Investigation of Peripheral Arterial Tonometry as a Potential Surrogate Marker of Myocardial Blood Flow during Mental Stress Open Access

Mengxi Wang (Spring 2018)

Permanent URL: https://etd.library.emory.edu/concern/etds/tx31qh73c?locale=en
Published

Abstract

Background: Mental stress-induced myocardial ischemia (MSIMI) has been linked with increased adverse cardiovascular events in patients with CAD (coronary artery disease). The current best detection technique Positron emission tomography (PET) measuring myocardial blood flow is invasive and expensive. As peripheral arterial vasoconstriction measured by Peripheral Arterial Tonometry (PAT) has been found associated with the development of MSIMI, we aim to find the potential relationship of peripheral and coronary blood flow for possible noninvasive detection.

Methods and Results: 20 participants with CAD were recruited and randomized to biofeedback treatment and control group. Mental stress was induced by a standardized arithmetic test. PET were performed in stress and rest condition while PAT response was measured continuously every 30 seconds. Participants repeated the same tests after six weeks. Spearman correlation between the PAT and PET was not significant. Moderate correlations were found in African Americans (r=0.5, p=0.07), and females (r=0.42, p=0.23). Linear regression analysis shows biofeedback treatment did not predict any changes in the PAT ratio over time (β=0.46, p=0.20).Possible predictors of dissociation between PET and PAT include heart failure (β=1.30,p=0.64), hypertension (β= 1.17, p=0.19), antidepressant intake (β= 0.64, p=0.62), CABG(β=-0.90, p=0.42) and gender (β= 0.38, p=0.72).

Conclusion: We did not find a statistically significant relationship between the peripheral and cardiac vasomotor responses to mental stress. A larger study is warranted to further investigate the potential relationship.

Table of Contents

Table 1. Selected baseline characteristics1 of the study participants (n=20) by treatment group in the study

　

HRVB(n = 10)

Controls (n = 10)

Demographic factors

   

  Age at enrollment, years (SD)

60.6 (4.6)

59.8 (7.1)

   Race/ethnicity

   

       Caucasian

40%

70%

       African American

60%

30%

   Female

30%

30%

Cardiovascular risk factors

   

   BMI, kg/m2 (SD)

31.8(4.3)

27.4(4.6)

   Diabetes

30%

40%

   Depression

20%

10%

   Ever smoke

70%

30%

   Hypertension

80%

60%

   Cardiac disease history

   

      Heart failure

10%

10%

      PSIMI

50%

80%

      MSIMI

60%

70%

      CABG

0%

40%

   Gensini score, mean (SD)

32.3 (30.0)

42.9 (45.0)

   Medications

   

      Antidepressant

10%

30%

      Beta blocker

70%

70%

   Hemodynamics

   

      SBP, mmHg (SD)

139.8(22.5)

128.7(16.5)

      DBP, mmHg (SD)

80.7(8.4)

71.4(8.4)

      HR, beats/min(SD)

65.2(11.9)

59.1(11.1)

Abbreviations: HRVB, Heart rate variability biofeedback; BMI, body mass index; PSIMI, physical stress-induced myocardial ischemia; MSIMI, metal stress-induced myocardial ischemia; Gensini, total amount of cardiac diseases; CABG, Coronary artery bypass grafting; SBP, Systolic blood pressure;  DBP, Diastolic blood Pressure. HR, heart rate.               1. Continuous variables are presented as means (standard deviation), categorical variables are presented percentages.                                                                                                     

 

 

Table 2. Spearman Correlation between Mental Stress Ratios of Cardiac and Peripheral Blood Flow, Stratified by Visit

 

Mean

 

Last 2.5 min

 

Minimum

 

Maximum

r

P-value

 

r

P-value

 

r

P-value

 

r

P-value

Visit 1(n=16)

                     

   Total Pet Ratio7

-0.11

0.68

 

-0.14

0.60

 

0.03

0.94

 

-0.17

0.53

   LAD

0.06

0.83

 

0.04

0.88

 

0.08

0.77

 

0.06

0.83

   LCX

-0.19

0.48

 

-0.23

0.39

 

-0.02

0.94

 

-0.24

0.35

   RCA

-0.16

0.56

 

-0.17

0.53

 

-0.03

0.92

 

-0.20

0.46

Visit 2(n=15)

                     

   Total Pet Ratio

0.33

0.23

 

0.28

0.32

 

0.35

0.20

 

0.06

0.82

   LAD

0.24

0.40

 

0.19

0.50

 

0.31

0.26

 

0.00

0.99

   LCX

0.37

0.18

 

0.21

0.44

 

0.30

0.28

 

0.10

0.71

   RCA

0.29

0.30

 

0.24

0.38

 

0.30

0.28

 

0.10

0.71

Total(n=31)

                     

   Total Pet Ratio

0.07

0.72

 

0.06

0.73

 

0.03

0.85

 

0.05

0.80

   LAD

0.12

0.51

 

0.14

0.45

 

0.07

0.69

 

0.12

0.51

   LCX

0.07

0.70

 

0.02

0.92

 

0.02

0.90

 

0.03

0.86

   RCA

0.02

0.91

 

0.05

0.77

 

-0.02

0.92

 

0.03

0.88

Abbreviation: LAD, left anterior descending artery; LCX, left circumflex; RCA, right coronary artery.

 

 

Table 3. Spearman Correlation between Mental Stress Ratios of Cardiac and Peripheral Blood Flow-Subgroup Analysis

 

Caucasian

 

African American

 

Male

 

Female

 

r

P-value

 

r

P-value

 

r

P-value

 

r

P-value

Visit 1(n=16)

-0.72

0.02

 

0.37

0.47

 

-0.24

0.46

 

0.2

0.8

Visit 2(n=16)

0.33

0.42

 

0.29

0.49

 

0.35

0.33

 

0.31

0.54

Total(n=32)

-0.18

0.48

 

0.5

0.07

 

0.04

0.87

 

0.42

0.23

 

Table 4.  Changes from Visit 1 to Visit 2 in Mental Stress PAT Ratio1 in Biofeedback vs. Control Groups, Stratified by Treatment group in the study

Pat ratio, mean(SD)

HRVB(n=6)

Control(n=7)

P value2

Visit1

1.06 (0.33)

0.88 (0.21)

0.18

Visit2

1.14 (0.27)

0.99 (0.47)

0.23

Visit2-Visit1

0.08 (0.27)

0.11 (0.45)

0.73

Abbreviation: HRVB, Heart rate variability biofeedback. 1: Average peripheral blood flow measured by PAT of 14 time points in 7 minutes experiment period of operational and control arms. 2: P values calculated by Wilcoxon-Mann Whitney test.   

 

 

 

 

 

 

 

 

 

 

 

Table 5. Linear Regression  Predicting difference between Visit 2 and Visit 1 for PAT Ratio

 

Model1

Parameter estimate for HRVB arm

P value

95% Confidence Limits

Unadjusted model

Unadjusted

-0.24

0.69

-1.55

1.06

Adjusted model

Adjusted for diabetes and African American race

0.46

0.20

-0.29

1.20

 

 

Table 6. Linear Regression Analysis of Predictive Variables for Difference between PET and PAT Ratio

Variable

Parameter Estimate

P value

95% Confidence Limits

   Treatment Group

0.23

0.68

-0.96

1.43

   Visit time

0.13

0.74

-0.66

0.92

   Diabetes

0.10

0.92

-1.95

2.15

   Depression

-1.34

0.48

-5.24

2.56

   Hypertension

1.17

0.19

-0.65

2.99

   Smoke History

-0.58

0.35

-1.86

0.69

   Enrolled Age

0.04

0.72

-0.21

0.30

   BMI

-0.16

0.26

-0.46

0.13

   Gender

0.38

0.72

-1.88

2.65

   Caucasian

0.23

0.81

-1.79

2.25

   Heart Failure

1.30

0.64

-4.53

7.13

   PSIMI

-1.22

0.23

-3.28

0.84

   MSIMI

-0.18

0.75

-1.42

1.05

   Antidepressant

0.64

0.62

-2.07

3.35

   CABG

-0.90

0.42

-3.20

1.40

Abbreviations: BMI, body mass index; CABG, Coronary artery bypass grafting; MSIMI, metal stress-induced myocardial ischemia; PSIMI, physical stress-induced myocardial ischemia.

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