American Heart Association

Monthly Archives: September 2017

Sleep Apnea and Stroke: Interview with Antonio Culebras, MD

Antonio Culebras

Antonio Culebras

A conversation with Antonio Culebras, MD, Professor of Neurology, SUNY Upstate Medical University, about the association between sleep apnea and stroke.

Interviewed by Gurmeen Kaur, MBBS, Vascular Neurology Fellow, Icahn School of Medicine at Mount Sinai.

Dr. Kaur: What can you tell us about the association between sleep apnea and atrial fibrillation? What is the strength of the evidence supporting this association?

Dr. Culebras: Obstructive sleep apnea is a risk factor for stroke because of its association with systemic hypertension and other risk factors for stroke, including atrial fibrillation. The Stroke Risk in Atrial Fibrillation Working Group 2007 demonstrated a 5–10% increase in risk of stroke in patients with atrial fibrillation.

Gami et al studied a cohort of over 3000 patients over 65 years who underwent polysomnography. Over a 5-year follow-up period, nocturnal oxygen desaturations emerged as a predictor for new onset atrial fibrillation. In a study of 47 women and 111 men with subacute ischemic stroke admitted for neurorehabilitation (Chen et al, 2017), mean nocturnal desaturation was significantly associated with atrial fibrillation after adjusting for age, neck circumference, Barthel index, and high-density lipoprotein level. Poli et al also concluded that there is a strong correlation between age and sleep apnea that drives the increased frequency of stroke related to atrial fibrillation.

In-Patient Code Strokes — A Need for Speed

Hatim Attar, MD

Kassardjian CD, Willems JD, Skrabka K, Nisenbaum R, Barnaby J, Kostyrko P, et al. In-Patient Code Stroke: A Quality Improvement Strategy to Overcome Knowledge-to-Action Gaps in Response Time. Stroke. 2017

On account of various comorbidities, procedures, and acute ongoing illnesses, hospitalized patients suffer an increased risk of strokes as compared to the general population. About 7–15% of all acute cerebrovascular insults affect in-patients. A larger percent of these strokes are noted in the peri-operative period and following cardiac procedures. The authors point out that an intuitive assumption would suggest that in-hospital strokes would meet with better outcome. This would be due to a presumed higher rate of stroke symptom recognition, immediate availability of nurses and physicians, proximity to neuroimaging, and a streamlined system for management. However, time and again, it has been seen that in-patient strokes are paradoxically associated with worse outcomes. Prior studies that have been cited in this paper have identified various factors, like inadequate education about stroke symptoms, delayed notification of the appropriate personnel, and poor communication of symptoms between the different teams and need for urgent evaluation and management.

In this original study, Kassardjian et al have identified and confirmed these gaps by interviewing all personnel involved in the acute stroke process. The authors then successfully administered educational sessions, which had well-described learning objectives, including the ability to identify different types of stroke, understand the ramifications of acute stroke and available interventions, and describe the role of the medical teams in code stroke. An algorithm was created and made readily available throughout a tertiary care academic teaching hospital.

By |September 25th, 2017|clinical|0 Comments

Cerebral Microbleeds: A Risk Factor for Intracranial Hemorrhage and Worse Outcomes After Thrombolytic Therapy for Acute Ischemic Stroke

Mark R. Etherton, MD PhD

Charidimou A, Turc G, Oppenheim C, Yan S, Scheitz JF, Erdur H, et al. Microbleeds, Cerebral Hemorrhage, and Functional Outcome After Stroke Thrombolysis: Individual Patient Data Meta-Analysis. Stroke. 2017

In this entry, I discuss the recent meta-analysis, using individual patient data, by Andreas Charidimou and colleagues on cerebral microbleeds (CMB) and the risk of intracerebral hemorrhage (ICH) and poor functional outcomes after intravenous thrombolytic therapy for acute ischemic stroke.

Prior to this study, a recent meta-analysis had demonstrated that the mere presence of pre-treatment CMBs was associated with increased odds of symptomatic intracerebral hemorrhage (sICH) after intravenous thrombolytic therapy for acute ischemic stroke (Charidimou et al. Stroke. 2015). Building on this study, the authors performed a pooled, individual patient data meta-analysis to evaluate several hypotheses pertaining to the presence, quantity, and location of pre-treatment CMBs in relation to ICH risk and post-stroke outcomes.

By |September 20th, 2017|clinical|0 Comments

Beyond Drip and Ship: The Role of Baseline Vascular Imaging for Referring Hospitals in Acute Ischemic Stroke Triage for the Endovascular Era

Danny R. Rose, Jr. MD

Boulouis G, Siddiqui K, Lauer A, Charidimou A, Regenhardt R, Viswanathan A, et al.  Immediate Vascular Imaging Needed for Efficient Triage of Patients With Acute Ischemic Stroke Initially Admitted to Nonthrombectomy Centers. Stroke. 2017

The landmark publication of multiple positive endovascular thrombectomy (EVT) trials in 2015 was a pivotal moment for treatment of acute ischemic stroke. The most significant development in acute stroke treatment in the nearly twenty years since the FDA approval of tissue plasminogen activator in 1996 has led to much discussion with respect to improving stroke systems of care to be able to provide this treatment to as many eligible patients as possible. Reflecting this new development in acute stroke treatment, the American Heart Association released a focused update to their guidelines on acute stroke treatment that recommended endovascular therapy be offered to patients who present within 6 hours of last known normal and have a favorable imaging profile and a National Institutes of Health Stroke Scale (NIHSS) of 6 or greater.

Just as the time-sensitive nature of intravenous thrombolytic administration led to the development of prehospital stroke scales and the stroke alert process, the most effective way to triage and treat patients with suspected emergent large vessel occlusions (LVO) amenable to endovascular treatment is a topic of ongoing research and debate. An important facet of this discussion concerns the most effective method to triage and transfer patients with suspected LVO to a thrombectomy-capable stroke center. A cohort by Sarraj et al. presented at the 2017 International Stroke Conference showed comparably good outcomes for patients transferred to thrombectomy-capable centers as compared to patients who presented directly to the facility, suggesting that the “drip and ship” transfer paradigm can be successfully augmented to accommodate endovascular therapy.

Author Interview: Søren Bache, MD

Søren Bache

Søren Bache

A conversation with Søren Bache, MD, from the Neurointensive Care Unit, Department of Neuroanaesthesiology and Centre for Genomic Medicine, Rigshospitalet, University of Copenhagen, Denmark, about microRNA changes after subarachnoid hemorrhage.

Interviewed by José G. Merino, MD, Associate Professor of Neurology, University of Maryland School of Medicine.

They will be discussing the paper, “MicroRNA Changes in Cerebrospinal Fluid After Subarachnoid Hemorrhage,” published in the September 2017 issue of Stroke.

​Dr. Merino: Thank you for agreeing to the interview. First, I would like you to explain some things about delayed cerebral ischemia (DCI) after subarachnoid hemorrhage (SAH) for our readers: How common is it? How soon after SAH does it develop? How does it affect outcome after SAH?

Dr. Bache: The reported prevalence of DCI after SAH varies, but newer randomized clinical trials have found a risk of 21–38% in patients who survive the initial bleeding and aneurism-securing surgery. The variation in calculated risk may be due to discrepancies both in case definition (i.e. the numerator) and in the definition of which patients are entered into the denominator. Today, most researchers base their case definition of DCI on the criteria suggested by Vergouwen et al. (Vergouwen MD, et al. Stroke. 2010). Before this consensus work, the definition varied even more, and many used their own criteria for DCI, delayed ischemic neurological deficits (DIND) or cerebral vasospasm. However, not all patients are conscious enough to be assessed clinically for a deterioration in consciousness, and such patients may be either included or excluded in the total number of patients; hence, the variation in the denominator. Based on Vergouwen’s criteria, in our center, we found a prevalence of 23% in 450 patients admitted from 2009–12 with SAH (unpublished data). These patients all receive prophylactic nimodipine, which lowers the risk of DCI; therefore, one should expect publications from the pre-nimodipine era to report a higher prevalence of DCI (Dorhout Mees SM, et al. Cochrane Database of Systematic Reviews. 2007).

Delayed cerebral ischemia occurs a median of 6–7 days after hemorrhage, but this varies, with a typical reported range from 3 to 14 days. DCI may be reversible, but in some cases it progresses to permanent brain injury, thereby affecting outcome.

Predicting Stroke Outcome with Multimodality CT

Kevin S. Attenhofer, MD

Dankbaar JW, Horsch AD, van den Hoven AF, Kappelle LJ, van der Schaaf IC, van Seeters T, et al. Prediction of Clinical Outcome After Acute Ischemic Stroke: The Value of Repeated Noncontrast Computed Tomography, Computed Tomographic Angiography, and Computed Tomographic Perfusion. Stroke. 2017

A significant aspect of stroke care is the long-term ramifications with respect to a patient’s ability to manage their activities of daily living. Part of the physician’s role is to help the patient navigate this challenge to maintain as much independence as possible. Understanding likely outcomes helps set the stage for realistic expectations and goals. Today, the most commonly used metric to score outcomes is the modified Rankin scale (mRS) performed well after the index event (often 90 days).

In stroke research, follow-up imaging markers such as computed tomographic angiography (CTA) recanalization and computed tomographic perfusion (CTP) reperfusion are sometimes used as proxy measurements for clinical outcomes. In this study, Dankbaar et al. used multimodality commuted tomography to predict mRS at 90 days.

By |September 11th, 2017|clinical, prognosis|0 Comments

Taking Patients Directly to Comprehensive Stroke Centers May Be Feasible for Patients and Hospitals

Neal S. Parikh, MD 
@NealSParikhMD

Katz BS, Adeoye O, Sucharew H, Broderick JP, McMullan J, Khatri P, et al. Estimated Impact of Emergency Medical Service Triage of Stroke Patients on Comprehensive Stroke Centers. An Urban Population-Based Study. Stroke. 2017

Whether all acute stroke patients should be taken to a comprehensive stroke center (CSC) remains unclear. However, there is mounting computer modeling and clinical data that support transporting acute stroke patients directly to CSCs, especially when the additional travel time is not excessive. The American Heart Association recommends transporting patients directly to CSCs if additional travel time does not exceed 15–20 minutes.

Brian Katz and colleagues performed an analysis to examine real-world EMS transport practices in the Greater Cincinnati/Northern Kentucky (GCNK) region. They performed computer modeling to evaluate the implications of adhering more closely to AHA recommendations. The authors identified patients with acute stroke from the GCNK Study who were transported by EMS in 2010. The GCNK region has 1 CSC and a total of 14 primary stroke centers (PSC) and acute stroke ready hospitals (ASRH). Patients’ addresses were geocoded, and software was used to estimate travel distances to each patient’s initial presenting hospital and also to the CSC.

Understanding Changing Temporal Trends in Dementia — Does Improving Vascular Health Have a Role?

Gurmeen Kaur, MBBS
@kaurgurmeen

Pase MP, Satizabal C, Seshadri S. Role of Improved Vascular Health in the Declining Incidence of Dementia. Stroke. 2017

It is projected that 13.8 million Americans will have dementia by the year 2050, making it a major public health epidemic. While the overall prevalence is on a rise, every individual’s chance of developing dementia per year is decreasing. The authors used the Framingham Heart Study (FHS) to demonstrate nearly a 20% decrease in developing dementia by a specific age over the past 30 years and have explored the temporal trends of this change.

Improved cardiovascular health and better management of stroke and vascular risk factors may be the reason for this observed decrease. Vascular risk factors have also been implicated in the pathophysiology of both vascular dementia and Alzheimer’s type dementia. A meta-analysis of 14,730 adults, including 862 with a history of stroke and 13,868 controls, demonstrated that a history of stroke increased the risk of AD dementia by 59%. Leukoariosis or increased burden of small vessel disease suggests silent ischemia. Many large databases show that the incidence of strokes is decreasing, which may be a contributing factor to decreased rates of dementia.