A novel tandem stent thrombectomy technique “seems to be a safe and effective” rescue treatment for acute large vessel occlusion (LVO) that is resistant to conventional attempts, concludes a study recently published in the Journal of NeuroInterventional Surgery.
The authors, Haowen Xu and colleagues from Zhengzhou University First Affiliated Hospital, Zhengzhou, Henan, China, included nine patients in their retrospective case series (six male; mean age: 65.2 years; median National Institutes of Health Stroke Scale [NIHSS] score: 18). The middle cerebral artery M1 segment and terminal internal carotid artery were occluded in six and three patients, respectively.
The investigation aimed to assess the feasibility, safety, and angiographic and clinical outcomes of the tandem stents thrombectomy technique.
“The technique was performed as a rescue treatment after unsuccessful stent thrombectomy alone in four cases, and stent thrombectomy plus aspiration in five cases,” Xu and colleagues write. They report that recanalisation, defined as modified treatment in cerebral ischaemic (mTICI) 2b/3, was achieved in all patients.
Moreover, no procedure-related complications occurred, except that reversible vasospasms were observed in three patients, while one patient developed haemorrhage transformation after the procedure, but was asymptomatic. The team reported that three patients had a good clinical outcome (modified Rankin Scale [mRS] score 0–2 at 90 days), and two patients (22.2%) died.
Speaking to the rationale behind the study, Xu and colleagues state that while successful recanalisation of an occluded cerebral artery is strongly associated with improved clinical outcome and reduced mortality, standard stent thrombectomy fails to achieve successful recanalisation in 10–35% of patients. “In these refractory cases,” they write, “various rescue treatments, such as direct aspiration, intra-arterial fibrinolysis, stent placement, and balloon angioplasty have been reported to achieve successful recanalisation, while rates of effective recanalisation following these rescue treatments are still not satisfied.”
Given this, the team set out to describe a novel treatment using the tandem stents thrombectomy technique for large and/or stubbornly-rooted thrombus that is refractory to single stent thrombectomy, even when combined with aspiration.
“This technique consists of deployment of two stents in tandem, placing the distal portion of the second stent 5–10mm beyond the thrombus and the tip of the first stent, and then pulling back both stents together. To the best of our knowledge, this technique has not been previously reported,” the authors write.
Delving into the potential advantages and disadvantages of the tandem stents thrombectomy technique, the authors acknowledge that it is beneficial in terms of removing large and/or stubbornly-rooted thrombi. “The proximal portion of the second stent is overlapped within the first deployed stent, which may prompt the degree to which stent retrievers penetrate the thrombus with their struts, increasing the efficacy of clot retrieval.”
Further, they note that if the distal stent used is the Revive SE device (Codman), then due to its design—with a closed-end—the incidence of clot migration/distal embolisation during the stent withdrawal may be decreased. Xi et al add: “Because the two stents are placed and deployed in tandem, the tandem stents thrombectomy technique might be a less traumatic procedure for the vessel wall than crossing or the parallel Y-Solitaire thrombectomy technique. In our case series, no vessel trauma or dissection occurred during stent retrieval with the tandem stents thrombectomy technique.”
Despite the technique’s advantages, the authors acknowledge that it remains a “relatively complex” endovascular technique, especially when compared with conventional mechanical thrombectomy. According to the team, it requires a higher level of operator experience, which they speculate “may limit the use of this technique”. Lastly, they write that the increased cost of two stent retrievers is another disadvantage.
However, the team concludes that while preliminary, the results show the technique to be a “safe and effective” alternative rescue technique to treat acute LVO refractory to conventional mechanical thrombectomy, and they call for further prospective studies to verify this technique.