The value of transesophageal echocardiography for embolic strokes of undetermined source

Management of Patients with Patent Foramen Ovale and Cryptogenic Stroke: An Update

Patent foramen ovale (PFO) is a common benign finding in healthy subjects, but its prevalence is higher in patients with stroke of unclear cause (cryptogenic stroke). PFO is believed to be associated with stroke through paradoxical embolism, and certain clinical and anatomical criteria seem to increase the likelihood of a PFO to be pathological. Recent trials have shown that closure of PFO, especially if associated with an atrial septal aneurysm and/or a large interatrial shunt, may reduce the risk of recurrent stroke as compared to medical treatment. However, it remains challenging to risk stratify patients with suspected PFO-related stroke and to decide if device closure is indicated. We sought to review contemporary evidence and to conclude an evidence-based strategy to prevent recurrence of PFO-related stroke.

Prolonged Cardiac Rhythm Monitoring and Secondary Stroke Prevention in Patients With Cryptogenic Cerebral Ischemia

Background and Purpose- Although prolonged cardiac rhythm monitoring (PCM) can reveal a substantial proportion of ischemic stroke (IS) patients with atrial fibrillation not detected by conventional short-term monitoring, current guidelines indicate an uncertain clinical benefit for PCM. We evaluated the impact of PCM on secondary stroke prevention using data from available to date randomized clinical trials and observational studies. Methods- We performed a comprehensive literature search in MEDLINE, SCOPUS, CENTRAL (Cochrane Central Register of Controlled Trial), and conference proceedings to identify studies reporting stroke recurrence rates in patients with history of cryptogenic IS or transient ischemic attack (TIA) receiving PCM compared with patients receiving conventional (non-PCM) cardiac monitoring. Results- We included 4 studies (2 randomized clinical trials and 2 observational studies), including a total of 1102 patients (mean age: 68 years, 41% women). We documented an increased incidence of atrial fibrillation detection (risk ratio=2.46; 95% CI, 1.61-3.76) and anticoagulant initiation (risk ratio=2.07; 95% CI, 1.36-3.17) and decreased risk of recurrent stroke (risk ratio=0.45; 95% CI, 0.21-0.97) and recurrent stroke/TIA (risk ratio=0.49; 95% CI, 0.30-0.81) during follow-up for IS/TIA patients who underwent PCM compared with IS/TIA patients receiving conventional cardiac monitoring. In the subgroup analysis, according to study type, atrial fibrillation detection, anticoagulant initiation, and IS/TIA recurrence rates were comparable between PCM and non-PCM in randomized clinical trials and observational studies. No evidence of heterogeneity (I²<12%) was documented across all the aforementioned subgroups. Conclusions- We provide preliminary evidence for a potential impact of PCM on secondary stroke prevention, as patients with cryptogenic IS/TIA undergoing PCM had higher rates of atrial fibrillation detection, anticoagulant initiation, and lower stroke recurrence.

Incidence, characteristics and outcomes in patients with embolic stroke of undetermined source: A population-based study

Embolic stroke of undetermined source (ESUS) represents a subgroup of cryptogenic ischemic stroke (CS) distinguished by high probability of an underlying embolic mechanism. There are scarce population-based data regarding the incidence, characteristics and outcomes of ESUS. Consecutive patients included with first-ever ischemic stroke of undetermined cause in the previously published population-based Evros Stroke Registry were further subdivided into ESUS and non-ESUS CS. Crude and adjusted [according to the European Standard Population (ESP), WHO and Segi population] incidence rates (IR) for ESUS and non-ESUS CS were calculated. Baseline characteristics, admission stroke severity (assessed using NIHSS-score), stroke recurrence and functional outcomes [determined by modified Rankin Scale (mRS) scores], were recorded during the 1-year follow-up period. We identified 21 and 242 cases with ESUS (8% of CS) and non-ESUS CS. The crude and ESP-adjusted IR for ESUS were 17.5 (95%CI: 10-25) and 16.6 (95%CI: 10-24) per 100,000 person-years. Patients with ESUS were younger (p < .001) and had lower median admission NIHSS-scores (p < .001). Functional outcomes were more favorable in ESUS at 28, 90 and 365 days. ESUS was independently (p = .033) associated with lower admission NIHSS-scores (unstandardized linear regression coefficient: -13.34;95%CI: -23.34, -3.35) on multiple linear regression models. ESUS was not related to 1-year stroke recurrence, mortality and functional improvement on multivariable analyses. In conclusion we found that ESUS cases represented 8% of CS patients in this population-based study. Despite the fact that ESUS was independently related to lower admission stroke severity, there was no association of ESUS with long-term outcomes.

Embolic strokes of undetermined source: theoretical construct or useful clinical tool?

In 2014, the definition of embolic strokes of undetermined source (ESUS) emerged as a new clinical construct to characterize cryptogenic stroke (CS) patients with complete vascular workup to determine nonlacunar, nonatherosclerotic strokes of presumable embolic origin. NAVIGATE ESUS, the first phase III randomized-controlled, clinical trial (RCT) comparing rivaroxaban (15 mg daily) with aspirin (100 mg daily), was prematurely terminated for lack of efficacy after enrollment of 7213 patients. Except for the lack of efficacy in the primary outcome, rivaroxaban was associated with increased risk of major bleeding and hemorrhagic stroke compared with aspirin. RE-SPECT ESUS was the second phase III RCT that compared the efficacy and safety of dabigatran (110 or 150 mg, twice daily) to aspirin (100 mg daily). The results of this trial have been recently presented and showed similar efficacy and safety outcomes between dabigatran and aspirin. Indirect analyses of these trials suggest similar efficacy on the risk of ischemic stroke (IS) prevention, but higher intracranial hemorrhage risk in ESUS patients receiving rivaroxaban compared to those receiving dabigatran (indirect HR = 6.63, 95% CI: 1.38-31.76). ESUS constitute a heterogeneous group of patients with embolic cerebral infarction. Occult AF represents the underlying mechanism of cerebral ischemia in the minority of ESUS patients. Other embolic mechanisms (paradoxical embolism via patent foramen ovale, aortic plaque, nonstenosing unstable carotid plaque, etc.) may represent alternative mechanisms of cerebral embolism in ESUS, and may mandate different management than oral anticoagulation. The potential clinical utility of ESUS may be challenged since the concept failed to identify patients who would benefit from anticoagulation therapy. Compared with the former diagnosis of CS, ESUS patients required thorough investigations; more comprehensive diagnostic work-up than is requested in current ESUS diagnostic criteria may assist clinicians in uncovering the source of brain embolism in CS patients and individualize treatment approaches.

Evaluation of a clinical score for predicting atrial fibrillation in cryptogenic stroke patients with insertable cardiac monitors: results from the CRYSTAL AF study

Background

The HAVOC score was previously developed to predict the risk of atrial fibrillation (AF) after cryptogenic stroke (CS) or transient ischemic attack (TIA). The purpose of this study was to apply the HAVOC score to patients who received insertable cardiac monitors (ICMs) in the CRYSTAL AF study.

Methods

All patients from the CRYSTAL AF study who received an ICM were included. HAVOC score (one point each for peripheral vascular disease and obesity with body mass index >30, two points each for hypertension, age ⩾ 75, valvular heart disease, and coronary artery disease, 4 points for congestive heart failure) was computed for all patients. The primary endpoint was AF detection by 12 months of ICM monitoring.

Results

A total of 214 patients who received ICM were included. AF was detected in 40 patients while the remaining 174 patients were AF negative. The HAVOC score was significantly higher among patients with AF [median 3.0 with interquartile range (IQR) 2-4] than those without AF [median 2.0 (IQR 0-3)], p = 0.01. AF increased significantly across the three HAVOC score groups: 11% in Group A (score 0-1), 18% in Group B (score 2-3), and 32 % in Group C (score ⩾ 4) with p = 0.02.

Conclusions

The HAVOC score was shown in this post hoc analysis of CRYSTAL AF to successfully stratify AF risk post CS or TIA. The 11% AF rate in the lowest HAVOC score group highlights the significance of nontraditional contributors to AF and ischemic stroke.

Large aortic arch plaques correlate with CHADS2 and CHA2DS2-VASc scores in cryptogenic stroke

BACKGROUND AND AIMS

Current trends have suggested covert atrial fibrillation as a mechanism of cryptogenic stroke. However, etiological heterogeneity regarding the underlying embolic sources remains a critical issue in cryptogenic stroke.

METHODS

CHALLENGE ESUS/CS (Mechanisms of Embolic Stroke Clarified by Transesophageal Echocardiography for Embolic Stroke of Undetermined Source/Cryptogenic Stroke) is a multicenter observational registry of cryptogenic stroke patients admitted to participating hospitals, who underwent transesophageal echocardiography between April 2014 and December 2016. We obtained baseline characteristics, radiological and laboratory data, and echocardiographic findings, especially for embolic sources demonstrated on transesophageal echocardiography, and conducted comparisons according to CHADS₂ and CHA₂DS₂-VASc scores (0-1 vs. ≥2, respectively). This study was registered at http://www.umin.ac.jp/ctr/(UMIN000032957).

RESULTS

The study comprised 677 patients (age, 68.7 ± 12.8 years; 455 males; median National Institutes of Health Stroke Scale score, 2) with cryptogenic stroke. On multiple logistic regression analysis, large aortic arch plaque ≥4 mm (odds ratio [OR], 2.25; 95% confidence interval [CI], 1.51-3.36; p < 0.001), with ulcerative or mobile components (OR, 2.37; 95%CI, 1.38-4.06; p = 0.002), was associated with CHADS₂ score ≥2. Large aortic arch plaque ≥4 mm (OR, 3.88; 95%CI, 2.07-7.27; p < 0.001) and ulcerative or mobile components (OR, 3.25; 95%CI, 1.44-7.34; p = 0.005) were linked to CHA₂DS₂-VASc score ≥2.

CONCLUSIONS

The CHALLENGE ESUS/CS registry is a large TEE registry, and clarifies potential embolic etiologies of cryptogenic stroke using TEE. Large aortic arch plaques were associated with high CHADS₂ and CHA₂DS₂-VASc scores, and represented important embolic sources in cryptogenic stroke.

Cardiac Myxoma and Cerebrovascular Events: A Retrospective Cohort Study

Background: Cardiac myxoma (CM) is the most frequent, cardiac benign tumor and is associated with enhanced risk for cerebrovascular events (CVE). Although surgical CM excision is the only curative treatment to prevent CVE recurrence, in recent reports conservative treatment with antiplatelet or anticoagulant agents in high-risk patients with CM-related CVE has been discussed. Methods: Case records at the University Hospital of Tübingen between 2005 and 2017 were screened to identify patients with CM-related CVE. Clinical features, brain and cardiac imaging findings, histological reports, applied treatments and long-term neurological outcomes were assessed. Results: 52 patients with CM were identified and among them, 13 patients with transient ischemic attack, ischemic stroke or retinal ischemia were included to the (to our knowledge) largest reported retrospective study of CM-related CVE. In all identified patients, CVE was the first manifestation of CM; 61% suffered ischemic stroke, 23% transient ischemic attack and 15% retinal ischemia. In 46% of the patients, CVE occurred under antiplatelet or anticoagulation treatment, while 23% of the patients developed recurrent CVE under bridging-antithrombotic-therapy prior to CM surgical excision. Prolonged time interval between CVE and CM-surgery was significantly associated with CVE recurrence (p = 0.021). One patient underwent i.v. thrombolysis, followed by thrombectomy, with good post-interventional outcome and no signs of hemorrhagic transformation. Discussion: Our results suggest that antiplatelet or anticoagulation treatment is no alternative to cardiac surgery in patients presenting with CM-related CVE. We found significantly prolonged time-intervals between CVE and CM surgery in patients with recurrent CVE. Therefore, we suggest that the waiting- or bridging-interval with antithrombotic therapy until curative CM excision should be kept as short as possible. Based on our data and review of the literature, we suggest that in patients with CM-related CVE, i.v. thrombolysis and/or endovascular interventions may present safe and efficacious acute treatments.

Intracranial Atherosclerosis is the Most Common Stroke Subtype: Ten-year Data from Hyderabad Stroke Registry (India)

Aim:

Limited data regarding stroke subtypes exist from South Asian countries. The aim of the study was to determine the pattern of ischemic stroke subtypes and their associated risk factors, in a 10-year long hospital-based registry in the South Indian city of Hyderabad.

Materials and Methods:

The Hyderabad stroke registry systematically collected clinical, radiological, and laboratory data of fully investigated consecutive stroke patients and studied pattern of ischemic stroke subtypes and their risk factor association.

Results:

The cohort comprised of 2642 patients: 2072 (78.4%) were ischemic and 570 (21.6%) were hemorrhagic strokes. In the ischemic stroke cohort, the mean age was 54.1 years and 1622 (78.3%) were men. The most common ischemic stroke subtype was large artery atherosclerosis (LAA) comprising 37.6% (n = 779), followed by small vessel occlusion comprising 19.9% (n = 413) and cardioembolism 11% (n = 228). Stroke of other determined etiologies constituted 4.2% (n = 86) and stroke of undetermined etiology was observed in 27.3%. Among patients with LAA, 610 (78.3%) patients had intracranial and 169 (21.7%) had extracranial disease as the underlying mechanism. Risk factor profile demonstrated that hyperlipidemia was significantly associated with LAA and ischemic heart disease with cardioembolic strokes.

Conclusions:

The study reveals a distinct pattern of ischemic stroke subtypes in the Indian context that has overlapping features of registries from West and East Asian countries. Both large artery and small vessel diseases are substantially represented with a predominance of intracranial atherosclerosis. The study results have significant implications for developing preventive and management strategies for stroke care and research in India.

Searching for Explanations for Cryptogenic Stroke in the Young: Revealing the Triggers, Causes, and Outcome (SECRETO): Rationale and design

BACKGROUND

Worldwide, about 1.3 million annual ischaemic strokes (IS) occur in adults aged <50 years. Of these early-onset strokes, up to 50% can be regarded as cryptogenic or associated with conditions with poorly documented causality like patent foramen ovale and coagulopathies.

KEY HYPOTHESES/AIMS

(1) Investigate transient triggers and clinical/sub-clinical chronic risk factors associated with cryptogenic IS in the young; (2) use cardiac imaging methods exceeding state-of-the-art to reveal novel sources for embolism; (3) search for covert thrombosis and haemostasis abnormalities; (4) discover new disease pathways using next-generation sequencing and RNA gene expression studies; (5) determine patient prognosis by use of phenotypic and genetic data; and (6) adapt systems medicine approach to investigate complex risk-factor interactions.

DESIGN

Searching for Explanations for Cryptogenic Stroke in the Young: Revealing the Etiology, Triggers, and Outcome (SECRETO; NCT01934725) is a prospective multi-centre case-control study enrolling patients aged 18-49 years hospitalised due to first-ever imaging-proven IS of undetermined etiology. Patients are examined according to a standardised protocol and followed up for 10 years. Patients are 1:1 age- and sex-matched to stroke-free controls. Key study elements include centralised reading of echocardiography, electrocardiography, and neurovascular imaging, as well as blood samples for genetic, gene-expression, thrombosis and haemostasis and biomarker analysis. We aim to have 600 patient-control pairs enrolled by the end of 2018.

SUMMARY

SECRETO is aiming to establish novel mechanisms and prognosis of cryptogenic IS in the young and will provide new directions for therapy development for these patients. First results are anticipated in 2019.

Increased risk for posterior circulation ischaemia in patients with vertebral artery hypoplasia: A systematic review and meta-analysis

Introduction

Although several study protocols reported that vertebral artery hypoplasia can predispose to posterior circulation ischaemia, the role of vertebral artery hypoplasia in the risk of posterior circulation ischaemia still remains controversial. The aim of the present meta-analysis was to investigate the association of vertebral artery hypoplasia and posterior circulation ischaemia.

Patients and methods

We performed a systematic review and random effects meta-analysis of all eligible observational study protocols reporting prevalence rates of vertebral artery hypoplasia in patients with anterior circulation ischaemia and posterior circulation ischaemia.

Results

We identified eight study protocols including a total of 3875 acute ischemic stroke patients (mean age: 64.2 years, 61.3% males) and reporting a pooled prevalence of vertebral artery hypoplasia 18.6% (95%CI: 10.8-30.0%). In the overall analysis, a significantly higher probability of vertebral artery hypoplasia presence was found in posterior circulation ischaemia patients compared to patients with anterior circulation ischaemia (risk ratio = 2.12, 95%CI: 1.60-2.82, p < 0.001). In the subsequent sensitivity analysis, vertebral artery hypoplasia was again found to be significantly more prevalent in patients with posterior circulation ischaemia compared to anterior circulation ischaemia (risk ratio = 1.81, 95%CI: 1.58-2.06, p < 0.001), with no evidence of heterogeneity (I²= 0%, p for Cochran Q = 0.55) between included studies.

Discussion

The present report is a meta-analysis of retrospective observational study protocols, with all the inherent limitations of included studies. The heterogeneity on the reported rates of vertebral artery hypoplasia could be attributed to differences in population age, sex, race, imaging protocols and vertebral artery hypoplasia definition between included studies.

Conclusion

Our meta-analysis provides further evidence for a possible causal relationship between vertebral artery hypoplasia and cryptogenic posterior circulation ischaemia, an association which undoubtedly deserves further investigation in future prospective study protocols.

Embolic Stroke of Undetermined Source: A Systematic Review and Clinical Update

BACKGROUND AND PURPOSE

Embolic stroke of undetermined source (ESUS) designates patients with nonlacunar cryptogenic ischemic strokes in whom embolism is the likely stroke mechanism. It has been hypothesized that anticoagulation is more efficacious than antiplatelet therapy for secondary stroke prevention in ESUS patients. We review available information about ESUS.

METHODS

Systematic literature review to assess the frequency of ESUS, patient features, and prognosis using PubMed from 2014 to present, unrestricted by language.

RESULTS

On the basis of 9 studies, the reported frequency of ESUS ranged from 9% to 25% of ischemic strokes, averaging 17%. From 8 studies involving 2045 ESUS patients, the mean age was 65 years and 42% were women; the mean NIH stroke score was 5 at stroke onset (4 studies, 1772 ESUS patients). Most (86%) ESUS patients were treated with antiplatelet therapy during follow-up, with the annualized recurrent stroke rate averaging 4.5% per year during a mean follow-up of 2.7 years (5 studies, 1605 ESUS patients).

CONCLUSIONS

ESUS comprises about 1 ischemic stroke in 6. Patients with ischemic stroke meeting criteria for ESUS were relatively young compared with other ischemic stroke subtypes and had, on average, minor strokes, consistent with small emboli. Retrospective methods of available studies limit confidence in stroke recurrence rates but support a substantial (>4% per year) rate of stroke recurrence during (mostly) antiplatelet therapy. There is an important need to define better antithrombotic prophylaxis for this frequently occurring subtype of ischemic stroke.

Thrombolytic therapy-associated acute myocardial infarction in patients with acute ischemic stroke: A treatment dilemma

Acute myocardial infarction (AMI) is uncommon in the acute phase of acute ischemic stroke (AIS) and occurs in approximately 1% of the population. Here, we report a paradoxical case of AMI during tissue plasminogen activator (t-PA) infusion for AIS. We review and analyze the previously reported cases. We found that only patients with AMI which occurred after thrombolytic therapy for AIS who received an adequate combination of anticoagulation plus percutaneous coronary intervention survived their events. Several mechanisms have been proposed for the development of AMI after thrombolytic therapy. These mechanisms include fragmented intra-cardiac thrombus, intensified platelet aggregation that may lead to an increased potential for intra-cardiac thrombus formation, and a reduction in clot-associated plasminogen that may lead to a paradoxical hypercoagulable state of the coronary arteries. Currently, there is no consensus regarding this specific scenario. We propose that the therapeutic benefit and the potential risk of hemorrhagic complications should be further investigated and individualized. In patients who receive thrombolytic therapy for AIS and who then develop post-thrombolytic AMI, we suggest that the maximum treatment for the subsequent AMI be instituted promptly to avoid short-term mortality.