AngioExpert is a medical device which uses the FMSF-PORH method to evaluate microvascular circulation.

AngioExpert is intended for non-invasive monitoring of microcirculation, metabolic regulation and vascular complications in diabetes.


The optical head of the AngioExpert is now based on photodiode technology. Two diodes are used, the first as a source of exciting light (LED) and the second as a fluorescence detector. A set of filters incorporated into the optical head ensures proper selection of excitation light for NADH (340 nm) and detection of fluorescence (460 nm). This solution allows for enhanced miniaturization and reduced signal noise.

Block scheme for AngioExpert device utilizing FMSF.

Front (a) and back (b) views of the commercial AngioExpert medical device.


Lifestyle-related diseases (so-called diseases of civilization), including cardiovascular disease, cancer and neurodegenerative diseases (such as Alzheimer’s disease), continue to affect growing numbers around the world. Many national health programs define diseases of civilization as the most serious threat to their populations’ quality of life. According to global statistics, ischemic heart disease is the most common cause of death and the main reason for hospitalization, followed by cancer (malignant tumors). The prevention and treatment of such diseases is one of the most important challenges for the future, and has become part of strategic research plans. There is therefore a need for extensive cooperation between science and industry to develop the most effective (especially non-invasive) solutions for early diagnosis and monitoring of patient health.

What is measured?

  • Flow Mediated Skin Fluorescence (FMSF) is a technique based on the measurement of NADH fluorescence from skin tissue cells.
  • Nicotinamide adenine dinucleotide (NADH) and its oxidized form (NAD+) play a crucial role in biological systems as redox coenzymes.
  • The NADH/NAD + pair is the carrier of electrons in the respiratory chain of each living cell.

Chemical structures of NADH and NAD+.


  • Although NADH emits significant fluorescence, this is not the case with NAD+.

Absorption and emission properties of NADH/NAD+ couple.
(a) Electronic absorption spectra of NADH and NAD+.
(b) Normalized absorption and fluorescence spectra of NADH.


  • The fluorescence from NADH is the strongest component of the overall fluorescence emitted from human skin.
  • The penetration depth of excitation light for NADH (340 nm) in skin tissue is low (about 0.5 mm), therefore a substantial fraction is absorbed by the epidermis and papillary dermis.
  • In these skin regions, the density of blood microvessels is low and the changes in NADH fluorescence depend on the supply of oxygen diffused from deeper layers.

How is it measured?

  • The FMSF technique measures changes in the intensity of NADH fluorescence from the skin on the forearm as a function of time, in response to blocking and releasing blood flow in the forearm.
  • Blood flow in the forearm is blocked using a typical occlusion cuff, as used to measure blood pressure.

Advantages of FMSF method:

  • useful for assessing circulatory status by comparing the vascular response to reactive hyperemia (PORH) to the resting state (before occlusion),
  • suitable for assessing the degree of ischemia and reperfusion in skin cells depending on blood flow in the vessels,
  • useful for assessing the progress and remission of microcirculation disorders, metabolic regulation and vascular complications,
  • optimal for the observation of microcirculation oscillations, the amplitude and frequency of which may signal irregularities in the microcirculation,
  • helpful for monitoring vascular circulation disorders and selecting individualized forms of therapy.


The FMSF method enables disorders to be detected at an early stage of development and monitoring of the treatment process. It helps to identify patients in possible need of preventive or therapeutic interventions, who may be referred for further diagnosis.

The FMSF method has intellectual property protection, including in the following countries: EU, USA, Canada, China, Japan, Australia, Russia.

The first test implemented by Angionica is the FMSF–PORH test (Flow Mediated Skin Fluorescence–Post-Occlusive Reactive Hyperemia), which is used to assess microvascular circulation (vascular endothelial function) based on circulatory stimulation in response to induced reactive hyperemia (PORH). The test makes it possible to assess levels of both contraction and vasodilation and to follow the kinetics of changes in response to reactive hyperemia. In general, the FMSF-PORH test enables identification of patients requiring prophylactic or therapeutic interventions, and more accurate and complex diagnostic tests. It also facilitates monitoring of the treatment process, the influence of drugs on the condition of vessels and the effects of training and physical exertion on overall health.

Main parts of a typical trace recorded for an individual patient using AngioExpert

  • Baseline – collected for 3 min (or 4 min if unstable).
  • Ischemic response (IR) – 3 min occlusion with cuff inflated to 60 mmHg above systolic blood pressure, resulting in an increase of NADH fluorescence.
  • Hyperemic response (HR) caused by releasing pressure in the occlusion cuff – NADH fluorescence decreases below the baseline, reaching a minimum followed by a return to the baseline.
  • Hyperemic response (HR) with two distinct phases:
    1) hyperemia – related to a sharp drop in NADH fluorescence for 20–30 s;
    2) reperfusion – a much slower return to the baseline.

Definition of measured parameters

Hyperemic response parameters HRmax and HRindex express changes in NADH fluorescence (mainly from the keratinocytes in the epidermis) and determine the metabolic reaction of the skin cells to hyperemia and reperfusion.
Ischemic response parameters IRmax and IRindex express changes in NADH fluorescence (mainly from keratinocytes in the epidermis) and determine the sensitivity of skin cells to hypoxia caused by blocking blood flow in the forearm. This sensitivity is determined primarily by the efficiency of oxygen transport to the epidermal cells just before occlusion.

Definition of the measured parameters, (a) IRmax and HRmax (b) IRindex and HRindex.


Interpretation of the measured parameters

  • HRmax refers to the efficacy of oxygen supply to the epidermis during hyperemia via skin microcirculation and can be treated as an indirect measure of NO bioavailability in the microcirculation.
  • HRindex refers to the recovery of metabolic status in the epidermis following hyperemia caused by the release of pressure in the occlusion cuff.
  • HRmax and HRindex are key parameters demonstrating the diagnostic power of the FMSF technique.
  • Parameters IRmax and IRindex are sensitive to deviations from the measurement procedure and carry auxiliary diagnostic significance.
  • Microvascular oscillations on the baseline and the hyperemic response line express the efficacy of vascular-metabolic regulation related to microvascular dermal flow. A weakening of their amplitude and changes in frequency may indicate the presence of microvascular dysfunction.

Threshold values of the key parameters for diabetes

Based on the results of tests and experiments, threshold values have been established indicating serious disorders in microvascular and metabolic regulation and signaling the risk of vascular complications in diabetes patients.
The HRindex parameter has particularly high diagnostic sensitivity and specificity for assessing the risk of developing vascular complications:

The FMSF technique enables early diagnosis of dysfunction and disturbances in vascular circulation and metabolic regulation. It is therefore suitable for monitoring diabetes at intervals adjusted to the individual patient’s needs and on the basis of medical consultations. The FMSF method is applicable to both type 1 and type 2 diabetes. The manufacturer recommends repeating the test annually or more frequently when significant changes in the HRindex parameter are observed, subject to medical advice.

Advantages of the FMSF technique:

  • enables early diagnosis of dysfunctional vascular circulation,
  • identifies diabetic patients at risk of vascular complications at an early stage,
  • assesses the risk of metabolic disorders in patients with type 1 diabetes,
  • assesses the risk of serious cardiovascular complications in patients with type 2 diabetes,
  • is recommended for monitoring patients with diabetes over time to enable early identification of dysfunction and disturbances in vascular circulation and metabolic regulation.


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Provides a simple and non-invasive procedure
for identifying patients at increased risk of vascular complications.
Helps detect vascular circulation dysfunction
at an early stage.
Suitable for use by diabetologists,
cardiologists and general practitioners.
Supports treatment selection
and monitoring of treatment response.


Angionica Ltd. is a spin-off company whose main goal is the implementation of the innovative Flow Mediated Skin Fluorescence (FMSF) method developed by Lodz University of Technology (TUL) and the Jagiellonian University (UJ).

FMSF is a new diagnostic method based on photodiode technology, protected by international patents in the world’s major markets.

The FMSF technique is intended for use in everyday clinical practice to assess microvascular circulation and disorders caused by lifestyle-related diseases.

ISO 13485:2016

Angionica Ltd. has implemented and maintains Quality management system in accordance with PN-EN ISO 13485:2016-04 – Medical devices – Quality management systems – Requirements for regulatory purposes.


MDD 93/42/EEC

Angionica Ltd. has established a quality system for design, production and final testing of AngioExpert according to the requirements of the Medical Device Directive 93/42/EEC.











This work was supported by the European Union under the European Regional Development Fund as part of the Smart Growth Operational Program, Grant No. POIR. 01.01.01-00-0540/15-00.


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