Usefulness of photoplethysmography and digital pressure indexes in the Raynaud's phenomenon

BACKGROUND: TO know the usefulness of plethysmography and digital pressure indexes (DPI) to assess the vasospasm and the response to medical treatment in patients with Raynaud's phenomenon. PATIENTS AND METHODS: During a four-month period, we carried out a prospect ive clinical trial, with a control group (15 subjects) and other of patient s with Raynaud's phenomenon (40 patients). We calculated the digital pressu res, plethysmography and the DPI, in basal status and after provacation wit h cold water. The Raynaud's group was divided randomly in two homogeneous s ubgroups of 20 subjects. One of the groups underwent treatment with calcium antagonists and the other group with placebo. These determinations were re peated at the middle and at the end of the treatment. RESULTS: The basal DPI and after provocation test were lower in the Raynaud 's group (0.61 ESD 0.26] and 0.25 [SD 0.26]), than in the control group (0. 93 [SD 0.06] and 0.88 [SD 0.07]), with a statistical significance (p < 0.00 1 and p < 0.0001). After the treatment, in the subgroup treated with calciu m antagonists, the DP[ were increased in a statistically significative way respect to those in the placebo subgroup (p < 0.0001). Sensitivity and spec ificity of the DPI associated to the provocation test were of 97 and 93%, r espectively. The plethysmographic wave did not suffer significant variation s; sensibility and specificity were 48 and 100%. CONCLUSIONS: In the Raynaud's phenomenon the DPI associated to the provocat ion test have a high sensitivity and specificity, and allows determination of the degree of vasospasm and the response to treatment.