Thrombolysis in Cerebral Infarction 2b Reperfusions: To Treat or to Stop?

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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Flat-panel Detector Perfusion Imaging and Conventional Multidetector Perfusion Imaging in Patients with Acute Ischemic Stroke : A Comparative Study

PURPOSE

Flat-panel detector computed tomography (FDCT) is increasingly used in (neuro)interventional angiography suites. This study aimed to compare FDCT perfusion (FDCTP) with conventional multidetector computed tomography perfusion (MDCTP) in patients with acute ischemic stroke.

METHODS

In this study, 19 patients with large vessel occlusion in the anterior circulation who had undergone mechanical thrombectomy, baseline MDCTP and pre-interventional FDCTP were included. Hypoperfused tissue volumes were manually segmented on time to maximum (Tmax) and time to peak (TTP) maps based on the maximum visible extent. Absolute and relative thresholds were applied to the maximum visible extent on Tmax and relative cerebral blood flow (rCBF) maps to delineate penumbra volumes and volumes with a high likelihood of irreversible infarcted tissue ("core"). Standard comparative metrics were used to evaluate the performance of FDCTP.

RESULTS

Strong correlations and robust agreement were found between manually segmented volumes on MDCTP and FDCTP Tmax maps (r = 0.85, 95% CI 0.65-0.94, p < 0.001; ICC = 0.85, 95% CI 0.69-0.94) and TTP maps (r = 0.91, 95% CI 0.78-0.97, p < 0.001; ICC = 0.90, 95% CI 0.78-0.96); however, direct quantitative comparisons using thresholding showed lower correlations and weaker agreement (MDCTP versus FDCTP Tmax 6 s: r = 0.35, 95% CI -0.13-0.69, p = 0.15; ICC = 0.32, 95% CI 0.07-0.75). Normalization techniques improved results for Tmax maps (r = 0.78, 95% CI 0.50-0.91, p < 0.001; ICC = 0.77, 95% CI 0.55-0.91). Bland-Altman analyses indicated a slight systematic underestimation of FDCTP Tmax maximum visible extent volumes and slight overestimation of FDCTP TTP maximum visible extent volumes compared to MDCTP.

CONCLUSION

FDCTP and MDCTP provide qualitatively comparable volumetric results on Tmax and TTP maps; however, direct quantitative measurements of infarct core and hypoperfused tissue volumes showed lower correlations and agreement.

Connecting the DOTs: a novel imaging sign on flat-panel detector CT indicating distal vessel occlusions after thrombectomy

BACKGROUND

Immediate non-contrast post-interventional flat-panel detector CT (FPDCT) has been suggested as an imaging tool to assess complications after endovascular therapy (EVT). We systematically investigated a new imaging finding of focal hyperdensities correlating with remaining distal vessel occlusion after EVT.

METHODS

A single-center retrospective analysis was conducted for all acute ischemic stroke patients admitted between July 2020 and December 2022 who underwent EVT and immediate post-interventional FPDCT. A blinded core lab performed reperfusion grading on post-interventional digital subtraction angiography (DSA) images and evaluated focal hyperdensities on FPDCT (here called the distal occlusion tracker (DOT) sign). DOT sign was defined as a tubular or punctiform, vessel confined, hyperdense signal within the initial occlusion target territory. We assessed sensitivity and specificity of the DOT sign when compared with DSA findings.

RESULTS

The median age of the cohort (n=215) was 74 years (IQR 63-82) and 58.6% were male. The DOT sign was positive in half of the cohort (51%, 110/215). The DOT sign had high specificity (85%, 95% CI 72% to 93%), but only moderate sensitivity (63%, 95% CI 55% to 70%) for detection of residual vessel occlusions. In comparison to the core lab, operators overestimated complete reperfusion in a quarter of the entire cohort (25%, 53/215). In more than half of these cases (53%, 28/53) there was a positive DOT sign, which could have mitigated this overestimation.

CONCLUSION

The DOT sign appears to be a frequent finding on immediate post-interventional FPDCT. It correlates strongly with incomplete reperfusion and indicates residual distal vessel occlusions. In the future, it may be used to complement grading of reperfusion success and may help mitigating overestimation of reperfusion in the acute setting.

Comparison of Thrombolysis In Cerebral Infarction (TICI) 2b and TICI 3 reperfusion in endovascular therapy for large ischemic anterior circulation strokes

BACKGROUND

Landmark thrombectomy trials have provided evidence that selected patients with large ischemic stroke benefit from successful endovascular therapy, commonly defined as incomplete (modified Thrombolysis In Cerebral Infarction (mTICI) 2b) or complete reperfusion (mTICI 3). We aimed to investigate whether mTICI 3 improves functional outcomes compared with mTICI 2b in large ischemic strokes.

METHODS

This retrospective multicenter cohort study was conducted to compare mTICI 2b versus mTICI 3 in large ischemic strokes in the anterior circulation. Patients enrolled in the German Stroke Registry between 2015-2021 were analyzed. Large ischemic stroke was defined as an Alberta Stroke Program Early CT Score (ASPECTS) of 3-5. Patients were matched by final mTICI grade using propensity score matching. Primary outcome was the 90-day modified Rankin Scale (mRS) score.

RESULTS

After matching, 226 patients were included. Baseline and imaging characteristics were balanced between mTICI 2b and mTICI 3 patients. There was no shift on the mRS favoring mTICI 3 compared with mTICI 2b in large ischemic strokes (adjusted common odds ratio (acOR) 1.12, 95% confidence interval (95% CI) 0.64 to 1.94, P=0.70). The rate of symptomatic intracranial hemorrhage was higher in mTICI 2b than in mTICI 3 patients (12.6% vs 4.5%, P=0.03). Mortality at 90 days did not differ between mTICI 3 and mTICI 2b (33.6% vs 37.2%; adjusted OR 0.69, 95% CI 0.33 to 1.45, P=0.33).

CONCLUSIONS

In endovascular therapy for large ischemic strokes, mTICI 3 was not associated with better 90-day functional outcomes compared with mTICI 2b. This study suggests that mTICI 2b might be warranted as the final angiographic result, questioning the benefit/risk ratio of additional maneuvers to seek for mTICI 3 in large ischemic strokes.

TRIAL REGISTRATION NUMBER

NCT03356392.

The effect of butylphthalide on improving the neurological function of patients with acute anterior circulation cerebral infarction after mechanical thrombectomy

Butylphthalide can improve blood circulation in patients with acute cerebral infarction. Complement 3a receptor 1 (C3aR1) is involved in the regulation of innate immune response and pathogen monitoring, which is closely related to the pathophysiological processes of breast cancer, neurogenesis and lipid catabolism. Our study explored the therapeutic effect of butylphthalide on improving the neurological function of patients with acute anterior circulation cerebral infarction after mechanical thrombectomy, and evaluated the correlation between serum C3aR1 and butylphthalide on improving the neurological function after mechanical thrombectomy. 288 patients with acute anterior circulation cerebral infarction who were admitted to our hospital from January 2019 to November 2022 and were treated with mechanical thrombectomy for the first time were included in this retrospective study and divided into the butylphthalide group and control group that they received treatment methods. The National Institutes of Health Stroke Scale (NIHSS) scale was used to evaluate the patient neurological function treatment efficacy, and the modified Rankin Scale (mRS) scale was used to measure the patient neurological function status 3 months after surgery. Enzyme-linked immunosorbent assay method was used to determine the content of C3aR1 in serum. Two weeks after thrombus removal, the NIHSS efficacy of the butylphthalide group and the control group were 94.44% and 72.22%, respectively. The butylphthalide group was significantly higher than the control group (P < .001). Three months after the operation, the mRS score of the butylphthalide group was significantly lower than that of the control group (P = .001), and the excellent and good rate was significantly higher than that of the control group (P < .001). The serum C3aR1 level of the butylphthalide group was significantly lower than that of the control group 2 weeks after operation and 3 months after operation (P < .001). The serum C3aR1 was positively correlated with the efficacy of NIHSS (R = 0.815, P = .004), which was positively correlated with mRS score (R = 0.774, P = .007). Butylphthalide can improve the therapeutic effect of neurological function in patients with acute anterior circulation cerebral infarction after mechanical thrombus removal. The patient serum C3aR1 is related to the patient neurotherapy efficacy and neurological function status, and its level can reflect the patient neurological function recovery to a certain extent.

Effect of incomplete reperfusion patterns on clinical outcome: insights from the ESCAPE-NA1 trial

BACKGROUND

Incomplete reperfusion (IR) after mechanical thrombectomy (MT) can be a consequence of residual occlusion, no-reflow phenomenon, or collateral counterpressure. Data on the impact of these phenomena on clinical outcome are limited.

METHODS

Patients from the ESCAPE-NA1 trial with IR (expanded Thrombolysis In Cerebral Infarction (eTICI) 2b) were compared with those with complete or near-complete reperfusion (eTICI 2c-3) on the final angiography run. Final runs were assessed for (a) an MT-accessible occlusion, or (b) a non-MT-accessible occlusion pattern. The primary clinical outcome was modified Rankin Scale (mRS) 0-2 at 90 days. Our imaging outcome was infarction in IR territory on follow-up imaging. Unadjusted and adjusted incidence rate ratios (aIRR) with 95% confidence intervals (95% CI) were obtained.

RESULTS

Of 1105 patients, 443 (40.1%) with IR and 506 (46.1%) with complete or near-complete reperfusion were included. An MT-accessible occlusion was identified in 147/443 patients (33.2%) and a non-MT-accessible occlusion in 296/443 (66.8%). As compared with patients with near-complete/complete reperfusion, patients with IR had significantly lower chances of achieving mRS 0-2 at 90 days (aIRR 0.82, 95% CI 0.74 to 0.91). Rates of mRS 0-2 were lower in the MT-accessible occlusion group as compared with the non-MT-accessible occlusion pattern group (aIRR 0.71, 95% CI 0.60 to 0.83, and aIRR 0.89, 95% CI 0.81 to 0.98, respectively). More patients with MT-accessible occlusion patterns developed infarcts in the non-reperfused territory as compared with patients with non-MT occlusion patterns (68.7% vs 46.3%).

CONCLUSION

IR was associated with worse clinical outcomes than near-complete/complete reperfusion. Two-thirds of our patients with IR had non-MT-accessible occlusion patterns which were associated with better clinical and imaging outcomes compared with those with MT-accessible occlusion patterns.

Prediction of delayed reperfusion in patients with incomplete reperfusion following thrombectomy

BACKGROUND

The clinical course of patients with incomplete reperfusion after thrombectomy, defined as an expanded Thrombolysis in Cerebral Infarction (eTICI) score of 2a-2c, is heterogeneous. Patients showing delayed reperfusion (DR) have good clinical outcomes, almost comparable to patients with ad-hoc TICI3 reperfusion. We aimed to develop and internally validate a model that predicts DR occurrence in order to inform physicians about the likelihood of a benign natural disease progression.

PATIENTS AND METHODS

Single-center registry analysis including all consecutive, study-eligible patients admitted between 02/2015 and 12/2021. Preliminary variable selection for the prediction of DR was performed using bootstrapped stepwise backward logistic regression. Interval validation was performed with bootstrapping and the final model was developed using a random forests classification algorithm. Model performance metrics are reported with discrimination, calibration, and clinical decision curves. Primary outcome was concordance statistics as a measure of goodness of fit for the occurrence of DR.

RESULTS

A total of 477 patients (48.8% female, mean age 74 years) were included, of whom 279 (58.5%) showed DR on 24 follow-up. The model's discriminative ability for predicting DR was adequate (C-statistics 0.79 [95% CI: 0.72-0.85]). Variables with strongest association with DR were: atrial fibrillation (aOR 2.06 [95% CI: 1.23-3.49]), Intervention-To-Follow-Up time (aOR 1.06 [95% CI: 1.03-1.10]), eTICI score (aOR 3.49 [95% CI: 2.64-4.73]), and collateral status (aOR 1.33 [95% CI: 1.06-1.68]). At a risk threshold of R = 30%, use of the prediction model could potentially reduce the number of additional attempts in one out of four patients who will have spontaneous DR, without missing any patients who do not show spontaneous DR on follow-up.

CONCLUSIONS

The model presented here shows fair predictive accuracy for estimating chances of DR after incomplete thrombectomy. This may inform treating physicians on the chances of a favorable natural disease progression if no further reperfusion attempts are made.

Evaluation of time-resolved whole brain flat panel detector perfusion imaging using RAPID ANGIO in patients with acute stroke: comparison with CT perfusion imaging

BACKGROUND

In contrast to conventional CT perfusion (CTP) imaging, flat panel detector CT perfusion (FD-CTP) imaging can be acquired directly in the angiosuite.

OBJECTIVE

To evaluate time-resolved whole brain FD-CTP imaging and assess clinically important qualitative and quantitative perfusion parameters in correlation with previously acquired conventional CTP using the new RAPID for ANGIO software.

METHODS

We included patients with internal carotid artery occlusions and M1 or M2 occlusions from six centers. All patients underwent mechanical thrombectomy (MT) with preinterventional conventional CTP and FD-CTP imaging. Quantitative performance was determined by comparing volumes of infarct core, penumbral tissue, and mismatch. Eligibility for MT according to the perfusion imaging criteria of DEFUSE 3 was determined for each case from both conventional CTP and FD-CTP imaging.

RESULTS

A total of 20 patients were included in the final analysis. Conventional relative cerebral blood flow (rCBF) <30% and FD-CTP rCBF <45% showed good correlation (R²=0.84). Comparisons of conventional CTP Tmax >6 s versus FD-CTP Tmax >6 s and CTP mismatch versus FD-CTP mismatch showed more variability (R²=0.57, and R²=0.33, respectively). Based on FD-CTP, 16/20 (80%) patients met the inclusion criteria for MT according to the DEFUSE 3 perfusion criteria, in contrast to 18/20 (90%) patients based on conventional CTP. The vessel occlusion could be correctly extrapolated from the hypoperfusion in 18/20 cases (90%).

CONCLUSIONS

In our multicenter study, time-resolved whole brain FD-CTP was technically feasible, and qualitative and quantitative perfusion results correlated with those obtained with conventional CTP.

Association of Intravenous Thrombolysis with Delayed Reperfusion After Incomplete Mechanical Thrombectomy

PURPOSE

Treatment of distal vessel occlusions causing incomplete reperfusion after mechanical thrombectomy (MT) is debated. We hypothesized that pretreatment with intravenous thrombolysis (IVT) may facilitate delayed reperfusion (DR) of residual vessel occlusions causing incomplete reperfusion after MT.

METHODS

Retrospective analysis of patients with incomplete reperfusion after MT, defined as extended thrombolysis in cerebral infarction (eTICI) 2a-2c, and available perfusion follow-up imaging at 24 ± 12 h after MT. DR was defined as absence of any perfusion deficit on time-sensitive perfusion maps, indicating the absence of any residual occlusion. The association of IVT with the occurrence of DR was evaluated using a logistic regression analysis adjusted for confounders. Sensitivity analyses based on IVT timing (time between IVT start and the occurrence incomplete reperfusion following MT) were performed.

RESULTS

In 368 included patients (median age 73.7 years, 51.1% female), DR occurred in 225 (61.1%). Atrial fibrillation, higher eTICI grade, better collateral status and longer intervention-to-follow-up time were all associated with DR. IVT did not show an association with the occurrence of DR (aOR 0.80, 95% CI 0.44-1.46, even in time-sensitive strata, aOR 2.28 [95% CI 0.65-9.23] and aOR 1.53 [95% CI 0.52-4.73] for IVT to incomplete reperfusion following MT timing <80 and <100 min, respectively).

CONCLUSION

A DR occurred in 60% of patients with incomplete MT at ~24 h and did not seem to occur more often in patients receiving pretreatment IVT. Further research on potential associations of IVT and DR after MT is required.

Continuing early mTICI 2b recanalization may improve functional outcome but is associated with a higher risk of intracranial hemorrhage

Background

Successful reperfusion (mTICI 2c/3) and low number of passes are key determinants for good clinical outcome in acute large vessel occlusion. While final mTICI 2c/3 reperfusion is superior to partial reperfusion (mTICI 2b) it remains unclear if this is also true for the subgroup of patients with early mTICI 2b (achieved in ≤2 retrieval attempts) reperfusion who are secondarily improved to mTICI 2c/3. This study was designed to examine if early mTICI2b should be continued or stopped during mechanical thrombectomy (MT).

Methods

Nine hundred and thirteen ischemic stroke patients who received MT were retrospectively analyzed. Angiography runs following each recanalization attempt were scored for mTICI. The patients with early mTICI 2b reperfusions were dichotomized in “TICI2b-stopped” (MT withdrawal after mTICI 2b was achieved with first or second retrieval) and “TICI2b-continued” (MT was continued after mTICI 2b was achieved with first or second retrieval). Functional outcome was obtained after 90 days using the modified Rankin scale (mRS90).

Results

Of 362 Patients with a M1-occlusion, 100 patients fulfilled the inclusion criteria with an early mTICI 2b. 78/100 patients were included in the “TICI2b-stopped” group and 22/100 patients were in the “TICI2b-continued” group. Of these 22 patients, none had a final mTICI score lower than 2b and 11 patients had a final mTICI score of 2c/3. Regarding good functional outcome at mRS90, “TICI2b-continued” showed by trend a slight advantage of 40.1 vs. 35.6% in “TICI2b-stopped” but in multivariate logistic regression analysis adjusted for confounders, no significant difference was found between the two groups (OR 0.75, 95% CI 0.19–2.87, p = 0.67). Symptomatic intracranial hemorrhage was significantly higher in “TICI2b-continued” compared to “TICI2b-stopped” (31.8 vs. 10.3%, p = 0.031).

Conclusion

Successfully improving an early mTICI 2b to mTICI 2c/3 reperfusion is possible in a substantial number of patients and might improve functional outcome. However, an increase in symptomatic intracranial hemorrhage (SICH) due to further retrieval attempts may diminish the potential functional benefit to continue early mTICI 2b. To support this finding, further investigation with more power is needed to account for the low number of events regarding SICH.

Predictors of malignant middle cerebral artery infarction after endovascular thrombectomy: results of DIRECT-MT trial

OBJECTIVES

Predictors of malignant middle cerebral artery infarction (mMCAi) in patients after intravenous thrombolysis were well documented, but the risk factors of mMCAi after endovascular thrombectomy (EVT) were not fully explored. Therefore, the present study aimed to investigate the predictors of mMCAi after EVT in stroke patients.

METHODS

This was a secondary analysis of the DIRECT-MT trial. Patients who underwent EVT for the occlusions of MCA and/or intracranial internal carotid artery were analyzed. Primary outcome was the occurrence of mMCAi after EVT. Demographic, clinical, imaging, and treatment data were recorded, and multivariate logistic regression analysis was used to identify independent predictors. All of the candidate predictors were included, and forward elimination was applied to establish the most effective predictive model. Predictive ability and calibration of the model were assessed using the area under the receiver operating characteristic curve (AUC) and Hosmer-Lemeshow test, respectively.

RESULTS

Of 559 enrolled patients, 74 (13.2%) patients developed mMCAi. Predictors of mMCAi included unsuccessful reperfusion, higher serum glucose, lower Alberta Stroke Project Early Computed Tomography Change Score (ASPECTS), higher clot burden score (CBS), lower collateral score, and higher pass number of thrombectomy device. AUC of predictive model integrating all independent variables was 0.836. The Hosmer-Lemeshow test showed appropriate calibration (p = 0.859).

CONCLUSIONS

Reperfusion, serum glucose, ASPECTS, CBS, collateral, and pass number of thrombectomy device were associated with the occurrence of mMCAi in stroke patients after EVT, while alteplase treatment was not. Our findings might facilitate the early identification and management of stroke patients at a high risk of mMCAi.

KEY POINTS

• A total of 13.2% of stroke patients with large vessel occlusion of anterior circulation developed mMCAi after EVT. • The occurrence of mMCAi had a definite negative impact on the outcome for stroke patients. • Reperfusion, serum glucose, ASPECTS, CBS, collateral score, and the pass number of thrombectomy device were associated with the occurrence of mMCAi after EVT in stroke patients.

The End of Tissue-Type Plasminogen Activator's Reign?

Mechanical thrombectomy is a highly effective treatment for acute ischemic stroke caused by large-vessel occlusion in the anterior cerebral circulation, significantly increasing the likelihood of recovery to functional independence. Until recently, whether intravenous thrombolysis before mechanical thrombectomy provided additional benefits to patients with acute ischemic stroke-large-vessel occlusion remained unclear. Given that reperfusion is a key factor for clinical outcome in patients with acute ischemic stroke-large-vessel occlusion and the efficacy of both intravenous thrombolysis and mechanical thrombectomy is time-dependent, achieving complete reperfusion with a single pass should be the primary angiographic goal. However, it remains undetermined whether extending the procedure with additional endovascular attempts or local lytics administration safely leads to higher reperfusion grades and whether there are significant public health and cost implications. Here, we outline the current state of knowledge and research avenues that remain to be explored regarding the consistent therapeutic benefit of intravenous thrombolysis in anterior circulation strokes and the potential place of adjunctive intra-arterial lytics administration, including alternative thrombolytic agent place.

Association of reperfusion success and emboli in new territories with long term mortality after mechanical thrombectomy

BACKGROUND

The degree of reperfusion is the most important modifiable predictor of 3 month functional outcome and mortality in ischemic stroke patients treated with mechanical thrombectomy. Whether the beneficial effect of reperfusion also leads to a reduction in long term mortality is unknown.

METHODS

Patients undergoing mechanical thrombectomy between January 2010 and December 2018 were included. The post-thrombectomy degree of reperfusion and emboli in new territories were core laboratory adjudicated. Reperfusion was evaluated according to the expanded Thrombolysis in Cerebral Infarction (eTICI) scale. Vital status was obtained from the Swiss population register. Adjusted hazard ratios (aHRs) using time split Cox regression models were calculated. Subgroup analyses were performed in patients with borderline indications.

RESULTS

Our study included 1264 patients (median follow-up per patient 2.5 years). Patients with successful reperfusion had longer survival times, attributable to a lower hazard of death within 0-90 days and for >90 days to 2 years (aHR 0.34, 95% CI 0.26 to 0.46; aHR 0.37, 95% CI 0.22 to 0.62). This association was homogeneous across all predefined subgroups (p for interaction >0.05). Among patients with successful reperfusion, a significant difference in the hazard of death was observed between eTICI2b50 and eTICI3 (aHR 0.51, 95% CI 0.33 to 0.79). Emboli in new territories were present in 5% of patients, and were associated with increased mortality (aHR 2.3, 95% CI 1.11 to 4.86).

CONCLUSION

Successful, and ideally complete, reperfusion without emboli in new territories is associated with a reduction in long term mortality in patients treated with mechanical thrombectomy, and this was evident across several subgroups.

Endovascular thrombectomy for acute ischemic stroke

This review describes the evolution of endovascular treatment for acute ischemic stroke, current state of the art, and the challenges for the next decade. The rapid development of endovascular thrombectomy (EVT), from the first attempts into standard of care on a global scale, is one of the major achievements in modern medicine. It was possible thanks to the establishment of a scientific framework for patient selection, assessment of stroke severity and outcome, technical development by dedicated physicians and the MedTech industry, including noninvasive imaging for patient selection, and radiological outcome evaluation. A series of randomized controlled trials on EVT in addition to intravenous thrombolytics, with overwhelmingly positive results for anterior circulation stroke within 6 h of onset regardless of patient characteristics with a number needed to treat of less than 3 for any positive shift in outcome, paved the way for a rapid introduction of EVT into clinical practice. Within the "extended" time window of 6-24 h, the effect has been even greater for patients with salvageable brain tissue according to perfusion imaging with a number needed to treat below 2. Even so, EVT is only available for a small portion of stroke patients, and successfully recanalized EVT patients do not always achieve excellent functional outcome. The major challenges in the years to come include rapid prehospital detection of stroke symptoms, adequate clinical and radiological diagnosis of severe ischemic stroke cases, enabling effective recanalization by EVT in dedicated angiosuites, followed by personalized post-EVT stroke care.

Heterogeneity of the Relative Benefits of TICI 2c/3 over TICI 2b50/2b67 : Are there Patients who are less Likely to Benefit?

PURPOSE

Incomplete reperfusion after mechanical thrombectomy (MT) is associated with a poor outcome. Rescue therapy would potentially benefit some patients with an expanded treatment in cerebral ischemia score (eTICI) 2b50/2b67 reperfusion but also harbors increased risks. The relative benefits of eTICI 2c/3 over eTICI 2b50/67 in clinically important subpopulations were analyzed.

METHODS

Retrospective analysis of our institutional database for all patients with occlusion of the intracranial internal carotid artery (ICA) or the M1/M2 segment undergoing MT and final reperfusion of ≥eTICI 2b50 (903 patients). The heterogeneity in subgroups of different time metrics, age, National Institutes of Health Stroke Scale (NIHSS), number of retrieval attempts, Alberta Stroke Programme Early CT Score (ASPECTS) and site of occlusion using interaction terms (p_i) was analyzed.

RESULTS

The presence of eTICI 2c/3 was associated with better outcomes in most subgroups. Time metrics showed no interaction of eTICI 2c/3 over eTICI 2b50/2b67 and clinical outcomes (onset to reperfusion p_i = 0.77, puncture to reperfusion p_i = 0.65, onset to puncture p_i = 0.63). An eTICI 2c/3 had less consistent association with mRS ≤2 in older patients (>82 years, p_i = 0.038) and patients with either lower NIHSS (≤9) or very high NIHSS (>19, p_i = 0.01). Regarding occlusion sites, the beneficial effect of eTICI 2c/3 was absent for occlusions in the M2 segments (aOR 0.73, 95% confidence interval [CI] 0.33-1.59, p_i = 0.018).

CONCLUSION

Beneficial effect of eTICI 2c/3 over eTICI 2b50/2b67 only decreased in older patients, M2-occlusions and patients with either low or very high NIHSS. Improving eTICI 2b50/2b67 to eTICI 2c/3 in those subgroups may be more often futile.

Predictive Value of CT Perfusion Imaging on the Basis of Automatic Segmentation Algorithm to Evaluate the Collateral Blood Flow Status on the Outcome of Reperfusion Therapy for Ischemic Stroke

Our objective was to study the predictive value of CT perfusion imaging based on automatic segmentation algorithm for evaluating collateral blood flow status in the outcome of reperfusion therapy for ischemic stroke. All data of 30 patients with ischemic stroke reperfusion in our hospital were collected and examined by CT perfusion imaging. Convolutional neural network (CNN) algorithm was used to segment perfusion imaging map and evaluate the results. The patients were grouped by regional leptomeningeal collateral score (rLMCs). Binary logistic regression was used to analyze the independent influencing factors of collateral blood flow on brain CT perfusion. The modified Scandinavian Stroke Scale was used to evaluate the prognosis of patients, and the effects of different collateral flow conditions on prognosis were obtained. The accuracy of CNN segmentation image is 62.61%, the sensitivity is 87.42%, the similarity coefficient is 93.76%, and the segmentation result quality is higher. Blood glucose (95% CI = 0.943, P=0.028) and ischemic stroke history (95% CI = 0.855, P=0.003) were independent factors affecting the collateral blood flow status of stroke patients. CBF (95% CI = 0.818, P=0.008) and CBV (95% CI = 0.796, P=0.016) were independent influencing factors of CT perfusion parameters. After 3 weeks of onset, the prognostic function defect score of the good collateral flow group (11.11%) was lower than that of the poor group (41.67%) (P < 0.05). The automatic segmentation algorithm has more accurate segmentation ability for stroke CT perfusion imaging and plays a good auxiliary role in the diagnosis of clinical stroke reperfusion therapy. The collateral blood flow state based on CT perfusion imaging is helpful to predict the treatment outcome of patients with ischemic stroke and further predict the prognosis of patients.

Identification of successful cerebral reperfusions (mTICI ≥2b) using an artificial intelligence strategy

BACKGROUND

The modified thrombolysis in cerebral infarction (mTICI) scale is a widely used and validated qualitative tool to evaluate angiographic intracerebral inflow following endovascular thrombectomy (EVT). We validated a machine-learning (ML) algorithm to grade digital subtraction angiograms (DSA) using the mTICI scale.

MATERIALS AND METHODS

We included angiograms of identified middle cerebral artery (MCA) occlusions who underwent EVT. The complete DSA sequences were preprocessed and normalized. We created three convolutional neural networks to classify DSA into two outcomes, low- (mTICI 0,1,2a) and high-grade (mTICI 2b,2c,3).

RESULTS

We included a total of 234 angiograms in this study. The area under the receiver operating characteristic was 0.863 (95% CI 0.816-0.909), 0.914 (95% CI 0.876-0.951), and 0.890 (95% CI 0.848-0.932) for the anteroposterior (AP), lateral (L), and combined models, respectively, when dichotomizing outcomes into low and high grade. The models' area under the precision-recall curve was 0.879 (95% CI 0.829-0.930), 0.906 (95% CI 0.844-0.968), and 0.887 (95% CI 0.834-0.941) for the AP, L, and combined models.

CONCLUSION

In complete cerebral DSA, our angiography-based ML strategy was able to predict mTICI scores following EVT rapidly and reliably for MCA occlusions.

Thrombectomy for secondary distal, medium vessel occlusions of the posterior circulation: seeking complete reperfusion

BACKGROUND

Whether to approach distal occlusions endovascularly or not in medium-sized vessels secondary to proximal large vessel occlusion stroke remains unanswered.

OBJECTIVE

To investigates the technical feasibility and safety of thrombectomy for secondary posterior circulation distal, medium vessel occlusions (DMVO).

METHODS

TOPMOST (Treatment fOr Primary Medium vessel Occlusion STroke) is an international, retrospective, multicenter, observational registry of patients treated for distal cerebral artery occlusions. This study subanalysis endovascularly treated occlusions of the posterior cerebral artery in the P2 and P3 segment secondary preprocedural or periprocedural thrombus migration between January 2014 and June 2020. Technical feasibility was evaluated with the modified Thrombolysis in Cerebral Infarction (mTICI) scale. Procedural safety was assessed by the occurrence of symptomatic intracranial hemorrhage (sICH) and intervention-related serious adverse events.

RESULTS

Among 71 patients with secondary posterior circulation DMVO who met the inclusion criteria, occlusions were present in 80.3% (57/71) located in the P2 segment and in 19.7% (14/71) in the P3 segment. Periprocedural migration occurred in 54.9% (39/71) and preprocedural migration in 45.1% (32/71) of cases. The first reperfusion attempt led in 38% (27/71) of all cases to mTICI 3. On multivariable logistic regression analysis, increased numbers of reperfusion attempts (adjusted odds ratio (aOR)=0.39, 95% CI 0.29 to 0.88, p=0.009) and preprocedural migration (aOR=4.70, 95% CI,1.35 to 16.35, p=0.015) were significantly associated with mTICI 3. sICH occurred in 2.8% (2/71).

CONCLUSION

Thrombectomy for secondary posterior circulation DMVO seems to be safe and technically feasible. Even though thrombi that have migrated preprocedurally may be easier to retract, successful reperfusion can be achieved in the majority of patients with secondary DMVO of the P2 and P3 segment.

Per-pass analysis of recanalization and good neurological outcome in thrombectomy for stroke: Systematic review and meta-analysis

BACKGROUND AND AIM

First pass effect (FPE) is defined as achieving a complete recanalization with a single thrombectomy device pass. Although clinically desired, FPE is reached in less than 30% of thrombectomy procedures. Multiple device passes are often necessary to achieve successful or complete recanalization. We performed a systematic review and meta-analysis to determine the recanalization rate after each pass of mechanical thrombectomy and its association with good neurological outcome.

METHODS

A literature search was performed for studies reporting the number of device passes required for either successful (mTICI 2b or higher) or complete (mTICI 2c or higher) recanalization. Using random-effect meta-analysis, we evaluated the likelihood of recanalization and good neurological outcome (measured with the modified Rankin Score <2 at 90 days) after each device pass.

RESULTS

Thirteen studies comprising 4197 patients were included. Among cases with failed first pass, 24% of them achieved final complete recanalization and 45% of them achieved final successful recanalization. Independently to the total number of previously failed attempts, the likelihood of achieving successful recanalization was 30% per pass, and the likelihood to achieve complete recanalization was about 20% per pass. The likelihood of good neurological outcome in patients with final successful recanalization decreased after each device pass: 55% after the first pass, 48% after the second pass, 42% after the third pass, 36% after the fourth pass, and 26% for 5 passes or more.

CONCLUSION

Each pass is associated with a stable likelihood of recanalization but a decreased likelihood of good neurological outcome.

[Border areas of thrombectomy]

Die mechanische Thrombektomie (MT) hat sich als Standardverfahren für die Behandlung akuter ischämischer Schlaganfälle aufgrund eines Verschlusses einer großen, proximalen Hirnarterie der vorderen Zirkulation etabliert. Dennoch sind nach aktuellen Guidelines noch große Patientenkollektive von dieser hocheffektiven Behandlungsmethode ausgeschlossen. Diese Arbeit gibt daher einen Überblick über mögliche Erweiterungen der Behandlungsindikationen für die MT, wie z. B. Patienten im erweiterten Zeitfenster, mit distalen Verschlüssen, mit großem Infarktkern oder auch für sehr alte (> 90 Jahre) und junge (0–17 Jahre) Patienten. Zusätzlich besprechen wir neue Entwicklungen in der interventionellen Behandlung von Schlaganfällen, wie z. B. neue Triage-Konzepte oder die Fragestellung, ob die zusätzliche intravenöse Thrombolyse bei MT-Patienten notwendig ist. Abschließend geben wir für die besprochenen Behandlungsindikationen unsere Einschätzungen basierend auf der aktuellen Literatur und unserer klinischen Erfahrung.

Factors associated with early reperfusion improvement after intra-arterial fibrinolytics as rescue for mechanical thrombectomy

Objective:

To identify factors associated with early angiographic reperfusion improvement (EARI) following intra-arterial fibrinolytics (IAF) after failed or incomplete mechanical thrombectomy (MT).

Methods:

A subset of patients treated with MT and IAF rescue after incomplete reperfusion included in the INFINITY (INtra-arterial FIbriNolytics In ThrombectomY) multicenter observational registry was analyzed. Multivariable logistic regression was used to identify factors associated with EARI. Heterogeneity of the clinical effect of EARI on functional independence (defined as modified Rankin Score ≤2) was tested with interaction terms.

Results:

A total of 228 patients (median age: 72 years, 44.1% female) received IAF as rescue for failed or incomplete MT and had a post-fibrinolytic angiographic control run available (50.9% EARI). A cardioembolic stroke origin (adjusted odds ratio (aOR) 3.72, 95% confidence interval (CI) 1.39–10.0) and shorter groin puncture to IAF intervals (aOR 0.82, 95% CI 0.71–0.95 per 15-min delay) were associated with EARI, while pre-interventional thrombolysis showed no association (aOR 1.15, 95% CI 0.59–2.26). The clinical benefit of EARI after IAF seemed more pronounced in patients without or only minor early ischemic changes (Alberta Stroke Program Early Computed Tomography Score (ASPECTS) ≥9, aOR 4.00, 95% CI 1.37–11.61) and was absent in patients with moderate to severe ischemic changes (ASPECTS ≤8, aOR 0.94, 95% CI 0.27–3.27, p for interaction: 0.095).

Conclusion:

Early rescue and a cardioembolic stroke origin were associated with more frequent EARI after IAF. The clinical effect of EARI seemed reduced in patients with already established infarcts. If confirmed, these findings can help to inform patient selection and inclusion criteria for randomized-controlled trials evaluating IAF as rescue after MT.