The Dinamap 845 blood pressure recorder has been evaluated over a wide range of blood pressure by comparison with the Hawksley random zero sphygmomanometer in 32 subjects, six of whom had a cardiac arrhythmia. Group mean radings for systolic and phase 5 diastolic pressure were almost identical but Dinamap diastolic values were on average significantly lower (mean difference 3.4 mmHg) than phase 4 diastolic readings obtained with the Hawksley machine. Correlations between readings with the two instruments were high but the slopes and intercepts of the regression for systolic but not diastolic pressure were significantly different from unity and zero, respectively. The Dinamap is easy to use, portable, and capable of rejecting some motion artefact. Its major disadvantage is that the systolic blood pressure measurement is limited to a maximum of 210 mmHg, a point not made clear in the manufacturer's literature. Nevertheless, the Dinamap 845 is acceptable for blood pressure determinations in subjects who are normotensive or who have mild hypertension.
A low ankle-brachial index (ABI) is associated with increased risk of coronary heart disease, stroke, and death. Regression model parameter estimates may be biased due to measurement error when the ABI is included as a predictor in regression models, but may be corrected if the reliability coefficient, R, is known. The R for the ABI computed from DINAMAP™ readings of the ankle and brachial SBP is not known.
A total of 119 participants in both the Atherosclerosis Risk in Communities (ARIC) study and the NHLBI Family Heart Study (FHS) had repeat ABIs taken within 1 year, using a common protocol, automated oscillometric blood pressure measurement devices, and technician pool.
The estimated reliability coefficient for the ankle systolic blood pressure (SBP) was 0.68 (95% CI: 0.57, 0.77) and for the brachial SBP was 0.74 (95% CI: 0.62, 0.83). The reliability for the ABI based on single ankle and arm SBPs was 0.61 (95% CI: 0.50, 0.70) and the reliability of the ABI computed as the ratio of the average of two ankle SBPs to two arm SBPs was estimated from simulated data as 0.70.
These reliability estimates may be used to obtain unbiased parameter estimates if the ABI is included in regression models. Our results suggest the need for repeated measures of the ABI in clinical practice, preferably within visits and also over time, before diagnosing peripheral artery disease and before making therapeutic decisions.
Noninvasive ankle systolic, mean and diastolic pressures were obtained with an oscillometric instrument available commercially. Systolic pressures were also measured at either the posterior tibial or dorsal pedal artery by using the Doppler technique with the ultrasound probe. Ankle pressures were obtained in normal subjects and in patients with peripheral vascular disease, particularly patients with calcified or incompressible vessels or with different posterior tibial and dorsal pedal Doppler pressures. Systolic pressures by oscillometry and by Doppler were equal in normal subjects and in functionally normal limbs of patients. In the presence of mild vascular disease, systolic pressure was decreased and mean and diastolic pressures were within normal limits. Measurements by Doppler and by oscillometry were similar. In patients with moderate disease, the systolic pressure by oscillometry, although decreased, was consistently higher than Dopper pressures, and the mean ankle pressure was decreased. In patients with different posterior tibial and dorsal pedal pressures, the systolic oscillometric pressure was closer to the highest Doppler pressure measured. In contrast, in patients with partially incompressible vessels, the systolic oscillometric pressure was consistently lower than Doppler pressures. The oscillometric instrument available did not detect pressure pulses in patients with severe vascular disease; the weak pressure pulses present can, however, be detected with more sensitive instrumentation.
There are few studies to be found in the literature on ankle–brachial index in sickle cell disease. The aim of this study was to compare ankle–brachial index of steady-state adult sickle cell anaemia patients with that of normal controls.
A descriptive cross-sectional study of 62 sickle cell anaemia patients and 62 age- and gender-matched normal controls was carried out in the adult outpatient sickle cell clinics and the cardiac centre of the University of Nigeria Teaching Hospital (UNTH), Enugu, Nigeria from February to August 2007. The supine brachial and ankle blood pressures were measured separately with the cuff of the mercury sphygmomanometer applied to the right arm and right calf, respectively.
The ankle systolic blood pressure was lower in patients with sickle cell anaemia than in the controls (p < 0.001). The mean indices for ankle–brachial index were 0.88 ± 0.09 and 1.03 ± 0.06, respectively for patients and controls. This difference was statistically significant (p < 0.001). Seventy three per cent of the patients had ankle–brachial index less than 0.9 compared with controls (5%). This was also significant (p < 0.001).
ankle–brachial blood pressure index; adult Nigerians; sickle cell anaemia
The precision and accuracy of an indirect oscillometric blood pressure measurement technique (Dinamap 8100) was assessed in 11 anesthetized Beagle dogs weighing 8 to 11.5 kg. Direct blood pressure measurements were made by catheterization of the lingual artery, and simultaneous indirect measurements were determined by placing a cuff over the median artery (midradial area). Blood pressure measurements at 2 different planes of anesthesia (light and deep) were recorded in triplicate. At a light plane of anesthesia, the Dinamap 8100 underestimated diastolic and mean arterial pressure, and at a deep anesthetic plane overestimated systolic pressure. The indirect technique had good repeatability of systolic pressures. Regression analysis for the 2 techniques showed excellent correlation (r = 0.93). The results indicate that the indirect oscillometric blood pressure measurement technique provides a good estimate of systolic, diastolic, and mean arterial pressure in dogs weighing 8-11.5 kg.
The aim of this study was to determine the variability of measurements of ankle and brachial systolic pressures and ankle brachial ratios in order to assess their suitability for use in epidemiological studies of arterial disease in the lower limbs. Thirty-six subjects had repeat measurements taken by four observers on two separate days using a Doppler probe and random zero sphygmomanometer. The variability in the measurement of ankle systolic pressure was comparable to that for brachial systolic pressure. The 95% confidence limits of one measurement of the ankle brachial ratio was estimated to be +/- 16%, reducing to +/- 10% for the mean of four measurements taken by two observers on two days. Analysis of variance indicated that the variability in the measurement of ankle brachial ratios attributable to observers, days, timing of measurements on the same day, and repeat measurements was considerably less than the "biological" variability between subjects and between legs. These results suggest that repeatability of the ankle brachial ratio is such that a single measurement is suitable for most epidemiological studies of atherosclerotic peripheral arterial disease.
Non-invasive automatic blood pressure monitors (BP-103N, DINAMAP 845XT, Finapres 2300) were compared with the auscultatory method. The blood pressure readings given by the oscillometric method (BP-103N, DINAMAP 845XT) were accurate and reproducible. Agreement with the auscultatory method was especially good for systolic pressure. For diastolic pressure readings, there was less agreement with the results of the auscultatory method. The finger arterial pressure method (Finapres 2300) occasionally displayed greater variability than the devices using the oscillometric method.
To investigate whether diabetes and regular hemodialysis are associated with false elevation of ankle systolic blood pressure and ankle-brachial systolic pressure index (ABI) because of their arterial calcification in patients with critical limb ischemia (CLI).
RESEARCH DESIGN AND METHODS
We recruited 269 Japanese patients who underwent endovascular therapy for CLI. Ankle systolic blood pressure and ABI were assessed before endovascular therapy. Arterial stenosis and calcification were evaluated angiographically. We investigated the associations among clinical comorbidities, arterial calcification, and measurements of ankle systolic blood pressure and ABI.
Ankle systolic blood pressure was 85 ± 56 mmHg, and ABI was 0.59 ± 0.37. Arterial calcification was observed in 69% of the patients. The prevalence of diabetes and regular hemodialysis was 71 and 47%. Diabetes and regular hemodialysis were both significantly associated with the presence of arterial calcification; their adjusted odds ratios were 2.33 (P = 0.01) and 7.40 (P < 0.01), respectively. However, there was no significant difference in ankle systolic blood pressure or ABI level between those with and without these comorbidities. Furthermore, the presence of arterial calcification was not associated with ankle systolic blood pressure or ABI level, whereas arterial stenoses of all segments in the lower body had independent associations with reduced ankle systolic blood pressure and ABI level.
Diabetes and regular hemodialysis were significantly associated with arterial calcification, but not with elevated measurements of ankle systolic blood pressure or ABI, in CLI patients.
The ankle-brachial index (ABI), defined as the ratio of systolic pressure in the ankle arteries and that in the brachial artery, was a useful noninvasive method to detect arterial stenoses. There had been a lot of researches about clinical regularities of ABI; however, mechanism studies were less addressed. For the purpose of a better understanding of the correlation between vascular stenoses and ABI, a computational model for simulating blood pressure and flow propagation in various arterial stenosis circumstances was developed with a detailed compartmental description of the heart and main arteries. Particular attention was paid to the analysis of effects of vascular stenoses in different large-sized arteries on ABI in theory. Moreover, the variation of ABI during the increase of the stenosis severity was also studied. Results showed that stenoses in lower limb arteries, as well as, brachial artery, caused different variations of blood pressure in ankle and brachial arteries, resulting in a significant change of ABI. Furthermore, the variation of ABI became faster when the severity of the stenosis increased, validating that ABI was more sensitive to severe stenoses than to mild/moderate ones. All these in findings revealed the reason why ABI was an effective index for detecting stenoses, especially in lower limb arteries.
Accurate blood pressure monitoring is critical for the management of chronic kidney disease, but changes in management in secondary care clinics may be based on a single blood pressure reading, with a subsequent lack of accuracy. The aim of this study was to evaluate a fully automated sphygmomanometer for optimising the accuracy of blood pressure measurements in the setting of secondary care renal clinics.
Patients had routine blood pressure measurements with a calibrated DINAMAP PRO400 monitor in a clinical assessment room. Patients then underwent repeat assessment with a DINAMAP PRO400 monitor and BpTRU device and subsequent 24 hour ambulatory blood pressure monitoring (ABPM).
The BpTRU systolic (± SD) reading (117.3 ± 14.1 mmHg) was significantly lower than the routine clinic mean systolic blood pressure (143.8 ± 15.5 mmHg; P < 0.001) and the repeat blood pressure taken with a DINAMAP PRO400 monitor in a quiet room (129.9 ± 19.9 mmHg; P < 0.001). The routine clinic mean diastolic (82.4 ± 11.2 mmHg) was significantly higher than the BpTRU reading (78.4 ± 10.0 mmHg; P < 0.001). Clinic BpTRU measurements were not significantly different to the daytime mean or overall mean of 24 hour ABPM.
In patients with CKD, routine clinic blood pressure measurements were significantly higher than measurements using a BpTRU machine in a quiet room, but there was no significant difference in this setting between BpTRU readings and 24 hour ABPM. Adjusting clinic protocols to utilise the most accurate blood pressure technique available is a simple manoeuvre that could deliver major improvements in clinical practice.
During shoulder surgery, blood pressure is frequently measured at the ankle. Anesthetic complications may result when ankle blood pressure is higher than brachial blood pressure and anesthesiologists misinterpret ankle blood pressure as brachial blood pressure. Therefore, we investigated whether ankle blood pressure is significantly higher than brachial blood pressure before anesthesia induction, during induction, after tracheal intubation, before beach chair position, and in the beach chair position.
Thirty patients requiring general anesthesia for shoulder surgery were included in this study. Ankle and brachial blood pressure were simultaneously measured before induction, during induction, after intubation, before beach chair position, and in the beach chair position.
Ankle blood pressure was higher than brachial blood pressure before induction, during induction, after intubation, before beach chair position, and in the beach chair position. Ankle-brachial blood pressure differences in the beach chair condition were much higher than in four other conditions. The correlation coefficient between mean ankle-brachial blood pressure differences before the beach chair position and mean ankle-brachial blood pressure differences in the beach chair position was 0.616. Brachial systolic blood pressure could be predicted by regression equations (R2 = 0.306-0.771).
These results suggest that anesthesiologists should consider these ankle-brachial blood pressure differences when monitoring anesthesia in the beach chair position.
Ankle blood pressure; Ankle-brachial blood pressure index; Beach chair position; Blood pressure; Brachial blood pressure; Shoulder surgery
Systolic ankle pressures are routinely measured as part of an ankle‐brachial index to screen for lower extremity peripheral arterial disease. Despite widespread use of this measurement, the effect of premeasurement duration of rest on the magnitude, or reliability of the ankle systolic pressure measurement is unknown. This study assessed the effect of premeasurement rest duration on systolic ankle pressures.
Methods and Results
One hundred and forty participants meeting guidelines for peripheral arterial disease screening volunteered for this study. Following 5 minutes of rest in the supine horizontal position, ankle systolic pressures of the lower extremity were taken. Measurements were repeated at 10 and 15 minutes. Testing was repeated 7 to 10 days later. A significant drop in ankle pressure of 5.02 mm Hg occurred between 5 and 10 minutes (P=0.004). No significant change occurred between 10 and 15 minutes (mean change 0.15 mm Hg, P=0.99). Presence of diabetes was associated with a smaller drop between 5 and 15 minutes (mean change 1.85 mm Hg) and predicted 13.4% of the variance in change in ankle pressure (β=−3.61, P=0.0001). Test‐retest reliability after 5 minutes was excellent (intraclass correlation coefficient: 0.84, 95% CI: 0.76 to 0.91) however increased for measurements taken at 10 and 15 minutes (intraclass correlation coefficient: 0.89 95% CI: 0.83 to 0.94 and 0.89 95% CI: 0.82 to 0.93).
Results suggest ankle systolic pressures stabilise after 10 minutes of rest. Longer periods of premeasurement rest did not improve reliability significantly. Though diabetes affects ankle pressure changes after rest, further investigation is required to identify the cause.
blood pressure; diabetes mellitus; peripheral arterial disease
Background. The aim of present study is to observe the association between the levels of ankle-brachial index (ABI) and cardiovascular risk factors among people with type 2 diabetes mellitus in north India. A cross-sectional study was carried out at a centre for heart and diabetic clinic in the state of Punjab on 1121 subjects (671 males and 450 females) with type 2 diabetes mellitus. History of symptoms related to cardiovascular diseases was noted, and blood pressure and anthropometric measurements were recorded. Ankle-brachial index (ABI) was measured using ultrasonic Doppler flow detector. Subjects with ABI ≤0.9 and ≥1.30 were classified as having low and high ABI, respectively. Females had a higher BMI and brachial-ankle pulse wave velocity (P < 0.001). Whereas, males had higher diastolic blood pressure and duration of type 2 diabetes mellitus. The differences of systolic blood pressure and ankle-brachial index were not found significant between the sexes. The prevalence of low ABI (<0.9) was 4.47% in men and 4.67% in women and high ABI (≥1.30) was prevalent in 14% of men and 10.45% of women. Age, BMI, baPWV, and blood pressures were significantly associated with ABI value in both sexes. The results suggested that the ABI might be used as a strong indicator for cardiovascular risk factors in type 2 diabetic subjects.
The Ankle Brachial Index is a useful clinical test for establishing blood supply to the foot. However, there are limitations to this method when conducted on people with diabetes. As an alternative to the Ankle Brachial Index, measuring Toe Systolic Pressures and the Toe Brachial Index have been recommended to assess the arterial blood supply to the foot. This study aimed to determine the intra and inter-rater reliability of the measurement of Toe Systolic Pressure and the Toe Brachial Index in patients with diabetes using a manual measurement system.
This was a repeated measures, reliability study. Three raters measured Toe Systolic Pressure and the Toe Brachial Index in thirty participants with diabetes. Measurement sessions occurred on two occasions, one week apart, using a manual photoplethysmography unit (Hadeco Smartdop 45) and a standardised measurement protocol.
The mean intra-class correlation for intra-rater reliability for toe systolic pressures was 0.87 (95% LOA: -25.97 to 26.06 mmHg) and the mean intra-class correlation for Toe Brachial Indices was 0.75 (95% LOA: -0.22 to 0.28). The intra-class correlation for inter-rater reliability was 0.88 for toe systolic pressures (95% LOA: -22.91 to 29.17.mmHg) and 0.77 for Toe Brachial Indices (95% LOA: -0.21 to 0.22).
Despite the reasonable intra-class correlation results, the range of error (95% LOA) was broad. This raises questions regarding the reliability of using a manual sphygmomanometer and PPG for the Toe Systolic Pressure and Toe Brachial Indice.
To evaluate the accuracy of the ankle brachial index (ABI) measured with the SCVL® (“screening cardiovascular lab”; GenNov, Paris, France), an automated device with synchronized arm and ankle cuffs with an automatic ABI calculation.
Patients were consecutively included in a cardiovascular prevention unit if they presented with at least two cardiovascular risk factors. ABI measurements were made using the SCVL, following a synchronized assessment of brachial and ankle systolic pressure. These values were compared to the ABI obtained with the usual Doppler-assisted method.
We included 157 patients. Mean age was 59.1 years, 56.8% had hypertension, 22.3% had diabetes mellitus, and 17.6% were current smokers. An abnormal ABI was observed in 17.2% with the SCVL and in 16.2% with the Doppler. The prevalence rates of an abnormal ABI by patient measured with each device, ie, 15.7% (confidence interval [CI] 0.95: [11.8; 20.4]) or 14.3% (CI 0.95: [10.7; 18.9]), did not differ. The coefficient of variation of Doppler and SCVL measures was 15.8% and 15.1%, respectively. The regression line between the two measurement methods was statistically significant. The value-to-value comparison also shows a difference of mean equal to 0.010 (CI 0.95: [−0.272; 0.291]) (r = −0.055). Reproducibility of ABI measurements with the SCVL showed a difference of mean equal to 0.009 (CI 0.95: [−0.203; 0.222]), without heteroscedasticity (r = −0.003).
The SCVL is a fast and easy to use automated oscillometric device for the determination of ABI. The use of this two-synchronized-cuff device correlates well with the gold standard Doppler ultrasound method and is reproducible. The SCVL may ease the screening for peripheral arterial disease in routine medical practice.
ankle brachial index; automated device; peripheral arterial disease screening
Arterial stiffening may affect regional myocardial function in hypertensive patients with normal ejection fraction (EF).
Brachial-ankle pulse wave velocity (PWV) was measured in 70 patients, of mean age 48 ± 14 years, with untreated hypertension and EF > 55%. Using two-dimensional-speckle tracking echocardiography, we measured longitudinal and circumferential strain (ε) and strain rate (SR). Basal and apical rotations were measured using short axis views.
The mean systolic and diastolic blood pressure in these patients was 152 ± 15 mmHg and 92 ± 11 mmHg, respectively. The mean value of PWV was 1578 ± 274 cm/s. PWV significantly correlated with age (r = 0.682, p < 0.001), body mass index (r = -0.330, p = 0.005), systolic blood pressure (r = 0.386, p = 0.001) and pulse pressure (r = 0.509, p < 0.001). PWV also significantly correlated with septal E' velocity (r = -0.570, p < 0.001), E/A ratio (r = -0.414, p < 0.001), E/E' ratio (r = 0.589, p < 0.001), systolic global longitudinal ε (r = 0.300, p = 0.012) and early diastolic SR (SRE) (r = -0.479, p < 0.001) suggesting impaired abnormal relaxation. PWV was also correlated with basal rotation (r = -0.301, p = 0.011) and basal-to-apical twist (r = -0.256, p = 0.032). The increases in apical rotation and basal-to-apical twist were attenuated in patients with PWV > 1700 cm/s compared to those with PWV ≤ 1400 cm/s or those with PWV 1400-1700 cm/s.
In hypertensive patients with normal ejection fraction, arterial stiffening contributes to impaired systolic and diastolic function of the regional myocardium. Compensatory increases in ventricular twist were diminished in patients with advanced stage of vascular stiffening.
Arterial stiffening; Regional myocardial function; Speckle tracking echocardiography
The ankle-brachial pressure index (ABI), the ratio of the systolic blood pressure of the ankle to the systolic brachial pressure, is commonly measured at rest, but ABI values post-exercise enhance the sensitivity of the test and can be used to identify atherosclerotic vascular damage. However, it has not been established whether or not enhanced post-exercise ABI is also associated with endothelial dysfunction. We hypothesized that a decrease in post-exercise ABI is related to impaired endothelial function.
To investigate alterations in post-exercise ABI values and endothelial dysfunction in the elderly.
The study population comprised 35 men and women aged 51–77 years (mean age: 66 years). Patients with peripheral arterial disease or a history of heart failure were excluded. The ABI was estimated at rest and immediately after exercise. The exercise protocol comprised 2.5 min of active pedal flexion exercises at a speed of 60 times/min. Endothelial function was assessed by measuring flow-mediated vasodilation (FMD) in the brachial artery using ultrasound imaging.
No correlation was found between FMD and the ABI at rest. However, a weak correlation was found between FMD and post-exercise ABI (r = 0.46, P = 0.06). A strong correlation was observed between FMD and a decrease in post-exercise ABI compared to baseline readings (r = −0.52, P = 0.01). Multiple linear regression analysis was used to generate a prediction equation for FMD using the percentage decrease in post-exercise ABI. Significant correlations were observed between the ultrasound imaging-measured FMD and the predicted FMD (R2 = 0.27, P = 0.001).
Post-exercise ABI appears to be a simple surrogate marker for endothelial function in the elderly, although larger studies are required for validation.
ABI; endothelial function; elder; FMD; exercise
Systolic time interval (STI) is an established noninvasive technique for the assessment of cardiac function. Brachial STIs can be automatically determined by an ankle-brachial index (ABI)-form device. The aims of this study are to evaluate whether the STIs measured from ABI-form device can represent those measured from echocardiography and to compare the diagnostic values of brachial and echocardiographic STIs in the prediction of left ventricular ejection fraction (LVEF) <50%. A total of 849 patients were included in the study. Brachial pre-ejection period (bPEP) and brachial ejection time (bET) were measured using an ABI-form device and pre-ejection period (PEP) and ejection time (ET) were measured from echocardiography. Agreement was assessed by correlation coefficient and Bland-Altman plot. Brachial STIs had a significant correlation with echocardiographic STIs (r = 0.644, P<0.001 for bPEP and PEP; r = 0.850, P<0.001 for bET and ET; r = 0.708, P<0.001 for bPEP/bET and PEP/ET). The disagreement between brachial and echocardiographic STIs (brachial STIs minus echocardiographic STIs) was 28.55 ms for bPEP and PEP, -4.15 ms for bET and ET and -0.11 for bPEP/bET and PEP/ET. The areas under the curve for bPEP/bET and PEP/ET in the prediction of LVEF <50% were 0.771 and 0.765, respectively. Brachial STIs were good alternatives to STIs obtained from echocardiography and also helpful in prediction of LVEF <50%. Brachial STIs automatically obtained from an ABI-form device may be helpful for evaluation of left ventricular systolic dysfunction.
Knowing the normative blood pressure (BP) in a newborn baby is important in order to identify abnormal BP readings. This study was done to determine normative BP values of Nigerian newborns, using the 8100 Dinamap monitor.
Consecutive full-term neonates delivered in a tertiary centre in Nigeria were recruited for the study. The babies’ systolic (SBP), diastolic (DBP) and mean arterial (MAP) blood pressures were measured within the first four days after birth.
A total of 473 babies were recruited for the study. The mean SBP, DBP and MAP readings on day 1 were 66.8 ± 7.7, 38.5 ± 6.3 and 47.9 ± 6.3 mmHg, respectively. The day 1 SBP of babies > 4 kg were significantly higher than those who weighed < 2.5 and 2.5–4 kg (p = 0.01, p = 0.05), respectively.
This study provided current normative SBP, DBP and MAP values for Nigerian neonates. The BP readings compared with their Caucasian counterparts.
An interarm systolic blood pressure (SBP) difference of 10 mmHg or more have been associated with peripheral artery disease and adverse cardiovascular outcomes. We investigated whether an association exists between this difference and ankle-brachial index (ABI), brachial-ankle pulse wave velocity (baPWV), and echocardiographic parameters. A total of 1120 patients were included in the study. The bilateral arm blood pressures were measured simultaneously by an ABI-form device. The values of ABI and baPWV were also obtained from the same device. Clinical data, ABI<0.9, baPWV, echocariographic parameters, and an interarm SBP difference ≥10 mmHg were compared and analyzed. We performed two multivariate forward analyses for determining the factors associated with an interarm SBP difference ≥10 mmHg [model 1: significant variables in univariate analysis except left ventricular mass index (LVMI); model 2: significant variables in univariate analysis except ABI<0.9 and baPWV]. The ABI<0.9 and high baPWV in model 1 and high LVMI in model 2 were independently associated with an interarm SBP difference ≥10 mmHg. Female, hypertension, and high body mass index were also associated with an interarm SBP difference ≥10 mmHg. Our study demonstrated that ABI<0.9, high baPWV, and high LVMI were independently associated with an interarm SBP difference of 10 mmHg or more. Detection of an interarm SBP difference may provide a simple method of detecting patients at increased risk of atherosclerosis and left ventricular hypertrophy.
Availability of a range of techniques and devices allow measurement of many variables related to the stiffness of large or medium sized arteries. There is good evidence that, pulse wave velocity is a relatively simple measurement and is a good indicator of changes in arterial properties. The pulse wave velocity calculated from pulse wave recording by other methods like doppler or tonometry is tedious, time-consuming and above all their reproducibility depends on the operator skills. It requires intensive resource involvement. For epidemiological studies these methods are not suitable. The aim of our study was to clinically evaluate the validity and reproducibility of a new automatic device for measurement of pulse wave velocity that can be used in such studies.
In 44 subjects including normal healthy control and patients with coronary artery disease, heart brachial, heart ankle, brachial ankle and carotid femoral pulse wave velocities were recorded by using a new oscillometric device. Lead I and II electrocardiogram and pressure curves were simultaneously recorded. Two observers recorded the pulse wave velocity for validation and one observer recorded the velocity on two occasions for reproducibility.
Results and Discussion
Pulse wave velocity and arterial stiffness index were recorded in 24 control and 20 coronary artery disease patients. All the velocities were significantly high in coronary artery disease patients. There was highly significant correlation between the values noted by the two observers with low standard deviation. The Pearson's correlation coefficient for various velocities ranged from (r = 0.88–0.90) with (p < 0.0001). The reproducibility was also very good as shown by Bland-Altman plot; most of the values were lying within 2 SD. The interperiod measurements of pulse wave velocity were also significantly correlated (r = 0.71 – 0.98) (P < 0.0001). Carotid-femoral pulse wave velocity was found to correlate significantly with heart brachial, heart ankle, brachial ankle pulse wave velocity and arterial stiffness index values. Reproducibility of our method was good with very low variability in both interobserver and interperiod analysis.
The new device "PeriScope" based on oscillometric technique has been found to be a simple, non-invasive and reproducible device for the assessment of pulse wave velocity and can be used to determine arterial stiffness in large population based studies.
Pulse wave velocity; Arterial stiffness index; Validity; Oscillometric device
The symptoms of orthostatic hypotension may be ignored or go unnoticed and may predispose some diabetic or elderly people to repeated falls and trauma, leading to immobility and prolongation of rehabilitation. The present investigation is concerned mainly with testing the reaction of the cardiovascular system in response to physiological stimuli, such as, standing upright from a supine position before and after meal intake in diabetic patients and the healthy Saudi population.
Materials and Methods:
Seventy-five healthy and 49 diabetic patients were selected for this study. Parameters of heart rate, systolic and diastolic blood pressures, and electrocardiograms (ECG) were obtained for each subject by Dinamap (an automatic recorder), after 10 minutes of rest in the supine position and then after one and two minutes of standing. All parameters were taken before and after an intake of a standard meal. The results were compared between the diabetic and non-diabetic groups, and between the elderly diabetic and the healthy elderly ≥ 65 year olds, and between the young adults ≤ 40 year olds and the elderly ≥ 65 year olds.
The postural changes of blood pressure and heart rate between the diabetic and non-diabetic groups, and between the elderly diabetic and the healthy elderly groups, were not significant. However, a highly significant postural drop in blood pressure, and an increase in the resting heart rate were recorded before and after a meal intake in the elderly compared to the young adults.
The highly significant postural drop in blood pressure and increase in the resting heart rate in the elderly diabetic and healthy elderly people can be attributed to a defect in the arterial baroreceptors control of blood pressure and parasympathetic control of heart rate in this population.
Blood pressure; diabetic; elderly; heart rate; orthostatic hypotension
STUDY OBJECTIVE--The aim was to compare the performance of the Dinamap 1846SX automated oscillometric blood pressure recorder with that of the Hawksley random zero sphygmomanometer during use under field study conditions. DESIGN--Two independent within subject measurement comparisons were made, one in adults and one in children, each conducted in three stages over several months while the Dinamap instruments were being used in epidemiological field surveys. SETTING--The studies were done in outpatients clinics (adults) and primary schools (children). PARTICIPANTS--141 adults (20-85 years) and 152 children (5-7 years) took part. MEASUREMENTS AND MAIN RESULTS--In adults a pair of measurements was made with each instrument, the order alternating for consecutive subjects. In children one measurements was made with each instrument, in random order. Measurements with the Dinamap 1846SX were higher than those with the random zero sphygmomanometer both in adults (mean difference 8.1 mm Hg; 95% CI 6.5 to 9.7 mm Hg) and in children (mean difference 8.3 mm Hg; 95% CI 6.9 to 9.7 mm Hg). Diastolic measurements were on average very similar both in adults and in children. The results were consistent at all three stages of both studies. The differences in systolic measurement were independent of blood pressure level. However, the extent of agreement in diastolic pressure depended on the diastolic blood pressure level; in both studies Dinamap diastolic measurements were higher at low diastolic pressures while random zero diastolic measurements were higher at high diastolic pressures. CONCLUSIONS--Systolic measurements made with the Dinamap 1846SX instrument are not directly comparable with those of the Hawksley random zero sphygmomanometer and are unlikely to be comparable with those of earlier Dinamap models. These differences have important implications for clinical practice and for comparisons of blood pressure measurement between epidemiological studies. However, the consistency of measurement by the Dinamap 1846SX over time suggests that the instrument may have a place in standardised blood pressure measurement in the research setting.
The ankle brachial index (ABI) is an efficient tool for objectively documenting the presence of lower extremity peripheral arterial disease (PAD). However, different methods exist for ABI calculation, which might result in varying PAD prevalence estimates. To address this question, we compared five different methods of ABI calculation using Doppler ultrasound in 6,880 consecutive, unselected primary care patients ≥65 years in the observational getABI study.
In all calculations, the average systolic pressure of the right and left brachial artery was used as the denominator (however, in case of discrepancies of ≥10 mmHg, the higher reading was used). As nominators, the following pressures were used: the highest arterial ankle pressure of each leg (method #1), the lowest pressure (#2), only the systolic pressure of the tibial posterior artery (#3), only the systolic pressure of the tibial anterior artery (#4), and the systolic pressure of the tibial posterior artery after exercise (#5). An ABI < 0.9 was regarded as evidence of PAD.
The estimated prevalence of PAD was lowest using method #1 (18.0%) and highest using method #2 (34.5%), while the differences in methods #3–#5 were less pronounced. Method #1 resulted in the most accurate estimation of PAD prevalence in the general population. Using the different approaches, the odds ratio for the association of PAD and cardiovascular (CV) events varied between 1.7 and 2.2.
The data demonstrate that different methods for ABI determination clearly affect the estimation of PAD prevalence, but not substantially the strength of the associations between PAD and CV events. Nonetheless, to achieve improved comparability among different studies, one mode of calculation should be universally applied, preferentially method #1.
To estimate the prevalence of lower extremity arterial disease, all patients aged over 65 years registered with a rural general practice near Cambridge were invited to attend for examination of the circulation to the lower extremities; 265 subjects (80%) accepted. Three methods were used to investigate the presence of lower extremity arterial disease - enquiring about symptoms of intermittent claudication; clinical examination (and particularly the detection of arterial bruits); and pressure index calculations from measurements of the ankle and brachial systolic blood pressure using a Doppler ultrasound probe. When examining the legs, the presence of a bruit was taken as stronger evidence of disease than inability to palpate the pulses which may be difficult or impossible to detect for a number of reasons. Forty seven of the 264 patients examined (18%) showed evidence of lower extremity arterial disease. Seven patients showed unequivocal evidence of lower extremity arterial disease as demonstrated by all three criteria, 12 by two criteria and 28 patients on one criterion alone. While the pressure index followed a normal distribution curve, there was a tendency for it to decline with age. Other risk factors which showed a correlation with evidence of disease including current, but not previous, cigarette smoking, and a history of stroke. The significance of the findings is discussed in the context of some degree of arterial pathology in many British subjects in this age group.