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Brachial–brachial index of systolic blood pressure in the patients under anti-hypertensive therapy
IJCA-18019; No of Pages 3 International Journal of Cardiology xxx (2014) xxx–xxx
Contents lists available at ScienceDirect
International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard
Letter to the Editor
Brachial–brachial index of systolic blood pressure in the patients under anti-hypertensive therapy Hanjun Sun a,1, Ping Li a,1, Hai Su a,⁎, Wenying Wang a, Jiwei Wang b, Weitong Hu a, Juxiang Li a, Yanna Liu b, Xiaoshu Cheng a a b
Department of Cardiology, Second Affiliated Hospital of Nanchang University, China Clinical Echocardiographic Laboratory, Second Affiliated Hospital of Nanchang University, China
a r t i c l e
i n f o
Article history: Received 5 April 2014 Accepted 9 April 2014 Available online xxxx Keywords: Brachial–brachial index Inter-arm SBP difference Hypertension Stenosis Artery
Inter-arm BP difference (IAD) has been demonstrated not only as a useful marker for subclavian artery stenosis [1,2], but also as a predicator for increased cardiovascular morbidity and mortality [1,3]. However, the detection rate of systolic IAD (sIAD) significantly varies with the SBP level in hypertensive patients under antihypertensive therapy [4]. Thus this phenomenon may induce confusion and decrease the clinical values of sIAD for diagnosing subclavian or brachial artery stenosis and predicting cardiovascular events. Therefore, it is necessary to create a new parameter, which could more correctly evaluate the difference between two arms at different BP levels. We hypothesize that systolic brachial–brachial index (sBBI), the ratio of right to left arm SBP, may be a more consistent index than sIAD. This study was to test our hypothesis and primarily evaluate the clinical value of sBBI. From May to November of 2012, 414 (200 males and 214 females, 61.3 ± 13.3 y) consecutively adult hypertensive patients admitted to our hospital ward were enrolled. The inclusion criteria were the baseline SBP/DBP (taken at admission) of at least 140/90 mm Hg on the higher value of two arms. The exclusion criteria were arrhythmia, acute myocardial infarction, aortic coarctation, congenital heart disease,
⁎ Corresponding author at: No. 1 Minded Road, Nanchang, Jiangxi 330006, China. Tel./ fax: +86 791 86301105. E-mail address: [email protected] (H. Su). 1 First coauthor.
heart failure, hemiplegia, pulseless disease and the history of transradial coronary intervention. All patients were right handedness. The BP of two arms was simultaneously measured using two validated automatic BP measurement devices (Omron, HEM-7112) for 3 times with a 2-min interval. The absolute SBP difference between right (SBPr) and left (SBPl) arms was calculated as SBPr-l. The SBPl-r of 10 mm Hg or more was diagnosed as sIAD [1,5–7]. sBBI was calculated on the formula: SBBI = SBPr / SBPl. The patients with consistent sIAD (diagnosed for 3 determinations) received color Doppler flow imaging examination for bilateral subclavian, axillary and brachial artery [8,9]. Continuous variables were expressed as mean ± SD. The t-test, variance (ANOVA) test and the omnibus test were used for the statistical analysis. The chi-square test was used to compare the IAD detection rate. The inter-measurement agreement was evaluated by Bland–Altman plots [10]. The inter-measurement sIAD or sBBI differences between two measurements (first minus second, second minus third, and third minus first) were calculated. With this method, inter-measurement differences were plotted against their means and the 95% limits of agreement (LoA) were determined (95% LoA = mean inter-measurement difference ± 1.96 standard deviation). In order to compare the inter-measurement agreement, the variability of bias, SD of bias, lower limit and upper limit from 3 Bland–Altman plots on sIAD and sBBI were calculated separately on the formula: variability = SD / Mean. Meanwhile, the plots of outside of 95% and their percentages for each pair of measurements on sIAD and sBBI were calculated separately. P b 0.05 was considered statistically significant. The SBP levels of right arm were higher (about 4 mm Hg) than those of left arm in the 3 stages. As SBP levels gradually decreased, SBPr-l gradually decreased, but the sBBIs were very similar. In this study, the abnormal sBBI limit was b0.95 or N1.10 based on the 1242 SBP values from 414 patients (normal limits = 1.023 ± 1.96 × 0.039). On these criteria, the detection rates of abnormal sBBI in three stages decreased from the first to the third as sIAD did, but the decreased extent was significantly less than that of sIAD (5:1 vs 2:1) (Table 1). The Bland–Altman plots on sIAD and sBBI among three measurements are showed in Fig. 1. The Bland–Altman plots on sIAD has rhombus-like left side and discrete right side, while the pictures of Bland–Altman plots on sBBI are like a core (Fig. 1). Meanwhile, the variability on the 4 parameters for sBBI was lower than their relative parameter on sIAD. Furthermore, point percentages
http://dx.doi.org/10.1016/j.ijcard.2014.04.118 0167-5273/© 2014 Elsevier Ireland. Ltd
Please cite this article as: Sun H, et al, Brachial–brachial index of systolic blood pressure in the patients under anti-hypertensive therapy, Int J Cardiol (2014), http://dx.doi.org/10.1016/j.ijcard.2014.04.118
2
H. Sun et al. / International Journal of Cardiology xxx (2014) xxx–xxx
Table 1 The SBP parameters and the detection rates of sIAD and sBBI in 3 stages (n = 414).
First Second Third
Right SBP
Left SBP
SBPr-l
sBBI
sIAD n (%)
Abnormal sBBI n (%)
163.7 ± 18.4 147.7 ± 15.3⁎ 135.4 ± 11.7⁎
159.7 ± 18.2 144.5 ± 15.4⁎ 132.9 ± 11.7⁎
5.74 ± 5.17 4.52 ± 4.05 3.68 ± 3.43
1.03 ± 0.043 1.02 ± 0.038 1.02 ± 0.035
76 (18.4) 43 (10.3)⁎ 13 (3.1)⁎
25 (6.0) 17 (4.1) 13 (3.1)⁎
First: after admission; second: 3 day after admission; third: 6 day after admission. ⁎ Compared with the first determination, P b 0.05.
located outside the 95% LoA between first and second, the first and third, and the second and third were lower on sBBI than on sIAD (4.59%, 3.87% and 3.38% vs 5.31%, 4.35% and 4.10%, respectively). In this study, ultrasonic examination was performed in 8 cases with consistent sIAD diagnosis [4]. One case with sBBI of 0.88, which indicated higher left arm SBP, had obvious stenosis in the right subclavian and brachial artery. In other 7 patients with sBBI of N1.10, which means higher right arm SBP, 3 cases had left subclavian and/or brachial artery stenosis, and one case has brachial artery dysplasia. However, in other 3 patients, 2 of the patients had sBBI N1.10 and one had mean sBBI of 1.08; no significant ultrasonic evidence for the left subclavian and/or brachial artery stenosis (more than 50%) was found (Table 2). At first, the present study showed that as compared with sIAD, sBBI was less dependent on SBP levels in the hypertensive patients under anti-hypertensive therapy. Secondly, the present study primarily provided a normal range for sBBI as 0.95–1.10 in these 414 hypertensive patients. On these criteria, the variation of the detection rates of abnormal sBBI in three stages was smaller than that of sIAD (5:1 vs 2:1). Therefore, the sBBI may be a more consistent index. Thirdly, the present study demonstrated that the agreement among the 3 sBBIs was better than that among 3 sIADs, as the variability on the 4 parameters for sBBI was lower than their relative parameter on sIAD,
and the point percentages located outside the 95% LoA were lower on sBBI than on sIAD. These results indicated that sBBI is an acceptable and more consistent index. Finally, the present study primarily demonstrates that the core point of abnormal sBBI (b 0.95 or N1.10) is useful for diagnosing subclavian and/or brachial artery stenosis as the consistent sIAD. The sBBI of b0.95 indicates obvious stenosis of right subclavian and brachial artery. On the other hand, sBBI of N 1.10 indicates artery stenosis in the left side. In hypertensive patients, the systolic brachial–brachial index (sBBI) is more consistent than sIAD. When patient with low (b0.95) or high (N 1.10) sBBI, the image of the subclavian and brachial artery is needed. This work was supported by National Science and Technology Infrastructure Program No. 2013BAI05B10. References [1] Clark CE, Taylor RS, Shore AC, Campbell JL. The difference in blood pressure readings between arms and survival: primary care cohort study. BMJ Mar 20 2012;344: e1327. http://dx.doi.org/10.1136/bmj.e1327. [2] Clark CE, Campbella JL, Powell RJ, Thompson JF. The inter-arm blood pressure difference and peripheral vascular disease: cross-sectional study. Fam Pract 2007;24:5420–6. [3] Clark CE, Taylor RS, Shore AC, Ukoumunne OC, Campbell JL. Association of a difference in systolic blood pressure between arms with vascular disease and mortality: a systematic review and meta-analysis. Lancet 2012;379:905–14. [4] Sun H, Li P, Su H, et al. The detection rates of inter-arm systolic blood pressure difference vary with blood pressure levels in hypertensive patients under antihypertensive
Fig. 1. The Bland–Altman plots for sIAD and sBBI measurements among three determinations.
Please cite this article as: Sun H, et al, Brachial–brachial index of systolic blood pressure in the patients under anti-hypertensive therapy, Int J Cardiol (2014), http://dx.doi.org/10.1016/j.ijcard.2014.04.118
H. Sun et al. / International Journal of Cardiology xxx (2014) xxx–xxx
3
Table 2 The relation sBBI with the ultrasonic diagnosis of artery stenos in 8 patients with consistent sIAD.SA: subclavian artery; BA: brachial artery. Sex
M M M F F M F F
Age (Y)
49 74 72 68 30 59 72 61
SBPr/SBPl (mm Hg)
SBPr-l (mm Hg)
First
Second
Third
First
Second
Third
134/150 152/131 157/139 151/128 149/127 210/192 169/149 159/149
111/127 148/124 149/137 147/125 131/120 191/177 145/134 155/145
109/126 146/122 137/125 137/120 128/116 180/170 137/115 139/115
−16 21 18 23 22 18 20 10
−16 24 12 22 11 14 11 10
−17 24 12 17 12 10 22 24
therapy. Int J Cardiol Jan 10 2014. http://dx.doi.org/10.1016/j.ijcard.2013.12.252 [pii: S0167-5273(14)00127-2]. [5] Orme S, Ralph SG, Birchall A, Lawson-Matthew P, McLean K, Channer KS. The normal range for inter-arm differences in blood pressure. Age Ageing 1999;28:537–42. [6] Cassidy P, Jones K. A study of inter-arm blood pressure differences in primary care. J Hum Hypertens 2001;15:519–22. [7] Lane D, Beevers M, Barnes N, et al. Inter-arm differences in blood pressure: when are they clinically significant? J Hypertens 2002;20:1089–95.
sBBI (mean)
Stenosis (≥50%)
0.89,0.87,0.87 (0.88) 1.16,1.19,1.20 (1.18) 1.12,1.09,1.20 (1.14) 1.18,1.18,1.15 (1.17) 1.17,1.10,1.10 (1.12) 1.09,1.08,1.06 (1.08) 1.13,1.08,1.19 (1.13) 1.07,1.07,1.21 (1.12)
Right SA and BA Left SA and BA Left BA Left BA Left BA dysplasia NO NO NO
[8] Hua Y, Jia L, Li L, Ling C, Miao Z, Jiao L. Evaluation of severe subclavian artery stenosis by color Doppler flow imaging. Ultrasound Med Biol 2011;37:358–63. [9] American Institute of Ultrasound in Medicine. American College of Radiology, Society of Radiologists in Ultrasound. AIUM Practice Guideline for the Performance of Peripheral Arterial Ultrasound Examinations Using Color and Spectral Doppler Imaging. J Ultrasound Med 2011;30:137–42. [10] Bland JM, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet 1986;1(8476):307–10.
Please cite this article as: Sun H, et al, Brachial–brachial index of systolic blood pressure in the patients under anti-hypertensive therapy, Int J Cardiol (2014), http://dx.doi.org/10.1016/j.ijcard.2014.04.118
Contents lists available at ScienceDirect
International Journal of Cardiology journal homepage: www.elsevier.com/locate/ijcard
Letter to the Editor
Brachial–brachial index of systolic blood pressure in the patients under anti-hypertensive therapy Hanjun Sun a,1, Ping Li a,1, Hai Su a,⁎, Wenying Wang a, Jiwei Wang b, Weitong Hu a, Juxiang Li a, Yanna Liu b, Xiaoshu Cheng a a b
Department of Cardiology, Second Affiliated Hospital of Nanchang University, China Clinical Echocardiographic Laboratory, Second Affiliated Hospital of Nanchang University, China
a r t i c l e
i n f o
Article history: Received 5 April 2014 Accepted 9 April 2014 Available online xxxx Keywords: Brachial–brachial index Inter-arm SBP difference Hypertension Stenosis Artery
Inter-arm BP difference (IAD) has been demonstrated not only as a useful marker for subclavian artery stenosis [1,2], but also as a predicator for increased cardiovascular morbidity and mortality [1,3]. However, the detection rate of systolic IAD (sIAD) significantly varies with the SBP level in hypertensive patients under antihypertensive therapy [4]. Thus this phenomenon may induce confusion and decrease the clinical values of sIAD for diagnosing subclavian or brachial artery stenosis and predicting cardiovascular events. Therefore, it is necessary to create a new parameter, which could more correctly evaluate the difference between two arms at different BP levels. We hypothesize that systolic brachial–brachial index (sBBI), the ratio of right to left arm SBP, may be a more consistent index than sIAD. This study was to test our hypothesis and primarily evaluate the clinical value of sBBI. From May to November of 2012, 414 (200 males and 214 females, 61.3 ± 13.3 y) consecutively adult hypertensive patients admitted to our hospital ward were enrolled. The inclusion criteria were the baseline SBP/DBP (taken at admission) of at least 140/90 mm Hg on the higher value of two arms. The exclusion criteria were arrhythmia, acute myocardial infarction, aortic coarctation, congenital heart disease,
⁎ Corresponding author at: No. 1 Minded Road, Nanchang, Jiangxi 330006, China. Tel./ fax: +86 791 86301105. E-mail address: [email protected] (H. Su). 1 First coauthor.
heart failure, hemiplegia, pulseless disease and the history of transradial coronary intervention. All patients were right handedness. The BP of two arms was simultaneously measured using two validated automatic BP measurement devices (Omron, HEM-7112) for 3 times with a 2-min interval. The absolute SBP difference between right (SBPr) and left (SBPl) arms was calculated as SBPr-l. The SBPl-r of 10 mm Hg or more was diagnosed as sIAD [1,5–7]. sBBI was calculated on the formula: SBBI = SBPr / SBPl. The patients with consistent sIAD (diagnosed for 3 determinations) received color Doppler flow imaging examination for bilateral subclavian, axillary and brachial artery [8,9]. Continuous variables were expressed as mean ± SD. The t-test, variance (ANOVA) test and the omnibus test were used for the statistical analysis. The chi-square test was used to compare the IAD detection rate. The inter-measurement agreement was evaluated by Bland–Altman plots [10]. The inter-measurement sIAD or sBBI differences between two measurements (first minus second, second minus third, and third minus first) were calculated. With this method, inter-measurement differences were plotted against their means and the 95% limits of agreement (LoA) were determined (95% LoA = mean inter-measurement difference ± 1.96 standard deviation). In order to compare the inter-measurement agreement, the variability of bias, SD of bias, lower limit and upper limit from 3 Bland–Altman plots on sIAD and sBBI were calculated separately on the formula: variability = SD / Mean. Meanwhile, the plots of outside of 95% and their percentages for each pair of measurements on sIAD and sBBI were calculated separately. P b 0.05 was considered statistically significant. The SBP levels of right arm were higher (about 4 mm Hg) than those of left arm in the 3 stages. As SBP levels gradually decreased, SBPr-l gradually decreased, but the sBBIs were very similar. In this study, the abnormal sBBI limit was b0.95 or N1.10 based on the 1242 SBP values from 414 patients (normal limits = 1.023 ± 1.96 × 0.039). On these criteria, the detection rates of abnormal sBBI in three stages decreased from the first to the third as sIAD did, but the decreased extent was significantly less than that of sIAD (5:1 vs 2:1) (Table 1). The Bland–Altman plots on sIAD and sBBI among three measurements are showed in Fig. 1. The Bland–Altman plots on sIAD has rhombus-like left side and discrete right side, while the pictures of Bland–Altman plots on sBBI are like a core (Fig. 1). Meanwhile, the variability on the 4 parameters for sBBI was lower than their relative parameter on sIAD. Furthermore, point percentages
http://dx.doi.org/10.1016/j.ijcard.2014.04.118 0167-5273/© 2014 Elsevier Ireland. Ltd
Please cite this article as: Sun H, et al, Brachial–brachial index of systolic blood pressure in the patients under anti-hypertensive therapy, Int J Cardiol (2014), http://dx.doi.org/10.1016/j.ijcard.2014.04.118
2
H. Sun et al. / International Journal of Cardiology xxx (2014) xxx–xxx
Table 1 The SBP parameters and the detection rates of sIAD and sBBI in 3 stages (n = 414).
First Second Third
Right SBP
Left SBP
SBPr-l
sBBI
sIAD n (%)
Abnormal sBBI n (%)
163.7 ± 18.4 147.7 ± 15.3⁎ 135.4 ± 11.7⁎
159.7 ± 18.2 144.5 ± 15.4⁎ 132.9 ± 11.7⁎
5.74 ± 5.17 4.52 ± 4.05 3.68 ± 3.43
1.03 ± 0.043 1.02 ± 0.038 1.02 ± 0.035
76 (18.4) 43 (10.3)⁎ 13 (3.1)⁎
25 (6.0) 17 (4.1) 13 (3.1)⁎
First: after admission; second: 3 day after admission; third: 6 day after admission. ⁎ Compared with the first determination, P b 0.05.
located outside the 95% LoA between first and second, the first and third, and the second and third were lower on sBBI than on sIAD (4.59%, 3.87% and 3.38% vs 5.31%, 4.35% and 4.10%, respectively). In this study, ultrasonic examination was performed in 8 cases with consistent sIAD diagnosis [4]. One case with sBBI of 0.88, which indicated higher left arm SBP, had obvious stenosis in the right subclavian and brachial artery. In other 7 patients with sBBI of N1.10, which means higher right arm SBP, 3 cases had left subclavian and/or brachial artery stenosis, and one case has brachial artery dysplasia. However, in other 3 patients, 2 of the patients had sBBI N1.10 and one had mean sBBI of 1.08; no significant ultrasonic evidence for the left subclavian and/or brachial artery stenosis (more than 50%) was found (Table 2). At first, the present study showed that as compared with sIAD, sBBI was less dependent on SBP levels in the hypertensive patients under anti-hypertensive therapy. Secondly, the present study primarily provided a normal range for sBBI as 0.95–1.10 in these 414 hypertensive patients. On these criteria, the variation of the detection rates of abnormal sBBI in three stages was smaller than that of sIAD (5:1 vs 2:1). Therefore, the sBBI may be a more consistent index. Thirdly, the present study demonstrated that the agreement among the 3 sBBIs was better than that among 3 sIADs, as the variability on the 4 parameters for sBBI was lower than their relative parameter on sIAD,
and the point percentages located outside the 95% LoA were lower on sBBI than on sIAD. These results indicated that sBBI is an acceptable and more consistent index. Finally, the present study primarily demonstrates that the core point of abnormal sBBI (b 0.95 or N1.10) is useful for diagnosing subclavian and/or brachial artery stenosis as the consistent sIAD. The sBBI of b0.95 indicates obvious stenosis of right subclavian and brachial artery. On the other hand, sBBI of N 1.10 indicates artery stenosis in the left side. In hypertensive patients, the systolic brachial–brachial index (sBBI) is more consistent than sIAD. When patient with low (b0.95) or high (N 1.10) sBBI, the image of the subclavian and brachial artery is needed. This work was supported by National Science and Technology Infrastructure Program No. 2013BAI05B10. References [1] Clark CE, Taylor RS, Shore AC, Campbell JL. The difference in blood pressure readings between arms and survival: primary care cohort study. BMJ Mar 20 2012;344: e1327. http://dx.doi.org/10.1136/bmj.e1327. [2] Clark CE, Campbella JL, Powell RJ, Thompson JF. The inter-arm blood pressure difference and peripheral vascular disease: cross-sectional study. Fam Pract 2007;24:5420–6. [3] Clark CE, Taylor RS, Shore AC, Ukoumunne OC, Campbell JL. Association of a difference in systolic blood pressure between arms with vascular disease and mortality: a systematic review and meta-analysis. Lancet 2012;379:905–14. [4] Sun H, Li P, Su H, et al. The detection rates of inter-arm systolic blood pressure difference vary with blood pressure levels in hypertensive patients under antihypertensive
Fig. 1. The Bland–Altman plots for sIAD and sBBI measurements among three determinations.
Please cite this article as: Sun H, et al, Brachial–brachial index of systolic blood pressure in the patients under anti-hypertensive therapy, Int J Cardiol (2014), http://dx.doi.org/10.1016/j.ijcard.2014.04.118
H. Sun et al. / International Journal of Cardiology xxx (2014) xxx–xxx
3
Table 2 The relation sBBI with the ultrasonic diagnosis of artery stenos in 8 patients with consistent sIAD.SA: subclavian artery; BA: brachial artery. Sex
M M M F F M F F
Age (Y)
49 74 72 68 30 59 72 61
SBPr/SBPl (mm Hg)
SBPr-l (mm Hg)
First
Second
Third
First
Second
Third
134/150 152/131 157/139 151/128 149/127 210/192 169/149 159/149
111/127 148/124 149/137 147/125 131/120 191/177 145/134 155/145
109/126 146/122 137/125 137/120 128/116 180/170 137/115 139/115
−16 21 18 23 22 18 20 10
−16 24 12 22 11 14 11 10
−17 24 12 17 12 10 22 24
therapy. Int J Cardiol Jan 10 2014. http://dx.doi.org/10.1016/j.ijcard.2013.12.252 [pii: S0167-5273(14)00127-2]. [5] Orme S, Ralph SG, Birchall A, Lawson-Matthew P, McLean K, Channer KS. The normal range for inter-arm differences in blood pressure. Age Ageing 1999;28:537–42. [6] Cassidy P, Jones K. A study of inter-arm blood pressure differences in primary care. J Hum Hypertens 2001;15:519–22. [7] Lane D, Beevers M, Barnes N, et al. Inter-arm differences in blood pressure: when are they clinically significant? J Hypertens 2002;20:1089–95.
sBBI (mean)
Stenosis (≥50%)
0.89,0.87,0.87 (0.88) 1.16,1.19,1.20 (1.18) 1.12,1.09,1.20 (1.14) 1.18,1.18,1.15 (1.17) 1.17,1.10,1.10 (1.12) 1.09,1.08,1.06 (1.08) 1.13,1.08,1.19 (1.13) 1.07,1.07,1.21 (1.12)
Right SA and BA Left SA and BA Left BA Left BA Left BA dysplasia NO NO NO
[8] Hua Y, Jia L, Li L, Ling C, Miao Z, Jiao L. Evaluation of severe subclavian artery stenosis by color Doppler flow imaging. Ultrasound Med Biol 2011;37:358–63. [9] American Institute of Ultrasound in Medicine. American College of Radiology, Society of Radiologists in Ultrasound. AIUM Practice Guideline for the Performance of Peripheral Arterial Ultrasound Examinations Using Color and Spectral Doppler Imaging. J Ultrasound Med 2011;30:137–42. [10] Bland JM, Altman DG. Statistical methods for assessing agreement between two methods of clinical measurement. Lancet 1986;1(8476):307–10.
Please cite this article as: Sun H, et al, Brachial–brachial index of systolic blood pressure in the patients under anti-hypertensive therapy, Int J Cardiol (2014), http://dx.doi.org/10.1016/j.ijcard.2014.04.118