OP14. THE INDIAN PERSPECTIVE OF TAKAYASU ARTERITIS AND DEVELOPMENT OF A DISEASE EXTENT INDEX (DEI.TAK) TO ASSESS TAKAYASU ARTERITIS

Abstract

Background: Takayasu aorto-arteritis is a rare form of primary systemic vasculitis that appears to be commoner in Asia than Europe or North America. The restricted distribution of vessel involvement leads to a pattern of disease that differs markedly from the well-documented small/medium vessel vasculitides. Thus assessments of disease activity or severity that have been used productively to document therapy response and outcome in ANCA Associated Systemic Vascultides are not helpful in Takayasu. The IRAVAS group therefore set out to devise an index of disease severity and extent that could be useful in studying this disease.Methods: The well-established activity index, Birmingham Vasculitis Activity Score (BVAS) was taken as a template for the initial discussions among an expert group with clinical experience of the condition, aimed at producing a consensus on necessary items. This was then applied to limited numbers of patients and rehoned by further group discussions, aiming for inclusivity at this stage in order not to omit important but infrequent items. The draft produced was then applied to a large group of patients seen at 2 centres. The data from this was used to further trim the draft index by omitting unused items that were agreed to be unnecessary while further emphasising key factors seen frequently.Results: 143 patients, mean age 38.8 (+/−13.5), sex ratio 1.5:1 female preponderance, from North and South India were studied. Systems scored commonly included systemic (59 patients), renal (62), and CVS (88). The latter focussed on pulse abnormalities, including pulse loss (40), pulse inequalities (42), and bruits (22). Ischaemia evidenced by claudication was seen in 22. Aspects of heart involvement included aortic incompetence, angina, and CCF (10 each). Systems rarely or never used included skin, mucous membranes, and abdominal. No further significant items were uncovered through the “Other” box, despite emphasising its importance to this exercise. The final format derived from this contains 59 items in 11 organ-based systems. The most important system, CVS, contains 19 items, with special emphasis on bruits, pulse loss and claudication. A glossary has been produced to aid standardisation of application. At this stage all positive items are included, irrespective of whether they are new or old, but the duration of involvement is also noted.Conclusion: The current index is in a usable size and format and this is now being applied to collect data on the pattern of aorto-arteritis in collaborating clinics across India. With further experience and a larger data set, additional minor modification may be required. However the current version is a practical tool which will be useful for studying important aspects of aorto-arteritis, such as differences in anatomical distribution between series/countries; individual disease severity; and outcome. It should also find use as a clinical tool to compare with newer imaging techniques to assess disease involvement such as MR and PET. We hope this will be a first step to producing a practical clinical index of disease activity for use in areas where access to expensive new imaging is very restricted.