A new approach to studying angiogenesis in rheumatoid arthritis by means of power Doppler ultrasonography and measurement of serum vascular endothelial growth factor

Abstract

Objective. To evaluate angiogenesis as an essential component of pannus formation and cartilage destruction in rheumatoid arthritis (RA) using power Doppler ultrasonography (PDUS) and serum vascular endothelial growth factor (VEGF) measurement. Methods. Twenty-one RA patients with a painful and swollen wrist and 12 healthy controls were examined with ultrasound. By means of standard scans, vascularity near and inside the joint capsule was visualized with PDUS. Two trained investigators performed sonography. Representative video clips were stored and read by two independent investigators, under blinded conditions, with regard to the microvascular Doppler flow being either inside or outside the joint capsule and with respect to a qualitative estimate of the intensity of blood flow, according to a grading from 1 to 3. Serum levels of VEGF were measured with a standard quantitative sandwich ELISA. Results. The power Doppler mode identified increased synovial microvascular blood flow inside the joint capsule in 17 of 21 RA patients (81%) vs one of the healthy controls. We found large variation in serum VEGF levels in RA patients and in healthy controls. The degree of synovial vascularity determined by PDUS showed no correlation with the immediate serum VEGF level in the same patient. Conclusion. The high correlation between intra-articular microvascular power Doppler flow and clinical synovitis in RA patients (P<0.0001) indicates that PDUS may be helpful in studying the role of synovial blood vessels in rheumatoid inflammation.