4. Patients and Users
The use of the device is indicated in all age groups. Subjects at risk for premature vascular aging, young
people with isolated systolic hypertension and adults at cardiovascular risk.
Patient selection criteria:
Subjects of all ages at risk for premature vascular aging.
Young subjects with isolated systolic hypertension.
Cardiovascular risk subjects in which subclinical vascular damage is hypothesized.
Pregnancy and breastfeeding are not a contraindication to the use of the device.
The neonatal age does not constitute a contraindication to the use of the device.
The user of the medical device is exclusively a professional user to be identified in personnel with a degree
in medicine and surgery / master's degree in nursing sciences or equivalent qualifications in various
countries, who are familiar with the "applanation tonometry" method. It is intended for use in hospitals,
medical clinics or research centers.
It is not considered necessary to provide specific training for users, as the User Manual contains all the
instructions for use.
5. Principle of Operation
The operation of the medical device is based on the method of "applanation tonometry" which consists in
exerting a slight pressure on a superficial artery from the outside, so that the artery flattens itself slightly
against rigid or semi-rigid structures (bone , muscle, ...) below. In an ideal equilibrium situation (left figure)
the internal arterial pressure (Pi) is equal to the external one (Pe). The pressure is detected by a sensor
placed at the end of the wTn1 Unit, which is also called "tonometric probe" or "tonometer" in the rest of
the documentation. The pressure signal obtained from the sensor, appropriately amplified and digitized, is
continuously acquired by the wTn1 Tonometric unit and graphically presented to the user on the computer
screen to which the medical device is connected.
In the real situation, it is necessary to consider the
presence of the skin and the superficial layers between the
sensor and the artery under examination (indicated with
Skin in the figure): in this case the internal arterial pressure
(Pi) is different from the external one (Pe). In fact, to
flatten the artery it is necessary to exert an extra pressure
from the outside that deforms the skin and the
intermediate layers and furthermore the pulsatory
pressure inside the artery is transmitted outwards
attenuated by the intermediate layers themselves.
The mechanical characteristics of the skin, such as
elasticity, thickness, consistency, ..., vary from patient to
patient, with age, etc. and it is for this reason that a
transcutaneous arterial tonometer is not able to establish
the exact values of the systolic and diastolic blood pressure while preserving an identical morphology of
the pressure curve.
Consequently, it is necessary to carry out a calibration at each examination using a traditional
