First-line Double Stentriever Thrombectomy for M1/TICA Occlusions

Recent trials have established the benefit of mechanical thrombectomy over medicinal management alone in patients with acute ischemic stroke from large-vessel occlusion of the anterior circulation, [1‐7] where treatment aims to restore reperfusion by restoring blood flow through recanalization [8]; however, mechanical thrombectomy fails to achieve adequate recanalization in nearly one third of these patients [4], and the rates of effective recanalization remain low after rescue treatment, such as intra-arterial recombinant tissue plasminogen activator (rtPA), aspiration thrombectomy, mechanical thrombus disruption, and balloon angioplasty with or without stent placement [9‐12].

Rescue therapy using two simultaneous stentrievers yields good results in patients with clots refractory to mechanical thrombectomy with a single stentriever [13‐19]; however, the feasibility of this technique as a first-line treatment remains to be determined.

This prospective study aimed to assess the efficacy and safety of first-line double stentriever thrombectomy for acute occlusion of the middle cerebral and/or terminal internal carotid arteries.

The double stentriever thrombectomy has been initially found out by T. Liebig (Department of Neuroradiology, TUM, Munich, Germany) and its primary systematic use in the treatment of large vessel occlusion by R. Chapot (Alfried Krupp Krankenhaus, Essen, Germany). The high rates of recanalization, especially after the first pass, the low rate of complications, and 90-day mortality rate in line with those reported in previous clinical trials with other mechanical thrombectomy techniques indicate that this promising new approach merits further investigation. First-line double stentriever thrombectomy for TICA and M1 occlusions achieved successful recanalization (TICI 2b/3) in all patients, representing a notably higher rate of successful recanalization than reported with standard stentriever techniques alone (58%–83%) [1, 4, 20], or with the direct aspiration first-pass thrombectomy technique with large-bore aspiration catheters alone (79%–83%) [20, 21]. In another study involving a retrospective analysis of 200 patients treated with stent retriever-assisted vacuum-locked extraction (SAVE) technique due to intracranial large vessel occlusion, Maus et al. documented 57% of first pass effect (TICI 2c/3) [22]. The efficiency of double stentriever thrombectomy seems however to be even higher with a 69% first pass effect rate to achieve TICI 2c/3. This rate is higher than the rates for standard stentriever techniques reported by Zaidat et al. [23] (64% and 10% in M1 and TICA occlusions, respectively), by MR CLEAN Investigators [24] (24%) and in the meta-analysis published by Bai et al. [25] (49.7%). The rate of patients with mRS 0–2 at 90 days in our series was 41%, similar to what was reported in the NASA Registry [24]. The percentage of patients with good clinical outcome was 55.5% in the first-pass effect subgroup, similar to the results reported by the Den Hartog et al. [25] (56%), higher than what was observed in the meta-analysis of Bai et al. [25] and lower than what was described by Zaidat et al. (61.3%) [23]; however, the rate of patients with mRS 0–2 at days was not better compared to the results from some randomized trials (e.g., ESCAPE 53%, EXTEND-IA 71%) [3, 26]. We have to take into account that pre-stroke mRS scores indicate moderate to severe disability (mRS score 3–5) in 5 (12.8%) of our patients.

Various authors have analyzed double stentriever thrombectomy as a rescue therapy in bifurcation occlusion [13‐19]. With the exception of Li et al. [18], all these reports were retrospective and included few patients. The rates of successful recanalization were high (80%–85% [14, 15, 18, 19]), but lower than ours. The only study that analyzed recanalization after the first pass, Cabral et al. [19], reported 75% success, higher than the 69% in our series. Those authors used the combined stentriever technique as rescue and not as primary technique. None of these studies reported serious complications from using two devices simultaneously. It reinforces the advantage of using this technique as a first line treatment.

Advantages of using a second device include better integration of the thrombus thanks to increased radial force from the second stentriever and more complete coverage of the thrombus [15]. Integration of the thrombus increases the retrieval force transmitted to the thrombus and improves the likelihood of successful thrombectomy. The dual stentriever technique may be particularly helpful for clots involving arterial bifurcations, which are often resistant to multiple passes of a single stentriever [3, 17], and the increased radial force from a second stentriever might also be especially beneficial in hard, fibrin-rich thrombi that are difficult to penetrate with a single device [15].

Possible disadvantages of the double stentriever technique include trauma to intracranial vessels, a potentially serious adverse event in mechanical thrombectomy that is uncommon in procedures performed with a single stentriever [27, 28]. The reported incidences of arterial dissection, symptomatic cerebral hemorrhage and subarachnoid hemorrhage were 4.5%, 1.1% and 1.1%, respectively. Using two stentrievers may potentially increase the force on the endothelium during the retrieval maneuver [14]. In our study, we observed sICH in 7.6% of patients and subarachnoid hemorrhage in 5.1%, these rates are lower than in reports where the technique was used in rescue therapy (10% sICH reported Klisch et al. [14] and Cabral et al. [19] and 10.7% subarachnoid hemorrhage in Li et al. [18]). We also observed extravasation of contrast material in two patients. One of these resulted in a Fisher grade 3 subarachnoid hemorrhage and the other in a direct carotid-cavernous fistula. Extravasation of contrast to the subarachnoid space is a complication we can observe occasionally even after the use of one stentriever and is believed to be due to the traction of the arteries during the extraction of the device [27]. Direct fistula is an unusual complication that happened in a patient in his 90s with a severely calcified carotid siphon. One possible explanation is that a stentriever was caught in a calcified plaque that was torn causing the fistula. Both resolved spontaneously after the proximal balloon was inflated for a few minutes without worsening the clinical situation of the patients. The limited literature of the double stentriever technique [15, 18, 19] suggests it is well-tolerated with a risk profile similar to conventional single stentriever technique. Klisch et al. [14] described 1 case of vessel perforation and 7 cases of mild vasospasm during mechanical thrombectomy using the double stentriever technique as a rescue therapy in 10 patients. Other disadvantages are the added complexity of using two stentrievers, which requires a higher level of operator experience, and potential increase in costs from using two stentrievers.

The present study has several limitations. First, the sample was relatively small. Given the scant corroborating evidence for the safety and efficacy of our treatment protocol, additional data is necessary before double stentriever thrombectomy can be included as a first-line therapeutic option for proximal occlusion in international guidelines. Second, patients in this prospective case series were not randomized to receive first-line double stentriever thrombectomy, and there was no control group for comparison. It is essential to carefully assess the possible risks and benefits of this approach before attempting it in individual patients. Randomized controlled trials comparing outcomes after mechanical thrombectomy using two stentrievers versus using a single stentriever will further clarify the effectiveness, safety and cost of this promising technique.

We found that double stentriever thrombectomy yielded high rates of successful recanalization after the first pass with a low rate of complications, suggesting it can be an effective and safe first-line treatment for M1 and TICA occlusions. Nevertheless, larger prospective studies are required to validate the feasibility and safety of this strategy and further determine its ability to improve clinical outcomes.