Cyclical aspiration using a novel mechanical thrombectomy device is associated with a high TICI 3 first pass effect in large-vessel strokes

 Your tyranny of low expectations is so low that you think your job is done as soon as reperfusion is created. That is only an intermediate step, you have a long way to go to get to 100% recovery. And you mention nothing on what you are doing next to get there.

Cyclical aspiration using a novel mechanical thrombectomy device is associated with a high TICI 3 first pass effect in large-vessel strokes

Vladimir Kalousek, Albert J. Yoo, Sunil A. Sheth, Vikram Janardhan, Josip Mamic, Vallabh Janardhan

First published: 08 June 2021

https://doi.org/10.1111/jon.12889

Abstract

Background and Purpose

Complete reperfusion (TICI 3) after the first thrombectomy attempt or first pass effect (FPE) is associated with best clinical outcomes in large-vessel occlusion (LVO) acute ischemic stroke. While endovascular therapy techniques have improved substantially, FPE remains low (24–30%), and new methods to improve reperfusion efficiency are needed.

Methods

In a prospective observational cohort study, 40 consecutive patients underwent cyclical aspiration thrombectomy using CLEAR^TM Aspiration System (Insera Therapeutics Inc., Dallas, TX). Primary outcome included FPE with complete/near-complete reperfusion (TICI 2c/3 FPE). Secondary outcomes included early neurological improvement measured by the National Institute of Health Stroke Scale (NIHSS), safety outcomes, and functional outcomes using modified Rankin Scale (mRS). Outcomes were compared against published historical controls.

Results

Among 38 patients who met criteria for LVO, median age was 75 (range 31–96). FPE was high (TICI 3: 26/38 [68%], TICI 2c/3: 29/38 [76%]). Among anterior circulation strokes, core lab-adjudicated FPE remained high (TICI 3: 17/29 [59%], TICI 2c/3: 20/29 [69%]), with excellent final successful revascularization results (Final TICI 3: 24/29 [83%], Final TICI 2c/3: 27/29 [93%]). FPE in the CLEAR-1 cohort was significantly higher compared to FPE using existing devices (meta-analysis) from historical controls (TICI 2c/3: 76% vs. 28%, p = 0.0001). High rates of early neurological improvement were observed (delta NIHSS≥4: 35/38 [92.1%]; delta NIHSS≥10: 27/38 [71%]). Similarly, high rates of good functional outcomes(NOT GOOD ENOUGH! It's not 100% recovery, is it?) (mRS 0–2: 32/38 [84%]) and low mortality (2/38 [5%]) were observed.

Conclusion

Cyclical aspiration using the CLEAR^TM Aspiration System is safe, effective, and achieved a high TICI 3 FPE for large-vessel strokes.

INTRODUCTION

Large-vessel strokes have a poor natural history with a high mortality (41.9%) and low rate of good functional outcomes defined by the modified Rankin Scale (mRS) of 0–2 (mRS 0–2 [20.7%]).¹ Vessel reopening with complete distal territory reperfusion (TICI 3) in the first thrombectomy attempt, also known as the first pass effect (FPE), has become the top-line metric for a successful thrombectomy in patients with large-vessel strokes.² TICI 3 FPE is associated with the lowest mortality (mRS 6 [16.3%]) and the highest rates of functional independence (mRS 0–2 [61.3%]).² When multiple passes are required, rates of good outcome decline (final TICI 3 in multiple passes: mRS 6 [20.5%]; mRS 0–2 [55%]). Similarly, when incomplete reperfusion (TICI 2b) is achieved, outcomes can suffer (TICI 2b or greater on first pass: mRS 6 [31%]; mRS 0–2 [52.4%], and final TICI 2b or greater in multiple passes: mRS 6 [30.2%]; mRS 0–2 [44.3%]).²

Although substantial technological improvements in endovascular therapy have been achieved since the initial studies in 2015,³ TICI 3 FPE remains low at 24–30% for retrievable stents (North American solitaire stent retriever acute [NASA] stroke registry,^{2, 4} TREVO Stent-Retriever acute Stroke registry [TRACK] registry,⁵ Analysis of Revascularization in Ischemic Stroke with EmboTrap [ARISE] 2 study⁶) or continuous uniform aspiration (continuous uniform aspiration arm of Aspiration versus Stent Retriever [ASTER],^{7, 8} Endovascular Treatment of Ischemic Stroke [ETIS] registry⁹). More recently, it has been suggested that near-complete reperfusion (TICI 2c) is associated with comparable good outcomes as TICI 3 Stroke Thrombectomy and Aneurysm Registry (STAR) registry.¹⁰ A recent meta-analysis has shown that FPE inclusive of near-complete reperfusion (TICI 2c/3) is also low at 28% with existing mechanical thrombectomy devices.¹¹ There is clearly an unmet need for a novel mechanical thrombectomy device to improve the relatively low rate of TICI 2c/3 FPE seen with current retrievable stents or continuous uniform aspiration systems,^4-9 and thereby help achieve better outcomes in patients with large-vessel strokes.

Preclinical results with a novel mechanical thrombectomy device that can generate cyclical aspiration, the CLEAR^TM Aspiration System (Insera Therapeutics Inc., Dallas, TX), have shown an improved safety profile,¹² and demonstrated that complete clot ingestion with cyclical aspiration also increases first pass recanalization and reduces distal embolization.¹³ There is a need to understand how these preclinical results translate from the bench to the bedside. The authors aim to describe the clinical safety and efficacy profile for cyclical aspiration, using the CLEAR^TM Aspiration System, and its impact on TICI 2c and 3 FPE.