肱动脉袖带血压与中心动脉血压差异的分析

目的：比较肱动脉袖带血压与中心动脉血压的差异性,并探讨两者间差异的可能影响因素及机制。方法：选择住院行诊断性冠脉造影患者128例,平均（60．87±9．36）．岁。术前测量脉搏波传导速度（PWV）,容量顺应性（C1）,振荡顺应性（C2）,术中记录升主动脉压力（中心动脉血压,CAP）,并同步测量肱动脉袖带血压。结果：（1）根据中心动脉与肱动脉袖带收缩压（SBP）差异程度分为3组：相符组（两者相差≤4mmHg）21例（16．40％）,高估组（后者高于前者,差值〉4mmHg）14例（10．94％）,低估组（后者低于前者,差值〉4mmHg）93例（72．66％）;（2）低估组人群传统心血管危险因素多,多为老年,高血压、冠心病较多（P〈0．05）;（3）低估组PWV明显增快（P〈0．05）;（4）低估组C2明显降低（P〈0．05）。结论：中老年人肱动脉袖带血压大多数低于中心动脉压,中心动脉硬化可能与之有关。     

Validation of a generalized transfer function to noninvasively derive central blood pressure during exercise

Exercise brachial blood pressure (BP) predicts mortality, but because of wave reflection, central (ascending aortic) pressure differs from brachial pressure. Exercise central BP may be clinically important, and a noninvasive means to derive it would be useful. The purpose of this study was to test the validity of a noninvasive technique to derive exercise central BP. Ascending aortic pressure waveforms were recorded using a micromanometer-tipped 6F Millar catheter in 30 patients (56+/-9 years; 21 men) undergoing diagnostic coronary angiography. Simultaneous recordings of the derived central pressure waveform were acquired using servocontrolled radial tonometry at rest and during supine cycling. Pulse wave analysis of the direct and derived pressure signals was performed offline (SphygmoCor 7.01). From rest to exercise, mean arterial pressure and heart rate were increased by 20+/-10 mm Hg and 15+/-7 bpm, respectively, and central systolic BP ranged from 77 to 229 mm Hg. There was good agreement and high correlation between invasive and noninvasive techniques with a mean difference (+/-SD) for central systolic BP of -1.3+/-3.2 mm Hg at rest and -4.7+/-3.3 mm Hg at peak exercise (for both r=0.995; P<0.001). Conversely, systolic BP was significantly higher peripherally than centrally at rest (155+/-33 versus 138+/-32 mm Hg; mean difference, -16.3+/-9.4 mm Hg) and during exercise (180+/-34 versus 164+/-33 mm Hg; mean difference, -15.5+/-10.4 mm Hg; for both P<0.001). True myocardial afterload is not reliably estimated by peripheral systolic BP. Radial tonometry and pulse wave analysis is an accurate technique for the noninvasive determination of central BP at rest and during exercise.     

Determination of central aortic systolic and pulse pressure from the radial artery pressure waveform

OBJECTIVE: Measurements of central aortic systolic and pulse pressure, either gauged directly or estimated indirectly, have been shown to be superior to brachial pressure in outcome studies. While the radial pressure convolution method has proved to satisfy the criteria for 'substantial equivalence' to measure central pressure non-invasively, this study sought simpler methods to generate central systolic and pulse pressure directly from the radial artery waveform. METHODS: Two sets of data were used, in which radial artery pressure waves were measured by applanation tonometry and ascending aortic pressure was generated by the SphygmoCor process. Different approaches were applied to each dataset: firstly, using the time period from wave foot to systolic peak in central arteries; secondly, through identifying the pressure surge from the reflected wave in the radial artery; and thirdly from extrapolation and calibration of carotid systolic pressure when mean and diastolic pressure considered to be equal with radial values. RESULTS: Both datasets showed good correspondence between the central systolic and pulse pressure obtained with each of the three approaches and respective pressures generated by SphygmoCor process; all were within AAMI SP10 criteria and grade A for BSH criteria. CONCLUSION: All three approaches gave results similar substantially equivalent to those obtained with the SphygmoCor system for aortic, systolic and pulse pressure. Hence, simple inspection of the radial waveform has the potential to improve the estimation of aortic systolic and pulse pressure.     

通过分析脉搏波形研究硝酸甘油对血管的作用

目的 用无创脉搏波分析方法揭示硝酸甘油(GTN)对不同特性血管的剂量依赖效应。方法 46名志愿者随机给予安慰剂或不同剂量的缓释GTN贴剂(0．1-0．6mg／h)，记录桡动脉脉搏波，并与传统的袖带血压计测量结果对照。中心动脉脉搏波通过已验证的转换函数从桡动脉脉搏波实时生成。结果 除了2个最大剂量组的肱动脉收缩压下降外，心率及肱动脉血压没有明显变化。通过脉搏波分析获得的中心动脉收缩压、反射波增压、积分平均压和左室射血分数均有一致的剂量依赖的改变。结论 脉搏波分析比传统袖带血压计有优势，揭示了很低剂量的GTN影响血流动力学的证据，其机制是传输动脉扩张，波反射降低，更大剂量的GTN可进一步引起静脉及阻力小动脉扩张。     

Potential for use of pulse wave analysis in determining the interaction between sildenafil and glyceryl trinitrate

BACKGROUND: The early part of the central aortic pressure pulse, with amplitude (PI - Pd), is generated by left ventricular ejection, while the latter part (or augmented pressure), with amplitude (Ps - Pi), is generated by the reflected wave arriving during systole. The effects of arterial vasodilator agents, especially nitrates, on central aortic systolic blood pressure are grossly underestimated by sphygmomanometric measurements of brachial artery pressure. HYPOTHESIS: The objective of this study was to investigate the potential for use of central arterial pulse wave analysis, obtained noninvasively from the radial pulse, in determining the interaction between sildenafil and the nitric oxide donor drug glyceryl trinitrate (GTN). METHODS: Central aortic pressure waveforms were generated from noninvasively measured radial artery pressure wave-forms and subjected to pulse wave analysis to determine the interaction between sildenafil and transdermally applied GTN. RESULTS: Transdermal GTN (2.5, 5.0, and 15 mg per 24-h patches) alone caused no consistent change in sphygmomanometer-determined systolic or diastolic pressures, but there was a consistent, dose-related fall in amplitude of the augmented systolic pressure, (Ps - Pi), of 4.0, 7.0, and 11 mmHg, respectively, with little change in diastolic pressure. The 2.5 mg patch caused a fall of 4.0 mmHg in aortic systolic pressure, while augmentation index (AIx) fell from 20 to 11% and pulse pressure fell 18%. When oral sildenafil (50 mg) was administered after GTN (2.5 mg), aortic systolic pressure fell another 4.0 mmHg. This decrease in systolic pressure caused a fall in AIx to almost 0.0%; pulse pressure fell another 9.0%. CONCLUSION: These modifications in aortic systolic and pulse pressure are due primarily to reduction in wave-reflection amplitude and are not detected by sphygmomanometer-measured brachial artery pressure.     

Arterial pulse waves and velocity and systolic time intervals in diabetic children

Arterial pulse wave velocities, pulse wave contours, and systolic time intervals were recorded in thirty-nine diabetic children and were compared with recordings taken in twenty-seven normal children. Systolic time intervals were similar in the two groups of subjects. However, brachial and aortic pulse wave velocities were significantly greater in the diabetic than in the normal children (p < 0.025 and < 0.005, respectively). Also, in the diabetic children the time interval from the incisura to the midpoint of the dicrotic wave (I-D) was significantly shortened in both the brachial (p < 0.005) and carotid (p < 0.05) pulse waves as compared to the normal children. These changes in pulse wave velocity and contour are associated with increased wall stiffness that occurs with aging and suggest that the large arteries of diabetic children may exhibit acceleration of the aging process. The severity of these changes bore no direct correlation with the degree of carbohydrate intolerance as judged by insulin requirement.     

无创中心动脉压测量设备的比较

目的:比较目前通用的无创中心动脉压检测仪A-PULSE CASPro和SphygmoCor测量中心动脉压的相关性和稳定性。方法:450名男性志愿者,年龄19～23(22±1)岁;采集病史、记录一般情况;告知并签署知情同意;坐位休息10 min后测量右上肢肱动脉血压、分别用A-PULSE CASPro和SphygmoCor测量中心动脉压;记录数据。结果:A-PULSE CASPRO与SphygmoCor 测量的中心动脉压平均差值为1.57 mmHg(1 mmHg=0.133 kPa)和标准偏差为2.53 mmHg。采用Bland-Altman评价两种方法测量中心动脉压的偏差是在(5±8) mmHg范围之内。两种设备的线性回归方程为Y=0.9231*X+9.9341。A-PULSE CASPro和SphygmoCor测量的中心动脉压数值一致性好,R2为0.9123。结论: A-PULSE CASPro和SphygmoCor测量中心动脉压数值基本一致,相关性好,稳定性好。     

Validation of a brachial cuff-based method for estimating central systolic blood pressure

The prognostic value of central systolic blood pressure has been established recently. At present, its noninvasive assessment is limited by the need of dedicated equipment and trained operators. Moreover, ambulatory and home blood pressure monitoring of central pressures are not feasible. An algorithm enabling conventional automated oscillometric blood pressure monitors to assess central systolic pressure could be of value. We compared central systolic pressure, calculated with a transfer-function like method (ARCSolver algorithm), using waveforms recorded with a regular oscillometric cuff suitable for ambulatory measurements, with simultaneous high-fidelity invasive recordings, and with noninvasive estimations using a validated device, operating with radial tonometry and a generalized transfer function. Both studies revealed a good agreement between the oscillometric cuff-based central systolic pressure and the comparator. In the invasive study, composed of 30 patients, mean difference between oscillometric cuff/ARCSolver-based and invasive central systolic pressures was 3.0 mm Hg (SD: 6.0 mm Hg) with invasive calibration of brachial waveforms and -3.0 mm Hg (SD: 9.5 mm Hg) with noninvasive calibration of brachial waveforms. Results were similar when the reference method (radial tonometry/transfer function) was compared with invasive measurements. In the noninvasive study, composed of 111 patients, mean difference between oscillometric cuff/ARCSolver-derived and radial tonometry/transfer function-derived central systolic pressures was -0.5 mm Hg (SD: 4.7 mm Hg). In conclusion, a novel transfer function-like algorithm, using brachial cuff-based waveform recordings, is suited to provide a realistic estimation of central systolic pressure.     

Benefits from angiotensin-converting enzyme inhibitor 'beyond blood pressure lowering': beyond blood pressure or beyond the brachial artery?

OBJECTIVE: The substantial benefits of ramipril over conventional therapy in high-risk patients are not always associated with clinically significant differences in brachial arterial pressure, and largely remain unexplained. We undertook this acute study to establish the magnitude of and reason for different acute effects of ramipril and atenolol on arterial pressure. METHODS: We enrolled 30 patients, who took 10 mg ramipril, 100 mg atenolol, and placebo at intervals of > or = 7 days, in a randomized, double-blind, placebo-controlled trial. After baseline, measurements were taken at 30-60 min intervals for 5 h, and comprised cuff brachial pressure, radial artery tonometry with generation of central aortic pressure, and pulse wave velocity for aorta, upper limb and lower limb arteries. RESULTS: Both ramipril and atenolol reduced arterial pressure, and the diastolic pressure fall was similar in the aorta and brachial artery, but the systolic pressure fall for ramipril was greater than for atenolol (by 5.2 mmHg, P < 0.0001) in the aorta compared with the brachial artery. The aortic systolic pressure difference with ramipril in comparison with atenolol was accompanied by an absolute difference of 10.7% (P < 0.0001) in the augmentation index, denoting a reduction in peripheral wave reflection by ramipril. The aortic pulse wave velocity fell to a similar degree with ramipril in comparison with atenolol, but fell to a greater degree (1.35 and 0.44 m/s, respectively, P < 0.0001 for both) in muscular arteries of the lower and upper limbs. CONCLUSION: A greater (average, 5.2 mmHg) decrease in aortic systolic pressure caused by ramipril may explain the greater benefit of ramipril over atenolol. The difference is attributable to decreased stiffness of peripheral arteries and a reduction in wave reflection.     

An analysis of the relationship between central aortic and peripheral upper limb pressure waves in man

Amplification of the pressure pulse between central and peripheralarteries renders pressure values in the upper limb an inaccuratemeasure of ascending aortic (AA) pressure. Accuracy could beimproved by allowance for such amplification. Transfer functions (TF) for pressures between AA and brachialartery (BA): (BATF) and between AA and radial artery (RA): (RATF)were derived from high-fidelity pressure recordings obtainedat cardiac catheterization in 14 patients under control conditions,and after sublingual nitroglycerine 0.3 mg. There was no significantdifference in BATF under control conditions and with nitroglycerine;hence results were pooled. Control and nitroglycerine resultswere also pooled to obtain a single RATF. BATF and RATF modulipeaked at 5 Hz and 4 Hz, reaching 2.5 and 2.8 times the valueat zero frequency respectively. Frequency-dependent changesin modulus and phase of BATF and RATF were attributable to wavetravel and reflection in the upper limb. BATF and RATF werecompared to published transfer functions and those derived fromanalysis of aortic and brachial or radial pressure waves inprevious publications. Results were similar. Our BATF and RATFwere used to synthesize AA pressure waves from published peripheralpulses. Correspondence was close, especially for systolic pressurewhich d by 2.4 ± 1.0 (mean ± SEM) mmHg, whereasrecorded systolic pressure differed by 20.4 ± 2.6 (mean± SEM) mmHg between central and peripheral sites. Results indicate that in adult humans a single generalized TFcan be used with acceptable accuracy to determine central fromperipheral pressure under different conditions. While this processis capable of refinement, it represents an advance on the presentpractice of assuming that central and peripheral pressures areidentical.     

Effect of different antihypertensive drug classes on central aortic pressure

Central aortic systolic blood pressure (BP) is an important determinant of cardiac workload and cardiac hypertrophy. The relationship of central aortic systolic BP and brachial BP varies depending on the stiffness of blood vessels. It is not certain whether the different drug classes affect the brachial and aortic systolic BP in a similar manner.In a double-blind crossover study, we measured the effects of the four major drug classes compared with placebo on central aortic pressure. Central aortic pressure and various indices were determined using the Sphygmo Cor apparatus. The study was undertaken in patients aged 65 to 85 years with systolic BP >150 mm Hg at study entry. Results are reported for 32 patients who had satisfactory applanation tonometry in all five periods.Calcium channel blockers and diuretics caused a greater fall in brachial artery systolic BP than angiotensin-converting enzyme (ACE) inhibitors or beta-blocking drugs. On placebo, central aorta augmentation pressure and index were 23 mm Hg and 33.3%; on ACE inhibitors the values were 18 mm Hg and 30%; on beta-blockers, 26 mm Hg and 38.5%; on calcium channel blockers, 16 mm Hg and 28%; and on diuretics, 17 mm Hg and 28.8%. The augmentation pressure on beta-blocking drugs was greater than on the other three drug classes (P <.05), and augmentation pressures on ACE inhibitors, calcium channel blockers, and diuretics were less than on placebo (P <.05). The lowest central aortic pressures were achieved with calcium blocking drugs and diuretics.Therapy based on brachial artery recordings may thus overestimate the effect of beta-blocking drugs on central aortic systolic BP and underestimate the effectiveness of ACE inhibitors and calcium blocking drugs. The clinical importance of this discrepancy needs to be evaluated.     

Amplitude and timing of central aortic pressure wave reflections in heart transplant recipients

BACKGROUND: Hypertension (HTN) assessed by sphygmomanometer is a common finding in heart transplant recipients (HTR); however, little is known about the contribution of arterial wave reflection to central aortic pressure in these patients. The aim of this study was to measure the central aortic pressure wave in HTR on antihypertensive therapy and determine the effects of amplitude and timing of wave reflection on the various components of the wave. METHODS: A total of 53 stable adult HTR on antihypertensive medication underwent brachial artery blood pressure ([BP]; by sphygmomanometry) and central aortic pressure (by noninvasive radial artery applanation tonometry and use of a generalized transfer function) measurements at rest. Central aortic augmentation index (Ala), an indicator of arterial stiffness, was calculated from the aortic pressure waveform. Patients were divided into three groups (A, B, and C) based on the amplitude of AIa. RESULTS: Mean brachial BP was 136 +/- 15/84 +/- 9.4 mm Hg. Group A patients (n = 25) had a higher AIa (average 21% +/- 7.6%) than group B (n = 18, AIa = 6.5% +/- 3.0%, P < .001) or group C (n = 10, AIa = -8.7% +/- 8.1%, P < .001) patients. The amplitude of AIa was inversely related to the travel time (delta(t)p/2) of the reflected pressure wave from the periphery to the heart (r = -0.78, P < .001). Despite this clear stratification of patients by aortic pulse wave analysis, standard cuff pressure was similar among the groups. Conclusions: Noninvasive analysis of the central aortic PRESSURE wave identified a subgroup of hypertensive HTR with increased arterial stiffness, increased propagation of the reflected wave, and augmented aortic systolic and pulse pressure not identified with the sphygmomanometer.     

Mechanisms of pulse pressure amplification dipping pattern during sleep time: the SAFAR study

The difference in pulse pressure (PP) between peripheral arteries and the aorta, called pulse pressure amplification (PPamp), is a well-described physiological phenomenon independently associated with cardiovascular events. Recent studies suggest that it exhibits circadian variability. Our aim was to detect the factors associated with the circadian variability of PPamp. In 497 consecutive subjects (aged 54 years, 56.7% male, 79.7% hypertensives), we assessed the circadian pattern of peripheral and central arterial hemodynamics by 24-hour evaluation of brachial and aortic blood pressure (BP), augmentation index (AI), and pulse wave velocity (PWV) using a validated oscillometric device (Mobil-O-Graph). All parameters exhibited a circadian variation. Sleep dipping (decrease) pattern was observed for PPamp, brachial and aortic systolic BP, mean BP, and PWV, whereas a rising pattern (higher sleep than wake values) was observed for brachial PP, aortic PP, and AI. The factors independently associated with the less sleep dipping in PPamp were older age, lower height, the use of antihypertensive medication, and sleep decrease in arterial stiffness (PWV), whereas female gender, the presence of hypertension, sleep increase of pressure wave reflections (AI), sleep decrease in heart rate, and mean BP were associated with a greater sleep-dipping in PPamp. These data provide further pathophysiological understanding of the mechanisms leading to PPamp dipping. Several implications regarding the clinical use of the aortic and brachial BP, especially during sleep time, are raised that should be addressed in future research.     

Radial artery pulse pressure variation correlates with brachial artery peak velocity variation in ventilated subjects when measured by internal medicine residents using hand-carried ultrasound devices

BACKGROUND: Rapid prediction of the effect of volume expansion is crucial in unstable patients receiving mechanical ventilation. Both radial artery pulse pressure variation (DeltaPP) and change of aortic blood flow peak velocity are accurate predictors but may be impractical point-of-care tools. PURPOSES: We sought to determine whether respiratory changes in the brachial artery blood flow velocity (DeltaVpeak-BA) as measured by internal medicine residents using a hand-carried ultrasound (HCU) device could provide an accurate corollary to DeltaPP in patients receiving mechanical ventilation. METHODS: Thirty patients passively receiving volume-control ventilation with preexisting radial artery catheters were enrolled. The brachial artery Doppler signal was recorded and analyzed by blinded internal medicine residents using a HCU device. Simultaneous radial artery pulse wave and central venous pressure recordings (when available) were analyzed by a blinded critical care physician. RESULTS: A Doppler signal was obtained in all 30 subjects. The DeltaVpeak-BA correlated well with DeltaPP (r = 0.84) with excellent agreement (weighted kappa, 0.82) and limited intraobserver variability (2.8 +/- 2.8%) [mean +/- SD]. A DeltaVpeak-BA cutoff of 16% was highly predictive of DeltaPP > or = 13% (sensitivity, 91%; specificity, 95%). A poor correlation existed between the CVP and both DeltaVpeak-BA (r = - 0.21) and DeltaPP (r = - 0.16). CONCLUSIONS: The HCU Doppler assessment of the DeltaVpeak-BA as performed by internal medicine residents is a rapid, noninvasive bedside correlate to DeltaPP, and a DeltaVpeak-BA cutoff of 16% may prove useful as a point-of-care tool for the prediction of volume responsiveness in patients receiving mechanical ventilation.     

Evaluation of aortic distensibility with transesophageal echocardiography.

Distensibility of the descending aorta was evaluated during routine transesophageal echocardiography (TEE) in 50 subjects (16 to 80 years, average age 53). M-mode measurements of aortic systolic (SD) and diastolic diameter (DD) were taken distal to the left subclavian artery. Simultaneously, cuff brachial artery systolic (SBP) and diastolic (DBP) pressures were measured. Aortic pressure strain modulus (Ep), calculated as brachial artery pulse pressure/aortic strain, averaged 1.19 +/- 0.95 10(6) dynes/cm2. Elasticity index beta, defined as 1n (SBP/DBP)/aortic strain, averaged 3.77 +/- 2.12. Both Ep and beta were correlated with age (r = 0.65, p less than 0.001; and r = 0.70, p less than 0.0001). In 20 subjects aortic pulse wave velocity was assessed at the same time using simultaneous high fidelity recordings of carotid and femoral artery pressure waveforms. Aortic pulse wave velocity averaged 818 +/- 231 cm/sec and was correlated with Ep (r = 0.60, p less than 0.01) and with age (r = 0.55, p less than 0.05). Intraobserver and interobserver variability for aortic diameter measurement ranged from 0.2 to 0.5 mm.     

A New Noninvasive Device for Measuring Central Ejection dP/dt

The current study describes a new noninvasive device for measuring central ejection dP/dt (dP/dt_ejc). The device consists of a sphygmonometric arm cuff and an array of proprietary sensors attached to the arm at the antecubital space over the brachial artery, and a computerized monitoring system. Noninvasive systolic pressure wave forms are generated by measuring time delay between the first sensor on the array serving as a reference and onset of brachial artery flow in subsequent sensors during controlled upper arm deflation. The delay decreases with falling cuff pressure so that the plot of pressure versus time delays yields ascending portion of arterial wave form. The present study describes our initial experience in 16 patients with coronary artery disease undergoing percutaneous transluminal coronary angioplasty. Noninvasive measurements were performed at baseline, after balloon inflation and at the end of catheterization. Mean balloon occlusion time was 37 ± 10 s. In 14 of 16 patients, dP/dt_ejc decreased from 149 ± 29 to 120 ± 33 (p < 0.0002). In 11 of 14, an immediate return to near baseline values after deflation (136±28 p < 0.001) occurred.     

Beyond blood pressure: Arterial stiffness as a new biomarker of cardiovascular disease

Arterial stiffness of the large, elastic conduit arteries is considered a risk marker of vascular aging, as well as a new biomarker of cardiovascular (CV) disease. Arterial stiffness also plays an important role in the development of isolated systolic hypertension (ISH) in the middle-aged and elderly population. ISH is characterized by an increase in pulse pressure (PP) in association with a rise in systolic blood pressure (SBP) and a fall in diastolic blood pressure (DBP). Increased PP, however, is not always a good surrogate for arterial stiffening because of the frequent discrepancy between peripheral brachial and central aortic PP values due to varying pressure amplification. Therefore, noninvasive, easily performed methods for more direct measurement of arterial stiffness and wave reflection, such as aortic pulse wave velocity (PWV) and pulse wave analysis, have been developed for clinical use. The present review aims to provide an understanding of the pathophysiology of arterial stiffness and wave reflection, to review the various techniques for their measurement, and to explore their usefulness in predicting CV risk and therapeutic benefit in comparison with traditional brachial artery cuff blood pressure (BP) by sphygmomanometry.     

Nitroglycerin has more favourable effects on left ventricular afterload than apparent from measurement of pressure in a peripheral artery

Nitroglycerin (0.3 mg) was administered sublingually to 14 patients undergoing cardiac catheterization, and pressure waves compared in the ascending aorta and brachial artery. After nitroglycerin, ascending aortic systolic pressure fell in all cases (by 6-44, average 22 mmHg) whereas brachial systolic pressure remained unchanged (in three) or fell to a lesser degree (4-33, average 12 mmHg). Diastolic pressure did not change significantly. Alterations in pressure and in wave contour were explained on the basis of arterial dilation, with reduction in wave reflection. Nitroglycerin reduces left ventricular afterload through arterial dilation as well as preload through venous dilation. This effect on afterload is not apparent from measurement of pressure in the brachial artery.     

Noninvasive assessment of local pulse pressure: importance of brachial-to-radial pressure amplification

The advocated SphygmoCor procedure uses a radial-to-aorta transfer function with calibration on brachial instead of radial artery pressure to assess the central pulse pressure. We compared these values with carotid artery pulse pressures obtained from a validated calibration method, assuming mean minus diastolic blood pressure constant throughout the large artery tree. From 44 healthy subjects (21 males; 22 to 68 years) pressure waves were obtained at the radial, brachial, and carotid artery with applanation tonometry. Using the calibration method, radial and carotid artery pressures were assessed from brachial artery waves and pressures. The effect of brachial-to-radial pulse pressure amplification, brachial pulse pressure, mean pressure, age, gender, height, body mass index, and smoking on differences between the 2 methods was assessed. Brachial artery pressure was 118+/-12/72+/-10 mm Hg. SphygmoCor central pulse pressure was 9.7+/-4.6 mm Hg lower (P<0.001) than the carotid artery pulse pressure (33.0+/-6.8 versus 42.7+/-8.9 mm Hg). The difference between the 2 methods strongly depended (P<0.001) on brachial-to-radial artery pulse pressure amplification (5.8+/-5.1 mm Hg; 12+/-11%) and less on brachial artery pulse pressure (P=0.005). After calibration of the radial pressure wave with radial instead of brachial artery pressures, the difference between SphygmoCor central pulse pressure and carotid pulse pressure decreased with 4 mm Hg. The advocated SphygmoCor procedure systematically underestimates the central pulse pressure with brachial-to-radial pulse pressure amplification as important determinant. Therefore, calibration of radial artery pressure waves on brachial artery pressures should be avoided. The underestimation of central aortic pulse pressure caused by the radial-to-aorta transfer function itself is much less than previously reported.     

Tracking of brachial and central aortic systolic pressure over the normal human lifespan: insight from the arterial pulse waveforms

Despite multiple studies, it has not been possible to account for the normal changes of blood pressure that occur from infancy to old age. We sought a comprehensive explanation, by linking brachial pressure with the well documented changes in the arterial pulse waveform, whose peak and nadir determine systolic, diastolic and pulse pressure in brachial arteries. Changes in humans arterial pulse wave contour from birth to old age can be readily explained on (i) growth, with increasing length of the body from birth to adolescence, and adult height maintained thereafter, and (ii) degeneration and dilation of the aorta from elastic fibre fracture throughout life, causing progressive increase in aortic pressure wave amplitude from early return of wave reflection, and summation of incident with reflected waves in systole. These changes throughout life complement arterial pulse waveform analysis and explain brachial cuff pressure values, with optimal pulse wave pattern for cardiac interaction apparent in adolescence.