Simultaneous double arm automated blood pressure measurement for the screening of subjects with potential vascular disease: a community study

[Interarm blood pressure difference: Concordance between two methods of automatic simultaneous measurement and between visits reproducibility]

OBJECTIVE

An increased interarm blood pressure difference (IAD) (≥10mmHg) has been associated with increased cardiovascular morbidity and mortality. There are few studies determining how IAD has to be measured and its reliability between visits. The objectives of our study were twofold. First, to evaluate the concordance between two automatic oscillometric devices for IAD measurement (two OMRON devices and one Microlife WatchBP™ device (WBP™)) and to analyse the reproducibility of IAD between visits in the general population attending a primary care centre.

DESIGN

Descriptive cross-sectional study of concordance between the two methods and reproducibility of IAD between two visits separated by one week. SITE: Parets del Vallès primary care centre (Barcelona).

PARTICIPANTS

General population aged 35-74 years.

INTERVENTIONS AND MAIN MEASUREMENTS

One hundred and forty-nine patients completed the two visits. At each visit, IAD was measured three times with both methods and the mean of the three determinations was considered. Other variables such as sociodemographic and anthropometric variables, pathological antecedents and pharmacological treatment were collected through a review of the medical history and an interview with the patient. Concordance between the two devices and between visits reproducibility were calculated using the Lin concordance coefficient (CCL) for IAD expressed continuously and kappa(k) indices for IAD categorised as normal or pathological.

RESULTS

Concordance for IAD expressed continuously was low: CCL=0.13 (0.02-0.24). Concordance was also low for IAD categorised as normal or pathological (k=-0.03 (-0.05-0.00)). Reproducibility between visits was low for both methods and for both continuous and categorised IAD: with OMRON™ CCL=0.19 (0.03-0.34) and k=-0.02 (-0.16-0.12) and for WBP™ CCL=0.14 (-0.01-0.29) and k=0.49 (0.33-0.64).

CONCLUSIONS

Concordance between two automatic oscillometers in the simultaneous IAD measurement was low. Reproducibility between visits was also low for both methods.

Clinical relevance of double-arm blood pressure measurement and prevalence of clinically important inter-arm blood pressure differences in Indian primary care

Hypertension guidelines recommend measuring blood pressure (BP) in both arms at least once. However, this is seldom done due to uncertainties regarding measurement procedure and the implications of finding a clinically important inter‐arm BP difference (IAD). This study aimed to provide insight into the prevalence of clinically important IADs in a large Indian primary care cohort.

A number of 134 678 (37% female) unselected Indian primary care participants, mean age 45.2 (SD 11.9) years, had BP measured in both arms using a standardized, triplicate, automated simultaneous measurement method (Microlife WatchBP Office Afib).

On average, there were clinically minor differences in right and left arm BP values: systolic BP 134.4 vs 134.2 mmHg (p < .01) and diastolic BP 82.7 vs 82.6 mmHg (p < .01), respectively.

Prevalence of significant mean systolic IAD between 10 and 15 mmHg was 7,813 (5.8%). Systolic IAD ≥ 15 mmHg 2,980 (2.2%) and diastolic IAD ≥ 10 mmHg 7,151 (5.3%). In total, there were 7,595 (5.6%) and 8,548 (6.3%) participants with BP above the 140/90 mmHg threshold in only the left or right arm, respectively. Prevalence of participants with elevated BP on one arm only was highest in patients with a systolic IAD ≥ 15 mmHg; 19.1% and 13.7%, for left and right arm, respectively.

This study shows that a substantial prevalence of IAD exists in Indian primary care patients. BP is above the diagnostic threshold for hypertension in one arm only for 6% of participants. These findings emphasize the importance of undertaking bilateral BP measurement in routine clinical practice.

Prevalence and associated factors of inter-arm blood pressure difference in Chinese community hypertensive population

OBJECTIVES

This study aimed to investigate the prevalence and associated factors of inter-arm blood pressure difference (IAD) in Chinese community hypertensive population.

METHODS

The cross-sectional study included 7788 hypertensive patients (3673 male and 4115 female, aged 62.3 ± 13.6 years) in Guangdong, China. IAD was defined as the absolute value of blood pressure (BP) difference between left and right arms. Bilateral BP was measured simultaneously by automated devices.

RESULTS

The mean IAD was 4.04 ± 4.33 mm Hg in systolic and 3.19 ± 3.43 mm Hg in diastolic. The prevalence rates of systolic IAD (sIAD)≥5 mm Hg and ≥10 mmHg were 28.9% (n = 2247) and 12.8% (n = 996), respectively. By univariate linear regression, higher sIAD correlated with aging, higher SBP, higher DBP, lower baseline estimated glomerular filtration rate (eGFR), and anti-hypertensive medication (p < 0.05). In multivariate linear regression analysis, higher sIAD was significantly associated with systolic BP (SBP, β = 0.033; 95%CI, 0.025-0.041; p < 0.001), triacylglycerol (β = 0.093; 95%CI, 0.017-0.169; p = 0.016), total cholesterol (β = -0.202; 95%CI, -0.396to -0.009; p = 0.04), and low-density lipoprotein cholesterol (LDL-C; β = 0.304; 95%CI, 0.027-0.582; p = 0.032).

CONCLUSION

The elevated prevalence of large IAD was shown in hypertensive population. Meanwhile, higher levels of SBP, triacylglycerol, total cholesterol, LDL-C, and lower eGFR were associated with higher sIAD.

Characterization of resting and exercise inter-arm differences in SBP to isometric handgrip exercise in males and females

A large inter-arm difference (IAD; ≥10 mmHg) in SBP is linked to cardiovascular and peripheral vascular disease, hypertension, and premature mortality. Exercise-induced IAD (eIAD) is related to resting IAD, and acute aerobic activity alters eIAD and reduces IAD in recovery. Isometric handgrip exercise (IHE) affects blood pressure (BP), though the eIAD response to IHE is unknown. Further, the eIAD response may differ between males and females.

OBJECTIVES

To characterize the eIAD response to IHE in males and females.

METHODS

On visit 1, participants (16 females and 15 males, aged 18-35 years) completed three maximal voluntary isometric contractions (MVIC) per arm. On visit 2, before IHE, a series of three simultaneous, bilateral BP measures were averaged at rest. During IHE, participants maintained handgrip at 20% of MVIC for 2 minutes (arm randomly assigned), at which time bilateral BP was measured (IHE) during exercise and subsequent recovery (REC1 and REC2). Repeated-measures analysis of variance assessed eIAD and SBP (time × sex).

RESULTS

IHE increased absolute eIAD (4 mmHg). Differences in relative eIAD were observed at IHE and REC2 based on resting IAD status (P < 0.05). Females only had an exaggerated SBP and pulse pressure response in the working arm.

CONCLUSION

Acute IHE was shown to augment eIAD. Further eIAD and resting IAD were related. Acute IHE induced different bilateral responses between males and females, though the impact of sex on eIAD warrants further investigation. Future studies should address the effects of repeated bouts of IHE, which may benefit individuals with a large resting IAD.