For more than 100 years, physicians have relied on the systolic and diastolic pressures measured with a brachial cuff sphygmomanometer to manage their patients. However, blood pressure in the brachial artery can be very different from the pressure in the aorta at the heart. Numerous studies have shown that the central aortic blood pressure explains differential effects of anti-hypertensive drugs and predicts clinical outcomes significantly better than brachial pressure.

Today, technology allows for the noninvasive measurement of the central aortic pressure waveform with the same fidelity as a pressure catheter placed in the ascending aorta, without the associated costs and risks. The predictive superiority of central arterial pressure waveform analysis over brachial blood pressure is primarily due to the closer proximity of the ascending aorta to important target organs such as the heart, brain, and kidney.1

Three aspects of central arterial pressure waveform analysis are especially important:

  • Individual variability in the difference between central and brachial pressures can be significant and clinically important.2,3,4 Central pressures cannot be reliably inferred from brachial pressures.2,3,4
  • Medications may have significantly different effects on brachial blood pressure than on the central arterial pressure waveform5,6,7.

SphygmoCor products allow for noninvasive assessment of the central arterial pressure waveform, measures of arterial stiffness and autonomic function – providing noninvasive measurement of pressure that the heart, brain and kidneys actually experience.

Noninvasive Central Arterial Pressure Waveform Analysis

Central systolic blood pressure cannot be estimated from the brachial systolic value. In one study of more than 10,000 adults aged 18 to 101 years, McEniery et al. reported individual brachial systolic pressures that ranged from 100 to 200mmHg. They found individual variability between brachial and central systolic pressures ranging from as few as 2-3mmHg to approximately 30mmHg. Because of individual variability, a patient’s central pressure cannot be reliably inferred from his or her brachial pressure measurement.

The SphygmoCor XCEL System derives the central aortic pressure waveform using a blood pressure cuff.  As in tonometer-based SphygmoCor systems, a generalized transfer function is used to derive the central aortic pressure waveform and corresponding indices (Figure 1). The SphygmoCor XCEL was cleared by the US Food and Drug Administration as substantially equivalent to previously validated SphygmoCor systems which were originally validated against an indwelling catheter.8,9,10 The procedure can be conducted in the office setting and is easy to perform, painless and reproducible.

Over 1,000 published clinical studies have featured SphygmoCor® noninvasive central arterial pressure waveform analysis technology. Major independent studies such as the Conduit Artery Function Evaluation (CAFE) Study, the Strong Heart Study and the Anglo-Cardiff Study have demonstrated that noninvasive central pressure measurement provides important data that cannot be obtained with standard brachial cuff blood pressure measurement.



  1. Hashimoto J. Tohoku J Exp Med 2014;233:1-8.
  2. O’Rourke et al. Br J Clin Pharmacol 2001;51:507-22.
  3. Sharman JE et al J Hum Hypertens 2008; Dec 22(12):838-844.
  4. McEniery et al Hypertension 2008; 6(51):1476-1482.
  5. Protogerou, AD et al. Curr Pharmaceut Des 2009; 15:272-289.
  6. McEniery, CM. Current Hypertension reports, 2009; 11:253-259.
  7. Townsend, RR et al. J Clin Hypertens 2015 Jul; 17(7):503-13.
  8. Chen CH et al. Circulation 1997; 95(7):1827-36.
  9. Pauca AL et al. Hypertension 2001; 38:932-937.
  10. Sharman JE et al. Hypertension 2006; 47:1203-1208.