Importance of Delayed Reperfusions in Patients With Incomplete Thrombectomy

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.

Perfusion Abnormalities on 24-Hour Perfusion Imaging in Patients With Complete Endovascular Reperfusion

BACKGROUND

Perfusion abnormalities in the infarct and salvaged penumbra have been proposed as a potential reason for poor clinical outcome (modified Rankin Scale score >2) despite complete angiographic reperfusion (Thrombolysis in Cerebral Infarction [TICI3]). In this study, we aimed to identify different microvascular perfusion patterns and their association with clinical outcomes among TICI3 patients.

METHODS

University Hospital Bern's stroke registry of all patients between February 2015 and December 2021. Macrovascular reperfusion was graded using the TICI scale. Microvascular reperfusion status was evaluated within the infarct area on cerebral blood volume and cerebral blood flow perfusion maps obtained 24-hour postintervention. Primary outcome was functional independence (90-day modified Rankin Scale score 0-2) evaluated with the logistic regression analysis adjusted for age, sex, and 24-hour infarct volume from follow-up imaging.

RESULTS

Based on microvascular perfusion findings, the entire cohort (N=248) was stratified into one of the 4 clusters: (1) normoperfusion (no perfusion abnormalities; n=143/248); (2) hyperperfusion (hyperperfusion on both cerebral blood volume and cerebral blood flow; n=54/248); (3) hypoperfusion (hypoperfusion on both cerebral blood volume and cerebral blood flow; n=14/248); and (4) mixed (discrepant findings, eg, cerebral blood volume hypoperfusion and cerebral blood flow hyperperfusion; n=37/248). Compared with the normoperfusion cluster, patients in the hypoperfusion cluster were less likely to achieve functional independence (adjusted odds ratio, 0.3 [95% CI, 0.1-0.9]), while patients in the hyperperfusion cluster tended to have better outcomes (adjusted odds ratio, 3.3 [95% CI, 1.3-8.8]).

CONCLUSIONS

In around half of TICI3 patients, perfusion abnormalities on the microvascular level can be observed. Microvascular hypoperfusion, despite complete macrovascular reperfusion, is rare but may explain the poor clinical course among some TICI3 patients, while a detrimental effect of hyperperfusion after reperfusion could not be confirmed.

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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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.

Outcome of Mechanical Thrombectomy for Acute Basilar Artery Occlusion in Patients with Intracranial Atherosclerotic Disease

INTRODUCTION

Intracranial atherosclerotic disease (ICAD) has been identified as a major cause of acute basilar artery occlusion (BAO).This study compared the characteristics and treatment outcomes in acute BAO patients with and without ICAD.

METHODS

A prospective cohort study was conducted at 115 People's Hospital, Ho Chi Minh city, Vietnam from August 2021 to June 2023. Patients with acute BAO who underwent endovascular treatment within 24 h from symptom onset were included (thrombectomy alone or bridging with intravenous alteplase). The baseline characteristics and outcomes were analyzed and compared between patients with and without ICAD. Good functional outcome was defined as mRS ≤3 at 90 days.

RESULTS

Among the 208 patients enrolled, 112 (53.8%) patients were categorized in the ICAD group, and 96 (46.2%) in the non-ICAD group. Occlusion in the proximal segment of the basilar artery was more common in patients with ICAD (55.4% vs. 21.9%, p < 0.001), whereas the distal segment was the most common location in the non-ICAD group (58.3% vs. 10.7%, p < 0.001). Patients in the ICAD group were more likely to undergo treatment in the late window, with a higher mean onset-to-treatment time compared to the non-ICAD group (11.6 vs. 9.5 h, p = 0.01). In multivariable logistic regression analysis, distal segment BAO was negatively associated with ICAD (aOR 0.13, 95% CI: 0.05-0.32, p < 0.001), while dyslipidemia showed a positive association (aOR 2.44, 95% CI: 1.15-5.17, p = 0.02). There was a higher rate for rescue stenting in the ICAD compared to non-ICAD group (15.2% vs. 0%, p < 0.001). However, no significant differences were found between the two groups in terms of good outcome (45.5% vs. 44.8%, p = 0.91), symptomatic hemorrhage rates (4.5% vs. 8.3%, p = 0.25), and mortality (42% vs. 50%, p = 0.25).

CONCLUSION

ICAD was a common etiology in patients with BAO. The location segment of BAO and dyslipidemia were associated with ICAD in patients with BAO. There was no difference in 90-day outcomes between BAO patients with and without ICAD undergoing endovascular therapy.

Value of Immediate Flat Panel Perfusion Imaging after Endovascular Therapy (AFTERMATH): A Proof of Concept Study

BACKGROUND AND PURPOSE

Potential utility of flat panel CT perfusion imaging (FPCT-PI) performed immediately after mechanical thrombectomy (MT) is unknown. We aimed to assess whether FPCT-PI obtained directly post-MT could provide additional potentially relevant information on tissue reperfusion status.

MATERIALS AND METHODS

This was a single-center analysis of all patients with consecutive acute stroke admitted between June 2019 and March 2021 who underwent MT and postinterventional FPCT-PI (n = 26). A core lab blinded to technical details and clinical data performed TICI grading on postinterventional DSA images and qualitatively assessed reperfusion on time-sensitive FPCT-PI maps. According to agreement between DSA and FPCT-PI, all patients were classified into 4 groups: hypoperfusion findings perfectly matched by location (group 1), hypoperfusion findings mismatched by location (group 2), complete reperfusion on DSA with hypoperfusion on FPCT-PI (group 3), and hypoperfusion on DSA with complete reperfusion on FPCT-PI (group 4).

RESULTS

Detection of hypoperfusion (present/absent) concurred in 21/26 patients. Of these, reperfusion findings showed perfect agreement on location and size in 16 patients (group 1), while in 5 patients there was a mismatch by location (group 2). Of the remaining 5 patients with disagreement regarding the presence or absence of hypoperfusion, 3 were classified into group 3 and 2 into group 4. FPCT-PI findings could have avoided TICI overestimation in all false-positive operator-rated TICI 3 cases (10/26).

CONCLUSIONS

FPCT-PI may provide additional clinically relevant information in a considerable proportion of patients undergoing MT. Hence, FPCT-PI may complement the evaluation of reperfusion efficacy and potentially inform decision-making in the angiography suite.

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.

Incidence, severity and impact on functional outcome of persistent hypoperfusion despite large-vessel recanalization, a potential marker of impaired microvascular reperfusion: Systematic review of the clinical literature

The reported incidence of persistent hypoperfusion despite complete recanalization as surrogate for impaired microvascular reperfusion (IMR) has varied widely among clinical studies, possibly due to differences in i) definition of complete recanalization, with only recent Thrombolysis in Cerebral Infarction (TICI) grading schemes allowing distinction between complete (TICI3) and partial recanalization with distal occlusions (TICI2c); ii) operational definition of IMR; and iii) consideration of potential alternative causes for hypoperfusion, notably carotid stenosis, re-occlusion and post-thrombectomy hemorrhage. We performed a systematic review to identify clinical studies that carried out brain perfusion imaging within 72 hrs post-thrombectomy for anterior circulation stroke and reported hypoperfusion rates separately for TICI3 and TICI2c grades. Authors were contacted if this data was missing. We identified eight eligible articles, altogether reporting 636 patients. The incidence of IMR after complete recanalization (i.e., TICI3) tended to decrease with the number of considered alternative causes of hypoperfusion: range 12.5-42.9%, 0-31.6% and 0-9.1% in articles that considered none, two or all three causes, respectively. No study reported the impact of IMR on functional outcome separately for TICI-3 patients. Based on this systematic review, IMR in true complete recanalization appears relatively rare, and reported incidence highly depends on definition used and consideration of confounding factors.

No-reflow phenomenon in stroke patients: A systematic literature review and meta-analysis of clinical data

BACKGROUND

The no-reflow phenomenon refers to the absence of microvascular reperfusion despite macrovascular reperfusion.

AIM

The aim of this analysis was to summarize the available clinical evidence on no-reflow in patients with acute ischemic stroke.

METHODS

A systematic literature review and a meta-analysis of clinical data on definition, rates, and impact of the no-reflow phenomenon after reperfusion therapy was carried out. A predefined research strategy was formulated according to the Population, Intervention, Comparison, and Outcome (PICO) model and was used to screen for articles in PubMed, MEDLINE, and Embase up to 8 September 2022. Whenever possible, quantitative data were summarized using a random-effects model.

RESULTS

Thirteen studies with a total of 719 patients were included in the final analysis. Most studies (n = 10/13) used variations of the Thrombolysis in Cerebral Infarction scale to evaluate macrovascular reperfusion, whereas microvascular reperfusion and no-reflow were mostly assessed on perfusion maps (n = 9/13). In one-third of stroke patients with successful macrovascular reperfusion (29%, 95% confidence interval (CI), 21-37%), the no-reflow phenomenon was observed. Pooled analysis showed that no-reflow was consistently associated with reduced rates of functional independence (odds ratio (OR), 0.21, 95% CI, 0.15-0.31).

CONCLUSION

The definition of no-reflow varied substantially across studies, but it appears to be a common phenomenon. Some of the no-reflow cases may simply represent remaining vessel occlusions, and it remains unclear whether no-reflow is an epiphenomenon of the infarcted parenchyma or causes infarction. Future studies should focus on standardizing the definition of no-reflow with more consistent definitions of successful macrovascular reperfusion and experimental set-ups that could detect the causality of the observed findings.

Intra-Arterial Thrombolysis is Associated with Delayed Reperfusion of Remaining Vessel Occlusions following Incomplete Thrombectomy

BACKGROUND AND PURPOSE

Intra-arterial thrombolytics may be used to treat distal vessel occlusions, which cause incomplete reperfusion following mechanical thrombectomy. Because immediate reperfusion after intra-arterial thrombolytics occurs rarely, the aim of this study was to assess the delayed effect of intra-arterial thrombolytics using follow-up perfusion imaging.

MATERIALS AND METHODS

We included patients from a prospective stroke registry (February 2015 to September 2022) who had undergone mechanical thrombectomy and had incomplete reperfusion (expanded TICI 2a-2c) and available 24 hour perfusion imaging. Perfusion imaging was rated as delayed reperfusion if time-sensitive perfusion maps did not show wedge-shaped delays suggestive of persisting occlusions corresponding to the post-mechanical thrombectomy angiographic deficit. Patients treated with intra-arterial thrombolytics were compared with controls using multivariable logistic regression and inverse probability of treatment weighting matching for baseline differences and factors associated with delayed reperfusion.

RESULTS

The median age of the final study population (n = 459) was 74 years (interquartile range, 63-81 years), and delayed reperfusion occurred in 61% of cases. Patients treated with additional intra-arterial thrombolytics (n = 40) were younger and had worse expanded TICI scores. After matching was performed, intra-arterial thrombolytics was associated with higher rates of delayed reperfusion (adjusted OR = 2.7; 95% CI, 1.1-6.4) and lower rates of new infarction in the residually hypoperfused territory after mechanical thrombectomy (adjusted OR = 0.3; 95% CI, 0.1-0.7). No difference was found in the rates of functional independence (90-day mRS, 0-2; adjusted OR = 1.4; 95% CI, 0.4-4.1).

CONCLUSIONS

Rescue intra-arterial thrombolytics is associated with delayed reperfusion of remaining vessel occlusions following incomplete mechanical thrombectomy. The value of intra-arterial thrombolytics as a potential therapy for incomplete reperfusions after mechanical thrombectomy should be assessed in the setting of randomized controlled trials.

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.

Association Between Intravenous Thrombolysis and Clinical Outcomes Among Patients With Ischemic Stroke and Unsuccessful Mechanical Reperfusion

Importance

Clinical evidence of the potential treatment benefit of intravenous thrombolysis preceding unsuccessful mechanical thrombectomy (MT) is scarce.

Objective

To determine whether intravenous thrombolysis (IVT) prior to unsuccessful MT improves functional outcomes in patients with acute ischemic stroke.

Design, Setting, and Participants

Patients were enrolled in this retrospective cohort study from the prospective, observational, multicenter German Stroke Registry-Endovascular Treatment between May 1, 2015, and December 31, 2021. This study compared IVT plus MT vs MT alone in patients with acute ischemic stroke due to anterior circulation large-vessel occlusion in whom mechanical reperfusion was unsuccessful. Unsuccessful mechanical reperfusion was defined as failed (final modified Thrombolysis in Cerebral Infarction grade of 0 or 1) or partial (grade 2a). Patients meeting the inclusion criteria were matched by treatment group using 1:1 propensity score matching.

Interventions

Mechanical thrombectomy with or without IVT.

Main Outcomes and Measures

Primary outcome was functional independence at 90 days, defined as a modified Rankin Scale score of 0 to 2. Safety outcomes were the occurrence of symptomatic intracranial hemorrhage and death.

Results

After matching, 746 patients were compared by treatment arms (median age, 78 [IQR, 68-84] years; 438 women [58.7%]). The proportion of patients who were functionally independent at 90 days was 68 of 373 (18.2%) in the IVT plus MT and 42 of 373 (11.3%) in the MT alone group (adjusted odds ratio [AOR], 2.63 [95% CI, 1.41-5.11]; P = .003). There was a shift toward better functional outcomes on the modified Rankin Scale favoring IVT plus MT (adjusted common OR, 1.98 [95% CI, 1.35-2.92]; P < .001). The treatment benefit of IVT was greater in patients with partial reperfusion compared with failed reperfusion. There was no difference in symptomatic intracranial hemorrhages between treatment groups (AOR, 0.71 [95% CI, 0.29-1.81]; P = .45), while the death rate was lower after IVT plus MT (AOR, 0.54 [95% CI, 0.34-0.86]; P = .01).

Conclusions and Relevance

These findings suggest that prior IVT was safe and improved functional outcomes at 90 days. Partial reperfusion was associated with a greater treatment benefit of IVT, indicating a positive interaction between IVT and MT. These results support current guidelines that all eligible patients with stroke should receive IVT before MT and add a new perspective to the debate on noninferiority of combined stroke treatment.

Patient characteristics associated with delayed neurological improvement following acute ischemic stroke: A systematic review and meta-analysis

BACKGROUND

Delayed neurological improvement (DNI) is a phenomenon that involves patient improvement in the absence of early neurological change following treatment for acute ischemic stroke. The patient characteristics associated with this condition are largely unexplored.

METHODS

Following the PRISMA guidelines, a systematic review of the English language literature was conducted using PubMed, Embase, Web of science, and Scopus. We calculated pooled odds ratios (ORs), mean differences (MDs), and their corresponding 95% confidence intervals (CIs) to test the association between patient characteristics and achievement of DNI.

RESULTS

Seven studies, with 3266 patients, were included in our analysis. All studies reported a different definition of DNI, with five studies focusing on rates of good functional outcome at 90 days post-treatment in the absence of early neurological improvement. Use of intravenous thrombolytics was associated with increased rates of DNI (OR 1.96, 95% CI 1.28 to 3.00; p = 0.002). Atrial fibrillation was associated with decreased rates of DNI (OR 0.69, 95% CI 0.57 to 0.82; p < 0.001), as was hypertension (OR 0.66, 95% CI 0.53 to 0.83, p < 0.001), and diabetes mellitus (OR 0.71, 95% CI 0.56 to 0.90; p = 0.005). On average, patients who achieved DNI were 6.30 years younger than their non-DNI counterparts (MD -6.30, 95% CI -9.19 to -3.41; p < 0.001). There were modest associations between male sex and DNI (OR 1.36, 95% CI 1.01 to 1.74, p = 0.042), and smoking and DNI (OR 1.28, 95% CI 1.03 to 1.59, p = 0.027).

CONCLUSIONS

DNI is a phenomenon that is not presently well understood. Lack of uniformity among definitions of DNI hinders efforts to explore DNI and the factors associated with its occurrence. Future studies should work to establish a consensus definition of DNI to determine its causes and significance more accurately.