CLINICAL PRACTICE. Cryptogenic Stroke

Recognition of giant cell arteritis in patients with polymyalgia rheumatica who have a stroke: a cautionary tale

An 82-year-old woman with polymyalgia rheumatica (PMR) on prednisone 7 mg daily was admitted to an acute stroke unit with a right homonymous hemianopia, a left posterior cerebral artery occlusion and occipital lobe infarct. She had raised inflammatory markers, did not have a temporal artery biopsy, and was discharged on the same dose of prednisone. After 21 months, off prednisone, her ophthalmologist, concerned about giant cell arteritis (GCA), restarted prednisone 40 mg daily, with rapid, profound visual improvement. After 3 days her general practitioner, noting normal baseline inflammatory markers, stopped treatment-with rapid visual reversion. It is critical to recognise GCA in patients with PMR admitted to a stroke unit and not to withdraw prematurely corticosteroids once commenced.

Atrial fibrillation and cryptogenic stroke. What is the current evidence? Role of electrocardiographic monitoring

The diagnosis of cryptogenic stroke is made by exclusion. However, current evidence supports the role of atrial fibrillation episodes as a cause of this condition. Prospective data have demonstrated the benefits of long‐term electrocardiographic monitoring to identify atrial fibrillation in association with cryptogenic stroke. This aim of this article was to analyze the contemporary evidence for the possible relationship between atrial fibrillation and cryptogenic stroke and the role of continuous electrocardiographic monitoring to clarify this hypothesis.

Prothrombotic factors do not increase the risk of recurrent ischemic events after cryptogenic stroke at young age: the FUTURE study

BACKGROUND

The role of hypercoagulable states and preceding infections in the etiology of young stroke and their role in developing recurrent ischemic events remains unclear. Our aim is to determine the prevalence of these conditions in patients with cryptogenic stroke at young age and to assess the long-term risk of recurrent ischemic events in patients with and without a hypercoagulable state or a recent pre-stroke infection with Borrelia or Syphilis.

PATIENTS AND METHODS

We prospectively included patients with a first-ever transient ischemic attack or ischemic stroke, aged 18-50, admitted to our hospital between 1995 and 2010. A retrospective analysis was conducted of prothrombotic factors and preceding infections. Outcome was recurrent ischemic events.

RESULTS

Prevalence of prothrombotic factors did not significantly differ between patients with a cryptogenic stroke and with an identified cause (24/120 (20.0%) and 32/174 (18.4%) respectively). In patients with a cryptogenic stroke the long-term risk [mean follow-up of 8.9 years (SD 4.6)] of any recurrent ischemic event or recurrent cerebral ischemia did not significantly differ between patients with and without a hypercoagulable state or a recent infection. In patients with a cryptogenic stroke 15-years cumulative risk of any recurrent ischemic event was 24 and 23% in patients with and without any prothrombotic factor respectively.

CONCLUSIONS

The prevalence of prothrombotic factors and preceding infections did not significantly differ between stroke patients with a cryptogenic versus an identified cause of stroke and neither is significantly associated with an increased risk of recurrent ischemic events after cryptogenic stroke.

Patent Foramen Ovale and Cryptogenic Stroke or Transient Ischemic Attack: To Close or Not to Close? A Systematic Review and Meta-Analysis

BACKGROUND

The optimal strategy of secondary stroke prevention in patients with patent foramen ovale (PFO) is controversial. This study was performed to evaluate the efficacy and safety of the device closure (DC) versus the medical therapy (MT) in patients with cryptogenic stroke or transient ischemic attack (TIA) and PFO.

SUMMARY

Randomized controlled trials with active and control groups receiving the DC plus MT and MT alone in patients with history of cryptogenic stroke/TIA and diagnosis of PFO were systematically searched. The main efficacy outcome was stroke recurrence. Subgroup-analyses were performed according to age, shunt size, and presence of atrial septal aneurysm (ASA). Safety endpoints included any serious adverse event (SAE), atrial fibrillation (AF), and major bleeding complications. Risk ratios (RRs) and hazard ratios (HRs) with 95% CIs were estimated. Five trials were included, involving 3,440 participants (DC = 1,829, MT = 1,611). There was a protective effect of closure in the risk of recurrent stroke (RR 0.43 [0.21-0.90]; p = 0.024; HR = 0.39 [0.19-0.83]; p = 0.014). The benefit of PFO closure was significant in patients with PFO associated with substantial right-to-left shunt or ASA. There were no differences in the risks of SAEs and major bleedings between the groups. The rate of new-onset AF was higher in the DC than in the MT arm (RR 4.46 [2.35-8.41]; p < 0.001). Successful device implantation and effective PFO closure were achieved in 96 and 91% of the patients respectively. Key Messages: In selected adult patients with PFO and history of cryptogenic stroke, the DC plus MT is more effective to prevent stroke recurrence and is associated with an increased risk of new-onset AF compared to the MT alone.

Patent foramen ovale closure versus medical therapy after cryptogenic stroke: An updated meta-analysis of all randomized clinical trials

BACKGROUND

Cryptogenic strokes can be attributed to paradoxical emboli through patent foramen ovale (PFO). However, the effectiveness of PFO closure in preventing recurrent stroke is uncertain and the results of previous randomized clinical trials (RCTs) have been inconclusive. Hence, this study pro- vides an updated meta-analysis of all RCTs comparing PFO closure with medical therapy for secondary prevention of cryptogenic stroke.

METHODS

All RCTs were identified by a comprehensive literature search of PubMed, Embase, the Cochrane Collaboration Central Register of Controlled Trials, Scopus, and Clinicaltrials.gov. The primary outcome was recurrent ischemic stroke and secondary outcomes were transient ischemic at- tack (TIA), all-cause mortality, new-onset atrial fibrillation (AF), serious adverse events, and major bleeding.

RESULTS

Five RCTs with 3440 participants were included in the present study (1829 patients under- went PFO closure and 1611 were treated medically). Pooled analysis showed a statistically significant reduction in the rate of recurrent stroke with PFO closure in comparison to medical therapy (OR 0.41; 95% CI 0.19-0.90; p = 0.03). However, there were no statistically significant reductions of recurrent TIAs (OR 0.77; 95% CI 0.51-1.14; p = 0.19) or all-cause mortality (OR 0.76; 95% CI 0.35-1.65; p = 0.48). The risk of developing new-onset AF was increased significantly with PFO closure (OR 4.74; 95% CI 2.33-9.61; p < 0.0001), but no significant differences in terms of serious adverse events or major bleeding between both groups.

CONCLUSIONS

Patent foramen ovale closure in adults with recent cryptogenic stroke was associated with a lower rate of recurrent strokes in comparison with medical therapy alone.

Percutaneous closure versus medical therapy for stroke with patent foramen Ovale: a systematic review and meta-analysis

BACKGROUND

Patent foramen ovale (PFO) closure has emerged as a secondary prevention option in patients with PFO and cryptogenic stroke. However, the comparative efficacy and safety of percutaneous closure and medical therapy in patients with cryptogenic stroke and PFO remain unclear.

METHODS

Randomized controlled trials (RCTs) and comparative observational studies that compared PFO closure against medical therapy, each with a minimal of 20 patients in the closure arm and 1-year follow-up were included.

RESULTS

We analyzed 6961 patients from 20 studies (5 RCTs and 15 observational studies) with a median follow-up of 3.1 years. Moderate-quality evidence showed that PFO closure was associated with a significantly lower incidence of the composite outcome of ischemic stroke, transient ischemic attack (TIA), or all-cause death (odds ratio [OR]: 0.57; 95% confidence interval [CI]: 0.38 to 0.85; P = 0.006), mainly driven by lower incidence of stroke (OR: 0.39; 95% CI: 0.24 to 0.63; P < 0.001). The numbers needed to treat were 43 and 39 for the composite outcome and recurrent ischemic stroke respectively. PFO closure increased the risks for atrial fibrillation or atrial flutter (OR: 5.74; 95% CI: 3.08 to 10.70; P < 0.001; high-quality evidence) and pulmonary embolism (OR: 3.03; 95% CI: 1.06 to 8.63; P = 0.038; moderate-quality evidence), with the numbers needed to harm being 30 and 143 respectively. The risks for TIA, all-cause death, and major bleeding were not statistically different. Analyses limited to RCTs showed similar findings, as did a series of other subgroup analyses.

CONCLUSION

In conclusion, PFO closure reduced the incidences of stroke and the composite outcome of ischemic stroke, TIA, or all-cause death, but increased risks for atrial fibrillation or atrial flutter and pulmonary embolism compared with medical therapy.

Patent foramen ovale closure versus medical therapy in cases with cryptogenic stroke, meta-analysis of randomized controlled trials

BACKGROUND

PFO is more common in cases with cryptogenic stroke compared to cases with no stroke or stroke of identified etiology. Several randomized controlled trials (RCTs) comparing PFO closure with medical therapy have been published with controversial findings.

METHODS

PubMed, Embase and Cochrane library databases were searched for RCT comparing PFO closure with medical therapy including antiplatelet therapy (aspirin or clopidogrel or combination) or anticoagulation. We identified 5 trials, including 3627 cases. The mean duration of follow-up was 4 years. Relative risk (RR) and 95% confidence intervals (CI) were calculated using fixed and random-effects models.

RESULTS

There was a significant reduction in the incidence of stroke among the PFO closure group compared to medical therapy group, 2.0 versus 4.2%, RR 0.48; 95% CI (0.3, 0.7), p < 0.001. The incidence of AF was higher in the PFO closure group compared to medical therapy group, 4.2 versus 0.7%, respectively, RR 5.9, 95% CI (3, 11), p < 0.001. After exclusion of oral anticoagulants cases (19%), analysis showed a lower incidence of stroke in the PFO closure group (2%) compared to antiplatelet therapy (5.2%), RR 0.4; 95% CI (0.3, 0.6), p < 0.001. There was no significant difference between both groups in the incidence of transient ischemic attacks or all-cause deaths.

CONCLUSION

PFO closure results in a significant reduction in the recurrence of ischemic stroke compared to medical therapy alone, primarily antiplatelet, among cases with PFO and cryptogenic stroke.

Atrial fibrillation is associated with anterior predominant white matter lesions in patients presenting with embolic stroke

OBJECTIVE

High white matter hyperintensity (WMH) burden is commonly found on brain MRI among patients with atrial fibrillation (AF). However, whether the link between AF and WMH extends beyond a common vascular risk factor profile is uncertain. We sought to determine whether AF relates to a distinct WMH lesion pattern which may suggest specific underlying pathophysiological relationships.

METHODS

We retrospectively analysed a cohort of consecutive patients presenting with embolic stroke at an academic hospital and tertiary referral centre between March 2010 and March 2014. In total, 234 patients (53% female, 74% anterior circulation infarction) fulfilled the inclusion criteria and were included in the analyses. WMH lesion distribution was classified according to previously defined categories. Multivariable logistic regression analysis was performed to determine variables associated with AF within 90 days of index hospital discharge.

RESULTS

Among included patients, 114 had AF (49%). After adjustment for the CHA₂DS₂-VASc score (congestive heart failure, hypertension, age ≥75 years (doubled), diabetes mellitus, prior stroke/TIA (doubled), vascular disease, age 65-74 years, sex category (female)) score, WMH lesion burden as assessed on the Fazekas scale, embolic stroke pattern, infarct distribution and pertinent interaction terms, AF was significantly associated with presence of anterior subcortical WMH patches (OR 3.647, 95% CI 1.681 to 7.911, p=0.001).

CONCLUSIONS

AF is associated with specific WMH lesion pattern among patients with embolic stroke aetiology. This suggests that the link between AF and brain injury extends beyond thromboembolic complications to include a cardiovasculopathy that affects the brain and can be detected and characterised by WMH.

Attenuation of Myeloid-Specific TGFβ Signaling Induces Inflammatory Cerebrovascular Disease and Stroke

RATIONALE

Cryptogenic strokes, those of unknown cause, have been estimated as high as 30% to 40% of strokes. Inflammation has been suggested as a critical etiologic factor. However, there is lack of experimental evidence.

OBJECTIVE

In this study, we investigated inflammation-associated stroke using a mouse model that developed spontaneous stroke because of myeloid deficiency of TGF-β (transforming growth factor-β) signaling.

METHODS AND RESULTS

We report that mice with deletion of Tgfbr2 in myeloid cells (Tgfbr2^Myeko) developed cerebrovascular inflammation in the absence of significant pathology in other tissues, culminating in stroke and severe neurological deficits with 100% penetrance. The stroke phenotype can be transferred to syngeneic wild-type mice via Tgfbr2^Myeko bone marrow transplant and can be rescued in Tgfbr2^Myeko mice with wild-type bone marrow. The underlying mechanisms involved an increased type 1 inflammation and cerebral endotheliopathy, characterized by elevated NF-κB (nuclear factor-κB) activation and TNF (tumor necrosis factor) production by myeloid cells. A high-fat diet accelerated stroke incidence. Anti-TNF treatment, as well as metformin and methotrexate, which are associated with decreased stroke risk in population studies, delayed stroke occurrence.

CONCLUSIONS

Our studies show that TGF-β signaling in myeloid cells is required for maintenance of vascular health and provide insight into inflammation-mediated cerebrovascular disease and stroke.

Patent foramen ovale closure to prevent secondary neurologic events

In October of 2016 the United States Food and Drug Administration approved the Amplatzer Patent Foramen Ovale (PFO) occluder device for use in patients with cryptogenic stroke, to reduce the risk of recurrent stroke. This event followed 15years of off-label use of atrial septal occluder devices, 3 randomized trials, and enormous controversy over the efficacy of this procedure. While none of the trials reached the primary endpoint needed to prove the efficacy of PFO closure in preventing recurrent stroke, meta-analyses and 5-year follow-up of 1 trial suggest that PFO closure decreases the risk of recurrent stroke, especially in sub-groups with large shunts and atrial septal aneurysms, and especially when the Amplatzer device (rather than other devices) is used. While the relative reduction in stroke associated with PFO closure is large (about 50%), the absolute reduction is low (1-2%) and must be balanced against complications of the procedure (about 3%). Thus, PFO closure is restricted to patients with cryptogenic stroke, and depends heavily on patients' personal preferences. Uncertainties about the etiology of stroke in patients with PFO and the efficacy of PFO closure cause a difficult problem for the internal medicine specialist. At one extreme the internist may wonder if every patient with a documented PFO should be referred to a cardiologist. At the other extreme, supported by specialty society guidelines, internists may conclude that PFO closure is rarely necessary. In this paper we review the current status of PFO closure and suggest a rational strategy for this procedure.

High-resolution vessel wall MRI for the evaluation of intracranial atherosclerotic disease

High-resolution vessel wall MRI (vwMRI) of the intracranial arteries is an emerging diagnostic imaging technique with the goal of evaluating vascular pathology. vwMRI sequences have high spatial resolution and directly image the vessel wall by suppressing blood signal. With vwMRI, it is possible to identify distinct morphologic and enhancement patterns of atherosclerosis that can provide important information about stroke etiology and recurrence risk. We present a review of vwMRI research in relation to intracranial atherosclerosis, with a focus on the relationship between ischemic stroke and atherosclerotic plaque T1 post-contrast enhancement or plaque/vessel wall morphology. The goal of this review is to provide readers with the most current understanding of the reliability, incidence, and importance of specific vwMRI findings in intracranial atherosclerosis, to guide their interpretation of vwMRI research, and help inform clinical interpretation of vwMRI. We will also provide a translational perspective on the existing vwMRI literature and insight into future vwMRI research questions and objectives. With increased use of high field strength MRI, powerful gradients, and improved pulse sequences, vwMRI will become standard-of-care in the diagnosis and prognosis of patients with cerebrovascular disease, making a firm grasp of its strengths and weakness important for neuroimagers.

Patterns and Appropriateness of Thrombophilia Testing in an Academic Medical Center

BACKGROUND

Clinical guidelines recommend against routine use of thrombophilia testing in patients with acute thromboembolism. Thrombophilia testing rarely changes acute management of a thrombotic event.

OBJECTIVE

To determine appropriateness of thrombophilia testing in a teaching hospital.

DESIGN

Retrospective cohort study.

SETTING

One academic medical center in Utah.

PARTICIPANTS

All patients who received thrombophilia testing between July 1, 2014, and December 31, 2014.

MAIN MEASUREMENTS

Proportion of thrombophilia tests occurring in situations associated with minimal clinical utility, defined as tests meeting at least 1 of the following criteria: discharged before results available; test type not recommended; testing in situations associated with decreased accuracy; duplicate testing; and testing following a provoked thrombotic event.

RESULTS

Overall, 163 patients received a total of 1451 thrombophilia tests for stroke (50% of tests; 35% of patients), venous thromboembolism (21% of tests; 21% of patients), and pregnancy-related conditions (15% of tests; 25% of patients). Of the 39 different test types performed, the most common were cardiolipin IgG and IgM antibodies (9% each), lupus anticoagulant (9%), and ß2-glycoprotein 1 IgG and IgM antibodies (8% each). In total, 911 tests (63%) were performed in situations associated with minimal clinical utility, with 126 patients (77%) receiving at least one such test. Only 2 patients (1%) had clear documentation of being offered genetic consultation.

CONCLUSIONS

Thrombophilia testing in this single-center study was often associated with minimal clinical utility. Strategies to improve testing practices (eg, hematology specialty consult prior to inpatient testing, improved order panels) might help minimize inappropriate testing and promote value-driven care.

Peptide Composition of Stroke Causing Emboli Correlate with Serum Markers of Atherosclerosis and Inflammation

Introduction

The specific protein composition of stroke-causing emboli is unknown. Because ischemic stroke has a varied etiology, it is possible that the composition of the thrombus from which an embolus originated will have distinctive molecular characteristics reflective of the underlying pathophysiology. We used mass spectrometry to evaluate the protein composition of retrieved emboli from patients with differing stroke etiologies and correlated the protein levels to serum predictors of atherosclerosis.

Methods

Emboli from 20 consecutive acute stroke patients were retrieved by thrombectomy during routine stroke care. Thrombus proteins were extracted, digested, and multidimensional fractionation of peptides was performed. Fractionated peptides underwent nano-liquid chromatography with tandem mass spectrometry. Spectra were searched using Mascot software in which results with p < 0.05 (95% confidence interval) were considered significant and indicating identity. The results were correlated to A₁C, low-density lipoprotein (LDL), and erythrocyte sedimentation rate (ESR) taken on admission.

Results

Eleven patients had atrial fibrillation, four had significant proximal vessel atherosclerosis, two were cryptogenic, and three had other identified stroke risk factors (left ventricular thrombus, dissection, endocarditis). Eighty-one common proteins (e.g., hemoglobin, fibrin, actin) were found in all 20 emboli. Serum LDL levels correlated with Septin-2 (r_s = 0.78, p = 0.028), Phosphoglycerate Kinase 1 (r_s = 0.75, p = 0.036), Integrin Alpha-M (r_s = 0.68, p = 0.033) and Glucose-6-phosphate dehydrogenase (r_s = 0.63, p = 0.05). Septin-7 levels inversely correlated to ESR (r_s = −0.84, p = 0.01). No significant protein correlations to A₁C or tPA use were found.

Conclusion

Our exploratory study presents mass spectrometry analysis of thrombi retrieved from acute stroke patients and correlates the thrombus proteome to clinical features of the patient. Notably, we found proteins associated with inflammation (e.g., Integrin Alpha-M) in emboli from patients with high LDL. Although these findings are tempered by a small sample size, we provide preliminary support for the feasibility of utilizing proteomic analysis of emboli to discover proteins that may be used as markers for stroke etiology.

Takayasu arteritis presenting as embolic stroke

A 52-year-old Caucasian woman presented to the emergency department with symptoms of acute ischaemic stroke (right-side weakness, confusion and aphasia) that resolved completely after administration of tissue plasminogen activator. During stroke work-up, she was found to have an enhancing infiltrate of the aorta at the level of the take-off of the great vessels, most consistent with early Takayasu arteritis. After being discharged home on steroids and dual antiplatelet therapy, she returned 2 days later with re-presentation of weakness and aphasia. Further work-up revealed two intraluminal clots in the left common carotid and left internal carotid arteries that had not been discovered during previous testing. This case illustrates the need to screen for sources of embolic stroke in patients with Takayasu arteritis, especially those with recurring symptoms.

High-Value Care in the Evaluation of Stroke

Value-based care emphasizes achieving the greatest overall health benefit for every dollar spent. We present an interesting case of stroke, which made us consider how frequently health care providers are utilizing value-based care. A 73-year-old Caucasian, who was initially admitted for a hypertensive emergency, was transferred to our facility for worsening slurring of speech and left-sided weakness. The patient had an extensive chronic cerebrovascular disease, including multiple embolic type strokes, mainly in the distribution of the right temporal-occipital cerebral artery and transient ischemic attacks (TIAs). The patient had a known history of patent foramen ovale (PFO) and occlusion of the right internal carotid artery. He was complicated by intracranial hemorrhage while on anticoagulation for pulmonary embolism. He was chronically on dual antiplatelet therapy (aspirin and clopidogrel) and statin.  Following the transfer, stroke protocol, including the activation of the stroke team, a computed tomography (CT) imaging study, and the rapid stabilization of the patient was initiated. His vitals were stable, and the physical examination was significant for the drooping of the left angle of the mouth, a nonreactive right pupil consistent with the previous stroke, a decreased strength in the left upper and lower extremities, and a faint systolic murmur. His previous stroke was shown to be embolic, involving both the right temporal and occipital regions, which was re-demonstrated in a CT scan. A magnetic resonance imaging (MRI) scan of the brain showed a new, restricted diffusion in the right pons that was compatible with an acute stroke as well as diffusely atherosclerotic vessels with a focal stenosis of the branch vessels. A transthoracic echocardiogram demonstrated no new thrombus in the heart. A transesophageal echocardiogram (TEE) showed known PFO, and repeat hypercoagulation evaluation was negative, as it was in his previous cerebrovascular accident (CVA) evaluation.  Appropriate medical treatment with antiplatelets, as indicated by the acute stroke guidelines, was started. The patient was not eligible for thrombolysis. Value-based care emphasizes the decreased usage in investigations or health care of options that do not contribute to the overall health and well-being of the patient. Given our patient's past medical history and the results of previous investigations, we questioned the value of ordering a hypercoagulable evaluation and TEE in our patient. The need for an evaluation of the hypercoagulable state in an elderly patient with ischemic stroke or TIA remains unknown. Our patient had a complete hypercoagulable evaluation done six years earlier. Repeating the hypercoagulable evaluation would not contribute to the treatment decisions and, as a result, would not satisfy the basic criteria for value-based care.The importance of a repeat TEE is uncertain in the evaluation of embolism for a known cause of stroke. Additionally, no change in management was anticipated regardless of the TEE findings, therefore, repeating TEE in our patient was an inappropriate use of resources. Being mindful of value-based care can reduce overall health care costs, maintain our role of being responsible stewards of our limited resources, and continue to provide high-value care for our patients.

Ticagrelor Versus Aspirin in Acute Embolic Stroke of Undetermined Source

BACKGROUND AND PURPOSE

Ticagrelor is an effective antiplatelet therapy among patients with atherosclerotic disease and, therefore, could be more effective than aspirin in preventing recurrent stroke and cardiovascular events among patients with embolic stroke of unknown source (ESUS), which includes patients with ipsilateral stenosis <50% and aortic arch atherosclerosis.

METHODS

We randomized 13 199 patients with a noncardioembolic, nonsevere ischemic stroke or high-risk transient ischemic attack to ticagrelor (180 mg loading dose on day 1 followed by 90 mg twice daily for days 2-90) or aspirin (300 mg on day 1 followed by 100 mg daily for days 2-90) within 24 hours of symptom onset. In all patients, investigators informed on the presence of ipsilateral stenosis ≥50%, small deep infarct <15 mm, and on cardiac source of embolism detected after enrollment or rare causes, which allowed to construct an ESUS category in all other patients with documented brain infarction. The primary end point was the time to the occurrence of stroke, myocardial infarction, or death within 90 days.

RESULTS

ESUS was identified in 4329 (32.8%) patients. There was no treatment-by-ESUS category interaction (P=0.83). Hazard ratio in ESUS patients was 0.87 (95% confidence interval, 0.68-1.10; P=0.24). However, hazard ratio was 0.51 (95% confidence interval, 0.29-0.90; P=0.02) in ESUS patients with ipsilateral stenosis <50% or aortic arch atherosclerosis (n=961) and 0.98 (95% confidence interval, 0.76-1.27; P=0.89) in the remaining ESUS patients (n=3368; P for heterogeneity =0.04).

CONCLUSIONS

In this post hoc, exploratory analysis, we found no treatment-by-ESUS category interaction. ESUS subgroups have heterogeneous response to treatment (Funded by AstraZeneca).

CLINICAL TRIAL REGISTRATION

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01994720.

Cryptogenic Stroke and Patent Foramen Ovale Risk Assessment

Stroke is a devastating condition. It is the fifth leading cause of death in the United States, and a leading cause of serious long-term disability. Stroke occurs at any age. Younger patients tend to have strokes of undetermined cause, termed cryptogenic. Herein, the authors describe the classification of stroke cause; the risk of recurrent cryptogenic stroke with patent foramen ovale (PFO); a risk assessment model to stratify incidental versus a pathogenic PFO in patients presenting with stroke; and patient selection for device occluder therapy in the context of the long-term follow-up of the RESPECT randomized clinical trial.

PFO Closure for Cryptogenic Stroke: A Review and Clinical Treatment Algorithm

With a high prevalence in the general population of approximately 25%, and a prevalence in the cryptogenic stroke population approaching 40%, the propensity of a patent foramen ovale (PFO) to precipitate or enable stroke, especially in young, otherwise healthy individuals, has been the subject of much debate. With proof of concept achieved via imaging modalities documenting thrombus-in-transit, and the development of minimally-invasive percutaneous approaches to closure, multiple observational studies and, more recently, several completed randomized controlled trials have sought to answer the question of when and in whom PFO closure should occur. We describe the historical context of PFO closure and review the observational and randomized control trial evidence in this field, culminating in the recent Food and Drug Administration approval of the first dedicated closure device for PFO. Guidelines and consensus statements are discussed, and a novel treatment algorithm is proposed. Future directions in PFO closure will include new devices, further data from completed and upcoming clinical trials, and potential expansion into other disease states associated with PFO.

Aortic valve papillary fibroelastoma causing embolic strokes: a case report and review

Papillary fibroelastomas (PFEs) are the second most common benign neoplasms of the cardiac valves and are being recognized more frequently because of higher resolution imaging technology. PFEs are associated with substantial complications that are secondary to systemic embolism. Surgical resection should be offered to all patients who have symptoms and to asymptomatic patients who have pedunculated lesions or tumors larger than 1 cm in diameter. Herein, we present a patient who presented for a second time in 2 months with stroke symptoms. During his first admission, a transthoracic echocardiogram was performed and he was sent home after resolution of his symptoms and a grossly negative workup. During his second admission, a transesophageal echocardiogram was performed and the PFE was found and later excised. While this discussion reviews the literature with regard to detection and management, it will hopefully serve as a reminder to keep this on the differential when the workup has remained without an obvious source.

Silent Atrial Fibrillation and Cryptogenic Strokes

A new suspected cause of cryptic strokes is "silent atrial fibrillation." Pacemakers and other implanted devices allow continuous recording of cardiac rhythm for months or years. They have discovered that short periods of atrial fibrillation lasting minutes or hours are frequent and usually are asymptomatic. A meta-analysis of 50 studies involving more than 10,000 patients with a recent stroke found that 7.7% had new atrial fibrillation on their admitting electrocardiogram. In 3 weeks during and after hospitalization, another 16.9% were diagnosed. A total of 23.7% of these stroke patients had silent atrial fibrillation; that is, atrial fibrillation diagnosed after hospital admission. Silent atrial fibrillation is also frequent in patients with pacemakers who do not have a recent stroke. In a pooled analysis of 3 studies involving more than 10,000 patients monitored for 24 months, 43% had at least 1 day with atrial fibrillation lasting more than 5 minutes. Ten percent had atrial fibrillation lasting at least 12 hours. Despite the frequency of silent atrial fibrillation in these patients with multiple risk factors for stroke, the annual incidence of stroke was only 0.23%. When silent atrial fibrillation is detected in patients with recent cryptogenic stroke, anticoagulation is indicated. In patients without stroke, silent atrial fibrillation should lead to further monitoring for clinical atrial fibrillation rather than immediate anticoagulation, as some have advocated.

Efficacy and safety of ticagrelor versus aspirin in acute stroke or transient ischaemic attack of atherosclerotic origin: a subgroup analysis of SOCRATES, a randomised, double-blind, controlled trial

BACKGROUND

Ticagrelor is an effective antiplatelet therapy for patients with coronary atherosclerotic disease and might be more effective than aspirin in preventing recurrent stroke and cardiovascular events in patients with acute cerebral ischaemia of atherosclerotic origin. Our aim was to test for a treatment-by-ipsilateral atherosclerotic stenosis interaction in a subgroup analysis of patients in the Acute Stroke or Transient Ischaemic Attack Treated with Aspirin or Ticagrelor and Patient Outcomes (SOCRATES) trial.

METHODS

SOCRATES was a randomised, double-blind, controlled trial of ticagrelor versus aspirin in patients aged 40 years or older with a non-cardioembolic, non-severe acute ischaemic stroke, or high-risk transient ischaemic attack from 674 hospitals in 33 countries. We randomly allocated patients (1:1) to ticagrelor (180 mg loading dose on day 1 followed by 90 mg twice daily for days 2-90, given orally) or aspirin (300 mg on day 1 followed by 100 mg daily for days 2-90, given orally) within 24 h of symptom onset. Investigators classified all patients into atherosclerotic and non-atherosclerotic groups for the prespecified, exploratory analysis reported in this study. The primary endpoint was the time to occurrence of stroke, myocardial infarction, or death within 90 days. Efficacy analysis was by intention to treat. The SOCRATES trial is registered with ClinicalTrials.gov, number NCT01994720.

FINDINGS

Between Jan 7, 2014, and Oct 29, 2015, we randomly allocated 13 199 patients (6589 [50%] to ticagrelor and 6610 [50%] to aspirin). Potentially symptomatic ipsilateral atherosclerotic stenosis was reported in 3081 (23%) of 13 199 patients. We found a treatment-by-atherosclerotic stenosis interaction (p=0·017). 103 (6·7%) of 1542 patients with ipsilateral stenosis in the ticagrelor group and 147 (9·6%) of 1539 patients with ipsilateral stenosis in the aspirin group had an occurrence of stroke, myocardial infarction, or death within 90 days (hazard ratio 0·68 [95% CI 0·53-0·88]; p=0·003). In 10 118 patients with no ipsilateral stenosis, 339 (6·7%) of 5047 patients in the ticagrelor group had an occurrence of stroke, myocardial infarction, or death within 90 days compared with 350 (6·9%) of 5071 in the aspirin group (0·97 [0·84-1·13]; p=0·72). There were no significant differences in the proportion of life-threatening bleeding or major or minor bleeding events in patients with ipsilateral stenosis in the ticagrelor group compared with the aspirin group.

INTERPRETATION

In this prespecified exploratory analysis, ticagrelor was superior to aspirin at preventing stroke, myocardial infarction, or death at 90 days in patients with acute ischaemic stroke or transient ischaemic attack when associated with ipsilateral atherosclerotic stenosis. An understanding of stroke mechanisms and causes is important to deliver safe and efficacious treatments for early stroke prevention.

FUNDING

AstraZeneca.

Stroke prevention

Patients who have had a stroke are at high risk for recurrent stroke, myocardial infarction, and vascular death. Prevention of these events should be initiated promptly after stroke, because many recurrent events occur early, and should be tailored to the precise cause of stroke, which may require specific treatment. Lifestyle advice including abstinence from smoking, regular exercise, Mediterranean-style diet, and reduction of salt intake and alcohol consumption are recommended for all patients with stroke. For most patients with ischemic stroke or TIA, control of risk factors, including lowering blood pressure under 140/90mmHg and LDL cholesterol under 1g/L, together with antiplatelet or oral anticoagulant therapy, depending on the cause of stroke, have been shown to decrease the risk of recurrent stroke and cardiovascular events. Aspirin, clopidogrel, or the combination of aspirin and dipyridamole, are all acceptable options for secondary prevention in patients with ischemic stroke or TIA of arterial origin. Dual therapy with aspirin and clopidogrel might be considered for 3 weeks after a minor ischemic stroke or TIA and for 3 months in patients with stroke due to severe intracranial stenosis. Oral anticoagulants are very effective to prevent cardioembolic stroke. Non-VKA oral anticoagulants have a favorable risk-benefit profile compared with VKAs, with significant reductions in stroke, intracranial hemorrhage, mortality, with similar major bleeding, but increased gastrointestinal bleeding. Carotid endarterectomy reduces the risk of ipsilateral stroke in patients with recent (<6 months) non disabling ischemic stroke or TIA in the territory and severe carotid artery stenosis. Carotid stenting is a potential alternative to surgery in patients younger than ≈70 years or patients with greater risk of surgery due to anatomic or medical conditions or specific circumstances such as radiation-induced stenosis or restenosis after surgery. For patients with hemorrhagic stroke due to hypertension-associated small vessel disease or cerebral amyloid angiopathy, strict control of blood pressure is essential. Restarting oral anticoagulants in patients after intracranial hemorrhage is a difficult decision that should weigh the risks of recurrent ischemic and hemorrhage stroke with and without oral anticoagulants. Several areas of uncertainty persist including the optimal target of blood pressure in patients with cerebrovascular disease, the benefit of PFO closure in patients with PFO-associated stroke, of stenting procedures in patients with atherosclerotic intracranial artery or extracranial vertebral artery stenosis, and of interventional procedures in patients with brain arteriovenous or cavernous malformations.

Cryptogenic Strokes and Patent Foramen Ovales: What's the Right Treatment?

More than 25% of all ischemic strokes per year are cryptogenic, that is, their cause is not determined after an appropriate evaluation. In 1988, it was reported that the incidence of a patent foramen ovale was 30 to 40% in young patients with a cryptogenic stroke compared with 25% in the general population. This led to the suspicion that cryptogenic strokes were due to paradoxical embolism, that is, a venous thrombus crossing a patent foramen ovale to enter the left atrium and then the arterial circulation. Few of the patients considered to have paradoxical embolism were shown to have coexistent venous thromboembolism. This suspicion of paradoxical embolism led to thousands of patients undergoing surgical closure of their patent foramen ovale. Surgical closure was replaced by closure of the patent foramen ovale by a variety of transvenous devices. Others recommended anticoagulant or antiplatelet therapy to prevent recurrent ischemic strokes. Three randomized clinical trials totaling more than 2000 patients compared closure of the patent foramen ovale with medical therapy. All 3 trials reported that closure of the patent foramen ovale provided no benefit compared with medical therapy. Subsequent trials have demonstrated no benefit of anticoagulation compared with antiplatelet therapy in patients with cryptogenic strokes with or without a patent foramen ovale. Patients with cryptogenic strokes should be evaluated for the presence of venous thromboembolism. If venous thromboembolism is present, treatment should be the same as for pulmonary embolism: anticoagulation. If venous thromboembolism is not present, antiplatelet therapy is indicated.