Reliability of Widefield Nailfold Capillaroscopy and Videocapillaroscopy in the Assessment of Patients With Raynaud's Phenomenon

ObjectiveTo analyze the diagnostic performance and reliability of different parameters evaluated by widefield nailfold capillaroscopy (NFC) with those obtained by videocapillaroscopy in patients with Raynaud's phenomenon (RP). MethodsTwo hundred fifty-two individuals were assessed, including 101 systemic sclerosis (SSc; scleroderma) patients, 61 patients with undifferentiated connective tissue disease, 37 patients with primary RP, and 53 controls. Widefield NFC was performed using a stereomicroscope under 10-25x magnification and direct measurement of all parameters. Videocapillaroscopy was performed under 200x magnification, with the acquirement of 32 images per individual (4 fields per finger in 8 fingers). The following parameters were analyzed in 8 fingers of the hands (excluding thumbs) by both methods: number of capillaries/mm, number of enlarged and giant capillaries, microhemorrhages, and avascular score. Intra- and interobserver reliability was evaluated by performing both examinations in 20 individuals on 2 different days and by 2 long-term experienced observers. ResultsThere was a significant correlation (P < 0.000) between widefield NFC and videocapillaroscopy in the comparison of all parameters. Kappa values and intraclass correlation coefficient analysis showed excellent intra- and interobserver reproducibility for all parameters evaluated by widefield NFC and videocapillaroscopy. Bland-Altman analysis showed high agreement of all parameters evaluated in both methods. According to receiver operating characteristic curve analysis, both methods showed a similar performance in discriminating SSc patients from controls. ConclusionWidefield NFC and videocapillaroscopy are reliable and accurate methods and can be used equally for assessing peripheral microangiopathy in RP and SSc patients. Nonetheless, the high reliability obtained may not be similar for less experienced examiners.