Background: Restenosis after carotid artery stenting (CAS) is a poorly described phenomenon. Studies have reported a variable incidence ranging from 4% to 19.7% at 1 year of follow-up. Doppler Ultrasound (DUS) is now routinely used in the follow-up after CAS and endarterectomy with optimal accuracy in detecting significant restenosis, compared to digital subtraction angiography (DSA).
Case report: We reported the case of a 76-year-old patient with evidence of recurrent severe in-stent restenosis (ISR) of the left internal carotid artery (ICA). In April 2007, due to evidence at DUS of severe left ICA disease, the patient underwent CAS. In January 2009, due to DUS evidence of severe ISR, the patient underwent balloon angioplasty. In September 2011, DUS showed a severe ISR with a peak systolic velocity (PSV) of 436 cm/s; in June 2012 angiography showed a sub-expanded stent in the middle medial side with severe ISR (70%). Multiple inflations were performed and a slight residual sub-expansion of the lateral side of the stent was observed. Post-procedural DUS showed a reduction of PSV to 283 cm/s and 266 cm/s at 1-month follow-up. An increasing value (322 cm/s) was noticed at 3-month follow-up DUS, while at 6-month follow-up DUS showed an important increase to 483 cm/s. Strict follow-up was adopted because of the patient's refusal of further treatment.
Conclusions: Criteria for diagnosis of restenosis are not well established. The optimal treatment is still debated and no indications have been established, due to the lack of sufficient data. Approaches to ISR include percutaneous transluminal angioplasty, cutting-balloon angioplasty (CB-PTA), stenting, and drug-eluting balloon (DEB) angioplasty. Several studies indicate that endovascular treatment, including balloon angioplasty and (CB-PTA) alone or in conjunction with stenting, is the preferred strategy.