高下 純平

BACKGROUND AND AIM: To investigate the prognostic implication of body mass index (BMI) on clinical outcomes after acute ischemic and hemorrhagic stroke. METHODS: The subjects of the study included adult patients with available baseline body weight and height data who had suffered an acute stroke and were registered in the Japan Stroke Data Bank-a hospital-based, multicenter stroke registration database-between January 2006 and December 2020. The outcome measures included unfavorable outcomes defined as a modified Rankin Scale (mRS) score of 5-6 and favorable outcomes (mRS 0-2) at discharge, and in-hospital mortality. Mixed effects logistic regression analysis was conducted to determine the relationship between BMI categories (underweight, normal weight, overweight, class I obesity, class II obesity; <18.5, 18.5-23.0, 23.0-25.0, 25-30, ⩾30 kg/m2) and the outcomes, after adjustment for covariates. RESULTS: A total of 56,230 patients were assigned to one of the following groups: ischemic stroke (IS, n = 43,668), intracerebral hemorrhage (ICH, n = 9741), and subarachnoid hemorrhage (SAH, n = 2821). In the IS group, being underweight was associated with an increased likelihood of unfavorable outcomes (odds ratio, 1.47 (95% confidence interval (CI):1.31-1.65)) and in-hospital mortality (1.55 (1.31-1.83)) compared to outcomes in those with normal weight. Being overweight was associated with an increased likelihood of favorable outcomes (1.09 (1.01-1.18)). Similar associations were observed between underweight and these outcomes in specific IS subtypes (cardioembolic stroke, large artery stroke, and small-vessel occlusion). Patients with a BMI ⩾30.0 kg/m2 was associated with an increased likelihood of unfavorable outcomes (1.44 (1.01-2.17)) and in-hospital mortality (2.42 (1.26-4.65)) in large artery stroke. In patients with ICH, but not those with SAH, being underweight was associated with an increased likelihood of unfavorable outcomes (1.41 (1.01-1.99)). CONCLUSIONS: BMI substantially impacts functional outcomes following IS and ICH. Lower BMI consistently affected post-stroke disability and mortality, while higher BMI values similarly affected these outcomes after large artery stroke.

BACKGROUND: Covert atrial fibrillation (AF) is a major cause of cryptogenic stroke. This study investigated whether a dose-dependent relationship exists between the frequency of premature atrial contractions (PACs) and AF detection in patients with cryptogenic stroke using an insertable cardiac monitor (ICM). METHODS: We enrolled consecutive patients with cryptogenic stroke who underwent ICM implantation between October 2016 and September 2020 at 8 stroke centers in Japan. Patients were divided into 3 groups according to the PAC count on 24-hour Holter ECG: ≤200 (group L), >200 to ≤500 (group M), and >500 (group H). We defined a high AF burden as above the median of the cumulative duration of AF episodes during the entire monitoring period. We evaluated the association of the frequency of PACs with AF detection using log-rank trend test and Cox proportional hazard model and with high AF burden using logistic regression model, adjusting for age, sex, CHADS2 score. RESULTS: Of 417 patients, we analyzed 381 patients with Holter ECG and ICM data. The median age was 70 (interquartile range, 59.5-76.5), 246 patients (65%) were males, and the median duration of ICM recording was 605 days (interquartile range, 397-827 days). The rate of new AF detected by ICM was higher in groups with more frequent PAC (15.5%/y in group L [n=277] versus 44.0%/y in group M [n=42] versus 71.4%/y in group H [n=62]; log-rank trend P<0.01). Compared with group L, the adjusted hazard ratios for AF detection in groups M and H were 2.11 (95% CI, 1.24-3.58) and 3.23 (95% CI, 2.07-5.04), respectively, and the adjusted odds ratio for high AF burden in groups M and H were 2.57 (95% CI, 1.14-5.74) and 4.25 (2.14-8.47), respectively. CONCLUSIONS: The frequency of PACs was dose-dependently associated with AF detection in patients with cryptogenic stroke.

BACKGROUND: Atrial fibrillation (AF) is known to be a strong risk factor for stroke. However, the risk of stroke recurrence in patients with cryptogenic stroke with AF detected after stroke by an insertable cardiac monitor (ICM) is not well known. We sought to evaluate the risk of ischemic stroke recurrence in patients with cryptogenic stroke with and without ICM-detected AF. METHODS AND RESULTS: We retrospectively reviewed patients with cryptogenic stroke who underwent ICM implantation at 8 stroke centers in Japan. Cox regression models were developed using landmark analysis and time-dependent analysis. We set the target sample size at 300 patients based on our estimate of the annualized incidence of ischemic stroke recurrence to be 3% in patients without AF detection and 9% in patients with AF detection. Of the 370 patients, 121 were found to have AF, and 110 received anticoagulation therapy after AF detection. The incidence of ischemic stroke recurrence was 4.0% in 249 patients without AF detection and 5.8% in 121 patients with AF detection (P=0.45). In a landmark analysis, the risk of ischemic stroke recurrence was not higher in patients with AF detected ≤90 days than in those without (hazard ratio, 1.47 [95% CI, 0.41-5.28]). In a time-dependent analysis, the risk of ischemic stroke recurrence did not increase after AF detection (hazard ratio, 1.77 [95% CI, 0.70-4.47]). CONCLUSIONS: The risk of ischemic stroke recurrence in patients with cryptogenic stroke with ICM-detected AF, 90% of whom were subsequently anticoagulated, was not higher than in those without ICM-detected AF.

BACKGROUND AND OBJECTIVE: The association between focal vs nonfocal presenting symptom and diffusion-weighted imaging (DWI) positivity in relation to onset-to-imaging time in patients with transient neurologic events remains unclear. We hypothesize that episodes consisting of focal symptoms would have proportionally higher DWI-positive imaging at later onset-to-imaging times. METHODS: Patients with transient neurologic symptoms and a normal neurologic examination who had DWI in the combined data set of 3 cohort studies were included. We used logistic regression models to evaluate the association between each type of presenting symptom (motor weakness, speech impairment, sensory symptoms, vision loss, diplopia, gait instability, dizziness, headache, presyncope, and amnesia) and DWI positivity after adjusting for clinical variables (age, sex, history of stroke, dyslipidemia, coronary artery disease, atrial fibrillation, symptoms duration [<10, 10-59, ≥60 minutes, or unclear], and study source). We stratified the results by onset-to-imaging time categories (<6 hours, 6-23 hours, and ≥24 hours). RESULTS: Of the total 2,411 patients (1,345 male, median age 68 years), DWI-positive lesions were detected in 598 patients (24.8%). The prevalence of DWI positivity was highest in those with motor weakness (34.7%), followed by speech impairment (33.5%). In a multivariable analysis, the presence of motor weakness, speech impairment, and sensory symptoms was associated with DWI positivity, while vision loss and headache were associated with lower odds of DWI positivity, but nevertheless had 13.6% and 15.3% frequency of DWI positive. The odds of being DWI positive varied by onset-to-imaging time categories for motor weakness, with greater odds of being DWI positive at later imaging time (<6 hours: odds ratio [OR] 1.25, 95% confidence interval [CI] 0.84-1.87; 6-23 hours: OR 2.24, 95% CI 1.47-3.42; and ≥24 hours: OR 2.42, 95% CI 1.74-3.36; interaction p = 0.033). Associations of other symptoms with DWI positivity did not vary significantly by time categories. DISCUSSION: We found that onset-to-imaging time influences the relationship between motor weakness and DWI positivity in patients with transient neurologic events. Compared with motor, speech, and sensory symptoms, visual or nonfocal symptoms carry a lower but still a substantive association with DWI positivity.

AIM: The nationwide verification of intravenous thrombolysis (IVT) was rarely performed after the extension of the therapeutic time window of alteplase or after the expansion of mechanical thrombectomy (MT). We aimed to examine the long-term change in accurate real-world outcomes of IVT in patients with acute ischemic stroke (AIS) using the Japan Stroke Databank, a representative Japan-wide stroke database. METHODS: We extracted all patients with AIS who received IVT with alteplase between October 11, 2005, the approval date for alteplase use for AIS in Japan, and December 31, 2020. Patients were categorized into three groups using two critical dates in Japan as cutoffs: the official extension date of the therapeutic time window for IVT to within 4.5 h of symptom onset and the publication date of the revised guideline, where the evidence level of MT was heightened. We assessed the yearly trend of IVT implementation rates and the secular changes and three-group changes in clinical outcomes at discharge. RESULTS: Of 124,382 patients with AIS, 9,569 (7.7%) received IVT (females, 41%; median age, 75 years). The IVT implementation rate has generally increased over time and plateaued in recent years. The proportion of favorable outcomes (modified Rankin Scale score of 0-2) increased yearly over 15 years. The results of the changes in the outcomes of the three groups were similar to those of the annual changes. CONCLUSIONS: We revealed that IVT implementation rates in patients with AIS increased, and the functional outcome in these patients improved over 15 years. Therefore, the Japanese IVT dissemination strategy is considered appropriate and effective.