Research Article: Clot reduction prior to embolectomy: mSAVE as a first-line technique for large clots

Date Published: May 9, 2019

Publisher: Public Library of Science

Author(s): Marios-Nikos Psychogios, Ioannis Tsogkas, Alex Brehm, Amelie Hesse, Ryan McTaggart, Mayank Goyal, Ilko Maier, Marlena Schnieder, Daniel Behme, Volker Maus, Jens Minnerup.


The “Stent retriever Assisted Vacuum-locked Extraction” (SAVE) technique is a promising embolectomy method for intracranial large vessel occlusion (LVO). We report our experience using a modified SAVE (mSAVE) approach for clot reduction prior to embolectomy in acute ischemic stroke patients with large clots.

We retrospectively analyzed 20 consecutive patients undergoing mSAVE in our center due to intracranial LVO. Angiographic data (including first-pass and overall complete reperfusion, defined as an expanded Thrombolysis in Cerebral Infarction (eTICI) score of 3, rate of successful reperfusion (eTICI ≥2c), number of passes, time from groin puncture to reperfusion) and clinical data (favorable outcome at 90 days, defined as modified Rankin Scale (mRS) ≤2) were assessed.

First-pass and overall eTICI 3 reperfusion was reached in 13/20 (65%) and 14/20 (70%), respectively. The rate of successful reperfusion (eTICI ≥2c) after one pass was 85% and on final angiogram 90% with an average number of 1.1 ± 0.3 attempts. Eight out of 11 (73%) ICA occlusions were reperfused successfully and 5 (46%) completely after a single pass. Median groin to reperfusion time was 33 minutes (IQR 25–46). A favorable clinical outcome was achieved in 9/20 (45%) patients at discharge and after 90 days, respectively.

Clot reduction followed by embolectomy (mSAVE) is feasible and may be an important tool in the treatment of large clots.

Partial Text

One of the major predictors of a favorable outcome in patients with acute intracranial large vessel occlusion (LVO) is complete and swift reperfusion of the affected territory [1]. Embolectomy in combination with intravenous thrombolysis (IVT) has been the state-of-the-art therapy for acute ischemic stroke (AIS) since 2015, after several randomized controlled trials (RCTs) demonstrated that endovascular treatment of LVO using stent retrievers is more effective than IVT alone [2–4]. Recent studies indicated that reperfusion success might be influenced by several factors. In a post hoc analysis of the Contact Aspiration vs Stent Retriever for Successful Revascularization (ASTER) trial it was shown that successful reperfusion was less frequently achieved in patients with high clot burden [5]. Furthermore, a sub-analysis of the North American Solitaire Acute Stroke (NASA) Registry revealed a lower first-pass effect and more embolectomy maneuvers in patients with internal carotid artery (ICA) terminus occlusions, which is known to be associated with a large clot amount [6,7]. As the probability of successful reperfusion and favorable clinical outcome decreases with the number of passes and prolonged procedure time, our aim was to develop an embolectomy technique which is able to solve the problem of large clot burden [8]. Therefore, we modified the recently published “Stent retriever Assisted Vacuum-locked Extraction” (SAVE) technique to increase the probability of reperfusion success and decrease the number of retrieval maneuvers by reducing the amount of clot prior to embolectomy [9]. We here present our first experience with the modified SAVE (“mSAVE”) technique in AIS patients.

A total of 207 patients with LVO were treated with SAVE over 29 months. Of those, 20 patients received mSAVE as the primary treatment approach. Median age was 79 years (interquartile range (IQR) 66–83) and 13/20 (65%) patients were male. Baseline characteristics are shown in Table 1. Median baseline NIHSS was 15 (IQR 14–16) and concomitant IVT was applied in 10/20 (50%) patients. Occlusion sites were as follows: ICA in 11/20 (55%), M1 in 8/20 (40%), and basilar artery in 1/20 (5%) patients. All patients presented with a pre-treatment eTICI score of 0. Median Alberta Stroke Program Early CT score (ASPECTS) was 8 (IQR 7–9). Median CBS was 4 (IQR 2–5) and median clot length was 18 mm (IQR 15–25). Individual patient data in displayed in Table 2.

Since endovascular therapy is standard of care in AIS patients suffering from intracranial LVO, existing embolectomy techniques were ameliorated and new methods were developed over the last years. The central requirements of embolectomy comprise a high efficacy including a fast recanalization of the occlusive lesion with a complete reperfusion of the affected downstream territory and a high safety profile including the prevention of ENT and intracranial hemorrhage. Taking these parameters as a benchmark, we recently were able to confirm our results of the SAVE technique with high rates of first-pass complete (modified TICI 3, 45%) and overall complete (56%) reperfusion rates in LVO of the anterior circulation [9]. However, as this technique seemed to be less effective in ICA occlusions compared to M1 occlusions, we modified our approach (so-called “mSAVE”) with the intention to increase probability of reperfusion success in patients with high amount of thrombus as this is often the case in ICA occlusions [7]. In this study, we demonstrate our first experience with mSAVE as a feasible method which seems to be safe and effective.

Embolectomy using mSAVE is feasible and seems to be safe and effective with high rates of first-pass and overall reperfusion. Therefore, mSAVE might be an alternative method especially in patients with ICA occlusions, where clots tend to be of larger size.




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