Measuring blood pressure invasively can be performed from different locations, such as one of the radial arteries. How much impact does the location of an invasive measurement have on the quality of the obtained blood pressure signal? I am looking for a quantified answer.
What is an appropriate site [for a properly performed invasive measurement]? It has been shown by many investigators that invasive pressure is greatly influenced by the measurement site. Systole in particular changes as the site in moved from the aorta away from the heart towards the extremity. Usually it is a surprise to the newcomer to this field that systole increases as one moves down the arterial stream. This increase (systolic heightening) is caused by the reflection of the incidence waveform adding to the pressure. The amount of this increase depends on the transmission speed of the artery, which is affected by the arterial compliance. Hard arteries produce more heightening than compliant arteries.
The pressure in the aorta is not much influenced by reflections, and may be the best indication of "true" blood pressure. Unfortunately this is a very difficult place to measure blood pressure except when undergoing cardiac evaluation or surgery, and there are no population studies to indicate the cardiovascular risk factors.