Blood pressure variability between radial artery and finger is influenced by haemodynamic factors, age and insulin resistance

In clinical practice, blood pressure (BP) is typically assessed using brachial measurements, whereas finger plethysmography is widely used in vascular physiology research. However, agreement between BP levels at the finger and more proximal sites is not straightforward because of interindividual differences in BP gradients along the arterial tree.

We investigated factors associated with the mean arterial pressure (MAP) difference between non-invasive radial artery and finger measurements in 574 normotensive and hypertensive individuals without cardiovascular disease, diabetes or antihypertensive medication. Recordings included pulse wave analysis from radial BP, plethysmographic finger BP and whole-body impedance cardiography. Radial BP signals were calibrated using oscillometric contralateral brachial artery measurements.

Simultaneous mean radial and finger BP (systolic/diastolic) were 131/75 and 122/69 mmHg, respectively (p < .001). When examined in quartiles of the radial-finger BP gradient, the average MAP difference was -7, 4, 10 and 20 mmHg, respectively. In linear regression analysis (enter method), a greater MAP difference was significantly associated with higher radial MAP (p < .001), age (p = .001) and stroke index (p = .015); and with lower pulse wave velocity (p < .001), pulse pressure amplification (p = .002) and insulin sensitivity check index (p = .022).

High MAP is a major factor contributing to greater BP difference between the radial and finger sites. However, the difference is also more pronounced in the presence of lower large artery stiffness, lower pulse pressure amplification, and higher stroke index, older age and greater insulin resistance.