Ioannis Tsogkas

Effects of Workflow Optimization in Endovascularly Treated Stroke Patients – A Pre-Post Effectiveness Study

Endovascular treatment of acute ischemic stroke has become standard of care for patients with large artery occlusion. Early restoration of blood flow is crucial for a good clinical outcome. We introduced an interdisciplinary standard operating procedure (SOP) between neuroradiologists, neurologists and anesthesiologists in order to streamline patient management. This study analyzes the effect of optimized workflow on periprocedural timings and its potential influence on clinical outcome. Data were extracted from a prospectively maintained university hospital stroke database. The standard operating procedure was established in February 2014. Of the 368 acute stroke patients undergoing endovascular treatment between 2008 and 2015, 278 patients were treated prior to and 90 after process optimization. Outcome measures were periprocedural time intervals and residual functional impairment. After implementation of the SOP, time from symptom onset to reperfusion was significantly reduced (median 264 min prior and 211 min after SOP-introduction (IQR 228–32 min and 161–278 min, respectively); P<0.001). Especially faster supply of imaging and prompt transfer of patients to the angiography suite contributed to this effect. Time between hospital admission and groin puncture was reduced by half after process optimization (median 64 min after versus 121 min prior to SOP-introduction (IQR 54–77 min and 96–161 min, respectively); P<0.001). Clinical outcome was significantly better after workflow optimization as measured with the modified Rankin Scale (common odds ratio (OR) 0.56; 95% CI 0.32–0.98; P = 0.038). Optimization of workflow and interdisciplinary teamwork significantly improved the outcome of patients with acute ischemic stroke due to a significant reduction of in-hospital examination, transportation, imaging and treatment times.

Comparing different thrombectomy techniques in five large-volume centers: a ‘real world’ observational study

Background and purpose Thrombectomy has become the standard of care for acute ischaemic stroke due to large vessel occlusion. Aim of this study was to compare the radiological outcomes and time metrics of the various thrombectomy techniques. Methods In this retrospective, multicenter study we analysed the data of 450 patients with occlusion of the anterior circulation, treated in five high-volume center from 2013 to 2016. The treatment techniques were divided in three categories: first-pass use of a large-bore aspiration-catheter; first-pass use of a stent-retriever; and primary combined approach (PCA) of an aspiration-catheter and stent-retriever. Primary endpoints were successful reperfusion and groin to reperfusion time. Secondary endpoints were the number of attempts and occurrence of emboli in new territory (ENT). The primary analysis was based on the intention to treat groups (ITT). Results The ITT-analysis showed significantly higher reperfusion rates, with 86% of successful reperfusion in the PCA-group compared with 73% in the aspiration group and 65% in the stent-retriever group. There was no significant difference in groin to reperfusion time regarding the used technique. The secondary analysis showed an impact of the technique on the number of attempts and the occurrence of ENTs. Lowest ENT rates and attempts were reported with the combined approach. Conclusions The combined first-pass deployment of a stent-retriever and an aspiration-catheter was the most effective technique for reperfusion of anterior circulation large vessel occlusion. Our results correlate with the latest single-centrere studies, reporting very high reperfusion rates with PCA variations.

One-Stop Management of Acute Stroke Patients: Minimizing Door-to-Reperfusion Times

Background and Purpose— Intrahospital time delays significantly affect the neurological outcome of stroke patients with large-vessel occlusion. This study was conducted to determine whether a one-stop management can reduce intrahospital times of patients with acute large-vessel occlusion. Methods— In this observational study, we report the first 30 consecutive stroke patients imaged and treated in the same room. As part of our protocol, we transported patients with a National Institutes of Health Stroke Scale score of ≥10 directly to the angio suite, bypassing multidetector computed tomography (CT). Preinterventional imaging consisted of noncontrast flat detector CT and flat detector CT angiography, acquired with an angiography system. Patients with large-vessel occlusions remained on the angio table and were treated with mechanical thrombectomy; patients with small artery occlusions were treated with intravenous thrombolysis, whereas patients with an intracranial hemorrhage and stroke mimics were treated as per guidelines. Door-to-groin puncture times were recorded and compared with our past results. Results— Thirty patients were transferred directly to our angio suite from June to December 2016. The time from symptom onset to admission was 105 minutes. Ischemic stroke was diagnosed in 22 of 30 (73%) patients, 4 of 30 (13.5%) had an intracranial hemorrhage, and 4 of 30 (13.5) were diagnosed with a Todd’s paresis. Time from admission to groin puncture was 20.5 minutes. Compared with 44 patients imaged with multidetector CT in the first 6 months of 2016, door-to-groin times were significantly reduced (54.5 minutes [95% confidence interval, 47–61] versus 20.5 minutes [95% confidence interval, 17–26]). Conclusions— In this small series, a one-stop management protocol of selected stroke patients using latest generation flat detector CT led to a significant reduction of intrahospital times.

Bridging-therapy with intravenous recombinant tissue plasminogen activator improves functional outcome in patients with endovascular treatment in acute stroke ☆

BACKGROUND Although endovascular treatment for proximal cerebral vessel occlusion is very effective, it remains controversial if intravenous thrombolysis (IVT) prior to endovascular treatment is superior compared to endovascular treatment alone. In this study we compared functional outcomes and recanalization rates of endovascularly treated stroke patients with and without bridging IVT. METHODS Patients with acute large artery occlusion within the anterior and posterior cerebral circulation eligible for intraarterial revascularization with and without prior IVT were included in this monocentric, prospective observational study. Modified Rankin Scale (mRS) and National Institute of Health Stroke Scale (NIHSS) were determined at baseline, discharge and 90-days follow up after stroke. Successful reperfusion was defined as a Thrombolysis in Cerebral Infarction (TICI) scale 2b-3. RESULTS Of the 109 patients included, 81 (74%) received bridging therapy with i.v.-rtPA prior to endovascular treatment, 28 (26%) received endovascular treatment alone. There was no difference in groin-to-reperfusion time between the groups (54 vs 50min; p=0.657), but a trend towards a higher reperfusion rate in patients with bridging therapy (69 vs 15 patients, p=0.099). Mean improvement of the NIHSS during hospitalization was 8 points (SD; ±8) in the bridging-group and 2 points (SD, ±7) in the non-bridging-group (p=0.001). Number of patients with discharge mRS 0-2 (34 vs 5; p=0.024) and 90-days mRS 0-2 (35 vs 6; p=0.061) was higher in the bridging-group compared to the non-bridging-group. CONCLUSIONS This study provides evidence that bridging therapy with i.v.-rtPA improves functional outcome in patients eligible for endovascular treatment. Further studies are needed to confirm our findings and to identify patients most likely benefitting from bridging therapy.

Latest generation of flat detector CT as a peri-interventional diagnostic tool: a comparative study with multidetector CT

Background and purpose Flat detector CT (FDCT) has been used as a peri-interventional diagnostic tool in numerous studies with mixed results regarding image quality and detection of intracranial lesions. We compared the diagnostic aspects of the latest generation FDCT with standard multidetector CT (MDCT). Materials and methods 102 patients were included in our retrospective study. All patients had undergone interventional procedures. FDCT was acquired peri-interventionally and compared with postinterventional MDCT regarding depiction of ventricular/subarachnoidal spaces, detection of intracranial hemorrhage, and delineation of ischemic lesions using an ordinal scale. Ischemic lesions were quantified with the Alberta Stroke Program Early CT Scale (ASPECTS) on both examinations. Two neuroradiologists with varying grades of experience and a medical student scored the anonymized images separately, blinded to the clinical history. Results The two methods were of equal diagnostic value regarding evaluation of the ventricular system and the subarachnoidal spaces. Subarachnoidal, intraventricular, and parenchymal hemorrhages were detected with a sensitivity of 95%, 97%, and 100% and specificity of 97%, 100%, and 99%, respectively, using FDCT. Gray–white differentiation was feasible in the majority of FDCT scans, and ischemic lesions were detected with a sensitivity of 71% on FDCT, compared with MDCT scans. The mean difference in ASPECTS values on FDCT and MDCT was 0.5 points (95% CI 0.12 to 0.88). Conclusions The latest generation of FDCT is a reliable and accurate tool for the detection of intracranial hemorrhage. Gray–white differentiation is feasible in the supratentorial region.

Validation of collateral scoring on flat-detector multiphase CT angiography in patients with acute ischemic stroke

Background The pivotal impact of collateral circulation on outcomes in endovascular therapy has fueled the development of numerous CTA collateral scales, yet synchronized validation with conventional angiography has never occurred. We validated multiphase flat-detector CTA (mpFDCTA) for collateral imaging in patients undergoing endovascular stroke treatment. Materials and methods Consecutive acute ischemic stroke patient data, including mpFDCTA shortly followed by digital subtraction angiography (DSA), in the setting of acute ICA- or MCA-occlusions were analyzed. An independent core lab scored mpFDCTA with an established collateral scale and separately graded American Society of Interventional and Therapeutic Neuroradiology (ASITN) collateral score on DSA, blind to all other data. Results 24 consecutive cases (age 76.7 ± 7.3 years; 58.3% women; baseline NIHSS median 17 (4–23)) of acute ICA- or MCA-occlusion were analyzed. Time from mpFDCTA to intracranial DSA was 23.04 ± 7.6 minutes. Median mpFDCTA collateral score was 3 (0–5) and median DSA ASITN collateral score was 2 (0–3), including the full range of potential collateral grades. mpFDCTA and ASITN collateral score were strongly correlated (r = 0.86, p<0.001). mpFDCTA provided more complete collateral data compared to selective DSA injections in cases of ICA-occlusion. ROC analyses for prediction of clinical outcomes revealed an AUC of 0.76 for mpFDCTA- and 0.70 for DSA ASITN collaterals. Conclusions mpFDCTA in the angiography suite provides a validated measure of collaterals, offering distinct advantages over conventional angiography. Direct patient transfer to the angiography suite and mpFDCTA collateral grading provides a novel and reliable triage paradigm for acute ischemic stroke.

Stent retriever placement in embolectomy: the choice of the post-bifurcational trunk influences the first-pass reperfusion result in M1 occlusions

Background Embolectomy using Stent retriever Assisted Vacuum-locked Extraction (SAVE) is effective in intracranial large vessel occlusion. Which post-bifurcational trunk should be chosen for distal stent retriever placement in M1 occlusions is, however, elusive. Methods We conducted a retrospective analysis of prospectively collected data from a comprehensive stroke center between 2015 and 2017. Eighty-nine consecutive patients with M1 occlusions were treated with SAVE. Digital subtraction angiography (DSA) series were studied to determine the anatomy of middle cerebral artery division, the position of the stent retriever, and to measure vessel diameters. The primary endpoint was first-pass complete/near-complete reperfusion, defined as a modified Thrombolysis in Cerebral Infarction (mTICI) score of 2c or 3, after distal stent retriever placement in the inferior trunk. Results In 76/89 (85%) patients, microcatheter series were documented. A microcatheter was placed within the inferior trunk in 30/76 (40%) cases. First-pass near-complete/complete reperfusion was more likely to be achieved when the inferior trunk was used for stent retriever placement rather than the superior trunk (mTICI ≥2c: 22/30 (73%) vs 22/46 (48%), P=0.034; and mTICI 3: 20/30 (67%) vs 17/46 (37%), P=0.018). Median diameter of the inferior trunk was larger than the superior trunk (1.4 mm (IQR 1.26–1.62) vs 1.18 mm (IQR 0.98–1.43), P=0.011). The inferior trunk was dominant in 56/76 (74%) cases. Successful reperfusion was associated with placement within the dominant trunk (33/40 (83%) vs 22/36 (61%), P=0.044). Conclusion The choice of the inferior trunk for distal stent retriever placement in M1 occlusions is associated with a high rate of first-pass near-complete/complete reperfusion when using SAVE.

High Systolic Blood Pressure after Successful Endovascular Treatment Affects Early Functional Outcome in Acute Ischemic Stroke

Background: Endovascular treatment (EVT) has been shown to significantly improve functional outcome in patients with acute large cerebral vessel occlusions. To date, no evidence-based recommendations on blood pressure management after successful EVT exist. Previous studies showed an association between high pre-EVT systolic blood pressure (SBP) and functional outcome, but do not answer the question on how to manage blood pressure after successful recanalization. The purpose of this study was to determine the role of blood pressure measurements as a predictor for early functional outcome in patients with successful EVT. Methods: Prospectively derived data from patients with acute large vessel occlusion within the anterior circulation and EVT was analyzed in this monocentric study. Mean systolic- and maximum SBP as well as SBP-peaks have been obtained for the first 24 h after successful EVT. Predictive value of SBP for discharge modified Rankin Scale (mRS) ≤2 has been investigated using logistic regression models. Results: From 168 patients with successful EVT, 74 (44%) had a favorable outcome with an mRS ≤2. Mean- (127 vs. 131 mm Hg, p = 0.035) and maximum SBP (157 vs. 169 mm Hg, p < 0.001) as well as the number of SBP-peaks (0 vs. 1.5, p = 0.004) were lower in patients with favorable outcomes. Multivariable logistic regression showed high mean- and maximum SBP to predict unfavorable outcomes. Cutoff mean SBP was 141 mm Hg and maximum SBP 159 mm Hg. Conclusions: High SBP in the first 24 h after recanalization of acute anterior cerebral vessel occlusions is associated with unfavorable functional outcome. Interventional studies are needed to determine the role of SBP management as a modifiable parameter in the early phase after successful EVT.

Outcome Prediction Using Perfusion Parameters and Collateral Scores of Multi-Phase and Single-Phase CT Angiography in Acute Stroke: Need for One, Two, Three, or Thirty Scans?

Background and Purpose Collateral status is an important factor determining outcome in acute ischemic stroke (AIS). Hence, different collateral scoring systems have been introduced. We applied different scoring systems on single- and multi-phase computed tomography (CT) angiography (spCTA and mpCTA) and compared them to CT perfusion (CTP) parameters to identify the best method for collateral evaluation in patients with AIS. Methods A total of 102 patients with AIS due to large vessel occlusion in the anterior circulation who underwent multimodal CT imaging and who were treated endovascularly were included. Collateral status was assessed on spCTA and mpCTA using four different scoring systems and compared to CTP parameters. Logistic regression was performed for predicting favorable outcome. Results All collateral scores correlated well with each other and with CTP parameters. Comparison of collateral scores stratified by extent of perfusion deficit showed relevant differences between groups (P<0.01 for each). An spCTA collateral score discriminated best between favorable and unfavorable outcome as determined using the modified Rankin Scale 3 months after stroke. Conclusions Collateral status evaluated on spCTA may suffice for outcome prediction and decision making in AIS patients, potentially obviating further imaging modalities like mpCTA or CTP.

Optimized Management of Endovascular Treatment for Acute Ischemic Stroke

This manuscript describes a streamlined protocol for the management of patients with acute ischemic stroke, which aims at the minimization of time from hospital admission to reperfusion. Rapid restoration of cerebral blood flow is essential for the outcomes of patients with acute ischemic stroke. Endovascular treatment (EVT) has become the standard of care to accomplish this in patients with acute stroke due to large vessel occlusion (LVO). To achieve reperfusion of ischemic brain regions as fast as possible, all in-hospital time delays have to be carefully avoided. Therefore, management of patients with acute ischemic stroke was optimized with an interdisciplinary standard operating procedure (SOP). Stroke neurologists, diagnostic as well as interventional neuroradiologists, and anesthesiologists streamlined all necessary processes from patient admission and diagnosis to EVT of eligible patients. Target times for every step were established. Actually achieved times were prospectively recorded along with clinical data and imaging scores for all endovascularly treated stroke patients. These data were regularly analyzed and discussed in interdisciplinary team meetings. Potential issues were evaluated and all staff involved was trained to adhere to the SOP. This streamlined patient management approach and enhanced interdisciplinary collaboration reduced time from patient admission to reperfusion significantly and was accompanied by a beneficial effect on clinical outcomes.