Skin perfusion pressure

SPP probes placed on the plantar

Skin perfusion pressure (SPP) is a diagnostic exam for assessing blood pressure in the microcirculatory system. It emerged as a clinical protocol in the 1960s . Since then, advances in technology have transformed SPP from a complex and invasive procedure to the noninvasive and easy-to-perform exam it is today.

SPP values are primarily used as an aid in wound-healing prognosis — especially diabetic foot ulcers (DFUs). SPP values taken before and after revascularization help clinicians assess the effectiveness of surgery.

Measurement techniques have evolved over time, but today, laser Doppler — which assesses the movement of red blood cells in the capillaries and small arteries — has become the most widely used technology for measuring SPP.

SPP in practice

SPP can be measured at multiple sites: on the foot (plantar, dorsal, and toes), on the ankle, and above and below the knee. Blood flow is occluded by placing a pressure cuff over an SPP probe and inflating it above the patient’s resting systolic pressure. The cuff is then gradually deflated until microcirculatory flow returns — this is the SPP value and is measured in millimeters of mercury (mmHg).

Application of skin perfusion presure

To determine the best course of treatment and address the complexity posed by individuals with diseases like diabetes and peripheral artery disease (PAD), modern guidelines include recommendations for multiple macro- and microcirculation measurements. In isolation, ankle-brachial index (ABI), for example, is not a reliable measurement for patients with diabetes, as they are misleading in up to 50% of cases .

For vascular diseases, toe pressure, skin perfusion pressure (SPP), and transcutaneous oxygen pressure (TcpO2) are among the exams recommended for diagnosis, prognosis, treatment, and follow-up. Both SPP and TcpO2 are invaluable aids in the assessment of patients whose ankles are non-compressible or whose toes have been amputated .

While both protocols provide insight into the status of a person’s microcirculatory system, the condition of the patient usually guides the choice of exam.

Interpreting SPP results

The 2023 update of the IWGDF guidelines, includes SPP values for wound-healing prognosis, stating that values ≥ 40 mmHg can increase the probability of healing by up to 30%. The main advantage of SPP is that it is not affected by vascular calcification or anatomical structure.

References

  1. 1 2 Nilsén, R.; Dahn, I.; Lassen, N. A.; Westling, H. (1967). "On the estimation of local effective perfusion pressure in patients with obliterative arterial disease by means of external compression over a Xenon-133 depot". Scandinavian Journal of Clinical and Laboratory Investigation. Supplementum. 99: 29–30. ISSN 0085-591X. PMID 6056929.
  2. ↑ Urabe, Go; Yamamoto, Kota; Onozuka, Atsuko; Miyata, Tetsuro; Nagawa, Hirokazu (2009). "Skin Perfusion Pressure is a Useful Tool for Evaluating Outcome of Ischemic Foot Ulcers with Conservative Therapy". Annals of Vascular Diseases. 2 (1): 21–26. doi:10.3400/avd.oa08029. ISSN 1881-641X.
  3. 1 2 Pan, Xuanliang; Chen, Guoxian; Wu, Pan; Han, Chunmao; Ho, Jon Kee (2018-04-01). "Skin perfusion pressure as a predictor of ischemic wound healing potential (Review)". Biomedical Reports. 8 (4). Spandidos Publications: 330–334. doi:10.3892/br.2018.1064. ISSN 2049-9434. PMC 5838289. PMID 29541454.
  4. 1 2 "IWGDF Guidelines – International Working Group on the Diabetic Foot". Retrieved 2026-10-28.
  5. ↑ Conte, Michael S.; Bradbury, Andrew W.; Kolh, Philippe; White, John V.; Dick, Florian; Fitridge, Robert; Mills, Joseph L.; Ricco, Jean-Baptiste; Suresh, Kalkunte R.; Murad, M. Hassan; GVG Writing Group (2019-06-01). "Global vascular guidelines on the management of chronic limb-threatening ischemia". Journal of Vascular Surgery. 69 (6S): 3S–125S.e40. doi:10.1016/j.jvs.2019.02.016. ISSN 1097-6809. PMC 8365864. PMID 31159978.
  6. ↑ Mills, Joseph L.; Conte, Michael S.; Armstrong, David G.; Pomposelli, Frank B.; Schanzer, Andres; Sidawy, Anton N.; Andros, George; Society for Vascular Surgery Lower Extremity Guidelines Committee (2014-01-01). "The Society for Vascular Surgery Lower Extremity Threatened Limb Classification System: risk stratification based on wound, ischemia, and foot infection (WIfI)". Journal of Vascular Surgery. 59 (1): 220–234.e1–2. doi:10.1016/j.jvs.2013.08.003. ISSN 1097-6809. PMID 24126108.
  7. ↑ Salaun, Pierre; Desormais, Ileana; Lapébie, François-Xavier; Rivière, Alessandra Bura; Aboyans, Victor; Lacroix, Philippe; Bataille, Vincent; Constans, Joël; Boulon, Carine (2019-03-01). "Comparison of Ankle Pressure, Systolic Toe Pressure, and Transcutaneous Oxygen Pressure to Predict Major Amputation After 1 Year in the COPART Cohort". Angiology. 70 (3): 229–236. doi:10.1177/0003319718793566. ISSN 1940-1574. PMID 30114947.
  8. ↑ Poredos, P.; Rakovec, S.; Guzic-Salobir, B. (2005-05-01). "Determination of amputation level in ischaemic limbs using tcPO2 measurement". VASA. Zeitschrift fur Gefasskrankheiten. 34 (2): 108–112. doi:10.1024/0301-1526.34.2.108. ISSN 0301-1526. PMID 15968892.
  9. ↑ Bunt, T. J.; Holloway, G. A. (1996-05-01). "TcPO2 as an accurate predictor of therapy in limb salvage". Annals of Vascular Surgery. 10 (3): 224–227. doi:10.1007/BF02001886. ISSN 0890-5096. PMID 8792989.