The granulomatous nature of inflammation in Takayasu’s arteritis suggests a potential role of tumor necrosis factor-alpha in disease pathogenesis. Hoffman et al published the first open-label prospective study in 2004 of 15 patients treated with infliximab or etanercept. Most patients had previously received other immunosuppressive agents in addition to glucocorticoids. Response was seen in 14 of 15 patients, with 10 patients experiencing sustained remission for one to 3.3 years off glucocorticoid therapy.11 Since that time, reviews of published case series note similar results with good response rates and the ability to taper prednisone. The majority of patients have been treated with traditional immunosuppressants, such as methotrexate or azathioprine, in addition to biologic therapy, most commonly infliximab. Relapse is common, however, as is the need for dose escalation of anti-TNF therapy.12,13
More recently, anti-interleukin-6 therapy with tocilizumab has been reported in case reports and small case-series of patients refractory to other treatments including, in some cases, anti-TNF therapy. Although results have been encouraging, it’s important to note the small numbers, limited follow-up and lack of controlled or even prospective trials to date. Even less data exists to guide the use of rituximab, although this remains an active area of investigation.12 The ongoing phase II AGATA trial (Abatacept for Treating Adults with Giant Cell Arteritis and Takayasu’s Arteritis) is the first randomized controlled trial in TAK. Additional controlled trials are needed to guide optimal therapy. Additionally, the best strategy to assess response to therapy is unknown but includes assessing symptoms, monitoring inflammatory markers and performing interval imaging to identify new or progressive vascular lesions.
Although immunosuppressant therapy may treat inflammation and prevent new vascular lesions, surgical or endovascular interventions are sometimes required to treat chronic, severe vascular complications. These include bypass grafting, endarterectomy, aortic valve replacement, angioplasty and stenting. Indications for intervention include extremity ischemia limiting activities of daily living, cerebral ischemia or symptomatic stenosis > 70% of cerebral vessels, refractory hypertension due to renal artery stenosis, coronary artery stenosis causing ischemia, moderate to severe aortic regurgitation, severe aortic co-arctation and progressively enlarging or dissecting aneurysms.11 Interventions should be avoided if possible and should only be performed when severe complications are present.
Procedures in patients without major complications have been associated with decreased survival.14,15 A higher rate of restenosis or occlusion after grafting, angioplasty or stenting has been observed in patients with TAK compared with patients with atherosclerotic disease. This difference may be due to the persistent inflammation observed in some operative specimens in patients thought to be in remission or because of reduced compliance of fibrotic vessels.5,16 The literature suggests that surgery is associated with a somewhat lower rate of complications than endovascular intervention. Importantly, outcomes are improved if procedures are done after active inflammation is treated.15-17 Whenever possible, medical treatment should come before surgical intervention.
