An objective method to estimate the severity of Raynaud phenomenon: digital blood pressure response to cooling.

The treatment efficacy of patients with Raynaud phenomenon (RP) is determined from the decrease in severity of this condition, usually based on a decrease in frequency of RP attacks as reported by patients in a diary. Although subjective, this method is still the main endpoint measure in clinical trials. The results of patients' digital blood pressure responses to cooling were compared with the reported RP attack frequency to determine whether the former could be used to estimate the severity of RP. The effect of local finger cooling on the digital systolic blood pressure was tested at 30 degrees C, 20 degrees C, 15 degrees C and 10 degrees C on 136 subjects with RP. The RP attack frequency was dichotomized into daily versus less than daily attacks. The frequency of attacks and the digital systolic pressure (DSP) showed a significant association at all cooling temperatures (those with daily attacks showed lower DSP than those with less frequent attacks). In addition, patients experiencing daily attacks of RP showed a zero reopening pressure at higher local temperatures than those with less frequent RP attacks. These results demonstrate that the response of the digital systolic blood pressure to cooling is closely associated with the RP attack frequency and therefore can be considered as an objective estimate of RP severity. This physiological measurement should be most useful in evaluating the clinical course of RP and the effect of its treatment, provided it is measured under standardized conditions.

Digital vascular responses to cooling in subjects with cold sensitivity, primary Raynaud's phenomenon, or scleroderma spectrum disorders.

OBJECTIVE: To define differences in digital vascular responses to cooling and to determine their usefulness for the differential diagnosis of 4 groups of subjects: patients with primary Raynaud's phenomenon (RP) (n = 96), patients with RP associated with scleroderma (systemic sclerosis, SSc) spectrum disorders (SSc spectrum RP) (n = 108), subjects complaining of cold sensitivity of the fingers (n = 88), and RP negative controls (n = 120). METHODS: Digital systolic blood pressure, digital blood flow, and digital skin temperature were measured in a temperature controlled room at 18 or 23 degrees C; the effect of local finger cooling was tested at 30, 20, 15, and 10 degrees C. RESULTS: Digital blood pressure responses clearly differentiate the 4 diagnostic groups from each other. By contrast, blood flow and skin temperature measurements, although showing different group means, fail to reach statistical significance due to a large variance. Digital pressure responses have high sensitivity and specificity for distinguishing not only between patients with RP and controls, but also between the 2 types of RP. A relative digital systolic pressure (digital systolic pressure over brachial systolic pressure) of less than 70% at low local finger cooling temperatures (15 and 10 degrees C) has a sensitivity of 97.1% in differentiating SSc spectrum RP from primary RP. A zero reopening pressure shows a specificity of 100% at 30 degrees C and 81.7% at 20 degrees C to separate the 2 groups. The zero reopening pressure is seldom associated with clinically visible RP (10.3% among SSc spectrum RP, 4.3% among primary RP). Although the study was not designed to investigate drug effects, our data from patients who failed to abstain from vasodilators, as instructed, show they have a protective effect at 15 and 10 degrees C. CONCLUSION: The digital pressure response to cooling is a useful test for RP and cold sensitive subjects. It has high sensitivity and specificity to differentiate between SSc spectrum RP and primary RP and between primary RP and cold sensitive subjects. Our preliminary data on vasodilator use suggest that the digital pressure response to cooling may also be useful in RP treatment studies.

Digital pressure responses to cooling in patients with suspected early vs definite scleroderma (systemic sclerosis) vs primary Raynaud's phenomenon.

OBJECTIVE: To compare digital vascular responses to local finger cooling in 4 groups of subjects: patients with definite scleroderma (SD, systemic sclerosis) meeting ARA criteria (n = 16), patients with suspected early SD (n = 12), patients with primary Raynaud's phenomenon (RP) (n = 23) and a control group of 29 healthy subjects. METHODS: Their digital systolic pressures were measured at 30, 20, 15 and 10 degrees C finger cuff temperature, in a room kept at 18 degrees C. RESULTS: The results of the digital pressure measurements showed a clearcut difference between the SD, primary RP and control groups, but there was no difference between patients with definite SD and those with suspected early SD. CONCLUSION: Under our experimental conditions, digital pressure response to local cooling separates groups of patients with primary RP and those with secondary RP related to SD from each other and from controls. The similarity between digital pressure responses of patients with suspected early SD and those with definite SD, suggests an early organic involvement of the digital vasculature in SD.