transfer function can give parameters for the curve which can provide very sensitive differentiation between states of vessel segments tested the device can be arranged to compare one or more of such parameters with predetermined values to provide an indication to a clinician as to whether or not a patient is to be considered at risk such analysis techniques can be readily automated of course by use of the appropriately programmed pc 27 in fig1 as explained earlier the invention envisages the simultaneous use of two cuffs which represents a considerable advance over the sequential use of a single cuff as available currently on the pvl 50 with a single cuff it is necessary sequentially to cuff and wake recordings at the proximal and distal sites store the pvrs produced and then initiate the analysis simultaneous recording by two cuffs at the two sites thus affords a valuable time saving moreover the pvrs taken sequentially are less likely to be directly comparable even if averaged over a certain train of pulses than pvrs taken of the same pulse or pulses the use of simultaneous recording therefore reduces possible error in the resulting pulse volume transfer analysis only one fourier transform analyser is required for this as the pvrs representing the two sites can be multiplexed to the single analyser additionally this two cuff arrangement allows the provision of information regarding the pulse time delay between sites which can also be of use in assessing the condition of the intermediate vessel segment the invention has been illustrated with reference to brachial femoral transfer function analysis in respect of the iliac segment clearly though it may be applied to any other sites and or in respect of other vessel segments where a pvr can be obtained a multiplicity of cuffs can be.