Mechanical Stroke Thrombectomy Cost-effective in Late Time Windows

(UPDATED) Mechanical thrombectomy, already shown to improve functional outcomes in appropriately selected patients with acute ischemic stroke who present up to 24 hours after symptom onset, is also highly cost-effective in this scenario, researchers found.

Using data from the DAWN and DEFUSE 3 trials, a team led by Anne-Claire Peultier, MSc (Erasmus School of Health Policy and Management, Rotterdam, the Netherlands), showed that adding thrombectomy to standard medical care was at least cost-effective—if not cost-saving—across all of the more than two dozen subgroups included in the analysis.

“This study provides the health-economic evidence that was needed to determine whether the short-term functional benefit of late mechanical thrombectomy (observed in the DAWN and DEFUSE 3 trials) translates to cost-effectiveness in the United States over a lifetime,” Peultier told TCTMD in an email.

In their paper, published online August 25, 2020, ahead of print in JAMA Network Open, she and her colleagues say the results also “suggest that attention should be placed on increasing access to mechanical thrombectomy rather than on developing subgroup-specific guidelines unless workforce and budget constraints require prioritization.”

Pooja Khatri, MD (University of Cincinnati, OH), who was not involved in the study, said she was not surprised by the findings. “They’re exactly what I’d expect, because based on the numbers needed to treat that we’ve been seeing with these trials, we know that they’re some of the lowest in medicine. And so it’s sort of expected that we would get a highly cost-effective result with a formal cost-effectiveness analysis,” she told TCTMD.

Asked about the implications regarding the use of stroke thrombectomy, Khatri responded, “The field has been changing so fast that one might even experience a sense of maybe we’re moving too fast, but I think these findings just really reinforce that this is absolutely the right thing to do and that we need to set up our systems to make it happen. I think it’s just that simple.”

I think these findings just really reinforce that this is absolutely the right thing to do and that we need to set up our systems to make it happen. I think it’s just that simple. Pooja Khatri

The field has indeed evolved quickly in recent years after several trials established that mechanical thrombectomy—primarily with stent retrievers—boosts functional outcomes in patients with large-vessel occlusion strokes. Those initial trials, however, evaluated treatment up to 6 hours after stroke onset.

That changed when the results of the 206-patient DAWN trial, released in 2017, showed that carefully selected patients presenting 6 to 24 hours after they were last seen healthy derived a benefit from thrombectomy. The following year, the 182-patient DEFUSE 3 trial showed a benefit in patients presenting up to 16 hours after they were last known well. Combined, the two trials prompted guideline writers to extend the treatment window up to 24 hours.

Peultier et al used data from those two trials and other sources to evaluate the cost-effectiveness of thrombectomy—on top of standard medical care—when performed 6 to 24 hours after symptom onset from a US healthcare perspective.

The models showed that the addition of endovascular therapy increased both cost and quality-adjusted life-years (QALYs), resulting in incremental cost-effectiveness ratios of $662/QALY in DAWN and $13,877/QALY in DEFUSE 3.

Thrombectomy improved clinical outcomes at 90 days across all 29 subgroups of patients defined by time from stroke onset, age, National Institutes of Health Stroke Scale (NIHSS) score, mode of presentation, clinical infarct mismatch, occlusion location, time symptoms were first observed, and trial eligibility criteria.

The procedure was cost-effective across all subgroups, and it was cost-saving in eight of 18 DAWN subgroups. Overall, the probability that thrombectomy was cost-effective versus standard medical care alone was at least 99.9% at a willingness-to-pay threshold of $100,000 per QALY and at least 97.5% at a threshold of $50,000 per QALY. The greatest uncertainty about cost-effectiveness was seen in patients with an NIHSS score of 16 or greater and those 80 or older.

“It seems pretty clear from the data that it’s highly cost-effective, whether you use the threshold of less than $50,000 per QALY or less than $100,000 per QALY, which are benchmarks in medicine in the United States,” Khatri commented.

The investigators delve into the implications of the findings. “Acute stroke treatment guidelines and quality measures should focus on increasing access to mechanical thrombectomy for all eligible US patients rather than on tailoring policies that prioritize specific subgroups,” they say. “Specifically, policies are needed to improve stroke recognition and transportation to comprehensive stroke centers (providing mechanical thrombectomy) in light of the cost-effectiveness of [the procedure], which does not depreciate significantly by stroke severity or age.”

If additional thrombectomy trials are performed, however, “our results suggest potential value in reducing the uncertainty regarding the cost-effectiveness of mechanical thrombectomy in certain subgroups,” such as those with higher NIHSS scores and the oldest patients, they add. That would serve to refine the degree of cost-effectiveness in these groups.