The GRASSROOT trial evaluating the Supernova stent retriever (Gravity Medical Technology) has found “excellent” safety and efficacy outcomes in the treatment of large vessel occlusion (LVO) strokes, potentially supporting the wider adoption and reimbursement of “value-priced thrombectomy devices” in low- and middle-income countries (LMICs).
In this prospective, single-arm study involving 32 patients treated at eight centres across India, the Supernova stent retriever achieved a 93.8% rate of successful reperfusion (modified thrombolysis in cerebral infarction [mTICI] ≥2b) and a 50% rate of 90-day functional independence (modified Rankin scale [mRS] 0–2), as well as 3.1% and 9.4% rates of symptomatic intracranial haemorrhage (sICH) and mortality, respectively. According to the GRASSROOT researchers, these outcomes are “comparable to and, in some aspects, better than” those seen in the present literature on established thrombectomy devices.
“We expect that these results, together with other initiatives, will encourage policymakers to invest in stroke systems of care—for example, by funding new thrombectomy-capable centres, supporting training programmes and improving referral networks—so that more patients can access timely thrombectomy,” the researchers write, reporting their findings in the Journal of NeuroInterventional Surgery.
Led by corresponding authors Dileep Yavagal (University of Miami, Miami, USA) and Shailesh Gaikwad (All India Institute of Medical Sciences, New Delhi, India), they also label GRASSROOT as “the first prospective, multicentre thrombectomy trial of a de-novo device in an LMIC”, positing that these data “provide a foundation for future comparative, implementation and health-economic studies” to help expand access to interventional stroke care.
A total of 32 consecutive adult patients (mean age, 58 years; 31% female) with median National Institutes of Health stroke scale (NIHSS) and Alberta stroke programme early computed tomography (ASPECT) scores of 14 and eight, respectively, were enrolled in the trial. Eligible patients presented within 24 hours from time last known well with clinical symptoms consistent with acute ischaemic stroke and imaging-confirmed intracranial LVOs in the internal carotid artery, M1 or M2 segments of the middle cerebral artery (MCA), or the basilar artery.
In addition to successful mTICI ≥2b reperfusion being achieved after 1–3 passes using the Supernova device without the need for adjunctive rescue therapy in 30 of these patients—with the median number of passes reported as one—the GRASSROOT investigators relay a near-complete reperfusion (mTICI ≥2c) rate of 75%, as well as a “notable” first-pass mTICI ≥2c reperfusion rate of 68.8%. Outlining further procedural details, they report a median time from puncture to final reperfusion of 51 minutes and no observed instances of device-related complications or deficiencies—also commenting that, “importantly”, no embolisation to previously uninvolved vascular territories was seen.
Regarding the study’s clinical findings, they share that the composite primary safety endpoint of either 24-hour sICH or all-cause mortality at 90 days occurred in three patients (9.4%), which was deemed to be “significantly below” the prespecified performance goal of 30.4%. Furthermore, median NIHSS scores improved from 14 at baseline, to seven at discharge, to four at 90 days. Asymptomatic haemorrhages were noted at a rate of 15.6%, while decompressive hemicraniectomy due to malignant cerebral oedema was required in 6.3% of patients. However, ultimately, no device-related serious adverse events—such as vessel dissections or perforations—were encountered.
“The favourable technical results of GRASSROOT validate Supernova’s design and engineering. The device features a collapsible, laser-cut stent architecture with a patented spiral fusiform cell geometry and a spatially optimised radial force profile. These engineering elements are intended to enhance clot integration and retrieval efficiency across a range of thrombus types,” the authors posit. “The initial clinical data suggest that the Supernova’s engineering is well-suited to real-world thrombectomy settings.”
Yavagal, Gaikwad and colleagues conclude by stating that high rates of first-pass reperfusion coupled with “value-based pricing” of devices could facilitate a “significant advancement” in access to acute stroke thrombectomy in India as well as other LMICs. They also assert, however, that further studies to validate these findings in larger populations are warranted—and wider adoption of Supernova will need to be combined with “rigorous post-market surveillance” in order to expand treatment availability while improving stroke outcomes across diverse healthcare settings.
