference in MSinduced change in CBF or CVR between those with high
response versus low response to sodium nitroprusside,
respectively (Figure 4B).
Journal of the American Heart Association
5
Coronary and Peripheral Vasomotion in Mental Stress
Hammadah et al
ORIGINAL RESEARCH
Figure 3. Relationship between coronary blood flow (CBF) and epicardial responses during mental stress (MS) and acetylcholine infusion. r values
are Spearman correlation coefficients. A, The solid line represents the line of best fit, and the dashed lines represent 95% confidence interval. B, The
vertical and the horizontal reference lines (dashed) represent no change in epicardial diameter in response to acetylcholine and MS, respectively.
Coronary Flow Reserve and Response to MS
Intracoronary adenosine, infused after the acetylcholine challenge, significantly increased CBF (244% [166%, 398%]) and
decreased CVR ( 71.6% [ 79.1%, 58.8%]), P<0.001 for both
(Table S1, Figures S4C and S5C). There was no statistically
significant correlation between the changes in CBF and CVR with
adenosine and MS-induced vasodilation (r= 0.10, P=0.6). In the
16 patients with normal coronary flow reserve >2.5 compared
to 15 with coronary flow reserve <2.5, there was no difference
in the coronary vasomotor responses during MS, (Figure 4C).
Relationship Between Coronary and Peripheral
Responses to MS
MS testing resulted in significant peripheral vasoconstriction; the PAT ratio was 0.760.17 (<1 indicates digital
microvascular constriction). There was a strong inverse
correlation (r= 0.60, P=0.004) between the PAT ratio and
the demand-adjusted coronary microvascular vasodilation,
measured as the ratio of rate-pressure product to CBF
(Table 2). Thus, subjects with reduced demand-adjusted
coronary vasodilation during MS also had reduced
Figure 4. Relationship between coronary microvascular responses during mental stress and during
(A) acetylcholine, (B) sodium nitroprusside, and (C) adenosine infusions. Subjects divided by median CBF
responses. Bars and error bars represent the median change and 95% CI, respectively. CBF indicates
coronary blood flow; CI, confidence interval; CVR, coronary vascular resistance.
DOI: 10.1161/JAHA.118.008532
Journal of the American Heart Association
6
Coronary and Peripheral Vasomotion in Mental Stress
Hammadah et al
Change With Mental Stress
Spearman Rank Correlation
P Value
Epicardial diameter
0.28
0.18
CBF
0.29
0.20
CVR
0.36
0.11
RPP/CBF
0.60
0.004*
CBF indicates coronary blood flow; CVR, coronary vascular resistance; MS, mental
stress; PAT, peripheral arterial tonometry; RPP, rate pressure response.
*Statistically significant P-value.
peripheral digital microvascular vasodilation (PAT ratio), and
vice versa (Figure 5). No significant correlations were
observed between the PAT ratio during MS and MS-induced
changes in the coronary epicardial diameter, CBF, or CVR
(Table 2).
Discussion
Our findings demonstrate that in patients with CAD, there is a
significant relationship between coronary microvascular
responses to MS, measured as changes in CBF and CVR,
and the underlying coronary microvascular endotheliumdependent, but not endothelium-independent function. Thus,
patients with worse coronary microvascular endothelial
Figure 5. Relationship between mental stress–induced digital
microvascular response, measured as the peripheral arterial
tonometry (PAT) ratio, and the coronary microvascular vasomotor
response, measured as the coronary blood flow (CBF) response
adjusted for the rate-pressure product (RPP). The solid line
represents the line of best fit, and the dashed lines represent the
95% confidence interval.
DOI: 10.1161/JAHA.118.008532
function had reduced microvascular vasodilation in response
to MS, whereas those with more preserved endothelial
function had greater vasodilation with MS. However, we did
not observe a clear relationship between coronary epicardial
endothelial function and the epicardial responses to MS.
Second, there was a strong relationship between the
magnitude of coronary microvascular vasodilation, adjusted
for myocardial oxygen demand, and the digital peripheral
microvascular response during MS, suggesting that similar
factors influence coronary and peripheral microvascular
reactivity during stress. Taken together, our study shows,
for the first time that the health of the coronary microvascular
endothelium, at least partly determines coronary vasodilation
during psychological stress, and the latter is reflected in the
peripheral microvascular vasomotor responses during MS.
These findings illustrate potential mechanisms in the pathogenesis of MSIMI that occurs frequently in patients with CAD
and is associated with poor outcomes.1,2,18,19 We have
previously shown that lower digital microvascular reactivity is
associated with MSIMI.4,13,14 In conclusion, this study shows
that the health of the endothelium, but not the endotheliumindependent pathways, modulates coronary and peripheral
microvascular reactivity, and therefore blood flow delivery
during MS.
We and others have previously shown that epicardial
segments of coronary arteries in individuals free of
atherosclerosis tend to vasodilate during MS, but in those
with CAD, even angiographically smooth segments do not
vasodilate, whereas segments with angiographic atherosclerosis tend to vasoconstrict.5,9-11 Kop et al further showed that
nonstenotic atherosclerotic segments vasoconstrict but not
segments with significant atherosclerosis.9 Two studies that
investigated the relationship between coronary epicardial
responses during MS and endothelial function showed that
segments with epicardial atherosclerosis vasoconstrict,
whereas segments without atherosclerosis vasodilate in
response to both MS and acetylcholine.10,11 In contrast to
these studies we investigated a homogenous population with
CAD in whom changes in epicardial arteries without significant (<20%) stenosis were studied. Although we found no
significant correlation between epicardial responses to MS
and acetylcholine, all epicardial segments that constricted
with acetylcholine also constricted during MS, whereas the
response in those without acetylcholine-mediated constriction
was more heterogeneous. It should be emphasized that we
selected a single straight unobstructed epicardial segment for
measurement in each subject. It is possible that more
diseased segments may have shown results similar to those
previously reported. Furthermore, with a larger sample size,
the correlation could have reached statistical significance.
We and others have previously shown that MS causes
greater microvascular vasodilation and thus increase in CBF in
Journal of the American Heart Association
7
ORIGINAL RESEARCH
Table 2. Relationship Between Peripheral Microvascular
Responses During MS Measured as the PAT Ratio and
Coronary Vasomotor Responses During MS
Coronary and Peripheral Vasomotion in Mental Stress
Hammadah et al
DOI: 10.1161/JAHA.118.008532
Strength and Limitations
This is the first study to demonstrate the relationship
between microvascular endothelial dysfunction and coronary
microvascular responses during MS in patients with CAD,
and to further demonstrate the similarity between peripheral and coronary microvascular reactivity with stress.
Limitations include the lack of information on MSIMI in
this cohort. Further studies comparing coronary endothelial
function between those with and without MSIMI are
needed. Because of the small number of subjects in the
study, lack of statistical significance with some tests may
have been due to lack of statistical power, and the
examination of subgroup differences according to sex and
other comorbidities was limited. A larger study would be
needed to make such comparisons. It should also be
emphasized that the correlation between endothelial dysfunction and MS-induced vasomotion does not imply
causality. Studies designed to improve endothelial function
and its impact on coronary and peripheral vasomotor
responses during MS are needed to establish causality.
Conclusions and Implications
MSIMI is associated with increased risk of adverse cardiovascular outcomes, but its underlying mechanisms are not
well understood.18 Herein we demonstrate the important
contribution of coronary microvascular endothelial dysfunction to the limitation in vasodilation during MS in patients
with CAD. Moreover, we demonstrate that coronary and
peripheral microvascular responses during MS are similar.
Whether improvement of endothelial dysfunction with
angiotensin antagonists, statins, and other agents will
improve coronary and peripheral responses to MS and
improve MSIMI needs to be examined.
Sources of Funding
Dr Vaccarino, Dr Quyyumi, Dr Bremner, Dr Shah, Dr Samady,
and Dr Sheps report research support from NIH. This work
was supported by the NIH (P01 HL101398, P20HL11345101, P01HL086773-06A1, R01 HL109413, R01HL10941302S1, UL1TR000454, KL2TR000455, K24HL077506, and
K24 MH076955). The sponsors of this study had no role in
the design and conduct of the study; collection, management,
analysis, and interpretation of the data or in the preparation,
review, or approval of the article.
Disclosures
None.
Journal of the American Heart Association
8
ORIGINAL RESEARCH
those without CAD compared to those with CAD, even with
similar increases in rate-pressure product and thus myocardial oxygen demand.5,9 We further showed that despite similar
activation of the sympathetic nervous system, measured as
coronary norepinephrine turnover with acute MS, patients
with CAD had impaired coronary microvascular vasodilation
compared to those without CAD.5 Thus, MS-induced sympathetic nervous system activation increases myocardial oxygen
demand and stimulates a-adrenergic receptor-mediated coronary constriction. In the presence of normal vascular
endothelial function, this vasoconstriction is countered by
shear-mediated release of nitric oxide and other endotheliumdependent vasodilators. With endothelial dysfunction, the
adrenergic receptor-mediated constriction supervenes, and
the resulting coronary vasoconstriction limits appropriate CBF
increase, potentially resulting in MSIMI. A novel finding of this
study is demonstration of the critical relationship between
coronary microvascular endothelial function and the
vasodilatory response to MS. Regardless of the underlying
atherosclerosis burden, endothelial function, and not endothelium-independent responses, modulates the coronary
microvascular dilator response to MS.
Endothelial dysfunction is a precursor for the development
and progression of CAD, and both epicardial and microvascular responses to acetylcholine are predictive of future risk
of adverse cardiovascular outcomes.20,21 An impaired
response to acetylcholine is indicative of reduced endothelial
production of nitric oxide and/or other endothelium-dependent vasodilators such as endothelium-dependent hyperpolarizing factor.22,23 Our current findings demonstrating the
contribution of coronary endothelial dysfunction to the
reduced microvascular dilation during MS, combined with
the observation that MSIMI occurs in some patients with CAD,
illustrate that 1 likely mechanism by which endothelial
dysfunction contributes to increased cardiovascular risk is
by promoting MSIMI.
Another important finding of our study is the similarity in
the coronary and peripheral microvascular vasomotor
responses during MS, demonstrated as a strong correlation
between the digital microvascular vasomotion during MS,
measured as the PAT ratio and coronary microvascular
vasodilation, measured as demand-adjusted change in CBF.
Combined with the previous observation that the PAT ratio
during MS is an important and independent predictor of
MSIMI,13,24,25 our current findings imply that microvascular
endothelial function is likely to be a critical determinant of
MSIMI and that the digital microvascular reactivity reflects
coronary microvascular reactivity during stress. Previous
studies have shown that forearm microvascular vasodilation
during mental stress is impaired in subjects with abnormal
endothelial function, lower nitric oxide bioactivity, and greater
endothelin activity.26-30
Coronary and Peripheral Vasomotion in Mental Stress
Hammadah et al
1. Vaccarino V. Mental stress-induced myocardial ischemia. In: Baune TB, Tully
JP, eds. Cardiovascular Diseases and Depression: Treatment and Prevention in
Psychocardiology. Cham: Springer International Publishing; 2016:105–121.
2. Burg MM, Soufer R. Psychological stress and induced ischemic syndromes.
Curr Cardiovasc Risk Rep. 2014;8:1–6.
3. Jiang W, Babyak M, Krantz DS, Waugh RA, Coleman RE, Hanson MM, Frid DJ,
McNulty S, Morris JJ, O’Connor CM, Blumenthal JA. Mental stress–induced
myocardial ischemia and cardiac events. JAMA. 1996;275:1651–1656.
4. Hammadah M, Alkhoder A, Al Mheid I, Wilmot K, Isakadze N, Abdulhadi N,
Chou D, Obideen M, O’Neal WT, Sullivan S, Tahhan AS, Kelli HM, Ramadan R,
Pimple P, Sandesara P, Shah AJ, Ward L, Ko YA, Sun Y, Uphoff I, Pearce B,
Garcia EV, Kutner M, Bremner JD, Esteves F, Sheps DS, Raggi P, Vaccarino V,
Quyyumi AA. Hemodynamic, catecholamine, vasomotor and vascular
responses: determinants of myocardial ischemia during mental stress. Int J
Cardiol. 2017;243:47–53.
design, and prevalence of inducible ischemia. Psychosom Med. 2017;79:311–
317.
16. Prasad A, Zhu J, Halcox JPJ, Waclawiw MA, Epstein SE, Quyyumi AA.
Predisposition to atherosclerosis by infections: role of endothelial dysfunction.
Circulation. 2002;106:184–190.
17. Dean J, Cruz SD, Mehta PK, Merz CN. Coronary microvascular dysfunction:
sex-specific risk, diagnosis, and therapy. Nat Rev Cardiol. 2015;12:406–414.
18. Wei J, Rooks C, Ramadan R, Shah AJ, Bremner JD, Quyyumi AA, Kutner M,
Vaccarino V. Meta-analysis of mental stress-induced myocardial ischemia and
subsequent cardiac events in patients with coronary artery disease. Am J
Cardiol. 2014;114:187–192.
19. Hammadah M, Al Mheid I, Wilmot K, Ramadan R, Alkhoder A, Obideen M,
Abdelhadi N, Fang S, Ibeanu I, Pimple P, Mohamed Kelli H, Shah AJ, Pearce B,
Sun Y, Garcia EV, Kutner M, Long Q, Ward L, Bremner JD, Esteves F, Raggi P,
Sheps D, Vaccarino V, Quyyumi AA. Association between high-sensitivity
cardiac troponin levels and myocardial ischemia during mental stress and
conventional stress. JACC Cardiovasc Imaging. 2018;11:603–611.
5. Dakak N, Quyyumi AA, Eisenhofer G, Goldstein DS, Cannon RO III.
Sympathetically mediated effects of mental stress on the cardiac microcirculation of patients with coronary artery disease. Am J Cardiol. 1995;76:125–
130.
20. Halcox JP, Schenke WH, Zalos G, Mincemoyer R, Prasad A, Waclawiw MA, Nour
K, Quyyumi AA. Prognostic value of coronary vascular endothelial dysfunction.
Circulation. 2002;106:653–658.
6. Nabel EG, Ganz P, Gordon JB, Alexander RW, Selwyn AP. Dilation of normal and
constriction of atherosclerotic coronary arteries caused by the cold pressor
test. Circulation. 1988;77:43–52.
21. Suwaidi JA, Hamasaki S, Higano ST, Nishimura RA, Holmes DR Jr, Lerman A.
Long-term follow-up of patients with mild coronary artery disease and
endothelial dysfunction. Circulation. 2000;101:948–954.
7. Duncker DJ, Bache RJ. Regulation of coronary blood flow during exercise.
Physiol Rev. 2008;88:1009–1086.
22. Quyyumi AA, Dakak N, Andrews NP, Husain S, Arora S, Gilligan DM, Panza JA,
Cannon RO III. Nitric oxide activity in the human coronary circulation. Impact
of risk factors for coronary atherosclerosis. J Clin Invest. 1995;95:1747–1755.
8. Lacy CR, Contrada RJ, Robbins ML, Tannenbaum AK, Moreyra AE, Chelton S,
Kostis JB. Coronary vasoconstriction induced by mental stress (simulated
public speaking). Am J Cardiol. 1995;75:503–505.
9. Kop WJ, Krantz DS, Howell RH, Ferguson MA, Papademetriou V, Lu D, Popma
JJ, Quigley JF, Vernalis M, Gottdiener JS. Effects of mental stress on coronary
epicardial vasomotion and flow velocity in coronary artery disease: relationship
with hemodynamic stress responses. J Am Coll Cardiol. 2001;37:1359–1366.
10. Yeung AC, Vekshtein VI, Krantz DS, Vita JA, Ryan TJ Jr, Ganz P, Selwyn AP. The
effect of atherosclerosis on the vasomotor response of coronary arteries to
mental stress. N Engl J Med. 1991;325:1551–1556.
11. Boltwood MD, Taylor CB, Burke MB, Grogin H, Giacomini J. Anger report
predicts coronary artery vasomotor response to mental stress in atherosclerotic segments. Am J Cardiol. 1993;72:1361–1365.
12. Arrighi JA, Burg M, Cohen IS, Kao AH, Pfau S, Caulin-Glaser T, Zaret BL, Soufer
R. Myocardial blood-flow response during mental stress in patients with
coronary artery disease. Lancet. 2000;356:310–311.
13. Hassan M, York KM, Li H, Li Q, Lucey DG, Fillingim RB, Sheps DS. Usefulness
of peripheral arterial tonometry in the detection of mental stress-induced
myocardial ischemia. Clin Cardiol. 2009;32:E1–E6.
23. Verma S, Buchanan MR, Anderson TJ. Endothelial function testing as a
biomarker of vascular disease. Circulation. 2003;108:2054–2059.
24. Burg MM, Graeber B, Vashist A, Collins D, Earley C, Liu J, Lampert R, Soufer R.
Noninvasive detection of risk for emotion-provoked myocardial ischemia.
Psychosom Med. 2009;71:14–20.
25. Vaccarino V, Wilmot K, Al Mheid I, Ramadan R, Pimple P, Shah AJ, Garcia EV,
Nye J, Ward L, Hammadah M, Kutner M, Long Q, Bremner JD, Esteves F, Raggi
P, Quyyumi AA. Sex differences in mental stress-induced myocardial ischemia
in patients with coronary heart disease. J Am Heart Assoc. 2016;5:e003630.
DOI: 10.1161/JAHA.116.003630.
26. Cardillo C, Kilcoyne CM, Quyyumi AA, Cannon RO III, Panza JA. Role of nitric
oxide in the vasodilator response to mental stress in normal subjects. Am J
Cardiol. 1997;80:1070–1074.
27. Cardillo C, Kilcoyne CM, Quyyumi AA, Cannon RO, Panza JA. Racial differences
in nitric oxide-mediated response to mental stress in the forearm circulation. J
Am Coll Cardiol. 1997;29:7433–7433 (Supplement A; Abstract).
28. Cardillo C, Kilcoyne CM, Quyyumi AA, Cannon RO, Panza JA. Abnormal nitric
oxide-dependent forearm vasodilation to mental stress in patients with essential
hypertension. Circulation. 1996;94:2681–2681 (Supplement S; Abstract).
14. Ramadan R, Sheps D, Esteves F, Maziar Zafari A, Douglas Bremner J, Vaccarino
V, Quyyumi AA. Myocardial ischemia during mental stress: role of coronary
artery disease burden and vasomotion. J Am Heart Assoc. 2013;2:e000321.
DOI: 10.1161/JAHA.113.000321.
29. Cardillo C, Kilcoyne CM, Cannon RO III, Panza JA. Impairment of the nitric
oxide-mediated vasodilator response to mental stress in hypertensive but not
in hypercholesterolemic patients. J Am Coll Cardiol. 1998;32:1207–1213.
15. Hammadah M, Al Mheid I, Wilmot K, Ramadan R, Shah AJ, Sun Y, Pearce B,
Garcia EV, Kutner M, Bremner JD, Esteves F, Raggi P, Sheps DS, Vaccarino V,
Quyyumi AA. The mental stress ischemia prognosis study: objectives, study
30. Spieker LE, Hurlimann D, Ruschitzka F, Corti R, Enseleit F, Shaw S, Hayoz D,
Deanfield JE, Luscher TF, Noll G. Mental stress induces prolonged endothelial
dysfunction via endothelin-A receptors. Circulation. 2002;105:2817–2820.
DOI: 10.1161/JAHA.118.008532
Journal of the American Heart Association
9
ORIGINAL RESEARCH
References
Supplemental Material
Table S1. Hemodynamic and intracoronary Doppler measurements during the individual steps of the study
protocol.
Step
HR change
(%)
MAP change
(%)
APV change
(%)
Diameter change
(%)
CBF change
(%)
CVR change
(%)
Baseline*
Reference
Reference
Reference
Reference
Reference
Reference
Acetylcholine
-2.9 [-7.7, 4.1]
-2.4 [-11.5,8.0]
55.0 [17.5, 100.0]
0.1 [-10.9, 8.2]
38.5 [8.1,91.3]
-29.1 [-49.0, -3.4]
Adenosine
0 [-5.3, 12.0]
3.5 [-17.5, 53.5]
193.5 [117.6, 269.6]
13.4 [8.7, 19.8]
244.4 [165.9, 397.9]
-71.6 [-79.1, 58.8]
Pre-MS†
Reference
Reference
Reference
Reference
Reference
Reference
MS
11.7 [5.9, 28.7]
11.9 [5.3, 21.1]
0 [-18.1, 28.1]
-5.9 [-10.5, -2.6]
-2.6 [-13.3, 15.7]
12.0 [-9.0, 18.6]
Reference
Reference
Reference
Reference
Reference
Reference
-3.7 [-6.67,4.23]
-4.9 [-9.2, 3.0]
43.2 [14.1, 132.2]
1.4 [-7.4, 7.6]
45.3 [16.7, 150.4]
-34.9 [-56.6, -15.1]
8.1 [0, 17.2]
-12.4 [-22.2, -1.9]
76.3 [55.2, 119.2]
11.9 [7.8, 22.3]
97.3 [58.2, 147.4]
-55.1 [-67.2, -47.7]
Post-MS
recovery‡
Post-MS
Acetylcholine
Nitroprusside
* Baseline was used as the reference for the steps of acetylcholine and adenosine
† Pre-Mental Stress (MS) was used as the reference for the step of MS.
‡ Post-MS recovery was used as the reference for the steps of post-MS acetylcholine and nitroprusside.
MAP: Mean arterial pressure. HR: Heart rate. APV: Average peak velocity. CBF: Coronary blood flow. CVR: Coronary
vascular resistance. MS: Mental Stress Test.
MAP
(mmHg)
HR
(bpm)
APV
(cm/s)
CBF change CVR change
(%)
(%)
A) Baseline
122
86
36
Ref
(B,C)
Ref
(B,C)
B) Acetylcholine
123
82
43
-4.8%
5.9%
C) Adenosine
144
84
80
173%
-57%
D) Pre-MS
121
81
38
Ref
(E)
Ref
(E)
E) MS
123
82
26
-19%
25%
F) Post-MS
105
70
26
Ref
(G)
Ref
(G)
G) Nitroprusside
100
85
57
56%
-47%
Figure S1. Intracoronary Doppler tracing and respective hemodynamic
measurements of a subject during the study protocol. Baseline (A) was the
reference for the acetylcholine (B) and adenosine (C). Pre-MS (D) was the reference for
MS (E), and post-MS (F) was the reference for nitroprusside (G). Abbreviations: MAP:
Mean arterial pressure. HR: Heart rate. BPM: beats per minute. APV: average peak
velocity. CBF: Coronary blood flow. CVR: Coronary vascular resistance. MS: Mental
stress test. Ref: Reference.
A) Baseline
B) Acetylcholine
C) Adenosine
D) Pre-MS
E) During MS
F) Nitroprusside
Figure S2. Illustrative example coronary angiography of a subject during the
study protocol. Left anterior descending artery was studied for this subject.
Abbreviations: MS: Mental stress test.
Figure S3. Coronary vascular responses to mental stress. Each line represents
one patient. CBF: Coronary blood flow. CVR: coronary vascular resistance.
Figure S4. Coronary epicardial and microvascular responses to acetylcholine,
nitroprusside, and adenosine. Data is expressed as percent change. Bars represent
median change, while error bars represent 95%CI.
Figure S5. Coronary vascular responses to acetylcholine, nitroprusside, and
adenosine. Each line represents one patient. CBF: Coronary blood flow. CVR: coronary
vascular resistance.