Background Vasomotor endothelial function is an emerging data in functional exploration. Its meaning is well established in cardiology, where it independently predicted the occurrence of cardiovascular events. It interest has been poorly assess in rheumatology. Recently it was shown that patients with rheumatoid arthritis (RA) and systemic sclerosis (SS) have impaired endothelial function compared to controls. In the SS, endothelial function was correlated with the microvascular disease observed in capillaroscopy (1,2).
Methods Reactive hyperhemia index (RHI), a simple, reliable and non invasive method for endothelial function exploration (3), taken at the estimated maximal vasodilatation (1 min 30 s after release of occlusion) using digital pulse amplitude tonometry was performed on 21 patients with SSc, 14 patients with IR and 15 healthy subjects. In IR and SSc patients, DAS 28, Rodnan score, cardiac echography, spirometry, DLCO and 6 minute walk test were also performed.
Results Characteristics of the 3 groups: Mean age of SSc was 57 years (28-75), sex ratio (SR) was 5/1 and mean disease duration was 4.5 years (0-22). 11 patients had limited form and 7 had diffuse form. The mean Rodnan score in 13 of 18 SSc patients was 10.2 (4-28). IA patients had a mean age of 60 years (38-73) and SR was 6/1. 11 patients had RA, 1 spondylarthropathy, one antisynthetase syndrome and one myositis with SRP antibody. Mean IR duration was 16 years (0-31). Mean DAS 28 in 11 of 14 IR patients was 4.45 (2.03-6.66) and 8 patients were treated with biologic treatments. Controls were 57 years old (53-64) and SR was 6/1. Patients mean weight was comparable: 67 kg (45-106), 67 kg (54-79) and 64 kg (54-91) in SSc, PR and controls respectively. Mean blood pressure was also similar (SSc: 127/73mmHg, PR: 128/76mmHg and controls: 130/75mmHg in SSc). One IR patient suffered of diabetes mellitus and had history of heart infarct.
Results: Median RHI was significantly lower in SSc patients (median 1.45, range 1.00-3.18) compared with IA patients (median 2.01, range 1.35-3.02) (p=0.03) and was significantly lower in both SSc and IA patients compared with controls (median 2.60, range 1.40-3.05) (p=0.001 and p=0.049 respectively). In SSc patient but not in IA patients, RHI value significantly correlated with echocardiograhic PAPs (r: -0.75; p=0.037), DLCO (r: 0.53; p=0.017), total pulmonary capacity (r: 0.46; p=0.032), functional and maximal vital capacity (r: 0.48; p=0.032 and r: 0.48; p=0.033 respectively).
Conclusions RHI, an easy and non invasive test, is associated with macroangiopathy and lung involvement in SSc. Further studies are necessary to determine whether RHI may represent disease activity and therapeutic response marker.
Rollando et al. J Rheumatol. 2010;37:1168-73.
Hannawi et al. Arthritis Res Ther. 2009;11:R51.
Hamburg et al. Trends Cardiovasc Med. 2009;19:6-11.
Disclosure of Interest None Declared