Kiwoong Nam

Nocturnal Desaturation in the Stroke Unit Is Associated With Wake-Up Ischemic Stroke.

Background and Purpose— Wake-up stroke (WUS) represents a quarter of all ischemic strokes and may be a specific subgroup. Nocturnal desaturation secondary to sleep-disordered breathing is an independent risk factor for stroke, but the association between nocturnal desaturation and WUS remains unclear. We investigated the relationship between nocturnal desaturation using oxygen desaturation index and WUS in patients with acute stroke in the stroke unit. Methods— A total of 298 patients admitted for acute ischemic stroke to the stroke unit between July 2013 and May 2015 were enrolled. The oxygen desaturation index was calculated using pulse oximetry data sampled every 1 minute during 9 hours on the first night (10:00 PM–7:00 AM) of the stroke unit admission, and nocturnal desaturation was defined as an oxygen desaturation index of 5 at least per hour. We compared the clinical characteristics and nocturnal desaturations between patients with and without WUS. Results— Among all patients (age, 67.7±12.6 years; male, 54.4%), 26.5% patients had WUS. The proportion of nocturnal desaturation was significantly greater in patients admitted with WUS (29.1% versus 12.3%, P=0.001). The age, sex, risk factors except for hyperlipidemia, stroke severity, and stroke mechanisms were similar between the 2 groups. After adjustment for covariates, it was found that nocturnal desaturation was significantly more common in the WUS group (odds ratio, 3.25; 95% confidence interval, 1.63–6.46). Conclusions— Nocturnal desaturation was more frequently observed in patients admitted with WUS during the first night in the stroke unit. This suggests that nocturnal desaturation is a possible modifiable risk factor for the occurrence of WUS.

Predictors of 30-day mortality and the risk of recurrent systemic thromboembolism in cancer patients suffering acute ischemic stroke

Background Stroke in cancer patients is not rare but is a devastating event with high mortality. However, the predictors of mortality in stroke patients with cancer have not been well addressed. D-dimer could be a useful predictor because it can reflect both thromboembolic events and advanced stages of cancer. Aim In this study, we evaluate the possibility of D-dimer as a predictor of 30-day mortality in stroke patients with active cancer. Methods We included 210 ischemic stroke patients with active cancer. The 30-day mortality data were collected by reviewing medical records. We also collected follow-up D-dimer levels in 106 (50%) participants to evaluate the effects of treatment response on D-dimer levels. Results Of the 210 participants, 30-day mortality occurred in 28 (13%) patients. Higher initial NIHSS scores, D-dimer levels, and CRP levels as well as frequent cryptogenic mechanism, systemic metastasis, multiple vascular territory lesion, hemorrhagic transformation, and larger infarct volume were related to 30-day mortality. In the multivariate analysis, D-dimer [adjusted OR (aOR) = 2.19; 95% CI, 1.46–3.28, P < 0.001] predicted 30-day mortality after adjusting for confounders. The initial NIHSS score (aOR = 1.07; 95% CI, 1.00–1.14, P = 0.043) and hemorrhagic transformation (aOR = 3.02; 95% CI, 1.10–8.29, P = 0.032) were also significant independent of D-dimer levels. In the analysis of D-dimer changes after treatment, the mortality group showed no significant decrease in D-dimer levels, despite treatment, while the survivor group showed the opposite response. Conclusions D-dimer levels may predict 30-day mortality in acute ischemic stroke patients with active cancer.

The presence and severity of cerebral small vessel disease increases the frequency of stroke in a cohort of patients with large artery occlusive disease

Background Cerebral small vessel disease (SVD) commonly coexists with large artery atherosclerosis (LAA). Aim We evaluate the effect of SVD on stroke recurrence in patients for ischemic stroke with LAA. Methods We consecutively collected first-ever ischemic stroke patients who were classified as LAA mechanism between Jan 2010 and Dec 2013. Univariate and multivariate Cox analyses were performed to evaluate the association between the 2-year recurrence and demographic, clinical, and radiological factors. To evaluate the impact of SVD and its components on recurrent stroke, we used the Kaplan-Meier analysis. SVD was defined as the presence of severe white matter hyperintensity (WMH) or old lacunar infarction (OLI) or cerebral microbleeds (CMB). We also compared frequency and burden of SVD among recurrent stroke groups with different mechanisms. Results Among a total of 956 participants, 92 patients had recurrent events. Recurrence group showed a higher frequency of severe WMH, OLI, asymptomatic territorial infarction, and severe stenosis on the relevant vessel in multivariate analysis. The impact of SVD and its components on recurrent stroke was significant in any ischemic recurrent stroke, and the presence of SVD was continuously important in stroke recurrence regardless of its mechanism, including recurrent LAA stroke, recurrent small vessel occlusion stroke, and even recurrent cardioembolic stroke. Additionally, the recurrence rate increased in dose-response manner with the increased number of SVD components. Conclusions Cerebral SVD is associated with recurrent stroke in patients with LAA. Additionally, it may affect any mechanisms of recurrent stroke and even with a dose response manner.

Severe White Matter Hyperintensity Is Associated with Early Neurological Deterioration in Patients with Isolated Pontine Infarction

Objective: Pontine infarction is a common type of brain stem infarction and early neurological deterioration (END). We evaluated the possibility of severe white matter hyperintensity (WMH) as a predictor of END in isolated pontine infarction. Methods: We recruited 2 types of patients with isolated pontine infarction within 24 h from symptom onset. END was defined as an increase of ≥1 point on the motor National Institutes of Health Stroke Scale (NIHSS) or ≥2 points on the total NIHSS score within 72 h from admission. We graded WMH using Fazekas scale, which is dichotomized into mild (grades 0-1) and moderate to severe (grades 2-3) on fluid-attenuated inversion recovery images. Results: A total of 82 patients with an isolated pontine infarction were selected. END was detected in 23 patients (28%). Severe periventricular and subcortical WMH (PVWMH and SCWMH, respectively) were more frequent in deteriorating patients (p = 0.001 and p = 0.019, respectively). A logistic regression analysis revealed that both severe PVWMH (OR 6.17; 95% CI 1.93-19.75, p = 0.002) and SCWMH (OR 3.19; 95% CI 1.10-9.23, p = 0.032) remained independent predictors of END. Conclusions: Both severe PVWMH and SCWMH were useful to predict END in patients with isolated pontine infarction.

Temporal changes in the neutrophil to lymphocyte ratio and the neurological progression in cryptogenic stroke with active cancer

Background Ischemic stroke patients with active cancer frequently experience early neurological deterioration (END); however, the predictors of END are not well studied. The neutrophil to lymphocyte ratio (NLR) has recently been described as a predictor of poor outcomes in cancer and stroke. However, its role in cancer-related stroke has not been addressed. Aim We aimed to evaluate the association between the NLR and END in cancer-related stroke patients. Methods We included 85 cryptogenic stroke patients with active cancer. END was defined as an increase ≥ 4 on the total National Institutes of Health Stroke Scale (NIHSS) score within 72 hours of admission. The NLR was calculated as the ratio of the absolute neutrophil count to the absolute lymphocyte count. We obtained the NLR during the following three periods: at admission, 1–3 days after admission (D 1–3 NLR) and 4–7 days after admission (D 4–7 NLR). Results END occurred in 15 (18%) of the 85 patients. END was significantly associated with the initial NIHSS score, infarction volume, and the D 1–3 NLR. In multivariate analysis, a higher D 1–3 NLR, measured before END events, remained an independent predictor of END [adjusted odds ratio = 2.78, 95% confidence interval = 1.09–7.08, P = 0.032]. In terms of temporal changes in the NLR, the END group showed a tendency toward temporal increase in the NLR at D 1–3 (P = 0.061) with subsequent decrements in the D 4–7 NLR (P = 0.088), while the non-END group showed no significant changes in the NLR between periods. Conclusions This study demonstrated that a higher NLR could predict END events in cryptogenic stroke patients with active cancer. However, the results should be confirmed in further large prospective studies.

FLAIR vascular hyperintensities predict early ischemic recurrence in TIA

Objective To evaluate the relationship between fluid-attenuated inversion recovery (FLAIR) vascular hyperintensity (FVH) and early ischemic lesion recurrence (follow-up diffusion-weighted imaging [FU-DWI] [+]) in patients with lesion-negative TIA. Methods We recruited consecutive patients with lesion-negative TIA within 24 hours of symptom onset, who underwent follow-up MRI during the acute period. FVH was defined as a focal or serpentine high signal intensity on FLAIR images. Other potential confounders were adjusted to evaluate the relationship between FVH and FU-DWI (+). Furthermore, to compare clinical outcomes between the FU-DWI (+) and FU-DWI (−) groups, we assessed 1-year recurrent ischemic stroke or TIA. Results Among 392 patients with lesion-negative TIA, 82 patients had FU-DWI (+) on the follow-up MRI. In the multivariate analysis, FVH remained an independent predictor of FU-DWI (+) (adjusted odds ratio [aOR] = 4.77, 95% confidence interval [CI] 2.45–9.29, p < 0.001). The time to initial MRI (aOR = 0.49, 95% CI = 0.33–0.70, p < 0.001) and intracranial atherosclerosis (aOR = 2.07, 95% CI = 1.10–3.92, p = 0.025) were also associated with FU-DWI (+), independent of FVH. In clinical outcomes, the FU-DWI (+) group showed more frequent 1-year recurrent ischemic stroke events than the FU-DWI (−) group (10.7% vs 3.1%, respectively, p = 0.007). Conclusions FVH is associated with FU-DWI (+) in patients with lesion-negative TIA. As FU-DWI (+) frequently occurs during the acute period and has a subsequent worse outcome after discharge, additional radiologic or clinical markers for it are necessary.

Nocturnal Desaturation is Associated With Neurological Deterioration Following Ischemic Stroke: A Retrospective Observational Study

STUDY OBJECTIVES The mechanism of early neurological deterioration (END) in patients with stroke remains unclear. We assessed the relationship between nocturnal oxygen desaturation (NOD) in the stroke unit (SU) and END, especially occurring at nighttime, following acute stroke. METHODS A retrospective analysis was performed on a total of 276 patients with ischemic stroke who were admitted to the SU between July 2013 and June 2015. The oxygen desaturation index was calculated from pulse oximetry data sampled every 1 minute during 9 hours on the first night (10:00 PM to 7:00 AM) after admission, and NOD was defined as oxygen desaturation index ≥ 5 events/h. END was defined as an increase of ≥ 2 points from the baseline National Institutes of Health Stroke Scale during 7 days after onset. We compared clinical characteristics and NOD between patients with and without END. RESULTS Among the included patients (mean age 69.2; male 55.4%), 42 patients (15.2%) experienced END. The proportion of NOD was significantly greater in the END group (45.2% versus 12.8%, P < .001). After adjusting for confounders, NOD was independently associated with END (odds ratio 7.57; 95% confidence interval 3.14-18.27). Among END patients, 47.6% patients (n = 20) had END during nighttime. Moreover, NOD was more frequent in patients with END during nighttime compared to those with END during daytime (73.7% versus 26.1%, P = .002). CONCLUSIONS NOD in the SU was associated with END, especially during nighttime, after ischemic stroke. This suggests that treatment of sleep-disordered breathing could be a modifiable factor to possibly reduce the risk of neurological worsening among acute stroke patients.