American Heart Association

Monthly Archives: March 2019

Breath Well During Sleep; Have Less Risk for Recurrent Ischemic Strokes

Lina Palaiodimou, MD

Brown DL, Shafie-Khorassani F, Kim S, Chervin RD, Case E, Morgenstern LB, et al. Sleep-Disordered Breathing Is Associated With Recurrent Ischemic Stroke. Stroke. 2019;50:571–576.

The role of sleep-disordered breathing (SDB) is well established in the development of a first stroke or death from any cause. Previous studies have shown that SDB is associated with an increased incidence of stroke or death from any cause, and this association is independent of other cardiovascular and cerebrovascular risk factors. This condition appears both in prestroke patients and in poststroke patients, and is more often obstructive than central. An association between SDB and recurrent strokes is also being presumed, but there are no sufficient prospective data to demonstrate and support this association.

The study of Brown et al. is an attempt to enrich the scarce data regarding the interaction between SDB and recurrent strokes. More specifically, the primary endpoint of this study is to investigate the association between SDB and recurrent ischemic stroke and secondary endpoints are: possible association between SDB and all-cause poststroke mortality and possible influence of ethnicity on the interaction between SDB and outcome measures (recurrent stroke or mortality). For that purpose, the investigators designed a prospective study of 842 patients who suffered from an index ischemic stroke and underwent a sleep apnea study shortly after the event. Additionally, patients had to be above 45 years old and be a resident of Nueces County, as the study was limited in 7 acute care hospitals of this certain county. Demographics, stroke risk factors, clinical variables and the REI (which is the sum of apneas plus hypopneas per hour of sleep apnea study duration) were recorded. Patients were followed until the first recurrent stroke, death or the last follow-up date, whichever came first. Proportional hazard models were conducted, both unadjusted and adjusted, to assess the association between REI and recurrent stroke or death. Finally, the interaction of ethnicity, REI and each outcome was statistically analyzed.

A New Look at ICAS from the SAMMPRIS Data

Richard Jackson, MD

Wabnitz AM, Derdeyn CP, Fiorella DJ, Lynn MJ, Cotsonis GA, Liebeskind DS, et al. Hemodynamic Markers in the Anterior Circulation as Predictors of Recurrent Stroke in Patients With Intracranial Stenosis. Stroke. 2018;50:143–147.

Ashley M. Wabnitz MD et al. introduced the finding that despite the superiority of aggressive medical management (AMM) in intracranial atherosclerotic arterial stenosis (ICAS), 15% of patients still had primary end point of stroke during a median follow up of 32.4 years.

The study was a post-hoc analysis of 154 patients of the total 227 patients with intracranial stenosis randomized to AMM, 49 ICA and 105 MCA. Non-MCA territory infracts and stenosis were excluded, as well as 53 patients for baseline imaging not corresponding to the qualifying event. All patients included in SAMMPRIS had angiographically verified 70-99% stenosis of ICA, MCA, vertebral or basilar arteries. Infarct patterns were classified into core, perforator, internal borderzone, or cortical borderzone based on published templates from a retrospective analysis of WASID lesions. Interobserve agreement for infarct patterns was k=0.8. Evaluation of collaterals was assessed by a validated scale by the American Society of Interventional and Therapeutic Neuroradiology/Society of Interventional Radiology; however, collaterals were assessed as impaired versus not impaired despite the validated scale having 4 grades.

Large Ischemic Core: Treat or Not Treat?

Elena Zapata-Arriaza, MD
@ElenaZaps

Campbell BCV, Majoie CBLM, Albers GW, Menon BK, Yassi N, Sharma G, et al. Penumbral imaging and functional outcome in patients with anterior circulation ischaemic stroke treated with endovascular thrombectomy versus medical therapy: a meta-analysis of individual patient-level data. Lancet Neurol. 2019;18:46-55.

Image selection in acute stroke involves a radiological prognostic marker in patients with large vessel occlusion. Ischemic penumbra is defined as hypoperfused tissue, which is at risk for irreversible damage (i.e., infarction) if blood flow is not rapidly restored and can widen the treatment time window for selected patients as seen in recent positive endovascular trials. The possibility of increasing target population that would experience clinical benefit after performing mechanical thrombectomy motivates the assessment of influence of ischaemic core volume and mismatch volume on functional outcome after endovascular treatment.

The HERMES collaboration performed a systematic review and meta-analysis from all randomized controlled trials published in PubMed from January 2010 to May 2017, assessing endovascular thrombectomy predominantly performed with stent retrievers versus medical therapy in patients with anterior circulation ischaemic stroke, according to PRISMA guidelines. For CTP, irreversibly injured ischaemic core was defined as a relative cerebral blood flow of less than 30% of normal brain blood flow. For diffusion MRI, ischaemic core was defined as an apparent diffusion coefficient of less than 620 μm²/s. The association of ischaemic core and penumbral volumes with 90-day mRS score (functional independence, defined as mRS score 0–2) and functional improvement by at least one mRS category in all patients and in a subset of those with more than 50% endovascular reperfusion was evaluated as highlights among other issues. Symptomatic intracerebral haemorrhage was assessed as a safety outcome.

By |March 26th, 2019|clinical|0 Comments

Author Interview: Dr. Raul Nogueira, MD, on “Mechanical Thrombectomy in Patients With Milder Strokes and Large Vessel Occlusions”

Dr. Raul Nogueira

Dr. Raul Nogueira

A conversation with Raul Nogueira, MD, Professor of Neurology, Neurosurgery and Radiology,Emory University School of Medicine, Director of Neuroendovascular Service, Marcus Stroke & Neuroscience Center, Grady Memorial Hospital, on endovascular thrombectomy for acute ischemic stroke with mild symptoms.

Interviewed by Mark R. Etherton, MD, PhD, Assistant in Neurology, Massachusetts General Hospital, Instructor, Harvard Medical School.

They will be discussing the paper “Mechanical Thrombectomy in Patients With Milder Strokes and Large Vessel Occlusions: A Multicenter Matched Analysis,” published in the October 2018 issue of Stroke.

Dr. Etherton: This is a very interesting paper that I think raises some good questions about the triage and management approaches to patients with large vessel occlusions and low severity ischemic strokes as assessed with the NIHSS. Could you speak a little bit regarding your management approaches to this patient population, including if any differences whether the stroke was involving the anterior or posterior circulation?

Dr. Nogueira: The first thing you have to acknowledge is there is not a lot of data to answer this question. The data is mostly retrospective in nature. There are methodological issues with these retrospective approaches in that you have to analyze them as intention-to-treat. So you have to separate out the cohorts as immediate treatment versus no immediate treatment. In reality, you really have three groups: immediate mechanical thrombectomy (MT), immediate medical therapy, and immediate medical therapy with subsequent deterioration and rescue MT. You cannot group this last group with the MT group because your initial intent was to treat this group medically. This is the equivalent of cross-over in a clinical trial which creates methodological problems.

Impact of Air Pollution on Stroke Mortality

Kristina Shkirkova, BSc

Chen G, Wang A, Li S, Zhao X, Wang Y, Li H, et al. Long-Term Exposure to Air Pollution and Survival After Ischemic Stroke. Stroke. 2019;50:563-570

The risk factors of stroke, a major contributor to the global burden of disability and mortality, include environmental exposure to air pollution. Pre-stroke long-term exposure to air pollution derived particulate matter is associated with higher mortality rates after ischemic stroke, the authors of the new study from China report.

The study by Chen et al. estimated the daily exposure of a cohort of 12291 ischemic stroke patients to air pollutants via a machine learning algorithm that accounted for temporal and spatial meteorological and satellite monitoring data for the geocoded location of patients’ home address. The authors looked at 3-year pre-stroke air levels of particulate matter with aerodynamic diameter ≤10 μm and nitrogen dioxide and the rates of mortality after ischemic stroke within 1 year follow up period between 2007 and 2008. Smaller coarse particles in the air mixture were the primary interest in this study, as they contain the most toxin and are able penetrate deeper through the respiratory system and cause an inflammatory response.

Malignant Brain Edema: Revascularization As a New Tool to Avoid It?

Elena Zapata-Arriaza, MD
@ElenaZaps

Wu S, Yuan R, Wang Y, Wei C, Zhang S, Yang X, et al. Early Prediction of Malignant Brain Edema After Ischemic Stroke: A Systematic Review and Meta-Analysis. Stroke. 2018;49:2918-2927

In cases of unsuccessful recanalization or prolonged hypoperfusion, large infarctions may occur, leading to malignant brain edema. In addition to decompressive craniectomy, there are few therapeutic strategies to alleviate this serious complication of ischemic stroke. Given its high mortality and disability in survivors, high-risk patients identification could lead to a more intensive monitoring and maybe an early intervention.

The authors performed a systematic review and meta-analysis based on Medline and Embase search from inception to March 2018, with studies assessing predictors or predictive models for malignant brain edema after ischemic stroke. Malignant edema was defined as a syndrome of clinical worsening (or death or requirement for decompressive hemicraniectomy) with imaging evidence of brain swelling. Studies included were observational with at least 1 potential predictor measured or a developed predictive model for malignant edema, and with published full-text report in a peer-reviewed journal. Studies were excluded if outcomes were defined as imaging-based edema or as clinical worsening or death not attributable to brain edema, or if the study assessed cross-sectional associations. Moreover, the authors performed a post-hoc literature search in May 2018 to identify randomized controlled trials (RCTs) to provide more robust evidence for the effect of reperfusion therapies and successful revascularization on the development of malignant edema. Reperfusion therapies included either intravenous thrombolysis or endovascular interventions.

By |March 20th, 2019|clinical|0 Comments

Neuronal Loss in Ischemic Stroke: Time is Relative

Alejandro Fuerte, MD
@DrFuerte1

Desai SM, Rocha M, Jovin TG, Jadhav AP. High Variability in Neuronal Loss: Time Is Brain, Requantified. Stroke. 2018;50:34–37

Acute ischemic stroke caused because of large-vessel occlusion (LVO) is a neurological emergency characterized by abrupt interruption in blood flow that causes rapid neuronal death. It has been shown that time in this situation is directly proportional to the infarcted brain tissue. In this context, there is an approximate loss of 1.9 million neurons every minute, which means “run!”. However, as we have observed in the DAWN and DEFUSE 3 trials, there is inter-individual variability, and the therapeutic window can be widened in those cases of patients whose ischemic core grows slowly.

The main goal of Desai et al. was to calculate the rate of loss of brain tissue within a cross-section of LVO patients with different infarct growth rate (IGR). For this purpose, they performed a retrospective review of a prospectively acquired database of acute ischemic strokes with occlusion of the internal carotid artery or middle cerebral artery. Ischemic core volume was measured with automated software and time from last known well to imaging was recorded. For the final calculations, they used what is already known about the volume of forebrain (total number of neurons, synapses, and myelinated fiber length) and, with the results, a statistical analysis was performed.

By |March 19th, 2019|clinical|0 Comments

Differences in Outcomes of Interhospital Transfer Patients Versus Direct Presentations

Gurmeen Kaur, MBBS
@kaurgurmeen

Shah S, Xian Y, Sheng S, Zachrison KS, Saver JL, Sheth KN, et al. Use, Temporal Trends, and Outcomes of Endovascular Therapy after Interhospital Transfer in the United States. Circulation. 2019

The current decade has seen a revolution in stroke care with the advent of endovascular therapy (EVT) and extended timelines for stroke intervention. With the expansion of stroke care, there is a tremendous increase in the need for angiographic suites and providers. Most smaller, non thrombectomy capable centers have set up contracts with academic or bigger centers nearby to transfer their stroke patients for emergent large vessel occlusions.

However, given that the number of treatable strokes far exceeds the number of thrombectomy capable centers, it is the right time to review our nationwide policies on transfers for improved patient care and quality improvement. In this paper, authors Shah et al. have done a great job elucidating the temporal trends in transfer of patients for EVT and how those transfer trends are influencing the final outcome, using the Get with the Guidelines database.

By |March 18th, 2019|clinical|0 Comments

Tandem Lesions: To Stent or Not To Stent?

Robert W. Regenhardt, MD, PhD
@rwregen

Jadhav AP, Zaidat OO, Liebeskind DS, Yavagal DR, Haussen DC, Hellinger FR, et al. Emergent Management of Tandem Lesions in Acute Ischemic Stroke: Analysis of the STRATIS Registry. Stroke. 2018;50:428–433.

With the 2015 trials irrefutably showing the superiority of endovascular thrombectomy (ET) over intravenous tPA alone for the treatment of stroke secondary to large vessel occlusion (LVO), and the 2018 trials showing it may be effective for up to 24 hours from symptom onset, current research efforts focus on expanding the number of patients who may be eligible for this highly effective treatment (e.g., larger core, more distal occlusions) and optimizing protocols for more complex cases. The latter is exemplified by questions that remain about the best approach to treating tandem lesions, which involve both the cervical internal carotid artery (ICA) and an intracranial artery. The most common etiology is cervical ICA atherosclerosis, but tandem lesions can also result from cervical ICA dissection.

Perhaps the biggest conundrum in the management of tandem lesions is whether or not to stent the cervical ICA in the acute setting. Given the risk of dual antiplatelet therapy, especially in patients who received tPA and have larger cores, some interventionalists choose to defer in the acute setting and offer stenting versus endarterectomy later. If stenting is offered in the acute setting, it is unclear whether cervical ICA stenting should be done before or after intracranial ET. Furthermore, the role of angioplasty and the optimum antithrombotic regimen have yet to be determined. There is limited data available to help guide these decisions. While many of the ET trials included patients with tandem lesions, the management was highly variable. Tandem lesions were present in 32% of MR CLEAN, 18% of REVASCAT, and 17% of ESCAPE, while they were excluded from SWIFT PRIME and EXTEND IA. An analysis of the 30 patients with tandem lesions that were treated with ET in ESCAPE showed 17 underwent cervical ICA stenting, 10 before and 7 after intracranial ET. Of the 13 for which stenting was deferred in the acute setting, only 4 underwent ICA revascularization later.

Using COMPASS for Primary and Secondary Ischemic Stroke Prevention?

Aristeidis H. Katsanos, MD, PhD

Sharma M, Hart RG, Connolly SJ, Bosch J, Shestakovska O, Ng KKH, et al. Stroke Outcomes in the COMPASS Trial. Circulation. 2019;139:1134–1145.

The Cardiovascular OutcoMes for People using Anticoagulation StrategieS (COMPASS) is a double-blind randomized clinical trial, which assigned a total of 27,395 participants with stable coronary artery or peripheral artery disease to receive either aspirin 100 mg once daily or rivaroxaban 5 mg twice daily or rivaroxaban 2.5 mg twice daily plus aspirin. Stroke occurrence during a mean follow-up of 23 months was reduced to 0.5% in the rivaroxaban 2.5 mg BID plus aspirin group (HR=0.58, 95%CI: 0.44-0.76, p<0.0001), while no significant difference was noted in the occurrence of stroke in the rivaroxaban 5 mg BID group (HR=0.82, 95%CI: 0.65-1.05) compared to aspirin monotherapy. Interestingly, the incidence of hemorrhagic stroke was significantly increased in the rivaroxaban 5mg BID group compared to the aspirin alone group (HR=2.70, 95%CI: 1.31-5.58, p=0.005), but no increase in the risk of hemorrhagic stroke was found for the combination of rivaroxaban 2.5 mg BID with aspirin group (HR=1.49, 95%CI: 0.67-3.31, p=0.33). The annualized rate of disabling or fatal stroke (modified Rankin Scale scores 3-6) was also found to be reduced in the rivaroxaban 2.5 mg BID plus aspirin group (HR=0.58, 95%CI: 0.37-0.89, p=0.01).

By |March 12th, 2019|clinical|0 Comments