Mechanical Thrombectomy For Ischemic Stroke Research Articles

Abstract WP32: Introducing STAR: A Multicenter International Collaborative Registry of Real-World Outcomes After Mechanical Thrombectomy for Ischemic Stroke

Introduction: Mechanical thrombectomy (MT) for acute stroke is the current standard of care treatment. Level 1 evidence for efficacy of thrombectomy has been established in multiple randomized controlled trials on selective patient populations; however, the high effect size of MT had led multiple centers in the US and globally to expand their patient selection to include populations that were not studied in major trials. To provide ongoing data on MT outcomes in different patient populations from the real-world, we have initiated an international multicenter initiative, STAR (Stroke Thrombectomy and Aneurysm Registry). Methods: STAR is a multicenter and international platform to curate patient outcome data after MT for acute ischemic stroke at comprehensive stroke centers. STAR includes all patients who underwent MT for acute ischemic stroke irrespective of age, time from onset, ASPECT score, and NIHSS. Patients were curated from 01/2015 to date and is prospectively maintained. Patient charts are reviewed for demographics, baseline functioning, and admission deficits. Procedure notes are reviewed for technical variables and technical outcomes. Clinical outcomes were collected at 90-day follow-up by stroke neurologist. Results: A total of 24 centers globally have enrolled in STAR. By December 2018, the total number of enrolled and verified patients in STAR was 3,850 (mean age 69±14, 51% females). Anterior circulation strokes were treated in 89% of cases, average NIHSS on admission was 15.5±7, and 73% had pre-stroke mRS below 2. Around 51% of patients received IV-tPA. Mechanical thrombectomy was performed using aspiration (45%), stent retriever (28%), primary combined approach (24%) or intracranial stenting (3%). Successful recanalization was achieved in 84% of cases, the rate of favorable outcome (mRS 0-2) was 41%, and mortality was 25%. Complication rate was 6% and rate of symptomatic post-procedural hemorrhage was 6%. Conclusions: STAR represent a large real-world international registry for outcomes after MT, and constitutes a statistically robust platform to study real-world practice outcome in patient sub-populations that are under-represented in randomized trials. Link: https://medicine.musc.edu/departments/neurosurgery/star

Abstract WP11: Timing of Blood Pressure Decreases During Mechanical Thrombectomy for Ischemic Stroke

Introduction: Decreases in blood pressure (BP) during endovascular therapy (EVT) are associated with infarct progression and poor outcome. The largest BP reductions are thought to occur during induction. The frequency and clinical relevance of late BP decreases after partial reperfusion has been achieved remain unknown. In this study, we aimed to characterize the timing of BP reductions during EVT and to assess their association with functional outcome. Methods: We retrospectively studied patients with LVO stroke who underwent EVT at two comprehensive stroke centers. BP was continuously monitored throughout the procedure and averaged for selected time points. Maximum BP drop was calculated as the difference between admission systolic BP (SBP) and lowest SBP during EVT and assigned to one of three intervals: 1) arrival to angiography suite to groin puncture, 2) groin puncture to first pass, and 3) first pass to recanalization. Functional outcome was assessed using the modified rankin scale (mRS) at 90 days. Associations with the outcome were analyzed using ordinal logistic regression and adjusted for the size of the maximum drop in SBP. Results: 401 patients (age 71.3±14, 57% female, mean NIHSS 17) were included. Mean SBP for all patients decreased from EVT start to first procedural angiogram and then stabilized (Figure 1A). While the majority of blood pressure reductions occurred during interval 1 and 2 (n=253, 70%), 30% took place after first pass. We found no relation between timing of BP reduction and outcome (p=0.780, Figure 1B). Decreases in SBP during all intervals were significantly associated with 90-day outcome (OR per 10 mmHg 1.2, p=0.013; OR 1.1, p=0.025; and OR 1.3, p=0.011 for interval 1-3, respectively). Conclusions: BP drops occur throughout EVT, including between first pass and recanalization. Regardless of when these drops occur, they associate with poor outcome and thus underline the importance of blood pressure management throughout the procedure.

Abstract 117: Fixed Compared to Autoregulation-oriented Blood Pressure Thresholds After Mechanical Thrombectomy for Ischemic Stroke

Background: Loss of cerebral autoregulation in the acute phase of ischemic stroke leaves patients vulnerable to blood pressure (BP) changes. Effective BP management after endovascular therapy (EVT) may protect the brain from hypo- or hyperperfusion. In this observational study, we compared personalized, autoregulation-guided BP management with two commonly used clinical approaches: (1) maintaining BP below a fixed, pre-determined value and (2) stratifying BP thresholds based on reperfusion status. Methods: We prospectively enrolled 90 patients undergoing EVT for stroke. Autoregulatory function was continuously measured by interrogating changes in near-infrared spectroscopy-derived tissue oxygenation (a cerebral blood flow surrogate) in response to changes in mean arterial pressure (MAP). The resulting autoregulatory index was used to trend the BP range at which autoregulation was most preserved. Percent time that MAP exceeded the upper limit of autoregulation (ULA) or decreased below the lower limit of autoregulation (LLA) was calculated for each patient. Time above fixed SBP thresholds was computed in a similar fashion. Functional outcome was measured with the modified Rankin Scale (mRS) at 90 days. Results: Personalized limits of autoregulation (LA) were successfully computed in all 90 patients (mean age 72 + 16, 47% female, mean NIHSS 14, mean monitoring time 28 + 18 hours). Percent time with MAP above the ULA associated with worse 90-day outcomes (OR per 10% 1.84, 95% CI 1.3-2.7, P=0.002), and patients suffering from hemorrhagic transformation spent more time above the ULA (10.9% vs. 16.0%, P=0.042). While there appeared to be a non-significant trend towards worse outcome with increasing time above SBP thresholds of 140 mmHg and 160 mmHg, the effect sizes were smaller compared to the personalized approach. Conclusions: Non-invasive determination of personalized BP thresholds for stroke patients is feasible. Deviation from these limits may increase risk of further brain injury and poor functional outcome. This approach may present a better strategy compared to the classical approach of maintaining SBP below a pre-determined value, though a randomized trial is needed to determine the optimal approach for hemodynamic management.

Revascularization and functional outcomes after mechanical thrombectomy: an update to key metrics.

The advent of mechanical thrombectomy (MT) has become an effective option for the treatment of acute ischemic stroke in addition to tissue plasminogen activator (tPA). With recent advances in device technology, MT has significantly altered the hospital course and functional outcomes of stroke patients. The authors' goal was to establish the most up-to-date reperfusion and functional outcomes with the evolution of MT technology. The authors conducted a retrospective study of 403 patients who underwent MT for ischemic stroke at their institution from 2010 to 2017. They collected data on patient comorbidities, National Institutes of Health Stroke Scale (NIHSS) score on arrival, tPA administration, revascularization outcomes, and functional outcomes on discharge. In 403 patients, the mean NIHSS score on presentation was 15.8 ± 6.6, with 195 (48.0%) of patients receiving tPA prior to MT. Successful reperfusion (thrombolysis in cerebral infarction score 2B or 3) was achieved in 84.4%. Hemorrhagic conversion with significant mass effect was noted in 9.9% of patients. The median lengths of ICU and hospital stay were 3.0 and 7.0 days, respectively. Functional independence (modified Rankin Scale score 0-2) was noted in 125 (31.0%) patients, while inpatient mortality occurred in 43 (10.7%) patients. As MT has established acute ischemic stroke as a neurosurgical disease, there is a pressing need to understand the hospital course, hospital- and procedure-related complications, and outcomes for this new patient population. The authors provide a detailed account of key metrics for MT with the latest device technology and identify the predictors of unfavorable outcomes and inpatient mortality.

Association between post-procedural hyperoxia and poor functional outcome after mechanical thrombectomy for ischemic stroke: an observational study

BackgroundThe actual effects of oxygen therapy on patients who have suffered a stroke are still unknown, and its recommendation as a routine measure in emergency services remains controversial. The aim of this study is to determine the effect of hyperoxia in functional recovery in patients with ischemic stroke who underwent intra-arterial mechanical thrombectomy (IAMT).MethodsA prospective observational cohort study that included all adult patients consecutively admitted to the intensive care unit (ICU) due to an ischemic stroke in the anterior cerebral circulation and following an IAMT intervention, between 2010 and 2015. All patients were intubated and connected to mechanical ventilation for the intra-arterial therapy, receiving supplementary oxygen to achieve saturations above 94%. Two groups were established regarding oxygen partial pressure (paO2) reached. It was based on a single ICU admission blood gas analysis. The hyperoxia group was defined as paO2 > 120 mmHg. We measured functional recovery in each of the groups according to the modified Rankin scale after 90 days.ResultsFor the analysis, a total of 333 patients were included. High levels of paO2 were mostly related to higher scores in modified Rankin scale (mRS) after 90 days. There were 60.6% cases with mRS ≥ 4 and 70.6% with mRS ≥ 3 in the hyperoxia group, compared to 43.0% and 56.1% in the paO2 ≤ 120 group, p < 0.01, respectively. Mortality was higher in the hyperoxia group, 28.6% vs 18.7%, p = 0.04. After regression adjustment by confounding factors, poor functional outcome was still significantly higher in the hyperoxia group, for both mRS ≥ 4 and mRS ≥ 3: OR 2.2.7, IC 95%, 1.22–4.23, p = 0.01 and OR 2.07, IC 95%, 1.05–4.029, p = 0.04, respectively. Both the National Institute of Health Stroke Scale Score (NIHSS) values at 24 h after the IAMT and the days of ICU stay were significantly higher in the hyperoxia group.ConclusionsIn patients with ischemic stroke in the anterior cerebral circulation treated with IAMT, we found an association between admission PaO2 > 120 mmHg and worse functional outcome 90 days after ischemic stroke, but this association needs further confirmation by other studies.

Variability in the decision-making process of acute ischemic stroke in difficult clinical and radiological constellations: analysis based on a cross-sectional interview-administered stroke questionnaire.

Notwithstanding guidelines, indications for mechanical thrombectomy (MT) in acute ischemic stroke are multifactorial and can be complex. Our aim was to exploratively evaluate decision-making on the advisability of performing MT in cases presented as an interview-administered questionnaire. Fifty international raters assessed 12 cases and decided to recommend or exclude MT. Each case contained a brief summary of clinical information and eight representative images of the initial multimodal CT. The demographic characteristics and stroke protocols were recorded for raters. For each case, the reasons for excluding MT were recorded. Uni- and multivariate logistic regression analysis were performed for the different demographic and case characteristics to identify factors that might influence decision-making. All raters performed MT (median MTs/hospital/year [IQR], 100 [50-141]) with a median of 7years of experience as first operator (IQR, 4-12). Per case, diversity in decision-making ranged between 1 (case 6, 100% yes MT) and 0.50 (case 12, 54.2% yes MT and 45.8% no MT). The most common reasons for excluding MT were small CBV/CBF mismatch (17%, 102/600), size of infarct core on the CBV map (15.2%, 91/600), and low NIHSS score (National Institute of Health Stroke Scale, 8.3%, 50/600). All clinical and radiological characteristics significantly affected the decision regarding MT, but the general characteristics of the raters were not a factor. Clinical and imaging characteristics influenced the decision regarding MT in stroke. Nevertheless, a consensus was reached in only a minority of cases, revealing the current divergence of opinion regarding therapeutic decisions in difficult cases. • This is the first study to explore differences in decision-making in respect of mechanical thrombectomy in ischemic stroke with complex clinical and radiological constellations. • Fifty experienced international neurointerventionalists answered this interview-administered stroke questionnaire and made decisions as to whether to recommend or disadvise thrombectomy in 12 selected cases. • Diversity in decision-making for thrombectomy ranged from 1 (100% of raters offered the same answer) to 0.5 (50% indicated mechanical thrombectomy). There was a consensus in only a minority of cases, revealing the current disparity of opinion regarding therapeutic decisions in difficult cases.

Thrombectomy with Conscious Sedation Compared with General Anesthesia: A DEFUSE 3 Analysis.

The optimal patient sedation during mechanical thrombectomy for ischemic stroke in the extended time window is unknown. The purpose of this study was to assess the impact of patient sedation on outcome in patients undergoing thrombectomy 6-16 hours from stroke onset. Endovascular Therapy Following Imaging Evaluation for Ischemic Stroke 3 (DEFUSE 3) was a multicenter, randomized, open-label trial of thrombectomy for ICA and M1 occlusions in patients 6-16 hours from stroke onset. Subjects underwent thrombectomy with either general anesthesia or conscious sedation at the discretion of the treating institution. Of the 92 patients who were randomized to intervention, 26 (28%) underwent thrombectomy with general anesthesia and 66 (72%) underwent thrombectomy with conscious sedation. Baseline clinical and imaging characteristics were similar among all groups. Functional independence at 90 days was 23% for general anesthesia, 53% for conscious sedation, and 17% for medical management (P = .009 for general anesthesia versus conscious sedation). Conscious sedation was associated with a shorter time from arrival in the angiosuite to femoral puncture (median, 14 versus 18 minutes; P = 0.05) and a shorter time from femoral puncture to reperfusion (median, 36 versus 48 minutes; P = .004). Sixty-six patients were treated at sites that exclusively used general anesthesia (n = 14) or conscious sedation (n = 52). For these patients, functional independence at 90 days was significantly higher in the conscious sedation subgroup (58%) compared with the general anesthesia subgroup (21%) (P = .03). Patients who underwent thrombectomy with conscious sedation in the extended time window experienced a higher likelihood of functional independence at 90 days, a lower NIHSS score at 24 hours, and a shorter time from femoral puncture to reperfusion compared with those who had general anesthesia. This effect remained robust in institutions that only treated patients with a single anesthesia technique.

Stable Extracranial ICA Patency after Mechanical Thrombectomy for Ischemic Stroke Patients with Tandem Occlusions: Major determinant of favorable outcome

Mechanical thrombectomy (MT) for acute ischemic stroke (AIS) with tandem occlusion is efficient, but optimal management of the extracranial occlusive component remains controversial. We investigated the association between extracranial internal carotid artery (ICA) patency on day 1 follow-up MR-Angiography and clinical outcome after MT in AIS patients with tandem occlusion. Consecutive AIS patients with tandem occlusion were identified from a hospital-based prospective registry from January 2011 to January 2017. Baseline clinical-imaging characteristics, angiographic outcomes and day 1 follow-up imaging findings (including extracranial ICA patency as assessed by MR-Angiography) were analyzed with regards to their associations with 3-month modified Rankin scale (mRS) scores. Favorable outcome was defined as a mRS score 0–2 at 3 months. Out of 594 AIS patients treated with MT during the study period, 83 met inclusion criteria (69.9% male, aged 62.3 ± 12.3). Mean NIHSS was 17.9 ± 4.8 and median ASPECTS was 7. Successful re-canalization (mTICI 2b/3) was achieved in 61.5%. Extracranial ICA was patent in 37/83 patients (44.6%) at day 1, more frequently in those with prior IV thrombolysis (P = 0.035) or with cervical re-vascularization procedure (balloon angioplasty or stenting, P = 0.034). Favorable 3-month functional outcome was more frequent in patients with patent extracranial ICA at day 1 (64.9% vs 21.7%, P < 0.0001) independently of intracranial recanalization success. No difference was found in terms of sICH (13.5% vs 10.9%, P = 0.75) or 3-month mortality rate (8.1% vs 17.4%, P = 0.33). This study highlights the importance of stable extracranial ICA patency in determining outcome of AIS patients with tandem occlusions. Randomized studies are needed.

High Stress Hyperglycemia Ratio Predicts Poor Outcome after Mechanical Thrombectomy for Ischemic Stroke

Objective: The present study aimed to evaluate the association between stress hyperglycemia ratio (SHR) and outcome at 3 months after mechanical thrombectomy (MT) for acute occlusion in the anterior circulation. Methods: Data from 160 consecutive patients with large vessel occlusion in the anterior circulation who underwent MT from May 2013 to March 2018 were retrospectively reviewed. SHR was calculated as the fasting glucose concentration divided by the estimated average glucose concentration (derived from the glycosylated hemoglobin level). Patients were dichotomized into 2 groups in accordance with the median SHR. Univariate and multivariate analyses were used to identify predictors of functional outcome. Good and poor outcomes were defined as modified Rankin Scale scores of 0-2 and 3-6, respectively. Results: patients with unfavorable outcome had significantly higher levels of SHR than those with favorable outcome (median in SHR = 1.02 versus .84, P = .000). The median SHR was .96. Univariate analysis showed that significantly more patients with a poor outcome had SHR ≥ .96 compared with those with a good outcome (65.2% versus 31.0%, P = .000). After adjusting for potential covariates, Increased SHR (odds ratio [OR] 6.97, 95% confidence intervals [CI] 1.22-39.65, P = .029, for continuous SHR levels) and SHR ≥ .96 (OR 3.12, 95% CI 1.39-6.96, P = .006) remained independent predictors of poor outcome. Conclusions: Increased SHR is strongly correlated with poor outcome at 3 months after MT for proximal artery occlusion in the anterior circulation.

Validation studies of virtual reality simulation performance metrics for mechanical thrombectomy in ischemic stroke

IntroductionMechanical thrombectomy (MT) has transformed the treatment of ischemic stroke. However, patient access to MT may be limited due to a shortage of doctors specifically trained to perform MT. The...

Incidence, predictors, and outcome of early seizures after mechanical thrombectomy

ObjectiveDespite the wide utilization of mechanical thrombectomy (MT) for acute ischemic stroke treatment, little is known about the incidence of early post-thrombectomy seizures, its predictors, and association with long-term outcome. MethodsUsing a prospective registry of mechanical thrombectomy in ischemic stroke between January 2013 and July 2017, we identified patients who developed a seizure within 7 days (early seizure) of qualifying event. Backward stepwise regression analysis was used to assess independent predictors of seizure occurrence and the association between seizure and functional outcome (modified Rankin scale of 0–2 vs. ≥3). ResultsA total of 459 patients were included in the final analysis. Mean age was 67.5 (SD 15.1), and 49.9% of patients were female. Successful recanalization (TICI≥2B) was achieved in 92.8% of patients. Eleven (2.4%) patients developed at least one seizure. Only an Alberta Stroke Program Early CT (ASPECT) score of <6 was independently associated with the occurrence of early seizures [Odds ratio, 95% confidence interval: 8.188, (2.219–30.214); P = .002]. On multivariate analysis, early seizures were associated with 90-day mortality rate [OR,6.487; 95% confidence interval, (1.481–28.405); P = .013] and poor functional outcome (OR, 4.7; 95% confidence interval (1.08–20.83); p = .039). ConclusionIn the studied cohort, 2.4% of ischemic stroke patients treated with MT developed at least one seizure within 7 days of stroke onset. A low ASPECT score was associated with the occurrence of early seizures. The occurrence of seizures was associated with 90-day mortality and poor functional outcome.

Impact of Anesthetic Management on Safety and Outcomes Following Mechanical Thrombectomy for Ischemic Stroke in SWIFT PRIME Cohort.

Background and purpose: The optimal anesthetic management of acute ischemic stroke patients during mechanical thrombectomy (MT) remains controversial. In this post-hoc analysis, we investigated the impact of anesthesia type on clinical outcomes in patients included in SWIFT PRIME trial.Methods: Ninety-seven patients treated with MT were included. Patients treated in centers with general anesthesia (GA) policy (n = 32) were compared with those treated in centers with conscious sedation (CS) policy (n = 65). Primary outcomes studied included times to treatment initiation (TTI), rates of successful recanalization (TICI 2b/3), and functional independence (mRS 0–2 at 90 days). Secondary outcomes were adverse events, lowest systolic and diastolic blood pressures (LSBP and LDBP) during MT. Univariate analysis and multivariate regression logistic modeling were conducted.Results: The GA-policy and CS-policy groups presented comparable TTI (94 ± 36 min vs. 102 ± 48 min; p = 0.44), rates of TICI 2b/3 recanalization (22/32 [68.8%] vs. 51/65 [78.5%]; p = 0.32). CS-policy was associated to higher rate of functional independence than GA-policy, but the difference was not significant (43/65 [66.2%] vs. 16/32 [50.0%]; p = 0.18). GA-policy patients had a higher rate of postoperative pneumonia (11/32 [34.4%] vs. 8/65 [12.3%]; p = 0.02) and lower LSBP (110 [30,160] mmHg vs. 119 [77,170] mmHg; p = 0.03) and LDBP (55 (15,75) mmHg vs. 67 [40,121]; p < 0.001). When corrected for differences in baseline characteristics, GA-policy was associated with lower rate of functional independence (OR 0.32; p = 0.05). A 10-point increase in perprocedural LDBP was associated with an increased likelihood of favorable outcome (OR 1.51; p = 0.01).Conclusions: GA-policy for MT presented comparable TTI and rates of successful revascularization to CS-policy. However, GA-policy was associated with lower rates of functional independence and with higher incidence of perprocedural hypotension and postoperative pneumonia.Clinical Trial Registration: URL—http://www.clinicaltrials.gov. Unique identifier: NCT01657461

Association of Blood Pressure With Short- and Long-Term Functional Outcome After Stroke Thrombectomy: Post Hoc Analysis of the SIESTA Trial.

Outcome after mechanical thrombectomy for ischemic stroke may be influenced by blood pressure (BP). This study aims to assess the association of BP changes during general anesthesia versus conscious sedation with functional outcome after mechanical thrombectomy. SIESTA (Sedation vs Intubation for Endovascular Stroke Treatment) was a monocentric randomized trial of general anesthesia versus conscious sedation during mechanical thrombectomy involving BP target protocols. In this post hoc analysis, BP measurements were divided into 4 phases: preintervention, prerecanalization, postrecanalization, and postintervention. We examined the association between BP and functional outcomes (defined by improvement of 24-hour National Institutes of Health Stroke Scale [NIHSS] and 3-month modified Rankin Scale). We found no association between the difference in systolic BP, diastolic BP, and mean arterial pressure from baseline to the different phases of intervention and NIHSS change after 24 hours. Only baseline diastolic BP was associated with a reduced improvement in NIHSS (β=0.17, P<0.01). There was no association of BP drops with a change in modified Rankin Scale at 3 months. About sedation, only baseline mean arterial pressure preintervention revealed significant associations (β=0.16, P<0.01) with less change in 24-hour NIHSS in conscious sedation group. Otherwise, there was no association for differences of any of the BP measurements with a change in 24-hour NIHSS and long-term functional outcome either in general anesthesia or the conscious sedation group when analyzed separately, consistent with our findings in the entire cohort. Doses of propofol (β=0.84, P=0.04) and norepinephrine (β=1.87, P=0.01) administered during intervention before recanalization were associated with reduced improvement of NIHSS at 24 hours. In a setting, where both sedation regimes general anesthesia and conscious sedation were performed according to strict protocols directed at avoiding BP extremes, our findings suggest that peri-interventional BP drops were not associated with either early neurological improvement or long-term functional outcome. URL: https://www.clinicaltrials.gov. Unique identifier: NCT02126085.

Periprocedural Antithrombotic Treatment During Acute Mechanical Thrombectomy for Ischemic Stroke: A Systematic Review.

More than one-third of the patients with ischemic stroke caused by an intracranial large vessel occlusion do not recover to functional independence despite fast and successful recanalization by acute mechanical thrombectomy (MT). This may partially be explained by incomplete microvascular reperfusion. Some antithrombotics, e.g., antiplatelet agents and heparin, may be able to restore microvascular reperfusion. However, antithrombotics may also increase the risk of symptomatic intracranial hemorrhage (sICH). The aim of this review was to assess the potential safety and functional outcome of periprocedural antiplatelet or heparin use during acute MT for ischemic stroke. We systematically searched PubMed, Embase, Medline, Web of Science, and Cochrane for studies investigating the safety and functional outcome of periprocedural antiplatelet or heparin treatment during acute MT for ischemic stroke. The primary outcome was the risk for sICH. Secondary outcomes were functional independence after 3-6 months (modified Rankin Scale 0-2) and mortality within 6 months. 837 studies were identified through the search, of which 19 studies were included. The sICH risks of the periprocedural use of antiplatelets ranged from 6 to 17%, and for heparin from 5 to 12%. Two of four studies reporting relative effects of the use of antithrombotics are pointing toward an increased risk of sICH. Among patients treated with antiplatelet agents, functional independence varied from 23 to 60% and mortality from 18 to 33%. For heparin, this was, respectively, 19-54% and 19-33%. The three studies presenting relative effects of antiplatelets on functional independence showed neutral effects. Both studies reporting relative effects of heparin on functional independence found it to increase this chance. Randomized controlled trials investigating the effect of periprocedural antithrombotic treatment in MT are lacking. Some observational studies report a slight increase in sICH risk, which may be acceptable because they also suggest a beneficial effect on functional outcome. Therefore, randomized controlled trials are warranted to address the question whether the potentially higher risk of sICH could be outweighed by improved functional outcome.

Mechanical thrombectomy in ischemic stroke: Trends and predictors of utilization of thrombectomy using a national database (P4.202)

Mechanical thrombectomy in ischemic stroke: Trends and predictors of utilization of thrombectomy using a national database (P4.202)

Value-based procurement of medical devices: Application to devices for mechanical thrombectomy in ischemic stroke

ObjectivesIn the acute ischemic stroke, endovascular devices have shown promising clinical results and are also likely to represent value for money, as several modeling studies have shown. Pharmacoeconomic evaluations in this field, however, have little impact on the procurement of these devices. The present study explored how complex pharmacoeconomic models that evaluate effectiveness and cost can be incorporated into the in-hospital procurement of thrombectomy devices. Patients and methodsAs regards clinical modeling, we extracted outcomes at three months from randomized trials conducted for four thrombectomy devices, and we projected long-term results using standard Markov modeling. In estimating QALYs, the same model was run for the four devices. As regards economic modeling, we firstly estimated for each device the net monetary benefit (NMB) per patient (threshold = $60,000 per QALY); then, we simulated a competitive tender across the four products by determining the tender-based score (on a 0-to-100 scale). Prices of individual devices were obtained from manufacturers. Extensive sensitivity testing was applied to our analyses. ResultsFor the four devices (Solitaire, Trevo, Penumbra, Solumbra), QALYs were 1.86, 1.52, 1,79, 1.35, NMB was $101,824, $83,546, $101,923, $69,440, and tender-based scores were 99.70, 43.43, 100, 0, respectively. Sensitivity analysis confirmed findings from base-case. ConclusionOur results indicate that, in the field of thrombectomy devices, incorporating the typical tools of cost-effectiveness into the processes of tenders and procurement is feasible. Bridging the methodology of cost-effectiveness with the every-day practice of in-hospital procurement can contribute to maximizing the health returns that are generated by in-hospital expenditures for medical devices.

Abstract TP286: Efficacy of Quality Improvement Protocols Across Diverse Modes of Arrival for Thrombectomy Patients With Ischemic Stroke

Background: Quality improvement protocols (QI) aim to reduce in-hospital delays that result in prolonged door-to-groin-puncture time (DGPT) for the endovascular treatment of ischemic stroke. At our institution, we implemented a comprehensive QI protocol to reduce DGPT from June 2015 to December 2016. Here we discuss the QI protocol on DGPT across diverse modes of arrival to our interventional suite. Methods: 61 patients underwent mechanical thrombectomy for ischemic stroke during our QI period. Independent samples t-tests were used to investigate differences in DGPT early in the QI protocol (July 2015 to February 2016, n=30) versus late in the QI protocol (March 2016 to December 2016, n=31) for patients that presented via emergency medical services (EMS), inpatient, and hospital transfers. Results: Each mode of arrival demonstrated reductions in DGPT (Figure 1). The greatest reduction in DGPT was for the 23 patients within the emergency medical services (EMS) group with a mean reduction of 39 minutes which approached, but didn’t achieve, statistical significance (138 vs. 99; p=0.06). Discussion: QI interventions impact DGPT across different patient arrival methods. QI protocols accounting for patient presentation allow tailored approaches to institutional measures to reduce DGPT.

Necessary Catheter Diameters for Mechanical Thrombectomy with ADAPT.

Large-bore catheters allow mechanical thrombectomy in ischemic stroke by engaging and retrieving clots without additional devices (direct aspiration first-pass technique [ADAPT]). The purpose of this study was to establish a model for minimal catheter diameters needed for ADAPT. We established a theoretic model for the calculation of minimal catheter diameters needed for ADAPT. We then verified its validity in 28 ADAPT maneuvers in a porcine in vivo model. To account for different mechanical thrombectomy techniques, we factored in ADAPT with/without a hypothetic 0.021-inch microcatheter or 0.014-inch microwire inside the lumen of the aspiration catheter and aspiration with a 60-mL syringe versus an aspiration pump. According to our calculations, catheters with an inner diameter of >0.040 inch and >0.064 inch, respectively, are needed to be effective in the middle cerebral artery (2.5-mm diameter) or in the internal carotid artery (4 mm) in an average patient. There was a significant correlation between predicted and actual thrombectomy results (P = .010). Our theoretic model had a positive and negative predictive value of 78% and 79%, respectively. Sensitivity and specificity were 88% and 64%, respectively. Our theoretic model allows estimating the minimal catheter diameters needed for successful mechanical thrombectomy with ADAPT, as demonstrated by the good agreement with our animal experiments. Our model will be helpful to interventionalists in avoiding selecting catheters that are likely too small to be effective.

Initial Assessment and Triage of the Stroke Patient

Nearly 800,000 strokes occur in the United States each year, and stroke is the leading cause of preventable permanent disability. Timely recognition and treatment are imperative to reduce stroke-related morbidity and mortality. Given the evidence supporting intravenous thrombolysis and mechanical thrombectomy for ischemic stroke, stroke symptoms must be rapidly identified and mimics quickly excluded prior to therapeutic decisions. Intravenous tissue plasminogen activator is recommended for all qualified patients and patients with presentations suggesting large vessel occlusion should be evaluated for mechanical thrombectomy. Time to treatment is the most important prognostic factor for clinical outcome, highlighting the importance of reliable and efficient local and regional systems of care.

Abstract WP2: Anesthesia Technique and Outcomes of Mechanical Thrombectomy in Patients With Acute Ischemic Stroke

Background: The impact of anesthesia technique on the outcomes of mechanical thrombectomy for acute ischemic stroke remains an issue of debate, and has not been studied in clinical trials. We investigated the association of general anesthesia with outcomes in patients undergoing mechanical thrombectomy for ischemic stroke. Methods: We performed a cohort study involving patients undergoing mechanical thrombectomy for ischemic stroke from 2009-2013, who were registered in the New York Statewide Planning and Research Cooperative System (SPARCS) database. An instrumental variable (hospital rate of general anesthesia) analysis was used to simulate the effects of randomization and investigate the association of anesthesia technique with case-fatality and length of stay (LOS). Results: Of the 1,308 patients undergoing mechanical thrombectomy for acute ischemic stroke, 492 (37.6%) underwent general anesthesia, and 816 (62.4%) underwent conscious sedation. Employing an instrumental variable analysis, we identified that general anesthesia was associated with a 6.4% increased case-fatality (95% CI, 1.9% to 11.0%), and 8.4 days longer LOS (95% CI, 2.9 to 14.0) in comparison to conscious sedation. This corresponded to 15 patients needing to be treated with conscious sedation to prevent one death. Our results were robust in a sensitivity analysis utilizing mixed effects regression, and propensity score adjusted regression models. Conclusions: Using a comprehensive all-payer cohort of acute ischemic stroke patients undergoing mechanical thrombectomy in New York State, we identified an association of general anesthesia with increased case fatality and LOS. These considerations should be taken into account when standardizing acute stroke care.