Temporal changes in hemodynamic reactivity before, during and after a reallife stressor

1
Temporal changes in hemodynamic reactivity
before, during and after a real-life stressor

• Ydwine J. Zanstra
• Professor Derek W. Johnston

Health Psychology GroupUniversity of Aberdeen
2
Cardiovascular reactivity

• Psychological stress may play a role in the
  etiology of cardiovascular disease
• Link between stressor appraisals and exaggerated
  or maladaptive cardiovascular reaction patterns

3
Cardiovascular reactivityhemodynamic reaction
patterns

• Research into the pathogenic role of stress in
  the etiology of cardiovascular disease and
  hypertension will benefit from examining
  hemodynamic reaction patterns
• (Ottaviani et al., 2006 Sherwood Turner, 1995)
  

4
Cardiovascular reactivityhemodynamic reaction
patterns

• hemodynamic reaction patterns
• changes in the parameters underlying blood
  pressure

Blood Pressure Cardiac Output Total
Peripheral Resistance
5
Cardiovascular reactivityhemodynamic reaction
patterns

• Hemodynamic changes in response to a stressor are
  typically examined in the laboratory
• threat appraisals have been shown to be
  associated with increased Total Peripheral
  Resistance
• challenge appraisals were associated with
  increases in Cardiac Output.
• (e.g. Tomaka et al., 1993, 1997 Blascovich
  Tomaka, 1996)

6
Objective

• to obtain ambulatory measures of changes in
  hemodynamic variables
• Cardiac Output (CO),
• Total Peripheral Resistance (TPR),
• Mean Blood Pressure (MBP) and
• Heart Rate (HR)
• in response to a real-life stressor

7
Methods

• Participants 12 men aged 20-27.
• Within-subjects design
• Ambulatory blood pressure
• measured during before and after performance of a
  presentation
• anticipation, stressor, recovery

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Methods ambulatory blood pressure

• Portapres
• Ambulatory non-invasive
• blood pressure measurements
• Consists of
• Two finger cuffs
• Belt (pump, battery and memory card)
• Height correction system
• Records
• Continuous measurement
• Sampling rate 100 Hz

Hemodynamic variables (e.g. Cardiac Output, Total
Peripheral Resistance) can be derived from blood
pressure waveform
9

Analysis

• Heart Rate values were derived from the blood
  pressure waveform.
• Modelflow analysis was used to derive
  beat-to-beat values for Total Peripheral
  Resistance and Cardiac Output.
• After artefact correction, one-minute means were
  calculated for all variables.
• T-tests were used to compare stressor levels to
  those during the anticipation and recovery
  periods.
• Repeated measures analysis was performed on all
  variables for the 52 minutes preceding the
  stressor, (anticipation) and the 45 minutes after
  the stressor (recovery).

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Results

• T-tests
• 1. anticipation vs. stressor
• the mean of the of the first two minutes of the
  stressor compared to the last two minutes of the
  anticipatory period
• 2. stressor vs. recovery
• the mean of the of the first two minutes of the
  stressor compared to the first two minutes of the
  recovery period
• Significant effects in Mean Blood Pressure only
• anticipation vs. stressor was significant (t(11)
  2.57, P .026)
• stressor vs. recovery approached significance
  (t(11) -1.93, P .080)

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Results
anticipation (last two minutes), stressor (first
two minutes), and recovery (first two minutes)
12
Results
anticipation (last two minutes), stressor (first
two minutes), and recovery (first two minutes)
13
Results anticipation and recovery

• Repeated measures analysis of analysis of
  changes during anticipation and changes during
  recovery
• Heart Rate and Mean Blood Pressure
• Anticipation
• significant, upward linear trends in Mean Blood
  Pressure (F(1,11)6.21, P.03)
• and Heart Rate (F(1,11) 8.56, P.014)
• Recovery
• Mean Blood Pressure values decrease over time
  (n.s.)
• Heart Rate decreased during recovery, linear
  trend approached significance (F(1,11) 3.43,
  P.087).

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Results anticipation and recovery

• Anticipation
• significant, upward linear trends in Mean Blood
  Pressure and Heart Rate
• Recovery
• Mean Blood Pressure values decrease over time
  (n.s.)
• Heart Rate decreased during recovery linear
  trend approached significance

Mean Blood Pressure and Heart Rate as a function
of time during anticipation and recovery
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Results anticipation and recovery

• Repeated Measures analysis of changes during
  anticipation and changes during recovery
• Cardiac Output and Total Peripheral Resistance
• Anticipation
• Cardiac Output showed a quadratic trend
  approaching significance (F(1,11)3.36, P.094).
  Values increased initially and decreased just
  prior to the start of the stressor.
• Total Peripheral Resistance showed a quadratic
  trend that approached significance
  (F(1,11)3.49, P0.088). Initial decrease was
  followed by an increase
• Recovery no significant results

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Results anticipation and recovery

• Anticipation
• Cardiac Output
• quadratic trend approaching significance. Values
  increased initially and decreased just prior to
  the start of the stressor.
• Total Peripheral Resistance
• quadratic trend that approached significance
  Initial decrease was followed by an increase
• Recovery no significant results

Cardiac Output and Total Peripheral Resistance as
a function of time during anticipation and
recovery
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Summary of main findings

• Both heart rate and mean blood pressure increased
  initially.
• The anticipatory increase in mean blood pressure
  appears to be at first mediated by early rises in
  Cardiac Output.
• However, just before the start of the stressor,
  Cardiac Output decreases.
• Total Peripheral Resistance continues to rise
  throughout the anticipatory period and appears to
  be increasingly responsible for the continuing
  rise in mean blood pressure.
• Changes during recovery were nonsignificant

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Discussion

• Changes in hemodynamic parameters over time can
  be measured in real-life
• Linear increases in blood pressure may be
  mediated by more complicated patterns of change
  in hemodynamic parameters
• Future analysis will focus on the relationship of
  hemodynamic reaction patterns with stressor
  appraisal

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References

• Blascovich, J., Tomaka, J. (1996). The
  biopsychosocial model of arousal regulation.
  Advances in experimental social psychology, 28,
  1-51
• Ottaviani, C., Shapiro, D., Goldstein, I. B.,
  James, J. E., Weiss, R. (2006). Hemodynamic
  profile, compensation deficit, and ambulatory
  blood pressure. Psychophysiology, 43(1), 46-56.
• Sherwood, A., Turner, J. R. (1995). Hemodynamic
  responses during psychological stress
  Implications for studying disease processes.
  International Journal of Behavioral Medicine,
  2(3), 193-218.
• Tomaka, J., Blascovich, J., Kelsey, R. M.,
  Leitten, C. L. (1993). Subjective, physiological
  and behavioural effects of threat and challenge
  appraisal. Journal of Personality and Social
  Psychology, 65(2), 248-260
• Tomaka, J., Blascovich, J., Kibler, J., Ernst,
  J. M. (1997). Cognitive and Physiological
  Antecedents of Threat and Challenge Appraisal.
  Journal of Personality and Social Psychology,
  73(1), 63-72.

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Temporal changes in hemodynamic reactivity
before, during and after a real-life stressor

• Ydwine J. Zanstra
• Professor Derek W. Johnston

Health Psychology GroupUniversity of Aberdeen
21
Artefact correction

• The artefact detection and correction procedure
  was carried out using CARSPAN software (Mulder,
  1988)
• moving averages were calculated for time windows
  of 60 seconds
• a value was identified as an artefact if it
  exceeds a confidence interval of /- 4 S.D.s
  around that moving average.
• Artefact correction involved linear interpolation
  between two preceding and two successive values

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Modelflow AlgorithmsFor computing hemodynamic
parameters

• MAP COTPR
• Given
• MAP (Mean Arterial Pressure)
• HR (Heart Rate)
• Unknown
• SV (Stroke Volume)
• CO (Cardiac Output)
• TPR (Total Peripheral Resistance)

• SV Asys/Zao
• CO (l/min) SV (l) HR (beats/min)
• TPR (dyne-s cm-5) (MAP (mmHg) / CO (l/min)) x
  80
• area under the systolic portion of the pressure
  wave
• characteristic impedance of the aorta