MRI-based measure could help predict scleroderma finger sore risk
DAVIX calculates ratio of volume of arteries in a finger to total finger volume
An MRI-based measure called Digital Artery Volume Index, or DAVIX, may help predict the risk that people with scleroderma will develop ulcers on their fingers, a study suggests.
“The potential of DAVIX to detect and predict digital ulcer disease could render it a useful stratification tool in clinical trials,” the researchers wrote in “MRI Digital Artery Volume Index (DAVIX) as a surrogate outcome measure of digital ulcer disease in patients with systemic sclerosis: a prospective cohort study,” which was published in The Lancet Rheumatology.
Scleroderma, or systemic sclerosis, is marked by fibrosis, or scarring, in the skin and other organs. Among other complications and symptoms, the disease can lead to digital vasculopathy, that is, problems with the blood vessels in the fingers, which can contribute to Raynaud’s phenomenon and set the stage for ulcers or sores on the fingers.
While blood flow problems contribute to scleroderma symptoms, there’s no proven method to reliably assess blood vessel issues with the disease, leading scientists here to test whether DAVIX could be helpful.
DAVIX is an MRI-based measure that calculates the ratio of the volume of arteries in a finger, compared to the total volume of the finger. A low DAVIX score indicates the finger’s blood vessels are narrowed, which can impede proper blood flow.
Developing finger sores
The team calculated the DAVIX score in more than 900 fingers of 235 patients who were divided into two groups. The exploratory cohort was made up of 85 patients who were assessed once and then followed for a year to see if digital ulcers developed. The validation cohort had 150 patients who were still undergoing follow-up during the study’s submission for publication.
Most patients in both groups identified as women and as white, with a mean age in the early 50s. In both groups, the median DAVIX score at the start of the study was significantly lower in those with a history of finger ulcers.
Of the 85 patients in the exploratory cohort, 17 had had finger ulcers before the study and seven had new ulcers during the follow-up. Another five patients who’d never had ulcers reported new ones at follow-up.
The median DAVIX score during the initial measurement was significantly lower in those who developed ulcers over the follow-up (0.23% vs. 0.65%), statistical tests showed. Also, the median DAVIX score for individual fingers that developed ulcers was lower compared to the score for other fingers on the same hand (0.15% vs. 0.27%).
Further analyses showed that, at a cutoff value of 0.37%, the DAVIX score could accurately identify 67% of patients who developed finger ulcers and 84% of those who didn’t. In other words, patients with a DAVIX score lower than 0.37% were more than 18 times as likely to develop finger ulcers.
“We show that DAVIX can differentiate between patients with digital ulcer disease and those without and can predict the appearance of new digital ulcers,” the researchers wrote.
Patients with lower DAVIX scores were more likely to report worsening Raynaud’s or worsening hand function over the follow-up, statistical models showed. Patients with lower DAVIX also were more likely to have worsening on the Scleroderma Health Assessment Questionnaire-Disability Index (SHAQ-DI), an overall measure of scleroderma-related disability.
“DAVIX correlated with disease severity within the same patient, as assessed by patient-reported outcomes and clinical manifestations,” wrote the researchers, who said their findings must be validated by further research, but noted DAVIX could help predict serious complications of scleroderma, such as high blood pressure in the lung’s blood vessels, or pulmonary arterial hypertension, if the results are confirmed.
A number of other studies testing DAVIX are ongoing, the researchers said.
“By predicting the worsening of patient-reported outcomes and clinical manifestations in all patients — including those at high risk — DAVIX could provide insights into the role of vascular disease activity in the overall progression of systemic sclerosis,” they said.