Adjustable stent retriever beneficial in large vessel occlusive stroke

The novel, adjustable stent retriever that allows alignment of radial expansion with target vessel diameters effectively removes thrombus in acute ischaemic stroke patients with large vessel occlusion, as shown in a study.

Known as the Tigertriever, the device “yielded high rates of reperfusion … with substantial reperfusion achieved in more than eight of every 10 patients with the Tigertriever alone and more than nine of every 10 patients after additional interventions,” according to the investigators.

“[Furthermore], the rate of successful reperfusion surpassed the predefined performance goal against the [approved] Trevo and Solitaire devices derived from regulatory registration and additional pivotal trials. The high successful reperfusion rates with the Tigertriever device translated to favourable functional outcomes, with nearly six of every 10 patients achieving functional independence at day 90,” they added.

The analysis included 160 acute ischaemic stroke patients (43 lead-in, 117 main phase; mean age, 66 years) treated with the Tigertriever. These patients had National Institutes of Health Stroke Scale (NIHSS) score 8–29 due to large vessel occlusion within 8 hours of onset.

Successful reperfusion with the Tigertriever (defined as core laboratory-adjudicated modified Thrombolysis in Cerebral Ischemia [mTICI] score of 2b–3 within three passes) occurred in 84.6 percent. This number was noninferior to the 63.4 percent performance goal derived from adjudicated outcomes in six completed prospective trials of Solitaire and Trevo (p<0.0001) and superior to the 73.4 percent historical rate derived from trials and prospective studies of established devices (p<0.01). [Stroke 2021;doi:10.1161/STROKEAHA.121.034436]

The first pass successful reperfusion rate was 57.8 percent. After all interventions, successful reperfusion (mTICI ≥2b) was achieved in 95.7 percent and excellent reperfusion (mTICI 2c-3) in 71.8 percent.

Meanwhile, the composite endpoint of 90-day all-cause mortality and symptomatic intracranial haemorrhage (sICH) was 18.1 percent with Tigertriever, which was noninferior relative to the 30.4 percent performance goal (p=0.004), but was not superior as opposed to the 20.4 percent historical rate (p=0.57). Good clinical outcome (modified Rankin Scale 0–2) was achieved in 58 percent of patients at 90 days.

The current study results demonstrate that the median procedure time (from puncture to achievement of mTICI ≥2b) was 25 minutes, which compares favourably to the ARISE II study (median, 35 minutes) and similar to the contact aspiration first pass thrombectomy time in the COMPASS study (median, 25 minutes) [Stroke 2018;49:1107-1115; Lancet 2019;393:998-1008]

“In experienced, high-volume centres performing over 48 thrombectomies annually, the median puncture-to-reperfusion time with the Trevo device was 67 minutes. The reduced procedure times with the Tigertriever may reflect in part the technological advancement of the operator being able to adjust the radial force expansion to interact with the clot in a more productive manner,” the investigators pointed out. [Stroke 2019;50:2455-2460]

They acknowledged that the study was limited by its design, which applied objective performance criteria derived from pooled prior studies of predicate devices rather than a randomized trial with a contemporaneous control group.

“This approach constrains precision in delineating how well the Tigertriever compares with any particular comparator device,” the investigators said.