Neurological Deterioration May Play a Factor in Stroke Outcome

Results from a prospective observational study that included 29,446 patients with acute ischemic stroke (AIS) suggest that neurological deterioration (ND) should be taken into consideration as a factor that may influence the patient’s outcome in AIS.

Among the total number of patients with AIS admitted to 15 hospitals in Korea within 7 days of stroke onset, ND occurred in 4299 (14.6%) patients. Investigators expressed the incidence of ND as the number of events over person-hours at 11 different intervals, noting that the highest rate, 6.95 (95% CI, 6.26—7.71) per 1000 person-hours, was within the first 6 hours, which decreased to 2.09 within 24–48 hours and 0.66 within 72–96 hours after stroke onset.

The time-dependent changes in the incidence of ND differed according to age, recanalization therapy, and stroke mechanisms, but did not differ by sex. Those who received recanalization therapy had a higher incidence of ND compared to those who did not within 24 hours of onset, but not afterward (ND 26.6%; Non-ND 14.3%; unadjusted RR, 2.17; 95% CI 2.01—2.34).

“Our findings also suggest that even seemingly minor or transient ND may be associated with a poor functional outcome. ND should be taken into consideration as a factor that may influence the outcome in acute ischemic stroke,” study author Tai Hwan Park, MD, PhD, department of neurology, Seoul Medical Center, and colleagues concluded.

ND was defined as an increase in National Institutes of Health Stroke Scale (NIHSS) score ≥2, or an increase of ≥1 in any of the NIHSS subscores that focus on consciousness and motor functionality. Park and colleagues assessed change of incidence rate after stroke onset, causes, factors associated with ND, modified Rankin Scale (mRS) at 3 months and 1 year, and a compositive of stroke, myocardial infarction, and all-cause death at 1 year.

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Poor functional outcome represented as mRS scores 3—6 occurred in 70.1% of patients with ND and 29.7% of patients without ND at 3 months, respectively. Furthermore, 67.6% of patients with ND had poor functional outcome at 1 year compared to 29.3% of those without ND.

The crude relative risks (RRs) for poor functional outcomes of ND at 3 months and 1 year were 2.36 (95% CI, 2.29—2.43) and 2.31 (95% CI, 2.24–2.37), respectively. Additionally, the risk of poor functional outcome decreased with adjustment for age, sex, and initial NIHSS score, but was relatively constant in analyses that adjusted for further covariates. If ND was defined as an NIHSS score ≤1 point, fully adjusted RRs for poor functional outcomes at 3 months and 1 year were 1.54 (95% CI, 1.45–1.63) and 1.46 (95% CI, 1.37–1.55), respectively.

They also observed that the risk of ND was 3 times higher in patients who visited the hospital within 6 hours (18.3%) than those who visited after 72 hours (6.4%). When observing the underlying causes of ND, stroke progression accounted for the highest effect (71.8%), followed by stroke recurrence (8.5%), hemorrhage transformation (6.1%) and others (4.9%).

Half of the cases of ND during the 7—14 days after stroke were attributable to more than 7 out of every 10 NDs that occurred during the first 72 hours. Additionally, the proportion of recurrent strokes increased from 3.5% in the first 12 hours to 25.7% during the 7–14 days after stroke. Transient ischemic attacks (TIAs) accounted for fewer than 1% of all ND cases but comprised of 8% of all patients.

When discussing the higher frequency of stroke recurrence during the first few days of stroke, Park and colleagues noted, “This distinction between progression and recurrence as causes of ND, and their clinical implications, remain unclear. However, the fact that most of the causes of early ND were progression accompanying extension of existing ischemic lesions suggests the need for effective therapeutic strategies for treating early ND.”

REFERENCE

Park TH, Lee JK, Park MS, et al. Neurological deterioration in patients with acute ischemic stroke or transient ischemic attack. Neurology. Published online August 14, 2020. doi: 10.1212/WNL.0000000000010603