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Fractional Pulse Pressure as A simple Index of Impaired Coronary Flow Reserve in Hypertensive patients

By Ragab Abd-Esalam, (MD) Professor of Cardiology Zagazig University; Egypt


Background Brachial pulse pressure: o A strong predictor of coronary events and cardiovascular death. Fang, et al. Blood Press. 2000;9(5):260-6

o Higher PP is associated with increased incidence of CAD. Franklin, et al. Circulation,1999; 27; 100 (4): 340-60

Central pulse pressure: o Associated with severity of CAD Danchin, et al. Am, Journal of Hypertens.2004;17(2):129-33


Background There is growing evidence that arterial stiffness is a significant predictor of adverse cardiovascular outcomes. Laurent S, et al. Hypertension. 2001;37:1236–41


Background Fractional pulse pressure: – It is a better estimate of pressure burden. – Associated with increased risk CAD Nishijima, et al. Am J Hypertens. 2001;14: 469-73


Background Fractional pulse pressure (PPf), which is calculated as pulse pressure divided by mean arterial pressure, has been proposed as a good parameter of the pulsatile component of blood pressure


Background PPf is thought to be more directly reflect arterial stiffness than pulse pressure, because dividing by mean arterial pressure theoretically cancels out the influence of cardiac output and peripheral vascular resistance.


Hypothesis Because different combinations of SBP and DBP give the same pulse pressure value (e.g., blood pressures of 130/70 and 170/110 mmHg both give a pulse pressure of 60 mmHg), We supposed that a relationship exists between CFR, left ventricular dysfunction and fractional pulse pressure in essential hypertensive patients.


Objective The purpose of this investigation was to examine the relationship between (PPf) and coronary flow reserve and left ventricular function in hypertensive patients with angiographically normal coronary artery


Methods  109 hypertenive patients presented with typical chest pain/or stress induced myocardial ischemia, with angiographically normal coronaries.  Full echocardiographic examination  Non-invasive assessment of coronary flow reserve was successfully obtained in 106 patients {study population (aged 52.8+9.4years)}


Methods 1. Pulse pressure PP=SBP-DBP 2. Mean Arterial Preasure MAP=1/3 (PP) + DBP 3. Fractional pulse pressure PPf = PP/MAP


Statistics 1) Chi-square test and independent sample t-test 2) Linear regression analysis was used to test univariate relations. 3) Pearson's correlations were calculated to examine univariate 4) Receiver operating (ROC) curve analysis


Comparison Between Invasively and Noninvasively Determined fractional pulse pressure (PPf)


In 30 hypertensive patients, during cardiac catheterization, invasive derived PPf was estimated Catheter- and non-invasively brachial derived values for PPf were reasonably well correlated r=0.81, P <0.002


Table (1): CFR characteristics findings for hypertensives with low and normal CFR HTN with Low CFR (n=54)

HTN with Normal CFR (n= 52)

P value

29.5±9.2

19.0±1.4

<0.001

1.46±0.55

1.72±0.21

<0.05

Peak APV

62.96±17.2

72.5±9.4

<0.05

Peak DSVR

1.45±0.22

1.42±0.32

<0.05

CFR

1.8±0.21

3.23±0.29

<0.001

Baseline APV Baseline DSVR


Table (2)

HTN with Low HTN with normal P value CFR(n=54) CFR(n=52 )

Age (year) (males) (%) BMI (kg m−2) Smokers (%) SBP

52.8+9.4 91.6% 27.6±3.1 24.2 150.8+14.8

48.5+ 9.3 90% 29.8±4.8 32.5 145.7+ 16.1

NS NS NS NS NS

DBP PP MAP PPf%

75.3+11.3 75.6+5.7 101.1+8.3

81.4+11.7 67.5+8.4 104.9+7.4

NS NS NS

75.2 ±11.4

61.5±6.7

<0.001


Lab. results o Total cholesterol (mg dl−1)

186.6±48

192.2±45

NS

o HDL cholesterol (mg dl−1)

48.1±13

39.5±9

NS

o LDL cholesterol (mg dl−1)

127.8±38

142.5±31

NS

o Triglycerides (mg dl−1)

132.5±45

112.5±39

NS

o Glucose (mg dl−1)

104.5±14

99.3±14

NS

o Serum creatinine (mg dl−1)

0.88±0.12

0.92±0.13

NS

o Ca-blocker%

8(14.8%)

7(13.5%)

NS

o Beta-blocker%

15(27.8%)

13(25%)

NS

o ACE-inhibitors%

15(27.8%)

16(30.7%)

NS

o ARBs

10(18.5%)

11(21.2%)

NS

o Diuretics

6(11.1%)

5(9.6%)

NS

Medications


Table (3): Echocardiographic parameters for HTN with low and normal CFR HTN with Low CFR (n=54)

LVM Index (g m−2) Relative WT Left atrial volume index (ml m−2) E (ms) A (ms) E/A

HTN with Normal CFR (n=52 )

P value

94.2±18

73.5±9.5

<0.01

0.57±0.05

0.41±0.04

<0.05

25.2±4.1

21.0±3.6

<0.03

0.69±0.11

0.78±0.12

NS

0.79±0.14

0.61±0.10

<0.01

0.87±0.17

1.16±0.19

<0.01


Table (3): Continued IVRT(ms)

122.6±29

91.2±21.03

NS

DT (ms)

268.2±42

269.2±39

NS

7.4±1.3

9.9±1.9

<0.05

11.2±1.7

9.3±1.4

NS

Em (cm/s) Am (cm/s) Em/Am E/Em

0.69±0.12 11.9±1.3

0.95±0.23 <0.02 8.1±1.6

<0.01


Table (4): Pearson’ linear correlation between PPf and study variables Variable Age Systolic blood pressure Diastolic blood pressure Mean blood pressure LV mass index (g m−2) Relative wall thickness E/Em Coronary flow reserve

r 0.32 0.37 0.46 0.33 0.44 0.43 0.622 -0.815

P NS NS

<0.05 NS NS

<0.05 <0.001 <0.0001


Table (5): Independent predictors of impaired CFR in multiple linear regression analysis Variable Age Left ventricular mass index E/A ratio Em/Am ratio Systolic blood pressure Diastolic blood pressure PPf (%)

HR (95% CI) 1.08 (0.85-1.27) 1.12(1.07-1.78)

P NS <0.02

0.96 (0.64-1.52) 1.06(1.08-1.45) 1.01(0.82-1.22) 1.22(0.63-1.46) 1.92(1.22-3.05)

NS NS NS <0.05 <0.001


Table (6): Diagnostic Ability of

PPf >63% for the prediction of impaired CFR & LVD dysfunction

PPf >63% CFR

E/Em

Sensitivity

92.5%

94%

Specificity

71%

77%

Positive predictive value

77%

80%

Negative predictive value

95%

90%

AUC

0.916

0.929

<0.0001

<0.0001

P value


Conclusion In hypertensive patients with angiographically normal coronaries, fractional pulse pressure was associated with low coronary flow reserve , independent of other risk factors


Conclusion Moreover fractional pulse pressure was associated with a significantly impaired diastolic function (increased E/Em ratio), independent of other risk factors


Conclusion PPf could be considered as a simple parameter for prediction of impairment of coronary microcirculation and diastolic dysfunction in hypertensive patients with normal coronary arteries


Clinical implication 1. Fractional pulse pressure is an easy, daily practice for early diagnosis and follow-up of coronary microcirculation and myocardial dysfunction. 2. The early diagnosis of a sub-clinical myocardial dysfunction and impaired coronary microcirculation in hypertensive patients is useful for the appropriate clinical testing of new therapeutic approaches in high risk population.


SHA24/019005  

Presentation