Mental stress hemodynamic responses and myocardial ischemia: does left ventricular dysfunction alter these relationships?

Acute psychological stress-induced progenitor cell mobilization and cardiovascular events

OBJECTIVE

Certain brain activation responses to psychological stress are associated with worse outcomes in CVD patients. We hypothesized that elevated acute psychological stress, manifesting as greater activity within neural centers for emotional regulation, mobilizes CPC from the bone marrow to the peripheral blood and predicts future cardiovascular events.

METHODS

In 427 patients with stable CAD undergoing a laboratory-based mental stress (MS) test, CPCs were enumerated using flow cytometry as CD34-expressing mononuclear cells (CD34+) before and 45 min after stress. Changes in brain regional blood flow with MS were measured using high resolution-positron emission tomography (HR-PET). Association between the change in CPC with MS and the risk of cardiovascular death or myocardial infarction (MI) during a 5-year follow-up period was analyzed.

RESULTS

MS increased CPC counts by a mean of 150 [630] cells/mL (15%), P < 0.001. Greater limbic lobe activity, indicative of activation of emotion-regulating centers, was associated with greater CPC mobilization (P < 0.005). Using Fine and Gray models after adjustment for demographioc, clinical risk factors and medications use, greater CPC mobilization was associated with a higher adjusted risk of adverse events; a rise of 1000 cells/mL was associated with a 50% higher risk of cardiovascular death/MI [hazards ratio, 1.5, 95% confidence interval, 1.1-2.2).

CONCLUSION

Greater limbic lobe activity, brain areas involved in emotional regulation, is associated with MS-induced CPC mobilization. This mobilization isindependently associated with cardiovascular events. These findings provide novel insights into mechanisms through which psychological stressors modulate cardiovascular risk.

Sex Differences in Hemodynamic and Microvascular Mechanisms of Myocardial Ischemia Induced by Mental Stress

OBJECTIVE

To investigate sex-specific vascular mechanisms for mental stress-induced myocardial ischemia (MSIMI).

APPROACH AND RESULTS

Baseline data from a prospective cohort study of 678 patients with coronary artery disease underwent myocardial perfusion imaging before and during a public speaking stressor. The rate-pressure product response was calculated as the difference between the maximum value during the speech minus the minimum value during rest. Peripheral vasoconstriction by peripheral arterial tonometry was calculated as the ratio of pulse wave amplitude during the speech over the resting baseline; ratios <1 indicate a vasoconstrictive response. MSIMI was defined as percent of left ventricle that was ischemic and as a dichotomous variable. Men (but not women) with MSIMI had a higher rate-pressure product response than those without MSIMI (6500 versus 4800 mm Hg bpm), whereas women (but not men) with MSIMI had a significantly lower peripheral arterial tonometry ratio than those without MSIMI (0.5 versus 0.8). In adjusted linear regression, each 1000-U increase in rate-pressure product response was associated with 0.32% (95% confidence interval, 0.22-0.42) increase in inducible ischemia among men, whereas each 0.10-U decrease in peripheral arterial tonometry ratio was associated with 0.23% (95% confidence interval, 0.11-0.35) increase in inducible myocardial ischemia among women. Results were independent of conventional stress-induced myocardial ischemia.

CONCLUSIONS

Women and men have distinct cardiovascular reactivity mechanisms for MSIMI. For women, stress-induced peripheral vasoconstriction with mental stress, and not increased hemodynamic workload, is associated with MSIMI, whereas for men, it is the opposite. Future studies should examine these pathways on long-term outcomes.

Hemodynamic, catecholamine, vasomotor and vascular responses: Determinants of myocardial ischemia during mental stress

AIMS

Mental stress-induced myocardial ischemia (MSIMI) in patients with coronary artery disease (CAD) is associated with adverse cardiovascular outcomes. We aim to assess hemodynamic, neuro-hormonal, endothelial, vasomotor and vascular predictors of MSIMI.

METHODS AND RESULTS

We subjected 660 patients with stable CAD to 99mTc sestamibi myocardial perfusion imaging at rest, with mental (speech task) and with conventional (exercise/pharmacological) stress. Endothelium-dependent flow-mediated dilation (FMD), microvascular reactivity [reactive hyperemia index (RHI)] and arterial stiffness [pulse wave velocity (PWV)] were measured at rest and 30-min after mental stress. The digital microvascular vasomotor response during mental stress was assessed using peripheral arterial tonometry (PAT). A total of 106(16.1%) patients had MSIMI. Mental stress was accompanied by significant increases in rate-pressure-product (heart rate x systolic blood pressure; RPP), epinephrine levels and PWV, and significant decreases in FMD and PAT ratio denoting microvascular constriction. In comparison to those with no MSIMI, patients with MSIMI had higher hemodynamic and digital vasoconstrictive responses (p<0.05 for both), but did not differ in epinephrine, endothelial or macrovascular responses. Only presence of ischemia during conventional stress (OR of 7.1, 95%CI of 4.2, 11.9), high hemodynamic response (OR for RPP response≥vs<ROC cutoff of 1.8, 95%CI of 1.1, 2.8), and high digital vasoconstriction (OR for PAT ratio<vs≥ROC cutoff of 2.1, 95%CI of 1.3, 3.3) were independent predictors of MSIMI.

CONCLUSION

Ischemia during conventional stress testing and hemodynamic and vasoconstrictive responses to mental stress can help predict subjects with CAD at greater risk of developing MSIMI.

The Mental Stress Ischemia Prognosis Study: Objectives, Study Design, and Prevalence of Inducible Ischemia

OBJECTIVE

Mental stress-induced myocardial ischemia (MSIMI) is a common phenomenon in patients with coronary artery disease (CAD), but contemporary studies of its prognostic significance and its underlying pathophysiology are limited.

METHODS

We prospectively enrolled patients with confirmed CAD in the Mental Stress Ischemia Prognosis Study (MIPS) between 2011 and 2014. All patients underwent mental stress testing using a standardized public speaking task, and ischemia was detected by Tc-sestamibi myocardial perfusion imaging. Patients also underwent conventional stress testing for myocardial ischemia (CSIMI) using exercise or pharmacological stress testing. Furthermore, digital microvascular flow, endothelial function, arterial stiffness, and blood sample collections were performed before, during, and after mental stress. Two-year adverse clinical outcomes are being assessed.

RESULTS

Six-hundred ninety-five patients completed baseline enrollment in the MIPS. Their mean (standard deviation) age was 62.9 (9.1) years, 72% were men, 30% were African American, and 32% had a history myocardial infarction. The prevalence of MSIMI and CSIMI is 16.1% and 34.7%, respectively. A total of 151 patients (22.9%) had only CSIMI, 28 (4.2%) had only MSIMI, and 78 (11.8%) had both MSIMI and CSIMI. Patients with ischemia had a lower ejection fraction and higher prevalence of previous coronary artery bypass grafting compared with those without inducible ischemia (p < .050). The prevalence of obstructive CAD was not statistically different between patients with and without MSIMI (p = .426); in contrast, it was higher in patients with CSIMI (p < .001).

CONCLUSIONS

The MIPS data will provide useful information to assess the prognostic significance and underlying mechanisms of MSIMI.

High Concordance Between Mental Stress-Induced and Adenosine-Induced Myocardial Ischemia Assessed Using SPECT in Heart Failure Patients: Hemodynamic and Biomarker Correlates

Mental stress can trigger myocardial ischemia, but the prevalence of mental stress-induced ischemia in congestive heart failure (CHF) patients is unknown. We characterized mental stress-induced and adenosine-induced changes in myocardial perfusion and neurohormonal activation in CHF patients with reduced left-ventricular function using SPECT to precisely quantify segment-level myocardial perfusion.

METHODS

Thirty-four coronary artery disease patients (mean age±SD, 62±10 y) with CHF longer than 3 mo and ejection fraction less than 40% underwent both adenosine and mental stress myocardial perfusion SPECT on consecutive days. Mental stress consisted of anger recall (anger-provoking speech) followed by subtraction of serial sevens. The presence and extent of myocardial ischemia was quantified using the conventional 17-segment model.

RESULTS

Sixty-eight percent of patients had 1 ischemic segment or more during mental stress and 81% during adenosine. On segment-by-segment analysis, perfusion with mental stress and adenosine were highly correlated. No significant differences were found between any 2 time points for B-type natriuretic peptide, tumor necrosis factor-α, IL-1b, troponin, vascular endothelin growth factor, IL-17a, matrix metallopeptidase-9, or C-reactive protein. However, endothelin-1 and IL-6 increased, and IL-10 decreased, between the stressor and 30 min after stress. Left-ventricular end diastolic dimension was 179±65 mL at rest and increased to 217±71 after mental stress and 229±86 after adenosine (P<0.01 for both). Resting end systolic volume was 129±60 mL at rest and increased to 158±66 after mental stress (P<0.05) and 171±87 after adenosine (P<0.07), with no significant differences between adenosine and mental stress. Ejection fraction was 30±12 at baseline, 29±11 with mental stress, and 28±10 with adenosine (P=not significant).

CONCLUSION

There was high concordance between ischemic perfusion defects induced by adenosine and mental stress, suggesting that mental stress is equivalent to pharmacologic stress in eliciting clinically significant myocardial perfusion defects in CHF patients. Cardiac dilatation suggests clinically important changes with both conditions. Psychosocial stressors during daily life may contribute to the ischemic burden of CHF patients with coronary artery disease.

Brain natriuretic hormone predicts stress-induced alterations in diastolic function

BACKGROUND

Mental stress (MS) reduces diastolic function (DF) and may lead to congestive heart failure with preserved systolic function. Whether brain natriuretic hormone (brain natriuretic peptide [BNP]) mediates the relationship of MS with DF is unknown.

METHODS

One hundred sixty individuals aged 30 to 50 years underwent 2-hour protocol of 40-minute rest, videogame stressor and recovery. Hemodynamics, pro-BNP samples and DF indices were obtained throughout the protocol. Separate regression analyses were conducted using rest and stress E/A, E' and E/E' as dependent variables. Predictor variables were entered into the stepwise regression models in a hierarchical fashion. At the first level, age, sex, race, height, body mass index, pro-BNP and left ventricular mass (LVM) were permitted to enter the models. The second level consisted of systolic blood pressure (SBP), diastolic blood pressure (DBP) and heart rate (HR). The final level contained cross-product terms of race by SBP, DBP and HR.

RESULTS

E/A ratio was lower during stress compared to rest and recovery (P < 0.01). Resting E/A ratio was predicted by a regression model of age (-0.31), pro-BNP (0.16), HR (-0.40) and DBP (-0.23) with an R² = 0.33. Stress E/A ratio was predicted by age (-0.24), pro-BNP (0.08), HR (-0.38) and SBP (-0.21) with total R² = 0.22. Resting E' model consisted of age (-0.22), pro-BNP (0.26), DBP (-0.27) and LVM (-0.15) with an R² = 0.29. Stress E' was predicted by age (-0.18), pro-BNP (0.35) and LVM (-0.18) with an R² = 0.18. Resting E/E' was predicted by race (0.17, B > W) and DBP (0.24) with an R² = 0.10. Stress E/E' consisted of pro-BNP (-0.36), height (-0.26) and HR (-0.21) with an R² = 0.15.

CONCLUSIONS

pro-BNP predicts both resting and stress DF, suggesting that lower BNP during MS may be a marker of diastolic dysfunction in apparently healthy individuals.

Increases in B-type natriuretic peptide after acute mental stress in heart failure patients are associated with alcohol consumption

OBJECTIVE

The aim of this study was to investigate in heart failure (HF) patients whether acute mental stress induces increases in the HF-severity biomarker B-type natriuretic peptide (BNP) and if alcohol consumption is associated with such stress-induced increases.

METHOD

Twenty-one male HF patients and 19 male non-HF controls (M = 56 years, SEM = 2) underwent a 15-minute acute mental stress test combining public speaking and mental arithmetic. Plasma levels of BNP were determined immediately before as well as 2 hours after the stress test. Alcohol consumption was assessed by self-reported number of drinks per month and history of use.

RESULTS

HF patients had higher BNP levels before and after stress, F(1, 38) = 23.42, p < .001, and showed greater stress-induced increases in BNP levels, F(1, 38) = 4.52, p = .04, compared with controls. HF status (beta = .32, p = .015, deltaR(2) = .10) and higher alcohol consumption ((beta = .61, p< .001, deltaR(2) = .37) were independently associated with higher BNP stress increases. Moreover, higher alcohol consumption moderated the greater BNP stress increases in HF patients but not in controls (p = .49, p < .001, delta(2) = .20), although alcohol consumption did not differ between groups.

CONCLUSIONS

For individuals with HF, particularly those who drink moderate to more substantial amounts of alcohol, exposure to acute psychological stress leads to increases in circulating levels of BNP, a biomarker which is associated with increased morbidity and mortality in HF.