Michael V Mazya

Dr. Michael V Mazya

orcid

Research Focus & Metrics

Academic Career Length

15Years (2012-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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1 June 2012 in Stroke
Verified
Journal Article
Closed access
MMMichael V Mazya
Michael V Mazya
JEJosé A. Egido
José A. Egido
GFGary A. Ford
Gary A. Ford
KLKennedy R. Lees
Kennedy R. Lees
RMRobert Mikulik
Robert Mikulik
NANiaz Ahmed
Niaz Ahmed
Background and Purpose—: Symptomatic intracerebral hemorrhage (SICH) is a serious complication in patients with acute ischemic stroke treated with intravenous thrombolysis. We aimed to develop a clinical score that can easily be applied to predict the risk of SICH. Methods—: We analyzed data from 31 627 patients treated with intravenous alteplase enrolled in the Safe Implementation of Treatments in Stroke (SITS) International Stroke Thrombolysis Register. The outcome measure was SICH per the Safe Implementation of Thrombolysis in Stroke-Monitoring Study (SITS-MOST) definition: a Type 2 parenchymal hemorrhage with deterioration in National Institutes of Health Stroke Scale score of ≥4 points or death. Univariate risk factors associated with the outcome were entered into a logistic regression model after stratification of continuous variables. Adjusted ORs for the independent risk factors were converted into points, which were summated to produce a risk score. Results—: We identified 9 independent risk factors for SICH: baseline National Institutes of Health Stroke Scale, serum glucose, systolic blood pressure, age, body weight, stroke onset to treatment time, aspirin or combined aspirin and clopidogrel, and history of hypertension. The overall rate of SICH was 1.8%. The risk score ranged from 0 to 12 points and showed a >70-fold graded increase in the rate of SICH for patients with a score ≥10 points (14.3%) compared with a score of 0 point (0.2%). The prognostic discriminating capability by C statistic was 0.70. Conclusions—: The SITS SICH risk score predicts large cerebral parenchymal hemorrhages associated with severe clinical deterioration. The score could aid clinicians to identify patients at high as well as low risk of SICH after intravenous alteplase.

1 December 2019 in European Stroke Journal
Verified
Journal Article
Open access
PDF file
NANiaz Ahmed
Niaz Ahmed
HAHeinrich Audebert
Heinrich Audebert
GTGuillaume Turc
Guillaume Turc
CCCharlotte Cordonnier
Charlotte Cordonnier
HCHanne Christensen
Hanne Christensen
TSThorsten Steiner
Thorsten Steiner
The purpose of the European Stroke Organisation–Karolinska Stroke Update Conference is to provide updates on recent stroke therapy research and to give an opportunity for the participants to discuss how these results may be implemented into clinical routine. The meeting started 22 years ago as Karolinska Stroke Update, but since 2014 it is a joint conference with European Stroke Organisation. Importantly, it provides a platform for discussion on the European Stroke Organisation guidelines process and on recommendations to the European Stroke Organisation guidelines committee on specific topics. By this, it adds a direct influence from stroke professionals otherwise not involved in committees and work groups on the guideline procedure. The discussions at the conference may also inspire new guidelines when motivated. The topics raised at the meeting are selected by the scientific programme committee mainly based on recent important scientific publications. This year’s European Stroke Organisation–Karolinska Stroke Update Meeting was held in Stockholm on 11–13 November 2018. There were 11 scientific sessions discussed in the meeting including two short sessions. Each session except the short sessions produced a consensus statement (Full version with background, issues, conclusions and references are published as web-material and at www.eso-karolinska.org and http://eso-stroke.org) and recommendations which were prepared by a writing committee consisting of session chair(s), scientific secretary and speakers. These statements were presented to the 250 participants of the meeting. In the open meeting, general participants commented on the consensus statement and recommendations and the final document were adjusted based on the discussion from the general participants Recommendations (grade of evidence) were graded according to the 1998 Karolinska Stroke Update meeting with regard to the strength of evidence. Grade A Evidence: Strong support from randomised controlled trials and statistical reviews (at least one randomised controlled trial plus one statistical review). Grade B Evidence: Support from randomised controlled trials and statistical reviews (one randomised controlled trial or one statistical review). Grade C Evidence: No reasonable support from randomised controlled trials, recommendations based on small randomised and/or non-randomised controlled trials evidence.

1 March 2018 in European Stroke Journal
Verified
Journal Article
Open access
MMMichael V Mazya
Michael V Mazya
CCCharith Cooray
Charith Cooray
KLKennedy R Lees
Kennedy R Lees
DTDanilo Toni
Danilo Toni
GFGary A Ford
Gary A Ford
NANiaz Ahmed
Niaz Ahmed
Purpose: Beyond intravenous thrombolysis, evidence is lacking on acute treatment of minor stroke caused by large artery occlusion. To identify candidates for additional endovascular therapy, we aimed to determine the frequency of non-haemorrhagic early neurological deterioration in patients with intravenous thrombolysis-treated minor stroke caused by occlusion of large proximal and distal cerebral arteries. Secondary aims were to establish risk factors for non-haemorrhagic early neurological deterioration and report three-month outcomes in patients with and without non-haemorrhagic early neurological deterioration. Method: We analysed data from the SITS International Stroke Thrombolysis Register on 2553 patients with intravenous thrombolysis-treated minor stroke (NIH Stroke Scale scores 0–5) and available arterial occlusion data. Non-haemorrhagic early neurological deterioration was defined as an increase in NIH Stroke Scale score ≥4 at 24 h, without parenchymal hematoma on follow-up imaging within 22–36 h. Findings: The highest frequency of non-haemorrhagic early neurological deterioration was seen in 30% of patients with terminal internal carotid artery or tandem occlusions (internal carotid artery + middle cerebral artery) (adjusted odds ratio: 10.3 (95% CI 4.3–24.9), p < 0.001) and 17% in extracranial carotid occlusions (adjusted odds ratio 4.3 (2.5–7.7), p < 0.001) versus 3.1% in those with no occlusion. Proximal middle cerebral artery-M1 occlusions had non-haemorrhagic early neurological deterioration in 9% (adjusted odds ratio 2.1 (0.97–4.4), p = 0.06). Among patients with any occlusion and non-haemorrhagic early neurological deterioration, 77% were dead or dependent at three months. Conclusions: Patients with minor stroke caused by internal carotid artery occlusion, with or without tandem middle cerebral artery involvement, are at high risk of disabling deterioration, despite intravenous thrombolysis treatment. Acute vessel imaging contributes usefully even in minor stroke to identify and consider endovascular treatment, or intensive monitoring at a comprehensive stroke centre, for patients at high risk of neurological deterioration.

1 June 2020 in JAMA Neurology
Verified
Journal Article
Open access
PDF file
MMMichael V Mazya
Michael V Mazya
ABAnnika Berglund
Annika Berglund
NANiaz Ahmed
Niaz Ahmed
MEMia von Euler
Mia von Euler
SHStaffan Holmin
Staffan Holmin
EEEinar E. Eriksson
Einar E. Eriksson
The major positive effect of endovascular thrombectomy (EVT) and intravenous thrombolysis (IVT), as well as their time-dependent decay, has been established through several randomized clinical trials.1-3 Studies have shown shorter times (median difference, >90 minutes) from stroke onset to the start of EVT (onset-to-puncture time [OPT]) for patients arriving directly at a comprehensive stroke center (CSC), compared with those transferred to a CSC from a primary stroke center (PSC) following receiving an imaging proof of a large artery occlusion (LAO).4,5 This emphasizes the need for improved decision-making in prehospital stroke triage to identify patients with a high probability of requiring EVT.6 While numerous symptom-based scales have been designed for predicting LAO stroke, validation and implementation in the prehospital setting are still at an early stage.7 Importantly, studies are lacking on a combined triage approach using a symptom-based scale and teleconsultation between ambulance staff and a specialist stroke physician.

1 August 2013 in Annals of Neurology
Verified
Journal Article
Closed access
PDF file
MMMichael V Mazya
Michael V Mazya
KLKennedy R. Lees
Kennedy R. Lees
RMRomesh Markus
Romesh Markus
RRRisto O. Roine
Risto O. Roine
RSRaymond C. S. Seet
Raymond C. S. Seet
SISafe Implementation of Thrombolysis in Stroke Investigators
Safe Implementation of Thrombolysis in Stroke Investigators

1 June 2014 in Stroke
Verified
Journal Article
Closed access
MMMichael V Mazya
Michael V Mazya
NANiaz Ahmed
Niaz Ahmed
GFGary A. Ford
Gary A. Ford
CHCarsten Hobohm
Carsten Hobohm
RMRobert Mikulik
Robert Mikulik
MEMia von Euler
Mia von Euler
Background and Purpose—: Intracerebral hemorrhage after treatment with intravenous recombinant tissue-type plasminogen activator for ischemic stroke can occur in local relation to the infarct, as well as in brain areas remote from infarcted tissue. We aimed to describe risk factors, 3-month mortality, and functional outcome in patients with the poorly understood complication of remote intracerebral hemorrhage, as well as local intracerebral hemorrhage. Methods—: In this study, 43 494 patients treated with intravenous recombinant tissue-type plasminogen activator, with complete imaging data, were enrolled in the Safe Implementation of Treatments in Stroke-International Stroke Thrombolysis Register (SITS-ISTR) during 2002 to 2011. Baseline data were compared among 970 patients (2.2%) with remote parenchymal hemorrhage (PHr), 2325 (5.3%) with PH, 438 (1.0%) with both PH and PHr, and 39 761 (91.4%) without PH or PHr. Independent risk factors for all hemorrhage types were obtained by multivariate logistic regression. Results—: Previous stroke ( P =0.023) and higher age ( P <0.001) were independently associated with PHr, but not with PH. Atrial fibrillation, computed tomographic hyperdense cerebral artery sign, and elevated blood glucose were associated with PH, but not with PHr. Female sex had a stronger association with PHr than with PH. Functional independence at 3 months was more common in PHr than in PH (34% versus 24%; P <0.001), whereas 3-month mortality was lower (34% versus 39%; P <0.001). Conclusions—: Differences between risk factor profiles indicate an influence of previous vascular pathology in PHr and acute large-vessel occlusion in PH. Additional research is needed on the effect of pre-existing cerebrovascular disease on complications of recanalization therapy in acute ischemic stroke.