An objective hemodynamic assessment is mandatory to confirm critical limb ischemia (CLI). Toe pressure measurement is recommended. The laser Doppler (LD) is considered as the method of choice but the device is not always available in routine. More accessible devices using photoplethysmography (PPG) have been validated for the diagnosis of lower extremity artery disease, but have not been assessed in a population with a CLI clinical presentation to confirm CLI diagnosis.

We compared toe measurements obtained using the LD method (PERIMED PeriFlux, Sweden) considered as the reference test, with those obtained with a portable device using PPG (Sys Toe Atys Medical, France).

A total of 93 (123 legs) patients from 3 French hospitals with a clinical suspicion of CLI were included and had measurements with each device carried out by skilled operators. PPG was unable to provide a measurement in 10 patients. Lin's Coefficient correlation concordance (CCC) and Bland and Altman's scatter plot were analyzed for the 83 remaining patients, CCC was 0.84 95% CI (0.77–0.89). For detection of CLI, Cohen's kappa was 0.67 95% CI (0.53–0.81).

The PPG device is fairly reliable for toe pressure measurement in patients suspected of CLI and could be useful when LD is not available. However, it fails to deliver a measurement in approximately 10% of cases.

PPG devices can be used to confirm CLI diagnosis but are not fully interchangeable with LD devices. No conclusion should be made when no measurement is obtainable with PPG and other methods should be used when possible (LD, transcutaneous oxygen pressure) to better assess perfusion of the limbs.