Patients with systemic sclerosis (SSc; scleroderma) are at high risk for the development of ischemic digital ulcers (DUs), which occur in 35-60% of SSc patients. The aim of this study was to assess the correlation between intrarenal arterial stiffness and DUs in SSc patients and to evaluate the prognostic value of Doppler indices to predict new DU occurrence.
Seventy unselected, consecutive patients with SSc (58 women and 12 men, mean ± SD age 49.5 ± 13.8 years) were enrolled. In all patients, Doppler ultrasound examination was performed. The following Doppler indices of intrarenal stiffness were measured: peak systolic velocity (PSV), end diastolic velocity (EDV), resistive index (RI), pulsatile index (PI), and systolic/diastolic ratio (S/D).
In total, 30 (42%) of 70 patients experienced new DUs. RI, S/D, and PI were significantly higher in SSc patients with new DUs than in SSc patients without new DUs. The receiver operating characteristic (ROC) curves demonstrated a good accuracy of new DU prediction for RI (0.94, P < 0.0001), S/D (0.92, P < 0.0001), and PI (0.88, P < 0.0001). Conversely, the ROC curve showed no performance for PSV (0.58, P > 0.05) and EDV (0.28, P > 0.05). Using a cutoff value of 0.70 for RI and 3.25 for S/D, the positive predictive value was 90.6% and 92.9%, respectively.
We can conclude that Doppler indices of intrarenal stiffness are reliable markers of new DU occurrence. Doppler indices could be used in association with the capillaroscopic and clinical findings or serologic tests for the identification of patients at high risk of developing DUs.