Markov model analysis showed an average gain of 39 days of disability-free life for every 10 minutes of earlier treatment with EVT.
Wolfgang G. Kunz, MD
Based on findings from an analysis of stroke treatment times, investigators suggest that healthcare policies to implement efficient pre-hospital triage and accelerate in-hospital workflow may be needed after they found that any time delay to endovascular therapy (EVT) reduced quality-adjusted life years (QALY) and decreased the economic value of care provided by this intervention.1
Markov model analysis showed an average gain of 39 days (95% prediction interval, 23–53 days) of disability-free life for every 10 minutes of earlier treatment with EVT.
For each 10-minute interval, the net monetary benefit (NMB) increased by $10,593 (95% prediction interval, $5549–$14,847) and by $10,915 (95% prediction interval, $5928–$15,356) from health care and societal perspectives, respectively. The researchers combined weighted QALYs and costs into 1 composite outcome, NMB.
The study concluded 849 patients with a large vessel occlusion (LVO) stroke at 65 years of age who were among participants in intervention arms across 7 EVT trials. Wolfgang G. Kunz, MD, associate professor of radiology, Ludwig-Maximilians-University of Munich, and the HERMES collaborators were among those who conducted the study.
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Patients also gained an estimated 106 additional days of life in functional independence (95% prediction interval, 64–144 days) when EVT treatment was expedited by 10 minutes. Gained days of life in functional independence represented the additional cumulative time the simulated patient spent in the health states modified Rankin Scale (mRS) score 0–2 across the lifetime projection.
The similar accumulation of costs over time with later treatment were explained by the higher mortality rates, which resulted in proportionally lower acute costs within 90 days, thus equating a shorter overall life expectancy to overall lower long-term costs.
For early treatment within 60 to 119 minutes, EVT led to an average NMB of $425,738 from the health care perspective, adding on average more than $300,000 in care value compared to treatment within 360 to 419 minutes.
Kunz and colleagues also looked at the data from a nationwide perspective for the United States. They found that a median reduction of treatment time by 10 minutes was estimated to grant the annual patients with stroke treated with EVT 2440 additional QALYs (95% prediction interval, 1464–3316). Faster treatment by 10 minutes would increase the NMB of EVT by an estimated $242 million per year from a healthcare perspective (95% prediction interval, $127M–$339M) and $249 million from a societal perspective (95% prediction interval, $135M–$351M).
The sensitivity analyses confirmed that each later treatment has an annual continuous effect on QALYs, the percentage of patients living with functional independence, and the cumulative mortality.
Investigators used the age-specific annual death rate of the general population drawn from the United States Life Table. Hazard rate ratios by mRS health states reported by contemporary cohort studies were used to calculate the excess death rate of stroke survivors.
Understanding the outcomes of EVT has been continually examined within the stroke research community. A case-control study published in August indicated that patients with anterior circulation LVO presenting very late (>16 hours to 10 days) from their last well known (LKW) time can still benefit from EVT, despite notions that the therapy can only be effective in a window less than 16 to 24 hours from LKW.2
Age can also play a factor in outcomes of EVT. In Kunz et al, investigators performed an analysis on patients with a stroke onset at the age of 65. Recently published data from the MR CLEAN registry revealed that older age is associated with an increased absolute risk of poor clinical outcome in patients with acute ischemic stroke (AIS) treated with EVT, while the relative benefit of successful reperfusion seems to be high.3