Large vessel vasculitides (LVV) including giant cell arteritis (GCA), Takayasu’s arteritis (TA), isolated ascending aortitis, PMR-associated LVV, retroperitoneal fibrosis, periaortitis, inflammatory abdominal aneurysms, relapsing polychondritis and IgG4-related diseases, can be challenging to diagnose, treat and follow. They have varying manifestations and commonly present with constitutional symptoms alone.
Clinical symptoms of LVV are often non-specific and aside from bruits, there are no reliable clinical exam findings. This can lead to a delay in diagnosis, by which time damage (vessel stenosis and aneurysms) may have already occurred. Despite asymptomatic disease, ongoing damage can occur. This makes disease follow-up challenging. There is no specific outcome measure for LVV and acute phase reactants are generally unreliable for follow-up.
The gold standards for diagnosis include imaging and biopsy, neither of which correlate well with clinical symptoms. Depending on organ involvement, biopsy may not be possible. Furthermore, even in involved vessels, there can be false negatives, as skip lesions are possible. In contrast to GCA, where transmural inflammation is common, the adventitial layer is often spared in TA.
There have been recent advances in imaging for LVV. The most sensitive imaging for diagnosis of LVV is positron emission computer (PET) CT, especially for extra-cranial vessels. Unfortunately, it is not always readily available, can be expensive, and is associated with significant radiation. Colour-coded duplex sonography (CCDS), when done by an experienced reader, is a fast and effective way to evaluate vessel wall inflammation (including superficial temporal, axillary, carotid, vertebral and subclavian arteries), which may show a “halo-sign.” At present, MRI and MRA are probably our imaging options for evaluation of transmural inflammation. They are good for evaluation of most large vessels, more readily available than PET CT, not operator dependant like CCDS, and do not use radiation.
Glucocorticoids are routinely used to induce remission in both GCA and TA. Conventional immunosuppressives (MTX, LEF, MMF, AZA) have not been reliably successful for maintaining remission. In TA, there are multiple observational studies showing efficacy of TNF inhibitors (mostly infliximab) and more recently, tocilizumab. In contrast, TNFi do not work well for GCA. Tocilizumab, on the other hand, has demonstrated efficacy in GCA in a recent RCT, and several retrospective studies. There are even published cases of GCA managed successfully with tocilizumab monotherapy and no steroids. At ACR 2015, a small RCT showed abatacept (with prednisone) was superior to prednisone alone for preventing relapse in GCA. There was also a small, open-label study showing ustekinumab may be effective for refractory GCA. Finally, B-cell depleting therapy is under investigation in GCA. Over the next year, stay tuned for emerging data on biologic therapy and steroid-free therapy for GCA.
Dr. Jamal is a Clinical Associate Professor at the University of British Columbia and an active staff physician at Vancouver Coastal Health. Her interests include diagnosis and prognosis of early inflammatory arthritis, and timely assessment and access to care for patients with rheumatoid arthritis.View Full Bio