Discussion

Takayasu arteritis refers to chronic, granulomatous full-thickness arteritis involving the aorta and its primary branches. The aetiology is poorly understood, but it is believed that infectious sources, genetic factors, and autoimmune disease play a major role. Coronary artery involvement is found in 7–29% of patients with Takayasu arteritis. In the versus majority of cases, the proximal and ostium parts of the coronary arteries are affected.

However, the optimal treatment strategy for Takayasu arteritis with multiple coronary involvement is still unclear. The treatment options to improve prognosis include drugs (steroids, immunosuppressants), percutaneous transluminal coronary angioplasty, percutaneous coronary stenting and coronary artery bypass grafting. There have been many reports on the application of drug-eluting stents in coronary invasive therapy for Takayasu arteritis. ^{Reference Kang, Han, Ahn and Shin1,Reference Sakai, Oyama, Kishimoto, Takahashi, Urasawa and Tsutsui2} In the patient reported by Yokota et al ^{Reference Yokota, Shimpo and Iwata3} repeated stent restenosis appeared 5 months after Cypher stent implantation. Finally, stent restenosis was prevented by adding oral steroid therapy, and the patient was asymptomatic at the 4-year follow-up. However, the patient we reported regularly take steroid and other related drugs, and the symptoms recurred 9 months after percutaneous coronary stenting. The original left anterior descending artery stent was unobstructed by coronary artery angiography, which may be related to the application of the second-generation stent. Using the new generation of drug-eluting stents that is expected to further reduce the inflammatory response, the incidence of restenosis may be significantly reduced.

Drug-coated balloons are semi-compliant angioplasty balloons covered with an antiproliferative drug that is rapidly released from a lipophilic matrix upon contact with the vessel wall. The advantage of drug-coated balloons over stents is that it allows a “leaving nothing behind” strategy, no metal implants with biocompatible coatings or biodegradable coatings, which minimise the long-term inflammatory stimulation of foreign bodies to coronary artery. The principle of action is applicable to the pathological characteristics of Takayasu arteritis with endointimal hyperplasia of coronary artery lesions. ^{Reference Chiew and Lim4} A patient with active Takayasu arteritis presenting with acute coronary syndrome was recently reported to have been treated with drug-coated balloon under optical coherence tomography guidance in the critical left anterior descending artery lesion and remained asymptomatic for more than 3 years with long-term follow-up.

However, the reexamination of angiography in our case showed the progression of de novo lesions in the left main coronary artery. Unfortunately, the acute condition of the patient after occlusion of the angiography catheter at that time made the plan of reexamination of optical coherence tomography impossible to perform, so the pathological features of the lesions with left main coronary artery progression could not be observed. However, the progression of de novo left main coronary artery lesions from 40% stenosis to 75% after 9 months suggests the possibility of local inflammatory reaction and hyperplasia caused by the previous invasive manipulation of percutaneous coronary stenting. In our case, the SYNTAX score of the left coronary artery was 34 points based on the calculation of the second coronary angioplasthy, and IA was recommended according to the guidelines, ^{Reference Neumann, Sousauva and Ahlsson5} but the guidelines were based on research into atherosclerotic heart disease. Some cases have reported coronary artery bypass grafting results in patients with Takayasu arteritis that are not satisfactory. Although internal mammary artery transplantation has an excellent patency rate in atherosclerotic coronary heart disease, Takayasu arteritis patients have a greater risk of developing subclavian artery stenosis. ^{Reference Haridas, Kumar, Rajesh, Kumar and Pannekal6} Therefore, unlike most coronary artery bypass graftinggrafts, saphenous vein grafts are commonly used in patients with Takayasu arteritis. The 10-year survival rate after saphenous vein grafts-left anterior descending artery transplantation was 80%, and the event-free survival rate was 77%. ^{Reference de Soeiro, Almeida M.C. and Torres7} Some retrospective studies ^{Reference Wang, Zhang, Shen, Fang, Liu and Zhang8,Reference Huang, Zhang, Wang, Yang, Qiao and Hu9} showed that neither percutaneous coronary stenting nor coronary artery bypass grafting showed a reduction in MACE and mortality in patients with Takayasu arteritis complicated with coronary stenosis when compared with drug therapy alone. Percutaneous coronary stenting was independently associated with a higher incidence of MACE and revascularization than coronary artery bypass grafting. For patients with revascularization indications, coronary artery bypass grafting may be the preferred method of choice. Macedo et al reported a case of Takayasu arteritis with multiple coronary involvement. ^{Reference Macedo, Lima, Junior and Bannon10} Steroid and immunosuppressant treatment was started immediately after coronary artery bypass grafting treatment. However, 8 months after the operation, a 70% stenosis of the venous graft to the posterior descending artery occurred while the arterial graft remained patent. The patient has been asymptomatic for a long time after placing DES in the venous graft to the psterior descending artery. This shows the complexity of the treatment of these patients.