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151 result(s) for "Thaler, David E"
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Long-Term Outcomes of Patent Foramen Ovale Closure or Medical Therapy after Stroke
Patients who had had a cryptogenic stroke and had a PFO were randomly assigned to medical therapy or PFO closure. At a median of 5.9 years, the rate of recurrent ischemic strokes was lower in the PFO closure group than in the medical-therapy group.
The Risk of Paradoxical Embolism (RoPE) Study: Developing risk models for application to ongoing randomized trials of percutaneous patent foramen ovale closure for cryptogenic stroke
Background Despite the diffusion into practice of percutaneous closure of a patent foramen ovale (PFO) in patients with cryptogenic stroke (CS), the benefits have not been demonstrated, and remain unclear. For any individual presenting with a PFO in the setting of CS, it is not clear whether the PFO is pathogenically-related to the index event or an incidental finding. Further, the overall rate of stroke recurrence is low in patients with CS and PFO. How patient-specific factors affect the likelihood that a discovered PFO is related to an index stroke or affect the risk of recurrence is not well understood. These probabilities are likely to be important determinants of the benefits of PFO closure in CS. Design/Methods The goal of the Risk of Paradoxical Embolism (RoPE) Study is to develop and test a set of predictive models that can identify those patients most likely to benefit from preventive treatments for PFO-related stroke recurrence, such as PFO closure. To do this, we will construct a database of patients with CS, both with and without PFO, by combining existing cohort studies. We will use this pooled database to identify patient characteristics associated with the presence (versus the absence) of a PFO, and to use this \"PFO propensity\" to estimate the patient-specific probability that a PFO was pathogenically related to the index stroke (Model #1). We will also develop, among patients with both a CS and a PFO, a predictive model to estimate patient-specific stroke recurrence risk based on clinical, radiographic and echocardiographic characteristics. (Model #2). We will then combine Models #1 and #2 into a composite index that can rank patients with CS and PFO by their conditional probability that their PFO was pathogenically related to the index stroke and the risk of stroke recurrence. Finally, we will apply this composite index to completed clinical trials (currently on-going) testing endovascular PFO closure against medical therapy, to stratify patients from low-expected-benefit to high-expected-benefit.
Clinicians’ perspectives on incidentally discovered silent brain infarcts – A qualitative study
While silent brain infarcts (SBIs) in screened cohorts are associated with risk of symptomatic stroke and dementia, the clinical significance of incidentally discovered SBIs (id-SBIs) is unknown. Detection may offer an opportunity to initiate prevention measures, but uncertainties about id-SBIs may impede clinicians from addressing them and complicate further study of this condition. This study used semi-structured interviews of practicing clinicians. Interviews were audio recorded, transcribed, and analyzed using a grounded theory approach. A constant comparative method was used to organize emergent themes and examine new themes. Purposeful sampling was employed to achieve participant diversity. Fifteen clinicians were interviewed. Emergent themes centered on uncertainty about id-SBIs, clinical decision making in response to uncertainty, and evidence needed to resolve uncertainty. All clinicians reported uncertainty about id-SBIs: diagnostic, prognostic, or therapeutic. Differential responses to uncertainties resulted in practice variation within and between specialties. Diagnostic and prognostic uncertainty discouraged disclosure of imaging findings to patients. Vascular neurologists viewed the prognostic significance of id-SBIs as similar to symptomatic stroke. Therapeutic uncertainty was common, but most participants endorsed using stroke secondary prevention strategies. Regarding future research, all internists indicated they would consider changing practices in response to observational studies, whereas half of the neurologists expressed reluctance to modify practices based on non-randomized data. Several expressed concerns about clinical trial feasibility and lack of equipoise. id-SBIs are a focus of uncertainty for clinicians, leading to practice variation. Future studies must address diagnostic and prognostic uncertainty to facilitate implementation of prevention strategies.
The RoPE Score and Right-to-Left Shunt Severity by Transcranial Doppler in the CODICIA Study
Background: For patients with cryptogenic stroke (CS) and patent foramen ovale (PFO), it is unknown whether the magnitude of right-to-left shunt (RLSh) measured by contrast transcranial Doppler (c-TCD) is correlated with the likelihood an identified PFO is related to CS as determined by the Risk of Paradoxical Embolism (RoPE) score. Additionally, for patients with CS, it is unknown whether PFO assessment by c-TCD is more sensitive for identifying RLSh compared with transesophageal echocardiography (TEE). Our aim was to determine the significance of RLSh grade by c-TCD in patients with PFO and CS. Methods: We evaluated patients with CS who had RLSh quantified by c-TCD in the Multicenter Study into RLSh in Cryptogenic Stroke (CODICIA) to determine whether there is an association between c-TCD shunt grade and the RoPE Score. For patients who underwent c-TCD and TEE, we determined whether there is agreement in identifying and grading RLSh between these two modalities. Results: The RoPE score predicted the presence versus the absence of RLSh documented by c-TCD (c-statistic = 0.66). For patients with documented RLSh by c-TCD, shunt severity was correlated with increasing RoPE score (rank correlation (r) = 0.15, p = 0.01). Among 293 patients who had both c-TCD and TEE performed, c-TCD was more sensitive (98.7%) for detecting RLSh. Of the 97 patients with no PFO identified on TEE, 28 (29%) had a large amount of RLSh seen on c-TCD. Conclusions: For patients with CS, severity of RLSh by c-TCD is positively correlated with the RoPE score, indicating that this technique for shunt grading identifies patients more likely to have pathogenic rather than incidental PFOs. c-TCD is also more sensitive in detecting RLSh than TEE. These findings suggest an important role for c-TCD in the evaluation of PFO in the setting of CS.
Closure of Patent Foramen Ovale versus Medical Therapy after Cryptogenic Stroke
In this study, closure of a patent foramen ovale versus medical therapy alone after cryptogenic stroke was not effective in preventing recurrent stroke. Secondary analyses suggested a possible benefit, but the study did not permit a definitive conclusion. It is unknown whether closure of a patent foramen ovale is effective in the prevention of recurrent stroke after a cryptogenic ischemic stroke. Observational studies and meta-analyses have suggested that closure is associated with a benefit; however, a randomized trial, Evaluation of the STARFlex Septal Closure System in Patients with a Stroke and/or Transient Ischemic Attack due to Presumed Paradoxical Embolism through a Patent Foramen Ovale (CLOSURE I), failed to show the superiority of closure over medical therapy alone. 1 – 3 In observational studies, the Amplatzer PFO Occluder has been shown to have advantageous safety features as a closure device. 4 – . . .
Patients’ responses to incidentally discovered silent brain infarcts – a qualitative study
Background Incidentally discovered silent brain infarcts (id-SBIs) are an understudied condition with probable clinical significance, but it is not known how patients respond to or prioritize this condition. We sought to assess reporting of id-SBIs and how patients approach their diagnosis. Methods Patients with id-SBIs were identified from sequential scans between 12/2015–5/2016, were referred by treating clinicians, or self-referred for the study. This study used qualitative semi-structured interviews. Purposeful sampling was used to achieve diversity in acuity, setting, and recruitment strategy. Interviews were audio-recorded and transcribed. A constant comparative method was used to develop a coding schema, find consensus, and iteratively explore emergent themes until thematic saturation was achieved. Results Only 10 of 102 patients prospectively identified by neuroimaging were informed of the imaging findings. Twelve participants in total were interviewed. Among the study participants, the primary themes were cognitive, emotional, and behavioral responses to diagnostic, prognostic, and therapeutic uncertainty regarding id-SBIs. Clinicians described id-SBIs to participants as an ambiguous condition. Participants feared potential consequences of id-SBIs, including symptomatic stroke, dementia, and disability. Participants attempted to reduce uncertainty with strategies including equating id-SBIs with symptomatic stroke, self-education about stroke, and seeking second opinions. Conclusion Participants considered id-SBIs to be a serious medical condition. Ambiguous counseling by clinicians on id-SBIs provoked or failed to attenuate fear, leading to participants adopting strategies aimed at reducing uncertainty.
Asymptomatic Carotid Artery Stenosis Treated with Medical Therapy Alone: Temporal Trends and Implications for Risk Assessment and the Design of Future Studies
Background: The rate of adverse clinical outcomes among patients with asymptomatic carotid stenosis receiving medical therapy alone can be used to guide clinical decision-making and to inform future research. We aimed to investigate temporal changes in the incidence rate of clinical outcomes among patients with asymptomatic carotid stenosis receiving medical therapy alone and to explore the implications of these changes for the design of future comparative studies. Summary: We searched MEDLINE, the Cochrane Central Register of Controlled Trials, US Food and Drug Administration documents, and reference lists of included studies (last search: December 31, 2012). We selected prospective cohort studies of medical therapy for asymptomatic carotid artery stenosis and we extracted information on study characteristics, risk of bias, and outcomes. We performed meta-analyses to estimate summary incidence rates, meta-regressions to assess trends over time, and simulations to explore sample size requirements for the design of future studies comparing new treatments against medical therapy. The main outcomes of interest were ipsilateral stroke, any stroke, cardiovascular death, death, and myocardial infarction. We identified 41 studies of medical therapy for patients with asymptomatic carotid stenosis (last recruitment year: 1978-2009). The summary incidence rate of ipsilateral carotid territory stroke (25 studies) was 1.7 per 100 person-years. This incidence rate was significantly lower in recent studies (last recruitment year from 2000 onwards) as compared to studies that ended recruitment earlier (1.0 vs. 2.3 events per 100 person-years; p < 0.001). The incidence rates of any territory stroke (17 studies), cardiovascular death (6 studies), death (13 studies), and myocardial infarction (5 studies) were 2.7, 4.1, 4.6, and 1.8 per 100 person-years, respectively. Simulations showed that future studies would need to enroll large numbers of patients with a relatively high incidence rate under medical therapy, and evaluate interventions with large effect sizes, to have adequate power to reliably detect treatment effects. Key Messages: Improved prognosis under medical therapy alone has narrowed the potential range of risk reduction attainable with new treatments for asymptomatic carotid stenosis. Future comparative studies will need to enroll large numbers of patients to assess treatment effectiveness.
Closure of Patent Foramen Ovale and Cryptogenic Stroke: Unresolved Issues
Purpose of ReviewThis review summarises the results of randomised trials comparing closure of patent foramen ovale (PFO) with antithrombotic therapy in patients with cryptogenic stroke.Recent FindingsInitially, three randomised trials failed to show superiority of PFO closure over antithrombotic therapy in patients with cryptogenic stroke. Three recently performed trials and the prolongation of an earlier trial provided evidence that PFO closure in patients with cryptogenic stroke and an age range of 18–60 years is superior to stroke prevention with antiplatelet therapy. PFO closure was not superior to anticoagulation. Anticoagulation, however, has a higher long-term bleeding risk. PFO closure could result in atrial fibrillation (AF) in a small number of patients. In most patients, AF was transient in duration. Optimal patient selection requires future research.SummaryIn patients with cryptogenic stroke aged < 60 years, PFO closure is superior to antiplatelet therapy in the prevention of recurrent stroke.
Improving the U.S. Military’s Understanding of Unstable Environments Vulnerable to Violent Extremist Groups
For over a decade, operations associated with irregular warfare have placed large demands on U.S. ground forces and have led to development of new Army and Joint doctrine. This report helps analysts identify and assess twelve key factors that create and perpetuate environments susceptible to insurgency, terrorism, and other extremist violence and instability to inform military decisions on allocation of analytic and security assistance resources.