Influence of intravenous alteplase on endovascular treatment decision-making in acute ischemic stroke due to primary medium-vessel occlusion: a case-based survey study

External Validation of a Model for Persistent Perfusion Deficit in Patients With Incomplete Reperfusion After Thrombectomy: EXTEND-PROCEED

BACKGROUND AND OBJECTIVES

We recently developed a model (PROCEED) that predicts the occurrence of persistent perfusion deficit (PPD) at 24 hours in patients with incomplete angiographic reperfusion after thrombectomy. This study aims to externally validate the PROCEED model using prospectively acquired multicenter data.

METHODS

Individual patient data for external validation were obtained from the Endovascular Therapy for Ischemic Stroke with Perfusion-Imaging Selection, Tenecteplase versus Alteplase Before Endovascular Therapy for Ischemic Stroke part 1 and 2 trials, and a prospective cohort of the Medical University of Graz. The model's primary outcome was the occurrence of PPD, defined as a focal, wedge-shaped perfusion delay on 24-hour follow-up perfusion imaging that corresponds to the capillary phase deficit on last angiographic series in patients with

RESULTS

We included 371 patients (38% with PPD). The externally validated model had good discrimination (C-statistic 0.81, 95% CI 0.77-0.86) and adequate calibration (intercept 0.25, 95% CI 0.21-0.29 and slope 0.98, 95% CI 0.90-1.12). Across a wide range of probability thresholds (i.e., depending on the physicians' preferences on how the model should be used), the model shows net benefit on clinical decision curves, informing physicians on the likelihood of PPD. If a physician's attitude toward false-positive and false-negative ratings is equal, the model would reduce 13 in 100 unnecessary interventions by correctly predicting complete delayed reperfusion, without missing a patient with PPD.

DISCUSSION

The externally validated model had adequate predictive accuracy and discrimination. Depending on the acceptable threshold probability, the model accurately predicts persistent incomplete reperfusion and may advise physicians whether additional reperfusion attempts should be performed.

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MESH Headings

• Humans
• Thrombectomy/methods
• Male
• Female
• Aged
• Middle Aged
• Reperfusion/methods
• Ischemic Stroke/surgery
• Ischemic Stroke/diagnostic imaging
• Ischemic Stroke/therapy
• Perfusion Imaging
• Prospective Studies
• Cerebrovascular Circulation/physiology
• Aged, 80 and over

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Affiliation(s)

Adnan Mujanovic From the Departments of Diagnostic and Interventional Neuroradiology (A.M., E.I.P., T.D., J.G., J.K.), Neurology (T.R.M., M.A., D.J.S., U.F.), University Hospital Bern, Inselspital, Graduate School for Health Sciences (A.M.), and CTU Bern (M.B.), University of Bern, Switzerland; Department of Medicine and Neurology, Melbourne Brain Centre (F.C.N., N.Y., G.J.S., B.C.V.C.), Melbourne Medical School (L.C.), and Department of Radiology (P.J.M.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurology (F.C.N.), Austin Health, Heidelberg, Australia; Division of Neuroradiology, Vascular and Interventional Radiology Department of Radiology (H.A.D., O.N., T.G., M.K.), and Department of Neurology (T.G., M.K.), Medical University of Graz, Austria; Population Health and Immunity Division (N.Y.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Neurology (M.W.P.), Liverpool Hospital, University of New South Wales, Sydney, Australia; Department of Radiology and Nuclear Medicine (F.C.), Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Neuroscience, the Netherlands; Department of Neurology (T.J.K.), Royal Adelaide Hospital, Australia; and Department of Neurology (U.F.), University Hospital Basel, University of Basel, Switzerland
Felix C Ng From the Departments of Diagnostic and Interventional Neuroradiology (A.M., E.I.P., T.D., J.G., J.K.), Neurology (T.R.M., M.A., D.J.S., U.F.), University Hospital Bern, Inselspital, Graduate School for Health Sciences (A.M.), and CTU Bern (M.B.), University of Bern, Switzerland; Department of Medicine and Neurology, Melbourne Brain Centre (F.C.N., N.Y., G.J.S., B.C.V.C.), Melbourne Medical School (L.C.), and Department of Radiology (P.J.M.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurology (F.C.N.), Austin Health, Heidelberg, Australia; Division of Neuroradiology, Vascular and Interventional Radiology Department of Radiology (H.A.D., O.N., T.G., M.K.), and Department of Neurology (T.G., M.K.), Medical University of Graz, Austria; Population Health and Immunity Division (N.Y.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Neurology (M.W.P.), Liverpool Hospital, University of New South Wales, Sydney, Australia; Department of Radiology and Nuclear Medicine (F.C.), Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Neuroscience, the Netherlands; Department of Neurology (T.J.K.), Royal Adelaide Hospital, Australia; and Department of Neurology (U.F.), University Hospital Basel, University of Basel, Switzerland
Mattia Branca From the Departments of Diagnostic and Interventional Neuroradiology (A.M., E.I.P., T.D., J.G., J.K.), Neurology (T.R.M., M.A., D.J.S., U.F.), University Hospital Bern, Inselspital, Graduate School for Health Sciences (A.M.), and CTU Bern (M.B.), University of Bern, Switzerland; Department of Medicine and Neurology, Melbourne Brain Centre (F.C.N., N.Y., G.J.S., B.C.V.C.), Melbourne Medical School (L.C.), and Department of Radiology (P.J.M.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurology (F.C.N.), Austin Health, Heidelberg, Australia; Division of Neuroradiology, Vascular and Interventional Radiology Department of Radiology (H.A.D., O.N., T.G., M.K.), and Department of Neurology (T.G., M.K.), Medical University of Graz, Austria; Population Health and Immunity Division (N.Y.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Neurology (M.W.P.), Liverpool Hospital, University of New South Wales, Sydney, Australia; Department of Radiology and Nuclear Medicine (F.C.), Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Neuroscience, the Netherlands; Department of Neurology (T.J.K.), Royal Adelaide Hospital, Australia; and Department of Neurology (U.F.), University Hospital Basel, University of Basel, Switzerland
Hannes A Deutschmann From the Departments of Diagnostic and Interventional Neuroradiology (A.M., E.I.P., T.D., J.G., J.K.), Neurology (T.R.M., M.A., D.J.S., U.F.), University Hospital Bern, Inselspital, Graduate School for Health Sciences (A.M.), and CTU Bern (M.B.), University of Bern, Switzerland; Department of Medicine and Neurology, Melbourne Brain Centre (F.C.N., N.Y., G.J.S., B.C.V.C.), Melbourne Medical School (L.C.), and Department of Radiology (P.J.M.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurology (F.C.N.), Austin Health, Heidelberg, Australia; Division of Neuroradiology, Vascular and Interventional Radiology Department of Radiology (H.A.D., O.N., T.G., M.K.), and Department of Neurology (T.G., M.K.), Medical University of Graz, Austria; Population Health and Immunity Division (N.Y.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Neurology (M.W.P.), Liverpool Hospital, University of New South Wales, Sydney, Australia; Department of Radiology and Nuclear Medicine (F.C.), Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Neuroscience, the Netherlands; Department of Neurology (T.J.K.), Royal Adelaide Hospital, Australia; and Department of Neurology (U.F.), University Hospital Basel, University of Basel, Switzerland
Thomas R Meinel From the Departments of Diagnostic and Interventional Neuroradiology (A.M., E.I.P., T.D., J.G., J.K.), Neurology (T.R.M., M.A., D.J.S., U.F.), University Hospital Bern, Inselspital, Graduate School for Health Sciences (A.M.), and CTU Bern (M.B.), University of Bern, Switzerland; Department of Medicine and Neurology, Melbourne Brain Centre (F.C.N., N.Y., G.J.S., B.C.V.C.), Melbourne Medical School (L.C.), and Department of Radiology (P.J.M.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurology (F.C.N.), Austin Health, Heidelberg, Australia; Division of Neuroradiology, Vascular and Interventional Radiology Department of Radiology (H.A.D., O.N., T.G., M.K.), and Department of Neurology (T.G., M.K.), Medical University of Graz, Austria; Population Health and Immunity Division (N.Y.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Neurology (M.W.P.), Liverpool Hospital, University of New South Wales, Sydney, Australia; Department of Radiology and Nuclear Medicine (F.C.), Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Neuroscience, the Netherlands; Department of Neurology (T.J.K.), Royal Adelaide Hospital, Australia; and Department of Neurology (U.F.), University Hospital Basel, University of Basel, Switzerland
Leonid Churilov From the Departments of Diagnostic and Interventional Neuroradiology (A.M., E.I.P., T.D., J.G., J.K.), Neurology (T.R.M., M.A., D.J.S., U.F.), University Hospital Bern, Inselspital, Graduate School for Health Sciences (A.M.), and CTU Bern (M.B.), University of Bern, Switzerland; Department of Medicine and Neurology, Melbourne Brain Centre (F.C.N., N.Y., G.J.S., B.C.V.C.), Melbourne Medical School (L.C.), and Department of Radiology (P.J.M.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurology (F.C.N.), Austin Health, Heidelberg, Australia; Division of Neuroradiology, Vascular and Interventional Radiology Department of Radiology (H.A.D., O.N., T.G., M.K.), and Department of Neurology (T.G., M.K.), Medical University of Graz, Austria; Population Health and Immunity Division (N.Y.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Neurology (M.W.P.), Liverpool Hospital, University of New South Wales, Sydney, Australia; Department of Radiology and Nuclear Medicine (F.C.), Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Neuroscience, the Netherlands; Department of Neurology (T.J.K.), Royal Adelaide Hospital, Australia; and Department of Neurology (U.F.), University Hospital Basel, University of Basel, Switzerland
Oliver Nistl From the Departments of Diagnostic and Interventional Neuroradiology (A.M., E.I.P., T.D., J.G., J.K.), Neurology (T.R.M., M.A., D.J.S., U.F.), University Hospital Bern, Inselspital, Graduate School for Health Sciences (A.M.), and CTU Bern (M.B.), University of Bern, Switzerland; Department of Medicine and Neurology, Melbourne Brain Centre (F.C.N., N.Y., G.J.S., B.C.V.C.), Melbourne Medical School (L.C.), and Department of Radiology (P.J.M.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurology (F.C.N.), Austin Health, Heidelberg, Australia; Division of Neuroradiology, Vascular and Interventional Radiology Department of Radiology (H.A.D., O.N., T.G., M.K.), and Department of Neurology (T.G., M.K.), Medical University of Graz, Austria; Population Health and Immunity Division (N.Y.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Neurology (M.W.P.), Liverpool Hospital, University of New South Wales, Sydney, Australia; Department of Radiology and Nuclear Medicine (F.C.), Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Neuroscience, the Netherlands; Department of Neurology (T.J.K.), Royal Adelaide Hospital, Australia; and Department of Neurology (U.F.), University Hospital Basel, University of Basel, Switzerland
Peter J Mitchell From the Departments of Diagnostic and Interventional Neuroradiology (A.M., E.I.P., T.D., J.G., J.K.), Neurology (T.R.M., M.A., D.J.S., U.F.), University Hospital Bern, Inselspital, Graduate School for Health Sciences (A.M.), and CTU Bern (M.B.), University of Bern, Switzerland; Department of Medicine and Neurology, Melbourne Brain Centre (F.C.N., N.Y., G.J.S., B.C.V.C.), Melbourne Medical School (L.C.), and Department of Radiology (P.J.M.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurology (F.C.N.), Austin Health, Heidelberg, Australia; Division of Neuroradiology, Vascular and Interventional Radiology Department of Radiology (H.A.D., O.N., T.G., M.K.), and Department of Neurology (T.G., M.K.), Medical University of Graz, Austria; Population Health and Immunity Division (N.Y.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Neurology (M.W.P.), Liverpool Hospital, University of New South Wales, Sydney, Australia; Department of Radiology and Nuclear Medicine (F.C.), Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Neuroscience, the Netherlands; Department of Neurology (T.J.K.), Royal Adelaide Hospital, Australia; and Department of Neurology (U.F.), University Hospital Basel, University of Basel, Switzerland
Nawaf Yassi From the Departments of Diagnostic and Interventional Neuroradiology (A.M., E.I.P., T.D., J.G., J.K.), Neurology (T.R.M., M.A., D.J.S., U.F.), University Hospital Bern, Inselspital, Graduate School for Health Sciences (A.M.), and CTU Bern (M.B.), University of Bern, Switzerland; Department of Medicine and Neurology, Melbourne Brain Centre (F.C.N., N.Y., G.J.S., B.C.V.C.), Melbourne Medical School (L.C.), and Department of Radiology (P.J.M.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurology (F.C.N.), Austin Health, Heidelberg, Australia; Division of Neuroradiology, Vascular and Interventional Radiology Department of Radiology (H.A.D., O.N., T.G., M.K.), and Department of Neurology (T.G., M.K.), Medical University of Graz, Austria; Population Health and Immunity Division (N.Y.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Neurology (M.W.P.), Liverpool Hospital, University of New South Wales, Sydney, Australia; Department of Radiology and Nuclear Medicine (F.C.), Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Neuroscience, the Netherlands; Department of Neurology (T.J.K.), Royal Adelaide Hospital, Australia; and Department of Neurology (U.F.), University Hospital Basel, University of Basel, Switzerland
Mark W Parsons From the Departments of Diagnostic and Interventional Neuroradiology (A.M., E.I.P., T.D., J.G., J.K.), Neurology (T.R.M., M.A., D.J.S., U.F.), University Hospital Bern, Inselspital, Graduate School for Health Sciences (A.M.), and CTU Bern (M.B.), University of Bern, Switzerland; Department of Medicine and Neurology, Melbourne Brain Centre (F.C.N., N.Y., G.J.S., B.C.V.C.), Melbourne Medical School (L.C.), and Department of Radiology (P.J.M.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurology (F.C.N.), Austin Health, Heidelberg, Australia; Division of Neuroradiology, Vascular and Interventional Radiology Department of Radiology (H.A.D., O.N., T.G., M.K.), and Department of Neurology (T.G., M.K.), Medical University of Graz, Austria; Population Health and Immunity Division (N.Y.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Neurology (M.W.P.), Liverpool Hospital, University of New South Wales, Sydney, Australia; Department of Radiology and Nuclear Medicine (F.C.), Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Neuroscience, the Netherlands; Department of Neurology (T.J.K.), Royal Adelaide Hospital, Australia; and Department of Neurology (U.F.), University Hospital Basel, University of Basel, Switzerland
Gagan J Sharma From the Departments of Diagnostic and Interventional Neuroradiology (A.M., E.I.P., T.D., J.G., J.K.), Neurology (T.R.M., M.A., D.J.S., U.F.), University Hospital Bern, Inselspital, Graduate School for Health Sciences (A.M.), and CTU Bern (M.B.), University of Bern, Switzerland; Department of Medicine and Neurology, Melbourne Brain Centre (F.C.N., N.Y., G.J.S., B.C.V.C.), Melbourne Medical School (L.C.), and Department of Radiology (P.J.M.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurology (F.C.N.), Austin Health, Heidelberg, Australia; Division of Neuroradiology, Vascular and Interventional Radiology Department of Radiology (H.A.D., O.N., T.G., M.K.), and Department of Neurology (T.G., M.K.), Medical University of Graz, Austria; Population Health and Immunity Division (N.Y.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Neurology (M.W.P.), Liverpool Hospital, University of New South Wales, Sydney, Australia; Department of Radiology and Nuclear Medicine (F.C.), Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Neuroscience, the Netherlands; Department of Neurology (T.J.K.), Royal Adelaide Hospital, Australia; and Department of Neurology (U.F.), University Hospital Basel, University of Basel, Switzerland
Thomas Gattringer From the Departments of Diagnostic and Interventional Neuroradiology (A.M., E.I.P., T.D., J.G., J.K.), Neurology (T.R.M., M.A., D.J.S., U.F.), University Hospital Bern, Inselspital, Graduate School for Health Sciences (A.M.), and CTU Bern (M.B.), University of Bern, Switzerland; Department of Medicine and Neurology, Melbourne Brain Centre (F.C.N., N.Y., G.J.S., B.C.V.C.), Melbourne Medical School (L.C.), and Department of Radiology (P.J.M.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurology (F.C.N.), Austin Health, Heidelberg, Australia; Division of Neuroradiology, Vascular and Interventional Radiology Department of Radiology (H.A.D., O.N., T.G., M.K.), and Department of Neurology (T.G., M.K.), Medical University of Graz, Austria; Population Health and Immunity Division (N.Y.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Neurology (M.W.P.), Liverpool Hospital, University of New South Wales, Sydney, Australia; Department of Radiology and Nuclear Medicine (F.C.), Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Neuroscience, the Netherlands; Department of Neurology (T.J.K.), Royal Adelaide Hospital, Australia; and Department of Neurology (U.F.), University Hospital Basel, University of Basel, Switzerland
Marcel Arnold From the Departments of Diagnostic and Interventional Neuroradiology (A.M., E.I.P., T.D., J.G., J.K.), Neurology (T.R.M., M.A., D.J.S., U.F.), University Hospital Bern, Inselspital, Graduate School for Health Sciences (A.M.), and CTU Bern (M.B.), University of Bern, Switzerland; Department of Medicine and Neurology, Melbourne Brain Centre (F.C.N., N.Y., G.J.S., B.C.V.C.), Melbourne Medical School (L.C.), and Department of Radiology (P.J.M.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurology (F.C.N.), Austin Health, Heidelberg, Australia; Division of Neuroradiology, Vascular and Interventional Radiology Department of Radiology (H.A.D., O.N., T.G., M.K.), and Department of Neurology (T.G., M.K.), Medical University of Graz, Austria; Population Health and Immunity Division (N.Y.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Neurology (M.W.P.), Liverpool Hospital, University of New South Wales, Sydney, Australia; Department of Radiology and Nuclear Medicine (F.C.), Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Neuroscience, the Netherlands; Department of Neurology (T.J.K.), Royal Adelaide Hospital, Australia; and Department of Neurology (U.F.), University Hospital Basel, University of Basel, Switzerland
Fabiano Cavalcante From the Departments of Diagnostic and Interventional Neuroradiology (A.M., E.I.P., T.D., J.G., J.K.), Neurology (T.R.M., M.A., D.J.S., U.F.), University Hospital Bern, Inselspital, Graduate School for Health Sciences (A.M.), and CTU Bern (M.B.), University of Bern, Switzerland; Department of Medicine and Neurology, Melbourne Brain Centre (F.C.N., N.Y., G.J.S., B.C.V.C.), Melbourne Medical School (L.C.), and Department of Radiology (P.J.M.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurology (F.C.N.), Austin Health, Heidelberg, Australia; Division of Neuroradiology, Vascular and Interventional Radiology Department of Radiology (H.A.D., O.N., T.G., M.K.), and Department of Neurology (T.G., M.K.), Medical University of Graz, Austria; Population Health and Immunity Division (N.Y.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Neurology (M.W.P.), Liverpool Hospital, University of New South Wales, Sydney, Australia; Department of Radiology and Nuclear Medicine (F.C.), Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Neuroscience, the Netherlands; Department of Neurology (T.J.K.), Royal Adelaide Hospital, Australia; and Department of Neurology (U.F.), University Hospital Basel, University of Basel, Switzerland
Eike I Piechowiak From the Departments of Diagnostic and Interventional Neuroradiology (A.M., E.I.P., T.D., J.G., J.K.), Neurology (T.R.M., M.A., D.J.S., U.F.), University Hospital Bern, Inselspital, Graduate School for Health Sciences (A.M.), and CTU Bern (M.B.), University of Bern, Switzerland; Department of Medicine and Neurology, Melbourne Brain Centre (F.C.N., N.Y., G.J.S., B.C.V.C.), Melbourne Medical School (L.C.), and Department of Radiology (P.J.M.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurology (F.C.N.), Austin Health, Heidelberg, Australia; Division of Neuroradiology, Vascular and Interventional Radiology Department of Radiology (H.A.D., O.N., T.G., M.K.), and Department of Neurology (T.G., M.K.), Medical University of Graz, Austria; Population Health and Immunity Division (N.Y.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Neurology (M.W.P.), Liverpool Hospital, University of New South Wales, Sydney, Australia; Department of Radiology and Nuclear Medicine (F.C.), Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Neuroscience, the Netherlands; Department of Neurology (T.J.K.), Royal Adelaide Hospital, Australia; and Department of Neurology (U.F.), University Hospital Basel, University of Basel, Switzerland
Timothy J Kleinig From the Departments of Diagnostic and Interventional Neuroradiology (A.M., E.I.P., T.D., J.G., J.K.), Neurology (T.R.M., M.A., D.J.S., U.F.), University Hospital Bern, Inselspital, Graduate School for Health Sciences (A.M.), and CTU Bern (M.B.), University of Bern, Switzerland; Department of Medicine and Neurology, Melbourne Brain Centre (F.C.N., N.Y., G.J.S., B.C.V.C.), Melbourne Medical School (L.C.), and Department of Radiology (P.J.M.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurology (F.C.N.), Austin Health, Heidelberg, Australia; Division of Neuroradiology, Vascular and Interventional Radiology Department of Radiology (H.A.D., O.N., T.G., M.K.), and Department of Neurology (T.G., M.K.), Medical University of Graz, Austria; Population Health and Immunity Division (N.Y.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Neurology (M.W.P.), Liverpool Hospital, University of New South Wales, Sydney, Australia; Department of Radiology and Nuclear Medicine (F.C.), Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Neuroscience, the Netherlands; Department of Neurology (T.J.K.), Royal Adelaide Hospital, Australia; and Department of Neurology (U.F.), University Hospital Basel, University of Basel, Switzerland
David J Seiffge From the Departments of Diagnostic and Interventional Neuroradiology (A.M., E.I.P., T.D., J.G., J.K.), Neurology (T.R.M., M.A., D.J.S., U.F.), University Hospital Bern, Inselspital, Graduate School for Health Sciences (A.M.), and CTU Bern (M.B.), University of Bern, Switzerland; Department of Medicine and Neurology, Melbourne Brain Centre (F.C.N., N.Y., G.J.S., B.C.V.C.), Melbourne Medical School (L.C.), and Department of Radiology (P.J.M.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurology (F.C.N.), Austin Health, Heidelberg, Australia; Division of Neuroradiology, Vascular and Interventional Radiology Department of Radiology (H.A.D., O.N., T.G., M.K.), and Department of Neurology (T.G., M.K.), Medical University of Graz, Austria; Population Health and Immunity Division (N.Y.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Neurology (M.W.P.), Liverpool Hospital, University of New South Wales, Sydney, Australia; Department of Radiology and Nuclear Medicine (F.C.), Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Neuroscience, the Netherlands; Department of Neurology (T.J.K.), Royal Adelaide Hospital, Australia; and Department of Neurology (U.F.), University Hospital Basel, University of Basel, Switzerland
Tomas Dobrocky From the Departments of Diagnostic and Interventional Neuroradiology (A.M., E.I.P., T.D., J.G., J.K.), Neurology (T.R.M., M.A., D.J.S., U.F.), University Hospital Bern, Inselspital, Graduate School for Health Sciences (A.M.), and CTU Bern (M.B.), University of Bern, Switzerland; Department of Medicine and Neurology, Melbourne Brain Centre (F.C.N., N.Y., G.J.S., B.C.V.C.), Melbourne Medical School (L.C.), and Department of Radiology (P.J.M.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurology (F.C.N.), Austin Health, Heidelberg, Australia; Division of Neuroradiology, Vascular and Interventional Radiology Department of Radiology (H.A.D., O.N., T.G., M.K.), and Department of Neurology (T.G., M.K.), Medical University of Graz, Austria; Population Health and Immunity Division (N.Y.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Neurology (M.W.P.), Liverpool Hospital, University of New South Wales, Sydney, Australia; Department of Radiology and Nuclear Medicine (F.C.), Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Neuroscience, the Netherlands; Department of Neurology (T.J.K.), Royal Adelaide Hospital, Australia; and Department of Neurology (U.F.), University Hospital Basel, University of Basel, Switzerland
Jan Gralla From the Departments of Diagnostic and Interventional Neuroradiology (A.M., E.I.P., T.D., J.G., J.K.), Neurology (T.R.M., M.A., D.J.S., U.F.), University Hospital Bern, Inselspital, Graduate School for Health Sciences (A.M.), and CTU Bern (M.B.), University of Bern, Switzerland; Department of Medicine and Neurology, Melbourne Brain Centre (F.C.N., N.Y., G.J.S., B.C.V.C.), Melbourne Medical School (L.C.), and Department of Radiology (P.J.M.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurology (F.C.N.), Austin Health, Heidelberg, Australia; Division of Neuroradiology, Vascular and Interventional Radiology Department of Radiology (H.A.D., O.N., T.G., M.K.), and Department of Neurology (T.G., M.K.), Medical University of Graz, Austria; Population Health and Immunity Division (N.Y.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Neurology (M.W.P.), Liverpool Hospital, University of New South Wales, Sydney, Australia; Department of Radiology and Nuclear Medicine (F.C.), Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Neuroscience, the Netherlands; Department of Neurology (T.J.K.), Royal Adelaide Hospital, Australia; and Department of Neurology (U.F.), University Hospital Basel, University of Basel, Switzerland
Urs Fischer From the Departments of Diagnostic and Interventional Neuroradiology (A.M., E.I.P., T.D., J.G., J.K.), Neurology (T.R.M., M.A., D.J.S., U.F.), University Hospital Bern, Inselspital, Graduate School for Health Sciences (A.M.), and CTU Bern (M.B.), University of Bern, Switzerland; Department of Medicine and Neurology, Melbourne Brain Centre (F.C.N., N.Y., G.J.S., B.C.V.C.), Melbourne Medical School (L.C.), and Department of Radiology (P.J.M.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurology (F.C.N.), Austin Health, Heidelberg, Australia; Division of Neuroradiology, Vascular and Interventional Radiology Department of Radiology (H.A.D., O.N., T.G., M.K.), and Department of Neurology (T.G., M.K.), Medical University of Graz, Austria; Population Health and Immunity Division (N.Y.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Neurology (M.W.P.), Liverpool Hospital, University of New South Wales, Sydney, Australia; Department of Radiology and Nuclear Medicine (F.C.), Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Neuroscience, the Netherlands; Department of Neurology (T.J.K.), Royal Adelaide Hospital, Australia; and Department of Neurology (U.F.), University Hospital Basel, University of Basel, Switzerland
Markus Kneihsl From the Departments of Diagnostic and Interventional Neuroradiology (A.M., E.I.P., T.D., J.G., J.K.), Neurology (T.R.M., M.A., D.J.S., U.F.), University Hospital Bern, Inselspital, Graduate School for Health Sciences (A.M.), and CTU Bern (M.B.), University of Bern, Switzerland; Department of Medicine and Neurology, Melbourne Brain Centre (F.C.N., N.Y., G.J.S., B.C.V.C.), Melbourne Medical School (L.C.), and Department of Radiology (P.J.M.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurology (F.C.N.), Austin Health, Heidelberg, Australia; Division of Neuroradiology, Vascular and Interventional Radiology Department of Radiology (H.A.D., O.N., T.G., M.K.), and Department of Neurology (T.G., M.K.), Medical University of Graz, Austria; Population Health and Immunity Division (N.Y.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Neurology (M.W.P.), Liverpool Hospital, University of New South Wales, Sydney, Australia; Department of Radiology and Nuclear Medicine (F.C.), Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Neuroscience, the Netherlands; Department of Neurology (T.J.K.), Royal Adelaide Hospital, Australia; and Department of Neurology (U.F.), University Hospital Basel, University of Basel, Switzerland
Bruce C V Campbell From the Departments of Diagnostic and Interventional Neuroradiology (A.M., E.I.P., T.D., J.G., J.K.), Neurology (T.R.M., M.A., D.J.S., U.F.), University Hospital Bern, Inselspital, Graduate School for Health Sciences (A.M.), and CTU Bern (M.B.), University of Bern, Switzerland; Department of Medicine and Neurology, Melbourne Brain Centre (F.C.N., N.Y., G.J.S., B.C.V.C.), Melbourne Medical School (L.C.), and Department of Radiology (P.J.M.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurology (F.C.N.), Austin Health, Heidelberg, Australia; Division of Neuroradiology, Vascular and Interventional Radiology Department of Radiology (H.A.D., O.N., T.G., M.K.), and Department of Neurology (T.G., M.K.), Medical University of Graz, Austria; Population Health and Immunity Division (N.Y.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Neurology (M.W.P.), Liverpool Hospital, University of New South Wales, Sydney, Australia; Department of Radiology and Nuclear Medicine (F.C.), Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Neuroscience, the Netherlands; Department of Neurology (T.J.K.), Royal Adelaide Hospital, Australia; and Department of Neurology (U.F.), University Hospital Basel, University of Basel, Switzerland
Johannes Kaesmacher From the Departments of Diagnostic and Interventional Neuroradiology (A.M., E.I.P., T.D., J.G., J.K.), Neurology (T.R.M., M.A., D.J.S., U.F.), University Hospital Bern, Inselspital, Graduate School for Health Sciences (A.M.), and CTU Bern (M.B.), University of Bern, Switzerland; Department of Medicine and Neurology, Melbourne Brain Centre (F.C.N., N.Y., G.J.S., B.C.V.C.), Melbourne Medical School (L.C.), and Department of Radiology (P.J.M.), Royal Melbourne Hospital, University of Melbourne, Parkville; Department of Neurology (F.C.N.), Austin Health, Heidelberg, Australia; Division of Neuroradiology, Vascular and Interventional Radiology Department of Radiology (H.A.D., O.N., T.G., M.K.), and Department of Neurology (T.G., M.K.), Medical University of Graz, Austria; Population Health and Immunity Division (N.Y.), The Walter and Eliza Hall Institute of Medical Research, Parkville; Department of Neurology (M.W.P.), Liverpool Hospital, University of New South Wales, Sydney, Australia; Department of Radiology and Nuclear Medicine (F.C.), Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Neuroscience, the Netherlands; Department of Neurology (T.J.K.), Royal Adelaide Hospital, Australia; and Department of Neurology (U.F.), University Hospital Basel, University of Basel, Switzerland

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Contemporary Methods for Detection and Intervention of Distal Medium and Small Vessel Occlusions

The efficacy of using mechanical thrombectomy for proximal large vessel occlusions has been demonstrated in multiple large-scale trials and has further raised the question of its potential utility for distal medium and small vessel occlusions (DMSVOs). Their longer, more tortuous course and smaller corresponding vascular territories render a significant challenge for detection and intervention. The aim of this study is to provide a comprehensive overview of the current imaging and endovascular intervention options for DMSVOs and review the current works in the literature. Compared with traditional computed tomography angiography (CTA) and CT perfusion, recent advances such as multiphase CTA and maps derived from the time-to-maximum parameter coupled with artificial intelligence have demonstrated increased sensitivity for the detection of DMSVOs. Furthermore, newer generations of mini stent retrievers and thromboaspiration devices have allowed for the access and navigation of smaller and more fragile distal arteries. Preliminary studies have suggested that mechanical thrombectomy using this newer generation of devices is both safe and feasible in distal medium-sized vessels, such as M2. However, endovascular intervention utilizing such contemporary methods and devices must be balanced at the discretion of operator experience and favorable vascular anatomy. Further large-scale multicenter clinical trials are warranted to elucidate the indications for as well as to strengthen the safety and efficacy of this approach.

Middle Cerebral Artery M2 Thrombectomy: Safety and Technical Considerations in the German Stroke Registry (GSR)

There is ongoing debate concerning the safety and efficacy of various mechanical thrombectomy (MT) approaches for M2 occlusions. We compared these for MT in M2 versus M1 occlusions. Subgroup analyses of different technical approaches within the M2 MT cohort were also performed. Patients were included from the German Stroke Registry (GSR), a multicenter registry of consecutive MT patients. Primary outcomes were reperfusion success events. Secondary outcomes were early clinical improvement (improvement in NIHSS score > 4) and independent survival at 90 days (mRS 0−2). Out of 3804 patients, 2689 presented with M1 (71%) and 1115 with isolated M2 occlusions (29%). The mean age was 76 (CI 65−82) and 77 (CI 66−83) years, respectively. Except for baseline NIHSS (15 (CI 10−18) vs. 11 (CI 6−16), p < 0.001) and ASPECTS (9 (CI 7−10) vs. 9 (CI 8−10, p < 0.001), baseline demographics were balanced. Apart from a more frequent use of dedicated small vessel stent retrievers (svSR) in M2 (17.4% vs. 3.0; p < 0.001), intraprocedural aspects were balanced. There was no difference in ICH at 24 h (11%; p = 1.0), adverse events (14.4% vs. 18.1%; p = 0.63), clinical improvement (62.5% vs. 61.4 %; p = 0.57), mortality (26.9% vs. 22.9%; p = 0.23). In M2 MT, conventional stent retriever (cSR) achieved higher rates of mTICI3 (54.0% vs. 37.7−42.0%; p < 0.001), requiring more MT-maneuvers (7, CI 2−8) vs. 2 (CI 2−7)/(CI 2−2); p < 0.001) and without impact on efficacy and outcome. Real-life MT in M2 can be performed with equal safety and efficacy as in M1 occlusions. Different recanalization techniques including the use of svSR did not result in significant differences regarding safety, efficacy and outcome.

Interrater Agreement and Detection Accuracy for Medium-Vessel Occlusions Using Single-Phase and Multiphase CT Angiography

BACKGROUND AND PURPOSE

Accurate and reliable detection of medium-vessel occlusions is important to establish the diagnosis of acute ischemic stroke and initiate appropriate treatment with intravenous thrombolysis or endovascular thrombectomy. However, medium-vessel occlusions are often challenging to detect, especially for unexperienced readers. We aimed to evaluate the accuracy and interrater agreement of the detection of medium-vessel occlusions using single-phase and multiphase CTA.

MATERIALS AND METHODS

Single-phase and multiphase CTA of 120 patients with acute ischemic stroke (20 with no occlusion, 44 with large-vessel occlusion, and 56 with medium-vessel occlusion in the anterior and posterior circulation) were assessed by 3 readers with varying levels of experience (session 1: single-phase CTA; session 2: multiphase CTA). Interrater agreement for occlusion type (large-vessel occlusion versus medium-vessel occlusion versus no occlusion) and for detailed occlusion sites was calculated using the Fleiss κ with 95% confidence intervals. Accuracy for the detection of medium-vessel occlusions was calculated for each reader using classification tables.

RESULTS

Interrater agreement for occlusion type was moderate for single-phase CTA (κ  = 0.58; 95% CI, 0.56-0.62) and almost perfect for multiphase CTA (κ = 0.81; 95% CI, 0.78-0.83). Interrater agreement for detailed occlusion sites was moderate for single-phase CTA (κ = 0.55; 95% CI, 0.53-0.56) and substantial for multiphase CTA (κ = 0.71; 95% CI, 0.67-0.74). On single-phase CTA, readers 1, 2, and 3 classified 33/56 (59%), 34/56 (61%), and 32/56 (57%) correctly as medium-vessel occlusions. On multiphase CTA, 48/56 (86%), 50/56 (89%), and 50/56 (89%) medium-vessel occlusions were classified correctly.

CONCLUSIONS

Interrater agreement for medium-vessel occlusions is moderate when using single-phase CTA and almost perfect with multiphase CTA. Detection accuracy is substantially higher with multiphase CTA compared with single-phase CTA, suggesting that multiphase CTA might be a valuable tool for assessment of medium-vessel occlusion stroke.