Don Frei's research while affiliated with Swedish Medical Center and other places

Publications (20)

Conference Paper
Introduction The prospective INSIGHT Registry is a multicentre ‘multi-omic’ analysis of thrombi associated with acute haemorrhagic or ischemic stroke. Aim This interim analysis evaluated the performance of Penumbra RED catheters used during aspiration thrombectomy for acute ischemic stroke (AIS). Methods All cases in which Penumbra RED catheters...
Conference Paper
Introduction Flow diverters proved to be a safe and efficacious approach for the management of large intracranial lesions. The PREMIER trial was the first prospective study to examine the efficacy of the pipeline embolization device (PED, Medtornic) for the management of small and medium size wide-necked aneurysms. Herein, we present the 3-year fol...
Conference Paper
Background There is conflicting evidence on the utility of intravenous (IV) Alteplase in patients with emergent large vessel occlusion treated with mechanical thrombectomy (MT). The goal of this study was to examine whether there were differences in procedural and technical outcomes of MT depending on whether patients received IV Alteplase prior to...
Article
Full-text available
ObjectiveTo measure the global impact of COVID-19 pandemic on volumes of IV thrombolysis (IVT),IVT transfers, and stroke hospitalizations over 4 months at the height of the pandemic (March 1to June 30, 2020) compared with 2 control 4-month periods.MethodsWe conducted a cross-sectional, observational, retrospective study across 6 continents, 70count...
Article
Full-text available
Background During the COVID-19 pandemic, decreased volumes of stroke admissions and mechanical thrombectomy were reported. The study’s objective was to examine whether subarachnoid haemorrhage (SAH) hospitalisations and ruptured aneurysm coiling interventions demonstrated similar declines. Methods We conducted a cross-sectional, retrospective, obs...
Article
Full-text available
Background and purpose: The degree to which the coronavirus disease 2019 (COVID-19) pandemic has affected systems of care, in particular, those for time-sensitive conditions such as stroke, remains poorly quantified. We sought to evaluate the impact of COVID-19 in the overall screening for acute stroke utilizing a commercial clinical artificial in...
Article
Background: The degree to which the COVID-19 pandemic has affected systems of care, in particular those for time-sensitive conditions such as stroke, remains poorly quantified. We sought to evaluate the impact of COVID-19 in the overall screening for acute stroke utilizing a commercial clinical artificial intelligence (AI) platform. Methods: Data w...
Article
Full-text available
Background The COVID-19 pandemic led to the rationing of healthcare resources worldwide to accommodate the care of critically ill patients with SARS-CoV-2 infection.1 Changes in prehospital emergency medical service, emergency room care, acute stroke and subarachnoid haemorrhage (SAH) protocols2 3 were reported to conserve resources and to mitigate...
Article
Full-text available
Background and Purpose Stent-assisted coil embolization using the new generation Neuroform Atlas Stent System has shown promising safety and efficacy. The primary study results of the anterior circulation aneurysm cohort of the treatment of wide-neck, saccular, intracranial, aneurysms with the Neuroform Atlas Stent System (ATLAS trial [Safety and E...
Article
Full-text available
Background Preliminary clinical studies on the safety and efficacy of the pipeline embolization device (PED) for the treatment of small/medium aneurysms have demonstrated high occlusion rates with low complications. Objective To evaluate the safety and effectiveness of the PED for treatment of wide necked small and medium intracranial aneurysms....
Article
Background Thrombectomy is an efficacious treatment for acute ischemic stroke (AIS). However, relatively few studies to date have specifically examined the impact and clinical implications of age on outcomes for thrombectomy in anterior AIS. Objective To provide a snapshot of patient metrics and outcomes with respect to age following thrombectomy...
Article
Background Thrombectomy for anterior large vessel occlusion less than 24 hours since last known well is now standard of care. Certain aspects of clinical trials may limit generalizability to ’real-world' practice. Objective To compare revascularization rates and outcomes for direct aspiration (ADAPT) and stent retriever thrombectomy following ante...
Article
Background The development of new revascularization devices has improved recanalization rates and time, but not clinical outcomes. We report a prospectively collected clinical experience with a new technique utilizing a direct aspiration first pass technique with large bore aspiration catheter as the primary method for vessel recanalization. Metho...
Article
Background The development of new revascularization devices has improved recanalization rates and time but not clinical outcomes. We report our initial results with a new technique utilizing a direct aspiration first pass technique with a large bore aspiration catheter as the primary method for vessel recanalization. Methods A retrospective evalua...
Article
Purpose: Endovascular therapies are increasingly used in the revascularization of acute ischemic stroke from large vessel occlusions. There have been many design improvement of these devices from their initial implementation to the recent newer generations of devices. The goal of this case review study was to assess if there was corresponding impro...
Article
Purpose: The Penumbra START Trial was a multi-center, prospective trial with an aim of testing if core infarct size on pre-treatment neuroimaging predicts clinical response to IA stroke therapy. Presented herein are final results of this study. Methods: As prespecified, infarcts were trichotomized into small [lesion volume <50 cc (CTP, DWI) or ASPE...
Article
Purpose: The infarct core has been hypothesized to be highly predictive of treatment effect for endovascular intervention in acute ischemic stroke from large vessel proximal occlusion. The purpose of this study was to determine how it affects the number of patients needed to treat (NNT) by this therapy to improve long term functional status. Method...
Article
Purpose: Thin-section (≤2.5mm) NCCT can be used to reliably measure clot length in anterior circulation occlusions. Clots ≥8mm long have a low probability of recanalization with IV rtPA alone, and a majority in the proximal anterior circulation meet this criterion. However, previous studies have had sampling limitations, and correlates of clot leng...
Article
Background: The development of new revascularization devices has improved recanalization rates and time. We report our initial results with a new technique utilizing a direct aspiration first pass technique with large bore aspiration catheter as the primary method for vessel recanalization. Methods: A retrospective evaluation of a prospectively cap...

Citations

... The substantial stability of the thrombectomy rates indirectly indicates that patients with more severe symptoms did not modify their health-seeking attitude. These findings are in agreement with other studies [4,[8][9][10], even if some reports showed a significant reduction also in endovascular procedures [11][12][13]. There were significant variations across and within countries reflecting differences in the sociocultural behaviors and healthcare organization [11]. ...
... 国家 [18][19][20][21][22][23] 和全球 [6,[24][25][26][27][28][29] Abbreviations: N=number of hospitals; n1=number of admissions during twelve months before COVID-19 pandemic; n2= number of admissions during twelve months of the COVID-19 pandemic; CI=confidence interval; SE=standard error [*] The monthly volume analysis is adjusted for the date of peak COVID-19 volume for each country, the start date of the second wave, and the continent The monthly volume analysis is adjusted for the date of peak COVID-19 volume for each country, the start date of the second wave, and the continent Abbreviations: N=number of hospitals; n1=number of admissions during twelve months before COVID-19 pandemic; n2= number of admissions during twelve months of COVID-19 pandemic; CI=confidence interval; SE=standard error [*] The monthly volume analysis is adjusted for the date of peak COVID-19 volume for each country, the start date of the second wave, and the continent ...
... Soon thereafter many other regional and national reports suggested a significant decline in admissions due to AS and ACS in many countries with different healthcare systems. [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28] The reduction was larger during the various waves of COV-ID-19, and also after national lockdown conditions began, but was smaller than described in the initial reports. For example, a nationwide study in Germany found that hospitalizations for ischemic AS decreased by 10.9% during the first wave and by 4.6% during the second wave. ...
... One retrospective study from a single US comprehensive stroke center (CSC) showed that there was a 38% decrease in new stroke diagnoses in the first 6 weeks following the declaration of COVID-19 pandemic compared to the 5-month period prior to the pandemic [19•]. Another retrospective study of neuroimaging data on patients with suspected acute stroke across 97 hospitals in 20 states showed a 17.1% and 16.7% decrease in the incidence of large vessel occlusion and severe strokes on computed head angiography (CTA) and CT perfusion studies, respectively, in the pandemic period (March 1 to May 10, 2020) compared to the pre-pandemic period (November 4, 2019, to February 29, 2020) [23]. Additionally, a report from one US-based hub-and-spoke network showed 50% reduction in the number of TS activations and stroke diagnosis during the telestroke encounters in the first 30 days following the declaration of the pandemic [24••]. ...
... This may be due to the smaller diameter of the distal branch vessel, which renders it more susceptible to large blood flow velocity, thereby increasing the risk of rupture [33,34]. Although wide-necked aneurysms have been defined as those with a neck width of > 4 mm, this criterion may be too absolute [35]. Blood flow through aneurysms of different-sized parent arteries may be different, even when the aneurysms have similar neck widths [35]. ...
... Recently, many studies have examined the efficacy and safety of flow diverters for small/medium intracranial aneurysms and indicated high occlusion rates with low morbidity and mortality. The PREMIER study is the first prospective multicenter study to evaluate the use of flow diverters in small/medium, unruptured intracranial aneurysms, which suggests that treatment with the flowdiverting pipeline embolization device is safe and efficacious for small aneurysms, with complication rates comparable with those for traditional endovascular techniques (3). Another real-world study about the safety and efficacy of the pipeline embolization device for small/medium intracranial aneurysms in China also demonstrated high surgical success rates, high occlusion rates, and low morbidity and mortality (4). ...
... It is well known that age affects long-term functional outcomes of patients post-EVT. 19 Functional outcome at 3 months had a clear association with higher age in our study ( Table 6). The age effect on long-term functional outcome seemed to be mediated by a decreased probability of successful recanalization, although this association was not statistically significant. ...
... Although patients 2, 4, and 6 presented with embolization to the CCA, common carotid artery; ICA, internal carotid artery; MCA, middle cerebral artery; mRS, modified Rankin Scale 3 months after the procedure; NIHSS, National Institutes of Health Stroke Scale distal territory of the CCA, this had no significant impact on their prognosis. Others [24][25][26] reported that the time to revascularization was longer in patients with ICA and CCA occlusion than in patients with no CCA occlusion and that successful MT is more difficult to achieve in patients with a CCA than an ICA thrombus. 8,24,25,27) We suspect that the hardness and size of the thrombus and our attempts of evacuation via various techniques prolonged the time to revascularization (Table 3). ...
... With the continual expansion of indications, more patients can benefit from MT, including patients with wake-up stroke or unknown symptom onset, in an advanced timewindow beyond 6 hours of symptom onset, or with more distal occlusions (e.g., proximal M2 segment of the MCA) [23][24][25]. Novel technical developments, such as the direct aspiration first-pass technique (ADAPT) or a combined stent retriever and distal aspiration approach, might lead to further improvements in efficacy and safety [26,27]. Despite this progress, a striking number of uncertainties remain. ...
... Consistent with the current literature, we hypothesize that immediate ET should be considered in select patients with CCE LVO who exhibit evidence of poor collaterals and impaired perfusion in both partial and complete occlusions, a highly unstable acute ischemic stroke population. A direct aspiration approach using large-bore aspiration catheters may improve the outcomes [10]. Further studies are needed to better guide practitioners in selecting patients for the optimal revascularization strategy in CCE LVO. ...