Higher Frequency of Premature Atrial Contractions Correlates With Atrial Fibrillation Detection after Cryptogenic 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.

Magnetic Resonance Imaging-Guided Intravenous Thrombolysis in Cardioembolic Stroke Patients With Unknown Time of Onset　- Subanalysis of the THAWS Randomized Control Trial.

BACKGROUND: We investigated the clinical effect of intravenous thrombolysis using a magnetic resonance imaging (MRI)-guided approach in cardioembolic stroke (CE) patients with unknown time of onset. METHODS AND RESULTS: This subanalysis of the THAWS trial assessed the efficacy and safety of alteplase 0.6 mg/kg in CE patients with unknown time of onset and showing diffusion-weighted imaging-fluid-attenuated inversion recovery mismatch. Patients were classified as CE and non-CE using the SSS-TOAST classification system during the acute period. The efficacy outcome was a modified Rankin Scale score of 0-1 at 90 days. In all, 126 patients from the THAWS trial were included in this study, of whom 45 (35.7%) were diagnosed with CE. In the CE group, a favorable outcome was numerically more frequent in the alteplase than control group (52% vs. 35%; adjusted odds ratio [aOR] 2.25; 95% confidence interval [CI] 0.50-9.99). However, in the non-CE group, favorable outcomes were comparable between the alteplase and control groups (44% vs. 55%, respectively; aOR 0.39; 95% CI 0.12-1.21). Treatment-by-cohort interaction for a favorable outcome was modestly significant between the CE and non-CE groups (P=0.069). In the CE group, no patients experienced symptomatic intracranial hemorrhage (ICH) or parenchymal hematoma Type II following thrombolysis. CONCLUSIONS: When an MRI-guided approach is used, CE patients with unknown time of onset appear to be suitable candidates for thrombolysis.

P-wave terminal force in lead V1 and atrial fibrillation burden in cryptogenic stroke with implantable loop recorders.

Implantable loop recorders (ILRs) are useful for the detection of atrial fibrillation (AF) in patients with cryptogenic stroke (CS). P-wave terminal force in lead V1 (PTFV1) is associated with AF detection; however, data on the association between PTFV1 and AF detection using ILRs in patients with CS are limited. Consecutive patients with CS with implanted ILRs from September 2016 to September 2020 at eight hospitals in Japan were studied. PTFV1 was calculated by 12-lead ECG before ILRs implantation. An abnormal PTFV1 was defined as ≥ 4.0 mV × ms. The AF burden was calculated as a proportion based on the duration of AF to the total monitoring period. The outcomes included AF detection and large AF burden, which was defined as ≥ 0.5% of the overall AF burden. Of 321 patients (median age, 71 years; male, 62%), AF was detected in 106 patients (33%) during the median follow-up period of 636 days (interquartile range [IQR], 436-860 days). The median time from ILRs implantation to AF detection was 73 days (IQR, 14-299 days). An abnormal PTFV1 was independently associated with AF detection (adjusted hazard ratio, 1.71; 95% confidence interval [CI], 1.00-2.90). An abnormal PTFV1 was also independently associated with a large AF burden (adjusted odds ratio, 4.70; 95% CI, 2.50-8.80). In patients with CS with implanted ILRs, an abnormal PTFV1 is associated with both AF detection and a large AF burden.Clinical Trial Registration Information: UMIN Clinical Trials Registry 000044366.

High-risk patent foramen ovale and elderly in cryptogenic stroke.

BACKGROUND: High-risk patent foramen ovale (PFO) could be pathological in cryptogenic stroke (CS), but its clinical characteristics have not been fully studied, especially in elderly patients. METHODS: Patients with CS were enrolled in the CHALLENGE ESUS/CS registry, a multicenter registry of CS patients undergoing transesophageal echocardiography. Clinical characteristics were compared among three groups: high-risk PFO group, large shunt PFO (≥25 microbubbles) or PFO with atrial septal aneurysm (ASA); right-to-left shunt (RLS) group, RLS including PFO with <25 microbubbles or without ASA; and no-RLS group. RESULTS: In total, 654 patients were analyzed: 91, 221, and 342 in the high-risk PFO, RLS, and no-RLS groups, respectively. In multinomial logistic regression analysis, the male sex (odds ratio [OR] 1.825 [1.067-3.122]) was independently associated with high-risk PFO, but hypertension (OR, 0.562 [0.327-0.967]), multiple infarctions (OR, 0.601 [0.435-0.830]), and other cardioaortic embologenic risks (OR, 0.514 [0.294-0.897]) were inversely associated with high-risk PFO compared with non-RLS. In 517 patients aged ≥60 years, multiple infarctions (OR, 0.549 [0.382-0.788]) and other cardioaortic embologenic risks (OR, 0.523 [0.286-0.959]) were inversely associated with high-risk PFO. CONCLUSIONS: High-risk PFO had specific clinical characteristics and possible mechanistic associations, and this trend was consistent among CS patients aged ≥60 years. CLINICAL TRIAL REGISTRATION INFORMATION: http://www.umin.ac.jp/ctr/ (UMIN000032957).

Fatal Cerebral Venous Thrombosis in a Pregnant Woman with Inherited Antithrombin Deficiency after BNT162b2 mRNA COVID-19 Vaccination.

Antithrombin deficiency is a high-risk factor for venous thromboembolism during pregnancy, whereas cerebral venous thrombosis is rare. Cerebral venous thrombosis related to coronavirus disease 2019 (COVID-19) vaccines has been reported; however, there are a few reports of cerebral venous thrombosis after a messenger RNA (mRNA) vaccination. A 25-year-old female in her sixth week of pregnancy presented with headache 24 days after BNT162b2 mRNA COVID-19 vaccination. The following day, she presented with altered sensorium and was diagnosed with severe cerebral venous thrombosis. She demonstrated heparin resistance and was found to have an inherited antithrombin deficiency. A heterozygous missense variant in SERPINC1 (c.379T>C, p.Cys127Arg, 'AT Morioka') was detected by DNA analysis. Despite intensive care with unfractionated heparin, antithrombin concentrate, and repeated endovascular treatments, she died on the sixth day of hospitalization. Cerebral venous thrombosis in pregnant women with an antithrombin deficiency can follow a rapid and fatal course. Treatment with unfractionated heparin and antithrombin concentrate may be ineffective in severe cerebral venous thrombosis cases with antithrombin deficiency. Early recognition of antithrombin deficiency and an immediate switch to other anticoagulants may be required. Although the association between cerebral venous thrombosis and the vaccine is uncertain, COVID-19 vaccinations may require careful evaluation for patients with prothrombic factors.

Cardiac and Echocardiographic Markers in Cryptogenic Stroke with Incidental Patent Foramen Ovale.

OBJECTIVE: Some cardiac abnormalities could be a substrate for potential embolic source in cryptogenic stroke (CS). We evaluated whether cardiac and echocardiographic markers were associated with CS in patients with incidental patent foramen ovale (PFO) as defined using the Risk of Paradoxical Embolism (RoPE) score. MATERIALS AND METHODS: Among 677 patients enrolled in a multicenter observational CS registry, 300 patients (44%) had PFOs detected by transesophageal echocardiography. They were classified into probable PFO-related stroke (RoPE score>6, n = 32) and stroke with incidental PFO (RoPE score≤6, n = 268) groups, and clinical characteristics, laboratory findings, cardiac and echocardiographic markers (i.e. brain natriuretic peptide, left atrial [LA] diameter, ejection fraction, early transmitral flow velocity/early diastolic tissue Doppler imaging velocity [E/e'], LA appendage flow velocity, spontaneous echo contrast, atrial septal aneurysm, substantial PFO, and aortic arch plaques), stroke recurrence, and excellent outcome (modified Rankin scale score <2) at discharge were compared. Risk factors for low RoPE scores were determined using multiple logistic regression analysis. RESULTS: Higher brain natriuretic peptide levels (p = 0.032), LA enlargement (p < 0.001), higher E/e' (p = 0.001), lower LA appendage flow velocity (p < 0.001), non-substantial PFO (p = 0.021), and aortic arch plaques (p = 0.002) were associated with the low RoPE score group. Patients with high RoPE scores had excellent outcomes (58% versus 78%, p = 0.035). LA enlargement (age- and sex-adjusted odds ratio, 1.15; 95 % confidence interval, 1.00-1.32; p = 0.039) was an independent predictor of low RoPE scores. CONCLUSIONS: Abnormal cardiac substrate could be associated with CS occurrence in a subset of patients with PFO. Patients with CS who had incidental PFO may be at risk of cardioembolism.

Thrombolysis With Alteplase at 0.6 mg/kg for Stroke With Unknown Time of Onset: A Randomized Controlled Trial.

Background and Purpose- We assessed whether lower-dose alteplase at 0.6 mg/kg is efficacious and safe for acute fluid-attenuated inversion recovery-negative stroke with unknown time of onset. Methods- This was an investigator-initiated, multicenter, randomized, open-label, blinded-end point trial. Patients met the standard indication criteria for intravenous thrombolysis other than a time last-known-well >4.5 hours (eg, wake-up stroke). Patients were randomly assigned (1:1) to receive alteplase at 0.6 mg/kg or standard medical treatment if magnetic resonance imaging showed acute ischemic lesion on diffusion-weighted imaging and no marked corresponding hyperintensity on fluid-attenuated inversion recovery. The primary outcome was a favorable outcome (90-day modified Rankin Scale score of 0-1). Results- Following the early stop and positive results of the WAKE-UP trial (Efficacy and Safety of MRI-Based Thrombolysis in Wake-Up Stroke), this trial was prematurely terminated with 131 of the anticipated 300 patients (55 women; mean age, 74.4±12.2 years). Favorable outcome was comparable between the alteplase group (32/68, 47.1%) and the control group (28/58, 48.3%; relative risk [RR], 0.97 [95% CI, 0.68-1.41]; P=0.892). Symptomatic intracranial hemorrhage within 22 to 36 hours occurred in 1/71 and 0/60 (RR, infinity [95% CI, 0.06 to infinity]; P>0.999), respectively. Death at 90 days occurred in 2/71 and 2/60 (RR, 0.85 [95% CI, 0.06-12.58]; P>0.999), respectively. Conclusions- No difference in favorable outcome was seen between alteplase and control groups among patients with ischemic stroke with unknown time of onset. The safety of alteplase at 0.6 mg/kg was comparable to that of standard treatment. Early study termination precludes any definitive conclusions. Registration- URL: https://www.clinicaltrials.gov; Unique identifier: NCT02002325.

Frequent Premature Atrial Contractions in Cryptogenic Stroke Predict Atrial Fibrillation Detection with Insertable Cardiac Monitoring.

OBJECTIVE: To determine whether frequent premature atrial contractions (PAC) predict atrial fibrillation (AF) in cryptogenic stroke patients, we analyzed the association between frequent PACs in 24-h Holter electrocardiogram recording and AF detected by insertable cardiac monitoring (ICM). METHODS: We retrospectively analyzed a database of 66 consecutive patients with cryptogenic stroke who received ICM implantation between October 2016 and March 2018 at 5 stroke centers. We included the follow-up data until June 2018 in this analysis. We defined frequent PACs as the upper quartile of the 66 patients. We analyzed the association of frequent PACs with AF detected by ICM. RESULTS: Frequent PACs were defined as >222 PACs per a 24-h period. The proportion of patients with newly detected AF by ICM was higher in patients with frequent PACs than those without (50% [8/16] vs. 22% [11/50], p < 0.05). Frequent PACs were associated with AF detection and time to the first AF after adjustment for CHADS2 score after index stroke, high plasma -B-type natriuretic peptide (BNP; >100 pg/mL) or serum -N-terminal pro-BNP levels (>300 pg/mL), and large left atrial diameter (≥45 mm). CONCLUSION: High frequency of PACs in cryptogenic stroke may be a strong predictor of AF detected by ICM.

High Detection Rate of Atrial Fibrillation With Insertable Cardiac Monitor Implantation in Patients With Cryptogenic Stroke Diagnosed by Magnetic Resonance Imaging.

BACKGROUND: Detection and treatment of atrial fibrillation (AF) is a major goal in preventing secondary stroke. Insertable cardiac monitors (ICMs) are available for diagnosis of arrhythmia monitoring in patients with cryptogenic stroke. Magnetic resonance imaging (MRI)-based diagnostic evaluation for acute ischemic stroke subtype classification is common in Japan and can be useful for specific diagnosis of cryptogenic stroke. PURPOSE: We aimed to investigate the detection rate of AF with an ICM in patients with cryptogenic stroke who were diagnosed by MRI. METHODS: We performed a retrospective, multicenter, observational study. AF monitoring data of an ICM (Reveal LINQ) in patients with cryptogenic stroke were registered from 5 stroke centers in Japan between October 2016 and March 2018. ICM candidates in cryptogenic stroke were diagnosed by MRI-based evaluation and selected according to the criteria proposed by the Japan Stroke Society. Detection of AF was defined as AF for longer than 120 seconds. RESULTS: Eighty-four consecutive patients (64 men; aged 38-90 years) underwent ICM implantation after diagnosis of cryptogenic stroke. AF was detected in 22 of 84 (26.2%) patients with an ICM during a median follow-up of 221.5 days (range: 93-365 days). The detection rate of AF within 3 months after ICM implantation was 21.4%. CONCLUSIONS: The AF detection rate with an ICM is approximately one fifth within 3 months in patients with cryptogenic stroke as diagnosed by MRI. Our data suggest that the Japanese criteria based on MRI may be useful for selecting adequate candidates for ICM implantation.

How Commonly Is Stroke Found in Patients with Isolated Vertigo or Dizziness Attack?

BACKGROUND: The sudden development of vertigo or dizziness without focal neurological symptoms is generally attributable to vestibular diseases such as benign paroxysmal positional vertigo. Isolated vertigo or dizziness attack needs more attention than vestibular diseases. This retrospective study was performed to elucidate the frequency of strokes in patients with isolated vertigo or dizziness attack. SUBJECTS AND METHODS: We enrolled 221 patients (men, 119; women, 102; mean age, 68.4 ± 10.3 years) who were admitted to our hospital over the last 10 years because of sudden isolated vertigo or dizziness attack without other neurological symptoms except for nystagmus, deafness, or tinnitus. We investigated the clinical features, final diagnosis, neuroimaging findings, and short- or long-term outcome of these patients. RESULTS: One hundred eighteen patients had vertigo whereas the other 103 had dizziness. Brain computed tomography or magnetic resonance imaging revealed recent stroke lesions in 25 patients (11.3%) (ischemic, 21; hemorrhagic, 4).The lesions were generally small and localized in the cerebellum (n = 21), pons (n = 1), medulla oblongata (n = 1), or corona radiata (n = 1). Of the 25 patients, 19 (76%) had dizzy-type spells; none had neurological dysfunction at the time of discharge. In the remaining 196 patients, no stroke was detected on computed tomography or magnetic resonance imaging. CONCLUSIONS: Stroke was found in 11% of patients with isolated vertigo or dizziness attack. The posterior inferior cerebellar artery area was the most frequently implicated for isolated vertigo or dizziness.

Validation of ultrasound parameters to assess collateral flow via ophthalmic artery in internal carotid artery occlusion.

This study aimed to characterize the flow patterns using ultrasound (US) in the external carotid artery (ECA) in patients with total occlusion of internal carotid artery (ICA) and characterize collateral retrograde flow through the ophthalmic artery (OA, secondary collateral, internalization). This study was performed on 45 patients who were retrospectively selected with total occlusion of the ICA, who underwent digital subtraction angiography (DSA), magnetic resonance angiography (MRA), and US (43 men; mean age 68.1 ± 7.9 years). Collateral retrograde flow and collateral flow through the circle of Willis (primary collateral) were determined by DSA and MRA. We compared several US parameters such as ECA peak systolic velocity, mean velocity, end-diastolic (ED) velocity, pulsatility index (PI), and pulsatility transmission index (PTI). PTI was defined as the ratio of ipsilateral ECA PI to the ipsilateral common carotid artery (CCA). In this patient group, 27 patients showed retrograde flow through OA as assessed by DSA. The presence of primary collateral flow was significantly lower in patients with retrograde flow than without (P < .05). ECA ED velocity was significantly higher, and PI and PTI were significantly lower with retrograde flow through OA than without (P < .05). According to receiver operating characteristic analysis, PTI was the most highly correlated ultrasonologic parameter with internalization (cutoff value, .94; sensitivity, 92.6%; specificity, 94.5%). Using PTI was discriminative to determine internalization of ECA because a collateral pathway through OA in cases of ICA occlusion had less primary collateral pathways.

Acute Respiratory Failure Caused by Lateral Medullary Infarction - An Unknown Condition with Varied Etiology and Requiring Special Vigilance: A Case Series.

Acute respiratory failure (ARF) due to lateral medullary infarction (LMI) can be a fatal condition, although its details remain unclarified. To clarify clinical aspects of ARF due to LMI, we reviewed eight applicable cases treated in a tertiary hospital. Of them, we focused on the detailed clinical course of one case. We clarified that even patients with a serious clinical course may have no apparent magnetic resonance imaging abnormalities in respiratory control centers at the initial examination. We should be mindful that respiratory monitoring is necessary even without infarction of regions responsible for respiratory control at the initial presentation.

Atrial Fibrillation Detection and Ischemic Stroke Recurrence in Cryptogenic Stroke: A Retrospective, Multicenter, Observational Study.

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.

Removal of Insertable Cardiac Monitor for Cryptogenic Stroke: A Technical Note.

OBJECTIVES: Insertable cardiac monitors (ICM) allow continuous long-term electrocardiogram monitoring and the detection of paroxysmal atrial fibrillation (PAF) in patients with cryptogenic stroke (CS). Several years have passed since ICM was indicated for CS, and many stroke neurologists will experience cases in which ICM removal is required. As a standard protocol, reincision of the wound at the time of implantation has been proposed by ICM brands. However, it may be difficult due to adhesions of subcutaneous tissue, migration of the device from its original position, and the capsule formed around the device. Our objective is to describe simple alternative techniques for successful ICM removal. MATERIALS AND METHODS: From December 2016 to September 2021, 37 patients with CS underwent ICM removal at our institution. The device was removed through an incision directly above the proximal end of the device, perpendicular to the wound at the time of ICM implantation. The subcutaneous tissue was removed bluntly using forceps along the edges of the proximal end of the device. When a capsule was attached to the device, we cut the capsule with the blade to release the device. Once the device was visible, the proximal end of the device was grasped with forceps, and the device was pulled from the pocket with gentle traction. All patients undergoing ICM removal received a systematic check for wound dehiscence, wound infection, bleeding, and tissue ischemia at an outpatient examination of 1 week. The 37 patients who underwent removal of ICM were retrospectively reviewed in the medical record and analyzed for procedural success, intraoperative complications, and wound course at one week. RESULTS: All patients achieved procedural success. There were no intraoperative complications, wound dehiscence, bleeding, or skin ischemia at one week postoperatively. The reasons for removal were battery depletion in 65%, early removal before battery life after PAF detection in 32%, and exposure to the body surface in 3%. The devices removed were 62% Reveal LINQ (Medtronic, Minneapolis), 30% Confirm Rx (Abbott, Illinois), and 8% BioMonitor 2 (BIOTRONIK, Berlin), indicating that our method is effective regardless of model. CONCLUSION: We describe a simple technique for ICM removal for CS that is safe, reliable, and potentially effective in wound healing.

Evaluating the Potential Pathology and Short-Term Outcomes of Cryptogenic Stroke Using the Etiological Classification System.

AIM: Various embolic sources and pathogenetic mechanisms underlie cryptogenic stroke (CS). We investigated the association of etiological diversity with short-term outcomes in patients with CS using a modified atherosclerosis (A), small-vessel disease (S), cardiac pathology (C), other causes (O), and dissection (D) (ASCOD) system. METHODS: Patients with CS who underwent transesophageal echocardiography were registered in this multicenter, observational study. In the modified classification system, O and D were inapplicable and thus excluded. Instead, atherosclerosis, small-vessel disease, cardiac pathology-CS classification was specifically constructed for the etiological diagnosis of CS. We utilized this system to explore the mechanism of CS by grading each pathology and evaluated its association with poorer modified Rankin Scale scores of 3-6 at hospital discharge. RESULTS: A total of 672 patients (68.7±12.8 years, 220 females) were analyzed. In the multiple logistic regression model, female sex (odds ratio [OR], 1.87 [1.15-3.04]; P =0.012), body mass index (OR, 0.93 [0.88-0.99]; P =0.025), National Institute of Health Stroke Scale score (OR, 1.16 [1.12-1.21]; P＜0.001), CHADS2 score (OR, 1.56 [1.30-1.86]; P＜0.001), D-dimer (OR, 1.04 [1.01-1.08]; P =0.015), diffusion-weighted image (DWI) lesion size (OR, 1.44 [1.10-1.89]; P =0.009), and S＋C score (OR, 1.26 [1.03-1.56]; P =0.029) were associated with poor functional outcome at discharge whereas the S＋C score was marginally associated with poor functional outcome after excluding 137 patients with a premorbid modified Rankin Scale score of ≥ 3. CONCLUSIONS: The coexistence of small-vessel disease and cardiac pathology might be associated with poor in-hospital functional outcome in CS.

Left atrial appendage flow velocity predicts occult atrial fibrillation in cryptogenic stroke: a CRYPTON-ICM registry.

BACKGROUND: An insertable cardiac monitor (ICM) and transesophageal echocardiography (TEE) are useful for investigating potential embolic sources in cryptogenic stroke, of which atrial fibrillation (AF) is a critical risk factor for stroke recurrence. The association of left atrial appendage flow velocity (LAA-FV) on TEE with ICM-detected AF is yet to be elucidated. METHODS: CRYPTON-ICM (CRYPTOgenic stroke evaluation in Nippon using ICM) is a multicenter registry of cryptogenic stroke with ICM implantation, and patients whose LAA-FV was evaluated on TEE were enrolled. The primary outcome was the detection of AF (> 2 min) on ICM. Receiver operating characteristic (ROC) curve analysis was performed to determine the optimal cut-off of LAA-FV, and factors associated with ICM-detected AF were assessed. RESULTS: A total of 307 patients (age 66.6 ± 12.3 years; 199 males) with median follow-up of 440 (interquartile range 169-726) days were enrolled; AF was detected in 101 patients. The lower-tertile LAA-FV group had older age, more history of congestive heart failure, and higher levels of B-type natriuretic peptide (BNP) or N-terminal proBNP (all P < 0.05). On ROC analysis, LAA-FV < 37.5 cm/s predicted ICM-detected AF with sensitivity of 26.7% and specificity of 92.2%. After adjustment for covariates, the lower tertile of LAA-FV (hazard ratio [HR], 1.753 [1.017-3.021], P = 0.043) and LAA-FV < 37.5 cm/s (HR 1.987 [1.240-3.184], P = 0.004) predicted ICM-detected AF. CONCLUSIONS: LAA-FV < 37.5 cm/s predicts AF. TEE is useful not only to evaluate potential embolic sources, but also for long-term detection of AF on ICM by measuring LAA-FV in cryptogenic stroke. http://www.umin.ac.jp/ctr/ (UMIN000044366).

Intravenous Alteplase at 0.6 mg/kg for Unknown Onset Stroke with Prior Antithrombotic Medication: THAWS Randomized Clinical Trial.

AIM: This study aimed to assess the potential effect of prior antithrombotic medication for thrombolysis in an unknown onset stroke. METHODS: This was a predefined sub-analysis of the THAWS trial. Stroke patients with a time last known well ＞4.5 h who had a DWI-fluid-attenuated inversion recovery mismatch were randomly assigned (1:1) to receive alteplase at 0.6 mg/kg (alteplase group) or standard medical treatment (control group). Patients were dichotomized by prior antithrombotic medication. RESULTS: Of 126 patients (intention-to-treat population), 40 took antithrombotic medication (24 with antiplatelets alone, 13 with anticoagulants alone, and 3 with both), and the remaining 86 did not before stroke onset. Of these, 17 and 52 patients, respectively, received alteplase, and 23 and 34, respectively, had standard medical treatment. Antithrombotic therapy was initiated within 24 h after randomization less frequently in the alteplase group (12% vs. 86%, p＜0.01). Both any intracranial hemorrhage within 22-36 h (26% vs. 14%) and a modified Rankin Scale score of 0-1 at 90 days (good outcome) (47% vs. 48%) were comparable between the two groups. A good outcome was more common in the alteplase group than in the control group in patients with prior antithrombotic medication [relative risk (RR) 2.25, 95% confidence interval (CI) 1.02-4.99], but it tended to be less common in the alteplase group in those without (RR 0.69, 95% CI 0.46-1.03) (p＜0.01 for interaction). The frequency of any intracranial hemorrhage did not significantly differ between the two groups in any patients dichotomized by prior antithrombotic medication. CONCLUSION: Alteplase appears more beneficial in patients with prior antithrombotic medication.

Detection of Atrial Fibrillation Using Insertable Cardiac Monitors in Patients With Cryptogenic Stroke in Japan (the LOOK Study): Protocol for a Prospective Multicenter Observational Study.

BACKGROUND: Paroxysmal atrial fibrillation (AF) is a probable cause of cryptogenic stroke (CS), and its detection and treatment are important for the secondary prevention of stroke. Insertable cardiac monitors (ICMs) are clinically effective in screening for AF and are superior to conventional short-term cardiac monitoring. Japanese guidelines for determining clinical indications for ICMs in CS are stricter than those in Western countries. Differences between Japanese and Western guidelines may impact the detection rate and prediction of AF via ICMs in patients with CS. Available data on Japanese patients are limited to small retrospective studies. Furthermore, additional information about AF detection, including the number of episodes, cumulative episode duration, anticoagulation initiation (type and dose of regimen and time of initiation), rate of catheter ablation, role of atrial cardiomyopathy, and stroke recurrence (time of recurrence and cause of the recurrent event), was not provided in the vast majority of previously published studies. OBJECTIVE: In this study, we aim to identify the proportion and timing of AF detection and risk stratification criteria in patients with CS in real-world settings in Japan. METHODS: This is a multicenter, prospective, observational study that aims to use ICMs to evaluate the proportion, timing, and characteristics of AF detection in patients diagnosed with CS. We will investigate the first detection of AF within the initial 6, 12, and 24 months of follow-up after ICM implantation. Patient characteristics, laboratory data, atrial cardiomyopathy markers, serial magnetic resonance imaging findings at baseline, 6, 12, and 24 months after ICM implantation, electrocardiogram readings, transesophageal echocardiography findings, cognitive status, stroke recurrence, and functional outcomes will be compared between patients with AF and patients without AF. Furthermore, we will obtain additional information regarding the number of AF episodes, duration of cumulative AF episodes, and time of anticoagulation initiation. RESULTS: Study recruitment began in February 2020, and thus far, 213 patients have provided written informed consent and are currently in the follow-up phase. The last recruited participant (May 2021) will have completed the 24-month follow-up in May 2023. The main results are expected to be submitted for publication in 2023. CONCLUSIONS: The findings of this study will help identify AF markers and generate a risk scoring system with a novel and superior screening algorithm for occult AF detection while identifying candidates for ICM implantation and aiding the development of diagnostic criteria for CS in Japan. TRIAL REGISTRATION: UMIN Clinical Trial Registry UMIN000039809; https://tinyurl.com/3jaewe6a. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/39307.

Intravenous recombinant tissue plasminogen activator thrombolysis in acute ischemic stroke due to middle cerebral artery dissection.

Beneficial effect of recombinant tissue plasminogen activator (rtPA) in cerebral arterial dissection is controversial. We experienced a 45-year-old man with acute ischemic stroke due to middle cerebral artery dissection, who was treated with rtPA. Characteristic vascular findings indicating dissection became evident only in subsequent angiographic examinations. Our case indicates that serial angiographic examinations should be essential after acute thrombolytic therapy, especially in young patients who are at a high risk of cerebral arterial dissection.

[Detection of secondary atrial fibrillation following percutaneous foramen ovale closure for cryptogenic stroke using an insertable cardiac monitor: a case report].

A 61-year-old man presented with transient dysarthria and left upper extremity numbness. Head MRI showed an acute infarct in the left temporal lobe and multiple old infarcts in the bilateral cortices. A transesophageal echocardiogram revealed a patent foramen ovale with a large shunt. No deep vein thrombosis was found. He suffered a recurrent cerebral infarction while taking antiplatelet therapy. An insertable cardiac monitor was implanted on the 41st day, and the antiplatelet treatment was changed to warfarin. The insertable cardiac monitor did not detect atrial fibrillation, even when the patient had a recurrent transient ischemic attack on the 57th day under warfarin therapy. The patient underwent percutaneous foramen ovale closure on the 63rd day. On postoperative days 18-25, an insertable cardiac monitor detected brief atrial fibrillation, and he took rivaroxaban for three months. Atrial fibrillation may occur secondary to percutaneous patent foramen ovale closure for cryptogenic stroke. The insertable cardiac monitor may help diagnose the pathogenesis of secondary atrial fibrillation and determine the optimal antithrombotic therapy.