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Microbiology of Pneumonia in Patients with Stroke

Andrea Morotti, MD

Kishore AK, Vail A, Jeans AR, Chamorro A, Di Napoli M, Kalra L, et al. Microbiological Etiologies of Pneumonia Complicating Stroke: A Systematic Review. Stroke. 2018 

Pneumonia is a common medical complication in subjects suffering acute stroke and is independently associated with poor functional outcome. In this paper, Dr. Kishore and colleagues described the microbiological etiology of pneumonia in stroke patients through a systematic review of the available literature.

A total of 7968 subjects included in 15 studies were analyzed. The authors reported notable variability in the rate of pneumonia (2% to 63%), and the majority of patients (78%) developed this complication within one week from stroke onset. Sputum culture was the most common method to obtain biological samples for culture, whereas a minority of patients underwent tracheal aspirate or blood culture (15% and 20%, respectively). There was also significant heterogeneity in the prevalence of positive cultures (15% to 88%), and the following pathogens were more commonly identified: Klebsiella pneumoniae (12.8%), Escherichia coli (9%), Staphylococcus aureus (10.1%). Interestingly, Streptococcus Pneumoniae was identified in only 3.5% of cases.

Despite some relevant limitations (retrospective analysis and heterogeneous characteristics of the included subjects), this manuscript provided useful data for clinical practice and future clinical trials, and highlighted a major knowledge gap in the biology of pneumonia complicating acute stroke. Another major limitation is the lack of data on dysphagia and aspiration pneumonia. It would be of great interest to explore whether patients with aspiration pneumonia have a specific microbiological profile.

Clinicians prescribing empirical antibiotic treatment should consider that Gram-negative bacilli and Gram-positive cocci accounted for more than half of the isolated pathogens. A better knowledge of the microbiological profile of stroke-associated pneumonia may also provide helpful data for preventive antibiotic treatment in the setting of randomized clinical trials.

Standardization of microbiological samples collection and guidelines for antibiotic treatment of pneumonia in subjects with stroke are highly desired.

By |August 15th, 2018|clinical|0 Comments

How Should We Best Treat M2 Occlusions?

Kat Dakay, DO 

Saber H, Narayanan S, Palla M, Saver JL, Nogueira RG, Yoo AJ, et al. Mechanical thrombectomy for acute ischemic stroke with occlusion of the M2 segment of the middle cerebral artery: a meta-analysis. J Neurointerv Surg. 2018

While the data is more straightforward on the benefit of treating proximal large vessel occlusions such as the M1 or the internal carotid artery with mechanical thrombectomy, M2’s are less certain. The endovascular trials published in 2014 underrepresented M2 occlusions: SWIFT PRIME, ESCAPE and REVASCAT excluded M2 occlusions, whereas MR CLEAN and EXTEND IA had a few M2 occlusions included in their study populations [1].

The concerns about potential risks of treating M2 occlusions are understandable: M2 occlusions would theoretically have less penumbral tissue compared to M1 occlusions, and they may be more likely than proximal occlusions to recanalize with IV tPA [2]. There is a concern about procedural risks as well: Some believe that the narrow lumen diameter and thinner vessel wall may predispose to procedural complications [3]. On the other hand, the recanalization effect of tPA may be overestimated, with one series only demonstrating 6% recanalization with tPA alone [4]. Additionally, the natural history of M2 occlusions can be debilitating, with two retrospective studies of untreated patients showing that about half of patients being functionally dependent [5, 6] with even worse outcomes occurring in left M2 occlusions.

By |August 13th, 2018|clinical|0 Comments

Antiplatelet in Patients with Microbleeds: Prevent Ischemic Stroke or Precipitate Hemorrhage?

Qing Hao, MD

Lau KK, Lovelock CE, Li L, Simoni M, Gutnikov S, Küker W, et al. Antiplatelet Treatment After Transient Ischemic Attack and Ischemic Stroke in Patients With Cerebral Microbleeds in 2 Large Cohorts and an Updated Systematic Review. Stroke. 2018

With the recent advance in image techniques, MRI has helped tremendously in understanding the mechanism of cerebrovascular disease. “The more you know, the more you know you don’t know” (Aristotle). When patients not only have a TIA or ischemic stroke, but also cerebral microbleeds (CMB), what should we do with the antiplatelet agent?

Aiming to find some solutions for this treatment dilemma, Lau, Lovelock and colleagues prospectively studied 2156 patients with diagnosis of TIA/ischemic stroke from two large cohorts in the United Kingdom and Hong Kong, respectively, to study the risks and time course of recurrent ischemic events, ICH/extracranial hemorrhage stratified by microbleeds burden.

By |August 10th, 2018|clinical|0 Comments

Association of Renal Impairment and Cerebral SVD is Exclusive for Younger Individuals After Adjusting for Vascular Risk Factors: Genetic Predisposition or a Separate Vascular Entity?

Victor J. Del Brutto, MD

Liu B, Lau KK, Li L, Lovelock C, Liu M, Kuker W, et al. Age-Specific Associations of Renal Impairment With Magnetic Resonance Imaging Markers of Cerebral Small Vessel Disease in Transient Ischemic Attack and Stroke. Stroke. 2018

In this article, Bian Lui and colleagues assessed the association of renal impairment with imaging markers of small vessel disease (SVD). As shown in previous studies, small vessel disease usually coexists with renal damage and it has generally been considered that this association is related to simultaneous damage of both the cerebral and the renal microvasculature. The authors presented the results of a population-based study in which they studied age-specific associations of renal impairment and SVD burden adjusting for demographics and traditional vascular risk factors including premorbid blood pressure.

The study was conducted using the Oxford Vascular Study registry from Oxfordshire, United Kingdom. The analysis included 1028 patients with a transient ischemic attack or minor brain infarct that underwent brain MRI and baseline renal function measurement. Patients with systemic vasculitis, CADASIL and Fabry’s disease were excluded. The burden of SVD was determined by the presence of lacunar infarctions, cerebral microbleeds, enlarged basal ganglia perivascular spaces and white matter hyperintensities on brain MRI. Renal impairment was defined by an eGFR <60 mL/min per 1.73 m2. Remarkably, the authors used the premorbid creatinine within a year to avoid the influence of a recent vascular event in the measurement of baseline renal function.

By |August 8th, 2018|clinical|0 Comments

Article Commentary: “Virtual Reality for Stroke Rehabilitation”

Burton J. Tabaac, MD

Laver KE, Lange B, George S, Deutsch JE, Saposnik G, Crotty MC. Virtual Reality for Stroke Rehabilitation. Stroke. 2018

This review examined the efficacy of virtual reality, compared with an alternative intervention or no intervention, on upper limb function and activity. The publication is an update of the authors’ review first published in 2011 and then revised in 2015. The initial review, published in 2011, identified only 19 studies. For this iteration, 11 databases and trial registries were searched, including randomized and quasi-randomized trials of virtual reality in adults after stroke. A total of 72 trials (with 2470 participants) were included in the review.

While most recovery after stroke is thought to be made in the first few weeks, patients may make improvements on functional tasks many months after having a stroke. Prior research has shown that repetitive task training is effective in some aspects of rehabilitation, such as improving walking distance and speed and improving upper limb function. Virtual reality is a relatively recent approach that may enable simulated practice of functional tasks at a higher dosage than traditional therapies. Virtual reality has been defined as the “use of interactive simulations created with computer hardware and software to present users with opportunities to engage in environments that appear and feel similar to real-world objects and events.”

By |August 6th, 2018|clinical|0 Comments

More Than Meets the MRI: Texture Analysis Shows Normal Appearing White Matter is Not So Normal in SVD, Predicts Cognitive Impairment and Decline

Danny R. Rose, Jr., MD

Tozer DJ, Zeestraten E, Lawrence AJ, Barrick TR, Markus HS. Texture Analysis of T1-Weighted and Fluid-Attenuated Inversion Recovery Images Detects Abnormalities That Correlate With Cognitive Decline in Small Vessel Disease. Stroke. 2018

Cerebral small vessel disease (SVD) is a well-established but relatively poorly understood cause of lacunar stroke and vascular dementia. While the complex structural changes underpinning this disease process have yet to be fully elucidated, several MRI imaging markers have been identified in association with SVD, including white matter hyperintensities (WMH), cerebral microbleeds, and evidence of lacunar infarction. While these imaging markers have been useful in assessing severity of disease, they are less strongly associated with cognitive impairment. One particular area of interest as further imaging research into SVD has progressed is the so-called “normal appearing white matter” (NAWM), specifically the areas of white matter on traditional MRI that do not show the typical T2/FLAIR hyperintense changes.

Safety and Efficacy of Intravenous Thrombolysis for Non-Disabling Strokes Through the PRISM: “Primum Non Nocere” vs. “Remorseful Regretting”

Aristeidis H. Katsanos, MD, PhD

Khatri P, Kleindorfer DO, Devlin T, Sawyer Jr. RN, Starr M, Mejilla J, et al. Effect of Alteplase vs Aspirin on Functional Outcome for Patients With Acute Ischemic Stroke and Minor Nondisabling Neurologic Deficits: The PRISMS Randomized Clinical Trial. JAMA. 2018

The Potential of rtPA for Ischemic Strokes With Mild Symptoms (PRISMS) trial was designed as a phase 3, randomized, double-blind clinical trial with the aim to test the safety and efficacy of intravenous thrombolysis (IVT) administered within 3 hours of symptom onset in acute ischemic stroke (AIS) patients with mild, non-disabling neurological deficits [baseline National Institutes of Health Stroke Scale (NIHSS) score equal or less than 5]. The study was prematurely terminated by the sponsor (Genentech Inc.) after recruitment of 313 patients (one third of the initially planned sample size) due to low recruitment rates. Data analysis revealed comparable 3-month favorable functional outcome [FFO, defined as modified Rankin Scale (mRS) score of 0 or 1] rates between patients receiving IVT and aspirin (78.2% vs. 81.5%; adjusted absolute risk difference: -1.1%; 95%CI: -9.4% to 7.3%) and functional improvement in the ordinal analysis of mRS scores at 3-months (OR: 0.81; 95% CI: 0.5 to 1.2). However, patients randomized to IVT had increased sICH rates within 36 hours following rtPA bolus (3.2% vs. 0%; absolute risk difference: 3.3%; 95% CI: 0.8% to 7.4%) and serious adverse events (26.0% vs. 13.1%;  absolute risk difference: 12.9%, 95% CI: 4.1 to 21.7%), when compared to antiplatelet treated patients.

By |August 1st, 2018|clinical|0 Comments

Role of Combined Clopidogrel and Aspirin in High-Risk TIA and Stroke: Discussing the POINT Trial

Shashank Shekhar, MD, MS

Johnston SC, Easton JD, Farrant M, Barsan W, Conwit RA, Elm JJ, et al. Clopidogrel and Aspirin in Acute Ischemic Stroke and High-Risk TIA. N Engl J Med. 2018

The long-anticipated POINT trial has recently been presented at the 4th European Stroke Organization Conference 2018, and subsequently published in NEJM, in May 2018. After the CHANCE trial, many centers started using dual antiplatelet for lacunar strokes and TIA; there remained uncertainty over the validity of the non-Chinese population. The POINT trial results add validity to the five-years-old questions since the CHANCE trial.

The POINT trail is a multinational, randomized, placebo-controlled trial. The patients were assigned in 1:1 ratio between treatment and control arm. The treatment arm in the trial received a loading dose of 600mg Clopidogrel, followed by daily 75mg with daily aspirin (50mg-325mg). The control arm received same range of daily Aspirin with Placebo. The trial enrolled 4881 patients at 269 international sites in 10 different countries.

Blood Pressure During Thrombectomy: More Insights from SIESTA

Kat Dakay, DO

Schönenberger S, Uhlmann L, Ungerer M, Pfaff J, Nagel S, Klose C, et al. Association of Blood Pressure With Short- and Long-Term Functional Outcome After Stroke Thrombectomy: Post Hoc Analysis of the SIESTA Trial. Stroke. 2018

Now that mechanical thrombectomy for acute ischemic stroke has become a well-established treatment, the focus has become how best to manage patients peri-intervention.

As the authors mentioned, two major questions keep arising: What mode of sedation is best for patients undergoing thrombectomy? And, what is the ideal blood pressure goal to maintain before, during, and after intervention?

On the one hand, hypotension in the acute phase of stroke could theoretically lead to hypo-perfusion of the ischemic penumbra, leading to expansion of infarct. On the other hand, it is known that hypertension can increase the risk of intracerebral hemorrhage in patients who receive IV tPA [1], and it is unclear if this could translate to endovascular reperfusion as well. The optimal blood pressure for patients peri-intervention is not known.

No Cessation of Anticoagulants in Patients with Mild Acute Ischemic Strokes? A Post-hoc Analysis from the Preventive Antibiotics in Stroke Study

Aristeidis H. Katsanos, MD, PhD

Groot AE, Vermeij J-DM, Westendorp WF, Nederkoorn PJ, van de Beek D, Coutinho JM. Continuation or Discontinuation of Anticoagulation in the Early Phase After Acute Ischemic Stroke. Stroke. 2018

Stroke clinicians frequently are confronted with the dilemma of not only weighting the thrombembolic risk to the risk of bleeding in acute ischemic stroke (AIS) patients with indication for anticoagulation, but they should also decide the optimal timing for anticoagulation resumption. Even though numerous studies have investigated so far the optimal timing of anticoagulation resumption in AIS patients, no study has directly compared anticoagulant continuation (without cessation) to discontinuation in patients suffering an AIS while on anticoagulation.