Post Occlusive Reactive Hyperaemia (PORH)

The increase in microvascular blood flow following arterial occlusion, Post Occlusive Reactive Hyperaemia (PORH), can be assessed using the non-invasive laser Doppler technique. Following release of the arterial occlusion there is a marked transient increase in microvascular blood flow to the ischaemic tissues.

Laser Doppler derived PORH measurements have been shown to be highly reproducible (Yvonne-Tee et al, 2005). The mechanisms behind PORH are believed to be a combination of: myogenic relaxation of the vessels (Patterson, 1956), release of local mediators and metabolites from the ischaemic tissue (Kontos et al, 1965) and more recently the involvement of sensory nerves (Minson & Lorenzo, 2007). As a result of unknown mechanisms behind PORH there is extensive research in this area. Previous studies have shown the PORH response to ischaemia shows distinct patterns that are associated with cardiovascular risk i.e. area under curve (AUC) and peak flux following the period of ischaemia (Strain et al, 2005. Yamamoto-Suganuma et al, 2009).

The moorVMS-VASC system enables rapid, reproducible and user-friendly measurement of PORH. The user friendly PC software enables protocols to be written which exactly match user requirements for individual experimental conditions – whilst allowing your institution to create, save and repeat an assessment specifically designed for your institution easily enabling a reproducible method to be performed.

Equipment Recommendations

We recommend the moorVMS-VASC PC software to streamline the measurement and analysis together with a single or dual channel moorVMS-LDF monitor and multi-fibre skin probes (VP1T/7). The CUFF-Arm (or CUFF – Arm RD) can be used on the ankle and forearm, although a full range is available to accommodate a range of limb sizes. The moorVMS-PRES provides automation of the cuff inflation / deflation protocol.

Vascular Monitoring System

Non-invasive assessment of micro-vascular blood flow in response to standard, and your custom, pressure cuff inflation protocols


moorVMS-VASC - Non-invasive assessment of micro-vascular blood flow in response to standard, and your custom, pressure cuff inflation protocols
moorVMS-LDF - Advanced, laser Doppler blood flow and temperature monitor
moorVMS-PRES - Automatic pressure cuff control for routine microvascular testing
VP1T/7 - A combined temperature and optic probe that delivers light at a right angle to the probe cable with 8 collecting fibres in a 2mm ring with a central delivery fibre
CUFF-ARM - Arm Pressure Cuff (Adult) with airline and quick fit connector.
CUFF-ARM-RD - Rapid deflation arm pressure cuff with airline and quick fit connector

What Next?

Contact us to discuss your specific needs and to request your copy of our free Application Note which includes a detailed experimental method and practical suggestions. We also offer no obligation on-site visits so you can test the equipment in your facility.


American Diabetes Association, 2003.
Peripheral arterial disease in people with diabetes.
Diabetes care, V26 (12), pp3333- 3341.

Hyun S., Forbang N., Allison M. A., Denenberg J. O., Criqui M. H., Ix J. H. 2014.
Ankle brachial index, toe brachial index and cardiovascular mortality in persons with and without diabetes mellitus.
Original Research Article. Journal of Vascular Surgery, In Press, Corrected Proof, Available online 21 March 2014.

Potier L., Abi Khalil C., Mohammedi K., Roussel R. 2011.
Use and Utility of Ankle Brachial Index in Patients with Diabetes. Review Article.
European Journal of Vascular and Endovascular Surgery, V41 (1), pp110-116.