Study finds “dismally low” global access to thrombectomy and “enormous disparity” between countries

The Society of Vascular and Interventional Neurology (SVIN) has released its first global analysis of access to mechanical thrombectomy for the treatment of large vessel occlusion (LVO) stroke. Findings from MT-GLASS—a study conducted as part of the SVIN Mission Thrombectomy 2020-plus (MT2020+) initiative— have been published in the journal Circulation

THE MT-GLASS STUDY LOOKED AT worldwide access to life-saving thrombectomy treatments, and the factors that contribute to global access, including income class of the country, based on the World Bank classification; proportion of gross domestic product (GDP) spent on healthcare; availability of thrombectomy infrastructure, including operators and centres; availability of reimbursement for thrombectomy; and other relevant stroke systems of care policies. The study ultimately found an “extremely low” global rate of mechanical thrombectomy access, with an “enormous disparity” between countries by income level.

“The study findings validate why we founded Mission Thrombectomy in 2016 and our continued mission that has now grown to include 95 countries,” said Dileep Yavagal (University of Miami, Coral

24 hours, while functional outcomes were defined as favourable (modified Rankin Scale [mRS] score of 0–2) or excellent (mRS 0–1) at 90 days. Safety was assessed by the occurrence of mortality—during hospitalisation and at day 90—as well as symptomatic intracerebral haemorrhages (ICHs).

From a total of 154 patients who met the inclusion criteria, Meyer et al detail that 110 patients (median age=76 years, 50 men) underwent propensity score matching, with 55 having received a thrombectomy and 55, best medical management. Distal MVOs were located in the A2 (53% of patients), A3 (45%) and A4 (2%) segments.

Prior to propensity score matching, the authors observed a median time from symptom onset to groin puncture of 195 minutes across 94 patients who received a thrombectomy. The median number of reperfusion attempts was one, and successful thrombectomy (mTICI grade 2b–3) was achieved in 81% of patients. Complete reperfusion (mTICI 3) was achieved in 67% of patients— including a first-pass effect rate in 41%. Symptomatic and asymptomatic bleeding events were observed in 2% and 14% of patients, respectively, before propensity score matching.

The authors report a median 24hour NIHSS-point decrease of 2 in the thrombectomy cohort compared to 1 in the best medical management cohort. In addition, the distribution of mRS scores at 90 days showed “no evidence of a statistically significant difference”

Gables, USA), corresponding author of the study, chair of the MT2020+ initiative, and past president and cofounder of SVIN. “The global access to thrombectomy is dismally low, with the countries’ income level, prehospital protocols to bypass non-thrombectomy centres, and operator and thrombectomy centre availability, all playing critical roles in thrombectomy access.”

MT-GLASS was conducted throughout 75 countries using the Mission Thrombectomy global network of regions between November 2020 and February 2021, and received 887 responses from 67 countries, an SVIN press release details.

It found a median global thrombectomy access rate of 2.79% (interquartile range, 0.7–11.74%), and revealed a <1% rate of thrombectomy access in 18 countries and 0% in seven countries. In addition, there was a 460-fold disparity between the highest and lowest non-zero thrombectomy access regions, while low-income countries had an 88% lower rate of access compared to high-income countries.

The global rate of availability for thrombectomycapable operators and centres were found to be 16.5% and 20.8%, respectively, of what is considered to be the “optimal” rate, the authors report. Multivariable regression analyses showed that country income level (low/lower-middle versus high); operator and centre availability; and presence of prehospital acute stroke bypass protocols, were all “significantly associated” with increased odds of thrombectomy access.

“Mechanical thrombectomy has proven to be a highly effective therapy for mitigating death and disability since 2015, and it is the largest advancement between the thrombectomy and non-thrombectomy cohorts regarding mRS scores of 0–1 (38% vs 33%, respectively) and 0–2 (49% in both groups).

Functional outcomes stratified across several subgroups—including age, sex, occlusion site, NIHSS on admission, and whether IVT was given—showed no evidence of a difference in 90-day mRS score distributions between the two cohorts. Ninety-day mortality rates were similar with (22%) and without (31%) thrombectomy too, as were inhospital mortality rates (11% and 10%, respectively).

“We did not find a treatment effect in favour of one therapy option after propensity matching,” Meyer et al conclude. “These results show the potential efficacy of [best medical management] in the subgroup of ACA distal medium vessel occlusion. Mechanical thrombectomy may be considered a technically feasible treatment option for acute ischaemic stroke due to primary isolated occlusions in the A2 and A3 segments because it can lead to high rates of successful reperfusion associated with favourable long-term outcome and did not result in increased rates of symptomatic bleeding events if patients were treated at tertiary stroke centres.

“Nevertheless, patient selection for treatment allocation requires further investigation to identify patients who will benefit the most from available treatment options.” in stroke treatment in 30 years,” said SVIN president Ameer Hassan (Valley Baptist Neuroscience Institute, Harlingen, USA). “Given the widely distributed global burden of stroke, it is critical to have rapid access to mechanical thrombectomy, worldwide, in an equitable manner. In the USA, stroke is now the number-five killer—but, in the rest of the world, it is still number two! The findings highlight distressing results on a global scale, and represent many lives that could have been saved or significantly improved with better access to thrombectomy treatments.”

“We believe that insights gained from this study would inform global interventions to improve access to this life-saving treatment and enable researchers to study nuances of the obstacles to it further,” added Kaiz Asif (University of Illinois, Chicago, USA), corresponding and first author of the study. “While we continue to work on innovations in surgical treatments and technologies, we are also determined to expedite their dissemination— through Mission Thrombectomy—to a large majority across the world to whom they are not yet available.”