Cell Biochem Biophys (2015) 71:785–788 DOI 10.1007/s12013-014-0263-3
ORIGINAL PAPER
Correlation of Ascending Aorta Elasticity and the Severity of Coronary Artery Stenosis in Hypertensive Patients with Coronary Heart Disease Assessed by M-Mode and Tissue Doppler Echocardiography Qixiu Lu • Houlin Liu
Published online: 1 October 2014 Springer Science+Business Media New York 2014
Abstract The main objective of this study is to investigate the relationship between ascending aorta elasticity and the severity of coronary artery stenosis in essential hypertensive patients with coronary heart disease (CHD) using M-mode and tissue Doppler echocardiography. A total of 184 hypertensive patients with CHD were enrolled. Patients were divided into three groups based on the severity of coronary stenosis measured by coronary arteriography (CAG): slight stenosis (group 1), moderate stenosis (group 2) and serious stenosis (group 3). M-mode and tissue Doppler echocardiography were performed, and elasticity indexes of ascending aorta including stiffness index, distensibility index, and S wave speed of anterior wall were calculated and correlated with the severity of coronary stenosis. Ascending aorta stiffness index was increased, whereas distensibility index and S wave speed of anterior wall were decreased in moderate and severe stenosis groups compared with slight stenosis group (P \ 0.01). Elasticity indexes change in a stepwise pattern with the narrowness of coronary artery, and there was a significant correlation between aortic elasticity and severity of coronary artery by Pearson correlation analysis (P \ 0.01). Elasticity indexes of ascending aorta correlate well with severity of coronary stenosis. Elasticity indexes of ascending aorta can serve as predictors for coronary arterial lesion in hypertensive patients. Keywords Hypertension Coronary heart disease Ascending aorta elasticity Coronary artery stenosis Tissue Doppler imaging Q. Lu (&) H. Liu Department of Ultrasound, Shandong Jining No.1 People’s Hospital, Jining 272011, Shandong, China e-mail: [email protected]
Introduction Hypertension is the most common cardiovascular disease worldwide and is a main risk factor for coronary heart disease, with the latter being the leading cause of morbidity and mortality among the adults in Europe and North America [1]. Arterial stiffness, considered to be an independent predictor of all-cause and cardiovascular mortality in hypertensive patients [2], is now suggested as a tool for assessment of subclinical organ damage [3]. Arterial stiffness has a direct impact on the hemodynamics of coronary circulation. It leads to an increased pulse pressure, which results in a more pulsatile flow than the laminar flow, and thus reduces the coronary perfusion during diastole. Moreover, a higher pulse pressure may increase both preload and afterload of left ventricle, eventually promote left ventricle hypertrophy and subendocardial ischemia [4]. Clinically, arterial elasticity can be measured by several technologies including arteriography, MRI [5], CT Angiography [6], and PWV [2, 3]. However, allergy to the contrasting agent and potential threat of radiation limits the use of some methods. Doppler echocardiographic technology is advantageous in that it is a simple, noninvasive, nonradioactive, economic, and highly repeatable imaging modality. Tissue Doppler imaging (TDI) is a novel ultrasound technology developed in recent years to examine the low speed movement of tissue. Previous studies have shown that tissue Doppler imaging is a useful tool to measure arterial stiffness [7, 8]. The purpose of this study is to assess the ascending aorta elasticity in relation to the severity of coronary stenosis in hypertensive patients complicated with coronary heart disease (CHD) with the application of M-mode and tissue Doppler echocardiography.
123
786
Methods Baseline Demographics and Grouping Between June 2012 and April 2013, 184 patients (123 male cases and 61 female cases with an average age of 63.5 ± 9.4) with essential hypertension complicated with CHD were included in this study. Demographic parameters such as age, sex, height, body weight, previous history of hypertension, CHD, and related conditions (diabetes, blood lipid level etc.) were collected. Patients with secondary hypertension, rheumatic heart disease, valvular heart disease, pulmonary heart disease, myocardiopathy, Marfan’s syndrome, and other aortic diseases were excluded. BMI was calculated as weight divided by height squared (kg/ m2). Hypertension is defined by systolic blood pressure (SBP) C 140 mmHg and/or diastolic blood pressure (DBP) C 90 mmHg. Serum fasting glucose, triglyceride, total cholesterol, low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein cholesterol concentrations were assessed from a venous blood sample for biochemical measurement. Diabetes mellitus is defined as the fasting blood sugar levels C126 mg/dl or self reported. Patients were divided into three groups based on the severity of coronary stenosis measured by coronary arteriography (CAG): slight stenosis (group 1), moderate stenosis (group 2), and serious stenosis (group 3). Coronary Stenosis Assessed by Coronary Angiography All patients underwent coronary angiography using standard Judkins method. CAG diagnosis was made independently by two interventional physicians, and a third physician’s opinion was needed when the two interventional physicians did not reached agreement in diagnosis. Interventional physicians were blind to other information of patients. Modified Gensini scoring was used to evaluate the coronary artery disease. The coronary artery tree was divided into eight segments, and the modified Gensini score (GS) system was used for the quantitative scoring of the degrees of vascular lesions, recorded as GS [9]. Different degrees of coronary artery stenosis, namely 1–49, 50–74, 75–99, and 100 %, were rated 1, 2, 3, and 4 points, respectively. The addition of score for each segment was taken as the score of the patients. Coronary artery stenosis was graded based on GS with 1–6 points, 7–13 points, and over 13 points rated slight, moderate, and serious stenoses, respectively.
Cell Biochem Biophys (2015) 71:785–788
standard electrocardiograph II was recorded simultaneously. Parasternal left ventricle long axis view adjacent to sternum was taken, and probe was adjusted to display ascending aorta long axis. M-mode sampling line was placed 3 cm above aortic valve. M-mode diameter measurements were made in systole (point of maximal anterior motion of aorta) and at end-diastole (q wave on electrocardiogram) to determine systolic and diastolic diameters of ascending aorta, respectively. LVEDD was measured when aortic valve was closed, whereas LVSD was measured when aortic valve was completely opened. Measuring point was positioned at bottom border of anterior wall of the ascending aorta and upper border of posterior wall. The systolic pressure and diastolic pressure of the left brachial artery were measured before echocardiographic examination, and the average of three measurements was recorded. Stiffness index and distensibility index of ascending aorta were calculated according to the following formula [10, 11]: Stiffness index of ascending aorta ¼ ln ðsystolic pressure=diastolic pressureÞ= ½ðvascular systolic diameter vascular diastolic diameterÞ=vascular diastolic diameter Distensibility index ¼ 2 ðvascular systolic diameter vascular diastolic diameterÞ=½vascular diastolic diameter ðsystolic pressure diastolic pressureÞ cm2 =dyn
The instrument was switched to TDI speed mode, and TDI sampling volume was positioned at the same point of the above ascending aorta to determine movement frequency and S-wave speed. Continuous cardiac cycle was measured to obtain the average value. Statistical Analysis The SPSS19.0 software was used for the statistical processing. Measurement data are reported as mean ± standard deviation. Intragroup comparison was performed by single factor analysis of variance (ANOVA). The correlation between elasticity indexes of ascending aorta and severity of coronary artery was assessed using the Pearson correlation test.
Results M-Mode and Tissue Doppler Echocardiography Comparison of Baseline Demographics Echocardiographic examination was performed by an experienced cardiac sonologist. IE33 color Doppler Sonography was used with a probe frequency of 2.5 MHz, and
123
ANOVA was performed to analyze the baseline demographics, and we found an age difference between slight
Cell Biochem Biophys (2015) 71:785–788
787
Table 1 Patient demographics
Case (n)
Group 1
Group 2
Group 3
83
49
52
Age (year)
61.4 ± 10.7*
62.7 ± 8.9
65.9 ± 13.8
Male (%)
50 (60.2 %)*
35 (71.4 %)
38 (73.1 %)
BMI
23.7 ± 1.9
24.2 ± 2.9
24.6 ± 2.6
Diabetes (%)
27 (32.5 %)*
21 (42.9 %)
27 (51.9 %)
Hypercholesterolemia (%)
39 (47.5 %)
27 (55.1 %)
34 (65.4 %)
Pulse pressure (mmHg)
63 ± 19
65 ± 22
69 ± 20
Group 1 slight stenosis, group 2 moderate stenosis, group 3 serious stenosis * Statistical significance was found in age (P \ 0.01), male percentage (P \ 0.01) and diabetes percentage (P \ 0.05) between group 1 and the other two groups Table 2 Elasticity indexes of ascending aorta in different groups Group 1 Stiffness index Distensibility index S wave speed of anterior wall Gensini score
2.32 ± 0.43
Group 2
3.72 ± 0.49b
a
3.55 ± 0.62
2.47 ± 0.87
1.57 ± 0.56b
0.102 ± 0.006
0.063 ± 0.009a
0.046 ± 0.005b
10.67 ± 2.18
18.13 ± 5.24
Group 1 slight stenosis, group 2 moderate stenosis, group 3 serious stenosis a
Compared to slight stenosis group, P \ 0.01
b
Compared to slight stenosis group, P \ 0.01
Stiffness index
Distensibility index
S wave speed of anterior wall
R value
0.62
-0.486
-0.423
P value
0.0012
0.000
0.0016
Correlation of Elasticity Indexes of Ascending Aorta and Gensini Score Pearson analysis was performed, and the results showed positive correlation between Gensini scoring of coronary artery narrowing and stiffness index of ascending aorta (r = 0.62, P \ 0.01). In contrast, distensibility index was negatively correlated with Gensini score (r = 0.512, P \ 0.01). S-wave speed of anterior wall was also negatively correlated with Gensini score (r = -0.423, P \ 0.01). The results are listed in Table 3.
Group 3 a
3.41 ± 1.04
5.43 ± 1.52
Table 3 Correlation between elasticity indexes of ascending aorta and Gensini score of coronary artery
stenosis group and the other two groups, which is statistically significant (LSD methods, P \ 0.01). The percentage of male patients was significantly lower in slight stenosis group compared with the other two groups when analyzed by v2 test (P \ 0.01). In addition, diabetic cases were significantly less in slight stenosis group compared with the other two groups (P \ 0.05). No significant difference was found in the comparisons of other demographic data (Table 1). Elasticity Indexes of Ascending Aorta in Different Groups Ascending aorta stiffness index was greater in moderate and severe stenosis groups than the slight stenosis group (P \ 0.01), whereas distensibility index showed the opposite trend (P \ 0.01). S wave speed of anterior wall was decreased in moderate and severe stenosis groups than the slight stenosis group (P \ 0.01) (Table 2). All three indexes changed in a stepwise pattern with the narrowness of coronary artery.
Discussion Hypertension is the most common risk factor for coronary atherosclerotic heart disease. Other risk factors include hyperlipidemia, diabetes, fatty diet, high salt intake, stress, metabolic syndrome, lack of exercise, smoking, high alcohol consumption, abdominal obesity, renal failure, renal artery stenosis, and other genetic factors. Hypertension-induced lesion in large arteries mainly manifests as decreased elasticity instead of atherosclerotic plaque [12]. Arterial stiffness is now regarded an independent risk factor for cardiovascular morbidity and mortality [13]. In this study, we are trying to determine if aortic stiffness is predictive of the severity of coronary artery lesion in hypertensive patients with CHD using M-mode and tissue echocardiography. Our study suggests that hypertensive patients have increased aortic stiffness and reduced distensibility and wall velocities as measured by M-mode and tissue Doppler echocardiography. The elasticity indexes of ascending aorta correlate closely with the severity of coronary stenosis. Our findings agree well with previous studies using various technologies [8, 14–18]. Mechanism of how aortic stiffness leads to a comprised coronary perfusion has been recently reviewed by O’Rourke [19]. In general, aortic stiffness leads to an increase of pulse pressure, which in turn causes a reduced coronary perfusion during the diastole, an increased afterload of left ventricle, leading to injury of myocardium and left ventricle remodeling and subsequent symptoms of hypertensive heart disease. Disrupted flow can cause
123
788
damage to endothelial and artery wall and subsequent atheromatous plaque and mural thrombi, resulting in significantly increased risk of cardiovascular events. Coronary flow reserve may also be reduced in stress situation, resulting in increased chance of coronary insufficiency and angina . Tissue Doppler imaging is a novel ultrasound technology developed recently to examine the low speed movement of tissue. The principle and application of using TDI to characterize aortic wall movement has been described previously [20]. When the heart contracts, S wave is produced because of aortic dilation. Whereas when the heart relaxes, E wave and A wave are produced due to retraction of aortic. In the case of decreased elasticity of aorta, the stiffness will increase, resulting in decreased distensibility and lowered speed of S wave, E wave, and A wave of anterior wall of ascending aorta. However, our results from this study showed that only decrease in S-wave speed is of clinical significance. TDI has its own limitations. Doppler incident angle as well as respiration and heart rate of patients may affect the motion speed of arterial wall, leading to decreased accuracy. However, reproducibility test showed that heart rate affects the result only when the heart rate is over 70/min and the influence can be eliminated by medication. The error caused by respiration is neglectable. Overall, for application in clinical practice, M-mode and tissue Doppler echocardiography can be considered as a basic method for evaluating elasticity of aorta. In summary, using M-mode and tissue Doppler echocardiography to examine the dispensability, stiffness index and S-wave speed of anterior wall can provide useful information in patients with hypertension complicated with CHD. It can help predict cardiovascular event, which is of great importance for the severity evaluation of coronary stenosis, early intervention, and treatment and evaluation of therapeutic outcomes.
References 1. WHO causes of death 2008 summary tables. 2. Laurent, S., Boutouyrie, P., Asmar, R., Gautier, I., Laloux, B., Guize, L., et al. (2001). Aortic stiffness is an independent predictor of all-cause and cardiovascular mortality in hypertensive patients. Hypertension, 37, 1236–1241. 3. Laurent, S., Cockcroft, J., Van Bortel, L., Boutouyrie, P., Giannattasio, C., Hayoz, D., et al. (2006). European Network for non-invasive investigation of large arteries. Expert consensus document on arterial stiffness: Methodological issues and clinical applications. European Heart Journal, 27, 2588–2605. 4. Mottram, P. M., Haluska, B. A., Leano, R., et al. (2005). Relation of arterial stiffness to diastolic dysfunction in hypertensive heart disease. Heart, 91, 1551–1556.
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Cell Biochem Biophys (2015) 71:785–788 5. Mohiaddin, R. H., Underwood, S. R., Bogren, H. G., et al. (1989). Regional aortic compliance studied by magnetic resonance imaging: The effects of age, training and coronary heart disease. British Heart Journal, 62, 90–96. 6. Stefanadis, C., Stratos, C., Vlachopoulos, C., et al. (1995). Pressure-diameter relation of the human aorta. A new method of determination by the application of a special ultrasonic dimension catheter. Circulation, 92, 2210–2219. 7. Schmidt-Trucksass, A., Grathwohl, D., Schmid, A., et al. (1998). Assessment of carotid wall motion and stiffness with tissue Doppler imaging. Ultrasound in Medicine and Biology, 24, 639–646. 8. Yin, Quanzhong, Gao, Chunheng, Zheng, Ruolong, et al. (2007). Ascending aorta elastic and early—onset correlation between the degree of stenosis of coronary atherosclerotic heart disease. Jiangsu University Acta: Medicine, 17(2), 142–144. 9. Gensini, G. G. (1983). A more meaningful scoring system for determining the severity of coronary heart disease. American Journal of Cardiology, 51, 606–607. 10. Stefanadis, C., Stratos, C., Vlachopoulos, C., Marakas, S., Boudoulas, H., Kallikazaros, I., et al. (1995). Pressure diameter relation of the human aorta: A new method of determination by the application of a special ultrasonic dimension catheter. Circulation, 92, 2210–2219. 11. Stefanadis, C., Dernellis, J., Vlachopoulos, C., Tsioufis, C., Tsiamis, E., Toutouzas, K., et al. (1997). Aortic function in arterial hypertension determined by pressure-diameter relation: Effects of diltiazem. Circulation, 96, 1853–1858. 12. Edwards, M. S., & Corriere, M. A. (2009). Contemporary management of atherosclerotic renovascular disease. Journal of Vascular Surgery, 50(5), 1197–1210. ISSN 0741-5214. 13. Vlachopoulos, C., Aznaouridis, K., & Stefanadis, C. (2010). Prediction of cardiovascular events and all-cause mortality with arterial stiffness: A systematic review and meta-analysis. Journal of the American College of Cardiology, 55(13), 1318–1327. 14. Eryol, N. K., Topsakal, R., Cicek, Y., Abacı, A., Oguzhan, A., Basar, E., et al. (2002). Colour Doppler tissue imaging in assessing the elastic properties of the aorta and in predicting coronary artery disease. Japanese Heart Journal, 43, 219–230. 15. Herrington, D. M., Kesler, K., Reiber, J. C., et al. (2003). Arterial compliance adds to conventional risk factors for prediction of angiographic coronary artery disease. American Heart Journal, 146(4), 662–667. 16. Yildiz, A., Gur, M., Yilmaz, R., et al. (2008). The association of elasticity indexs of ascending aorta and the presence and the severity of coronary artery diseses. Coronary Artery Disease, 19(5), 311–317. 17. Ahmadi, N., Nabavi, V., […], & Budoff, M.J. (2011). Impaired aortic distensibility measured by computed tomography is associated with the severity of coronary artery disease. The International Journal of Cardiovascular Imaging, 27(3), 459–469. 18. Vitarelli, A., Giordano, M., Germano`, G., Pergolini, M., Cicconetti, P., Tomei, F., et al. (2010). Assessment of ascending aorta wall stiffness in hypertensive patients by tissue Doppler imaging and strain Doppler echocardiography. Heart, 96(18), 1469–1474. 19. O’Rourke, M. F. (2008). How stiffening of the aorta and elastic arteries leads to compromised coronary flow. Heart, 94(6), 690–691. 20. Vitarelli, A., Conde, Y., Cimino, E., et al. (2006). Assessment of aortic wall mechanics in Marfan syndrome by transesophageal tissue Doppler echocardiography. American Journal of Cardiology, 97, 571–577.
ORIGINAL PAPER
Correlation of Ascending Aorta Elasticity and the Severity of Coronary Artery Stenosis in Hypertensive Patients with Coronary Heart Disease Assessed by M-Mode and Tissue Doppler Echocardiography Qixiu Lu • Houlin Liu
Published online: 1 October 2014 Springer Science+Business Media New York 2014
Abstract The main objective of this study is to investigate the relationship between ascending aorta elasticity and the severity of coronary artery stenosis in essential hypertensive patients with coronary heart disease (CHD) using M-mode and tissue Doppler echocardiography. A total of 184 hypertensive patients with CHD were enrolled. Patients were divided into three groups based on the severity of coronary stenosis measured by coronary arteriography (CAG): slight stenosis (group 1), moderate stenosis (group 2) and serious stenosis (group 3). M-mode and tissue Doppler echocardiography were performed, and elasticity indexes of ascending aorta including stiffness index, distensibility index, and S wave speed of anterior wall were calculated and correlated with the severity of coronary stenosis. Ascending aorta stiffness index was increased, whereas distensibility index and S wave speed of anterior wall were decreased in moderate and severe stenosis groups compared with slight stenosis group (P \ 0.01). Elasticity indexes change in a stepwise pattern with the narrowness of coronary artery, and there was a significant correlation between aortic elasticity and severity of coronary artery by Pearson correlation analysis (P \ 0.01). Elasticity indexes of ascending aorta correlate well with severity of coronary stenosis. Elasticity indexes of ascending aorta can serve as predictors for coronary arterial lesion in hypertensive patients. Keywords Hypertension Coronary heart disease Ascending aorta elasticity Coronary artery stenosis Tissue Doppler imaging Q. Lu (&) H. Liu Department of Ultrasound, Shandong Jining No.1 People’s Hospital, Jining 272011, Shandong, China e-mail: [email protected]
Introduction Hypertension is the most common cardiovascular disease worldwide and is a main risk factor for coronary heart disease, with the latter being the leading cause of morbidity and mortality among the adults in Europe and North America [1]. Arterial stiffness, considered to be an independent predictor of all-cause and cardiovascular mortality in hypertensive patients [2], is now suggested as a tool for assessment of subclinical organ damage [3]. Arterial stiffness has a direct impact on the hemodynamics of coronary circulation. It leads to an increased pulse pressure, which results in a more pulsatile flow than the laminar flow, and thus reduces the coronary perfusion during diastole. Moreover, a higher pulse pressure may increase both preload and afterload of left ventricle, eventually promote left ventricle hypertrophy and subendocardial ischemia [4]. Clinically, arterial elasticity can be measured by several technologies including arteriography, MRI [5], CT Angiography [6], and PWV [2, 3]. However, allergy to the contrasting agent and potential threat of radiation limits the use of some methods. Doppler echocardiographic technology is advantageous in that it is a simple, noninvasive, nonradioactive, economic, and highly repeatable imaging modality. Tissue Doppler imaging (TDI) is a novel ultrasound technology developed in recent years to examine the low speed movement of tissue. Previous studies have shown that tissue Doppler imaging is a useful tool to measure arterial stiffness [7, 8]. The purpose of this study is to assess the ascending aorta elasticity in relation to the severity of coronary stenosis in hypertensive patients complicated with coronary heart disease (CHD) with the application of M-mode and tissue Doppler echocardiography.
123
786
Methods Baseline Demographics and Grouping Between June 2012 and April 2013, 184 patients (123 male cases and 61 female cases with an average age of 63.5 ± 9.4) with essential hypertension complicated with CHD were included in this study. Demographic parameters such as age, sex, height, body weight, previous history of hypertension, CHD, and related conditions (diabetes, blood lipid level etc.) were collected. Patients with secondary hypertension, rheumatic heart disease, valvular heart disease, pulmonary heart disease, myocardiopathy, Marfan’s syndrome, and other aortic diseases were excluded. BMI was calculated as weight divided by height squared (kg/ m2). Hypertension is defined by systolic blood pressure (SBP) C 140 mmHg and/or diastolic blood pressure (DBP) C 90 mmHg. Serum fasting glucose, triglyceride, total cholesterol, low-density lipoprotein (LDL) cholesterol, and high-density lipoprotein cholesterol concentrations were assessed from a venous blood sample for biochemical measurement. Diabetes mellitus is defined as the fasting blood sugar levels C126 mg/dl or self reported. Patients were divided into three groups based on the severity of coronary stenosis measured by coronary arteriography (CAG): slight stenosis (group 1), moderate stenosis (group 2), and serious stenosis (group 3). Coronary Stenosis Assessed by Coronary Angiography All patients underwent coronary angiography using standard Judkins method. CAG diagnosis was made independently by two interventional physicians, and a third physician’s opinion was needed when the two interventional physicians did not reached agreement in diagnosis. Interventional physicians were blind to other information of patients. Modified Gensini scoring was used to evaluate the coronary artery disease. The coronary artery tree was divided into eight segments, and the modified Gensini score (GS) system was used for the quantitative scoring of the degrees of vascular lesions, recorded as GS [9]. Different degrees of coronary artery stenosis, namely 1–49, 50–74, 75–99, and 100 %, were rated 1, 2, 3, and 4 points, respectively. The addition of score for each segment was taken as the score of the patients. Coronary artery stenosis was graded based on GS with 1–6 points, 7–13 points, and over 13 points rated slight, moderate, and serious stenoses, respectively.
Cell Biochem Biophys (2015) 71:785–788
standard electrocardiograph II was recorded simultaneously. Parasternal left ventricle long axis view adjacent to sternum was taken, and probe was adjusted to display ascending aorta long axis. M-mode sampling line was placed 3 cm above aortic valve. M-mode diameter measurements were made in systole (point of maximal anterior motion of aorta) and at end-diastole (q wave on electrocardiogram) to determine systolic and diastolic diameters of ascending aorta, respectively. LVEDD was measured when aortic valve was closed, whereas LVSD was measured when aortic valve was completely opened. Measuring point was positioned at bottom border of anterior wall of the ascending aorta and upper border of posterior wall. The systolic pressure and diastolic pressure of the left brachial artery were measured before echocardiographic examination, and the average of three measurements was recorded. Stiffness index and distensibility index of ascending aorta were calculated according to the following formula [10, 11]: Stiffness index of ascending aorta ¼ ln ðsystolic pressure=diastolic pressureÞ= ½ðvascular systolic diameter vascular diastolic diameterÞ=vascular diastolic diameter Distensibility index ¼ 2 ðvascular systolic diameter vascular diastolic diameterÞ=½vascular diastolic diameter ðsystolic pressure diastolic pressureÞ cm2 =dyn
The instrument was switched to TDI speed mode, and TDI sampling volume was positioned at the same point of the above ascending aorta to determine movement frequency and S-wave speed. Continuous cardiac cycle was measured to obtain the average value. Statistical Analysis The SPSS19.0 software was used for the statistical processing. Measurement data are reported as mean ± standard deviation. Intragroup comparison was performed by single factor analysis of variance (ANOVA). The correlation between elasticity indexes of ascending aorta and severity of coronary artery was assessed using the Pearson correlation test.
Results M-Mode and Tissue Doppler Echocardiography Comparison of Baseline Demographics Echocardiographic examination was performed by an experienced cardiac sonologist. IE33 color Doppler Sonography was used with a probe frequency of 2.5 MHz, and
123
ANOVA was performed to analyze the baseline demographics, and we found an age difference between slight
Cell Biochem Biophys (2015) 71:785–788
787
Table 1 Patient demographics
Case (n)
Group 1
Group 2
Group 3
83
49
52
Age (year)
61.4 ± 10.7*
62.7 ± 8.9
65.9 ± 13.8
Male (%)
50 (60.2 %)*
35 (71.4 %)
38 (73.1 %)
BMI
23.7 ± 1.9
24.2 ± 2.9
24.6 ± 2.6
Diabetes (%)
27 (32.5 %)*
21 (42.9 %)
27 (51.9 %)
Hypercholesterolemia (%)
39 (47.5 %)
27 (55.1 %)
34 (65.4 %)
Pulse pressure (mmHg)
63 ± 19
65 ± 22
69 ± 20
Group 1 slight stenosis, group 2 moderate stenosis, group 3 serious stenosis * Statistical significance was found in age (P \ 0.01), male percentage (P \ 0.01) and diabetes percentage (P \ 0.05) between group 1 and the other two groups Table 2 Elasticity indexes of ascending aorta in different groups Group 1 Stiffness index Distensibility index S wave speed of anterior wall Gensini score
2.32 ± 0.43
Group 2
3.72 ± 0.49b
a
3.55 ± 0.62
2.47 ± 0.87
1.57 ± 0.56b
0.102 ± 0.006
0.063 ± 0.009a
0.046 ± 0.005b
10.67 ± 2.18
18.13 ± 5.24
Group 1 slight stenosis, group 2 moderate stenosis, group 3 serious stenosis a
Compared to slight stenosis group, P \ 0.01
b
Compared to slight stenosis group, P \ 0.01
Stiffness index
Distensibility index
S wave speed of anterior wall
R value
0.62
-0.486
-0.423
P value
0.0012
0.000
0.0016
Correlation of Elasticity Indexes of Ascending Aorta and Gensini Score Pearson analysis was performed, and the results showed positive correlation between Gensini scoring of coronary artery narrowing and stiffness index of ascending aorta (r = 0.62, P \ 0.01). In contrast, distensibility index was negatively correlated with Gensini score (r = 0.512, P \ 0.01). S-wave speed of anterior wall was also negatively correlated with Gensini score (r = -0.423, P \ 0.01). The results are listed in Table 3.
Group 3 a
3.41 ± 1.04
5.43 ± 1.52
Table 3 Correlation between elasticity indexes of ascending aorta and Gensini score of coronary artery
stenosis group and the other two groups, which is statistically significant (LSD methods, P \ 0.01). The percentage of male patients was significantly lower in slight stenosis group compared with the other two groups when analyzed by v2 test (P \ 0.01). In addition, diabetic cases were significantly less in slight stenosis group compared with the other two groups (P \ 0.05). No significant difference was found in the comparisons of other demographic data (Table 1). Elasticity Indexes of Ascending Aorta in Different Groups Ascending aorta stiffness index was greater in moderate and severe stenosis groups than the slight stenosis group (P \ 0.01), whereas distensibility index showed the opposite trend (P \ 0.01). S wave speed of anterior wall was decreased in moderate and severe stenosis groups than the slight stenosis group (P \ 0.01) (Table 2). All three indexes changed in a stepwise pattern with the narrowness of coronary artery.
Discussion Hypertension is the most common risk factor for coronary atherosclerotic heart disease. Other risk factors include hyperlipidemia, diabetes, fatty diet, high salt intake, stress, metabolic syndrome, lack of exercise, smoking, high alcohol consumption, abdominal obesity, renal failure, renal artery stenosis, and other genetic factors. Hypertension-induced lesion in large arteries mainly manifests as decreased elasticity instead of atherosclerotic plaque [12]. Arterial stiffness is now regarded an independent risk factor for cardiovascular morbidity and mortality [13]. In this study, we are trying to determine if aortic stiffness is predictive of the severity of coronary artery lesion in hypertensive patients with CHD using M-mode and tissue echocardiography. Our study suggests that hypertensive patients have increased aortic stiffness and reduced distensibility and wall velocities as measured by M-mode and tissue Doppler echocardiography. The elasticity indexes of ascending aorta correlate closely with the severity of coronary stenosis. Our findings agree well with previous studies using various technologies [8, 14–18]. Mechanism of how aortic stiffness leads to a comprised coronary perfusion has been recently reviewed by O’Rourke [19]. In general, aortic stiffness leads to an increase of pulse pressure, which in turn causes a reduced coronary perfusion during the diastole, an increased afterload of left ventricle, leading to injury of myocardium and left ventricle remodeling and subsequent symptoms of hypertensive heart disease. Disrupted flow can cause
123
788
damage to endothelial and artery wall and subsequent atheromatous plaque and mural thrombi, resulting in significantly increased risk of cardiovascular events. Coronary flow reserve may also be reduced in stress situation, resulting in increased chance of coronary insufficiency and angina . Tissue Doppler imaging is a novel ultrasound technology developed recently to examine the low speed movement of tissue. The principle and application of using TDI to characterize aortic wall movement has been described previously [20]. When the heart contracts, S wave is produced because of aortic dilation. Whereas when the heart relaxes, E wave and A wave are produced due to retraction of aortic. In the case of decreased elasticity of aorta, the stiffness will increase, resulting in decreased distensibility and lowered speed of S wave, E wave, and A wave of anterior wall of ascending aorta. However, our results from this study showed that only decrease in S-wave speed is of clinical significance. TDI has its own limitations. Doppler incident angle as well as respiration and heart rate of patients may affect the motion speed of arterial wall, leading to decreased accuracy. However, reproducibility test showed that heart rate affects the result only when the heart rate is over 70/min and the influence can be eliminated by medication. The error caused by respiration is neglectable. Overall, for application in clinical practice, M-mode and tissue Doppler echocardiography can be considered as a basic method for evaluating elasticity of aorta. In summary, using M-mode and tissue Doppler echocardiography to examine the dispensability, stiffness index and S-wave speed of anterior wall can provide useful information in patients with hypertension complicated with CHD. It can help predict cardiovascular event, which is of great importance for the severity evaluation of coronary stenosis, early intervention, and treatment and evaluation of therapeutic outcomes.
References 1. WHO causes of death 2008 summary tables. 2. Laurent, S., Boutouyrie, P., Asmar, R., Gautier, I., Laloux, B., Guize, L., et al. (2001). Aortic stiffness is an independent predictor of all-cause and cardiovascular mortality in hypertensive patients. Hypertension, 37, 1236–1241. 3. Laurent, S., Cockcroft, J., Van Bortel, L., Boutouyrie, P., Giannattasio, C., Hayoz, D., et al. (2006). European Network for non-invasive investigation of large arteries. Expert consensus document on arterial stiffness: Methodological issues and clinical applications. European Heart Journal, 27, 2588–2605. 4. Mottram, P. M., Haluska, B. A., Leano, R., et al. (2005). Relation of arterial stiffness to diastolic dysfunction in hypertensive heart disease. Heart, 91, 1551–1556.
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