Digital ulcers in systemic sclerosis are strongly associated with digital arterial disease: a finger-by-finger analysis of Finger Brachial Pressure Index Measurements

Objectives: The digital ulcers of systemic sclerosis are disabling and frequent· Their pathogenesis involves a capillary microangiopathy and a digital arterial disease that few studies were able to quantify up to now. A multicentre observational study about the predictive value of capillaroscopy in systemic sclerosis offered us the opportunity to evaluate further the complementary information provided by both capillary and arterial evaluations.

Methods: During the SCLEROCAP study, five out of the nine centers performed a systematic evaluation of the finger brachial pressure index (FBPI) in the last four fingers of both hands at baseline, using the same laser-doppler device. In the present work, FBPI measurements were compared between fingers with vs without digital ulcers or scars, before and after adjusting for the capillaroscopic pattern and systemic factors.

Results: FBPI measurements were performed in 2537 fingers from 326 patients. Active ulcers or scars were found in 10·8% of those fingers, more often on the right hand, and in the second and third fingers. FBPI was lower than 0·70 in 26% of all fingers and in 57·5% of those with ulcers. A strong association was found between a low FBPI and the presence of digital ulcers, even after adjusting for capillaroscopic pattern, ulcer location and the patient himself.

Conclusion: These results confirm the importance of digital arterial disease in the pathogenesis of digital ulcers of systemic sclerosis, which is independent from the microangiopathy. FBPI measurements complement the information provided by capillaroscopy and might have an important predictive value for subsequent digital ulcers.