Impact of Balloon Guide Catheters in Elderly Patients Treated with Mechanical Thrombectomy: Insights from the ROSSETTI Registry

BACKGROUND AND PURPOSE

Several nonrandomized studies have demonstrated the effectiveness of balloon guide catheters in treating patients with anterior circulation large-vessel occlusion. However, their impact on the elderly populations has been underreported. We aimed to analyze the effect of balloon guide catheters in a cohort of elderly patients (80 years of age or older) with anterior circulation large-vessel occlusion.

MATERIALS AND METHODS

Consecutive patients from June 2019 to June 2022 were collected from the ROSSETTI Registry. Demographic and clinical data, angiographic endovascular technique, and clinical outcome were compared between balloon guide catheter and non-balloon guide catheter groups. We studied the association between balloon guide catheters and the rate of complete recanalization after a single first-pass effect modified TICI 2c-3, as well as their association with functional independence at 3 months.

RESULTS

A total of 808 patients were included during this period, 465 (57.5%) of whom were treated with balloon guide catheters. Patients treated with balloon guide catheters were older, had more neurologic severity at admission and lower baseline ASPECTS, and were less likely to receive IV fibrinolytics. No differences were observed in terms of the modified first-pass effect between groups (45.8 versus 39.9%, P = .096). In the multivariable regression analysis, balloon guide catheter use was not independently associated with a modified first-pass effect or the final modified TICI 2c-3, or with functional independence at 3 months.

CONCLUSIONS

In our study, balloon guide catheter use during endovascular treatment of anterior circulation large-vessel occlusion in elderly patients did not predict the first-pass effect, near-complete final recanalization, or functional independence at 3 months. Further studies, including randomized clinical trials, are needed to confirm these results.

Admission systolic blood pressure and effect of endovascular treatment in patients with ischaemic stroke: an individual patient data meta-analysis

BACKGROUND

Current guidelines for ischaemic stroke treatment recommend a strict, but arbitrary, upper threshold of 185/110 mm Hg for blood pressure before endovascular thrombectomy. Nevertheless, whether admission blood pressure influences the effect of endovascular thrombectomy on outcome remains unknown. Our aim was to study the influence of admission systolic blood pressure (SBP) on functional outcome and on the effect of endovascular thrombectomy.

METHODS

We used individual patient data from seven randomised controlled trials (MR CLEAN, ESCAPE, EXTEND-IA, SWIFT PRIME, REVASCAT, PISTE, and THRACE) that randomly assigned patients with anterior circulation ischaemic stroke to endovascular thrombectomy (predominantly using stent retrievers) or standard medical therapy (control) between June 1, 2010, and April 30, 2015. We included all patients for whom SBP data were available at hospital admission. The primary outcome was functional outcome (modified Rankin Scale) at 90 days. We assessed the association of SBP with outcome in both the endovascular thrombectomy group and the control group using multilevel regression analysis and tested for non-linearity and for interaction between SBP and effect of endovascular thrombectomy, taking into account treatment with intravenous thrombolysis.

FINDINGS

We included 1753 patients (867 assigned to endovascular thrombectomy, 886 assigned to control) after excluding 11 patients for whom SBP data were missing. We found a non-linear association between SBP and functional outcome with an inflection point at 140 mm Hg (732 [42%] of 1753 patients had SBP <140 mm Hg and 1021 [58%] had SBP ≥140 mm Hg). Among patients with SBP of 140 mm Hg or higher, admission SBP was associated with worse functional outcome (adjusted common odds ratio [acOR] 0·86 per 10 mm Hg SBP increase; 95% CI 0·81-0·91). We found no association between SBP and functional outcome in patients with SBP less than 140 mm Hg (acOR 0·97 per 10 mm Hg SBP decrease, 95% CI 0·88-1·05). There was no significant interaction between SBP and effect of endovascular thrombectomy on functional outcome (p=0·96).

INTERPRETATION

In our meta-analysis, high admission SBP was associated with worse functional outcome after stroke, but SBP did not seem to negate the effect of endovascular thrombectomy. This finding suggests that admission SBP should not form the basis for decisions to withhold or delay endovascular thrombectomy for ischaemic stroke, but randomised trials are needed to further investigate this possibility.

FUNDING

Medtronic.

Comparison of Three Scores of Collateral Status for Their Association With Clinical Outcome: The HERMES Collaboration

BACKGROUND

Leptomeningeal collateral status on baseline computed tomographic angiography (CTA) is associated with clinical outcome after acute ischemic stroke treatment. However, assessment of collateral status is not uniform. To compare 3 different CTA collateral scores (CS) and imaging techniques about their association with clinical outcome.

METHODS

Pooled analysis of patient-level data from the Highly Effective Reperfusion Using Multiple Endovascular Devices collaboration. Patients with large vessel occlusion from 7 randomized controlled trials that compared endovascular thrombectomy with standard medical care were included. Three different CS (Tan CS, regional CS [rCS], and regional Alberta Stroke Program Early CT Score CS) and 2 imaging techniques (single-phase [sCTA] and multiphase/dynamic CTA) were evaluated. Functional independence (modified Rankin Scale score 0-2) at 3 months poststroke was the primary outcome. Furthermore, we assessed the effect of sCTA image acquisition time on collateral status assessment using an adjusted ordinal logistic regression model to obtain predicted values for the trichotomized rCS.

RESULTS

Among 1147 pooled patients, 948 (82.7%) had sCTA and 199 (17.3%) multiphase/dynamic CTA as baseline angiography. With all 3 collateral scales, better CSs were associated with better 3-month functional outcome. With sCTA images, the rCS (area under the curve [AUC] 0.63) and regional Alberta Stroke Program Early CT Score CS (AUC 0.62) better predicted functional outcome than the Tan CS (AUC 0.60, respectively; P<0.001 and P=0.02). With multiphase/dynamic CTA images, all collateral scales performed similarly in predicting functional outcome (rCS [AUC 0.61]; regional Alberta Stroke Program Early CT Score CS [AUC 0.61] versus Tan CS [AUC 0.61], respectively; P=0.93 and P=0.91). Overall, no endovascular thrombectomy treatment effect modification by collateral status (rCS) was demonstrated (P=0.41). sCTA timing independently influenced CS assessment. On earlier timed sCTA, the predicted proportions of scans with poor collaterals was higher and vice versa.

CONCLUSIONS

In this data set of highly selected patients with stroke, using a regional CS on sCTA likely allows for the most accurate prediction of functional outcome while on time-resolved CTA, the type of CS did not matter. Patients across all collateral grades benefit from endovascular thrombectomy. sCTA timing independently influenced CS assessment.

Adjunct Thrombolysis Enhances Brain Reperfusion following Successful Thrombectomy

OBJECTIVE

This study was undertaken to investigate whether adjunct alteplase improves brain reperfusion following successful thrombectomy.

METHODS

This single-center, randomized, double-blind, placebo-controlled study included 36 patients (mean [standard deviation] = 70.8 [13.5] years old, 18 [50%] women) with large vessel occlusion undergoing thrombectomy resulting in near-normal (expanded Thrombolysis in Cerebral Infarction [eTICI] b50/67/2c, n = 23, 64%) or normal angiographic reperfusion (eTICI 3, n = 13, 36%). Seventeen patients were randomized to intra-arterial alteplase (0.225mg/kg), and 19 received placebo. At 48 hours, patients had brain perfusion/diffusion-weighted magnetic resonance imaging (MRI) and MRI-spectroscopy. The primary outcome was the difference in the proportion of patients with areas of hypoperfusion on MRI. Secondary outcomes were the infarct expansion ratio (final to initial infarction volume), and the N-acetylaspartate (NAA) peak relative to total creatine as a marker of neuronal integrity.

RESULTS

The prevalence of hypoperfusion was 24% with intra-arterial alteplase, and 58% with placebo (adjusted odds ratio = 0.20, 95% confidence interval [CI] = 0.04-0.91, p = 0.03). Among 14 patients with final eTICI 3 scores, hypoperfusion was found in 1 of 7 (14%) in the alteplase group and 3 of 7 (43%) in the placebo group. Abnormal brain perfusion was associated with worse functional outcome at day 90. Alteplase significantly reduced the infarct expansion ratio compared with placebo (median [interquartile range (IQR)] = 0.7 [0.5-1.2] vs 3.2 [1.8-5.7], p = 0.01) and resulted in higher NAA peaks (median [IQR] = 1.13 [0.91-1.36] vs 1.00 [0.74-1.22], p < 0.0001).

INTERPRETATION

There is a high prevalence of areas of hypoperfusion following thrombectomy despite successful reperfusion on angiography. Adjunct alteplase enhances brain reperfusion, which results in reduced expansion of the infarction and improved neuronal integrity. ANN NEUROL 2022;92:860-870.

Effect of Intra-arterial Alteplase vs Placebo Following Successful Thrombectomy on Functional Outcomes in Patients With Large Vessel Occlusion Acute Ischemic Stroke: The CHOICE Randomized Clinical Trial

IMPORTANCE

It is estimated that only 27% of patients with acute ischemic stroke and large vessel occlusion who undergo successful reperfusion after mechanical thrombectomy are disability free at 90 days. An incomplete microcirculatory reperfusion might contribute to these suboptimal clinical benefits.

OBJECTIVE

To investigate whether treatment with adjunct intra-arterial alteplase after thrombectomy improves outcomes following reperfusion.

DESIGN, SETTING, AND PARTICIPANTS

Phase 2b randomized, double-blind, placebo-controlled trial performed from December 2018 through May 2021 in 7 stroke centers in Catalonia, Spain. The study included 121 patients with large vessel occlusion acute ischemic stroke treated with thrombectomy within 24 hours after stroke onset and with an expanded Treatment in Cerebral Ischemia angiographic score of 2b50 to 3.

INTERVENTIONS

Participants were randomized to receive intra-arterial alteplase (0.225 mg/kg; maximum dose, 22.5 mg) infused over 15 to 30 minutes (n = 61) or placebo (n = 52).

MAIN OUTCOMES AND MEASURES

The primary outcome was the difference in proportion of patients achieving a score of 0 or 1 on the 90-day modified Rankin Scale (range, 0 [no symptoms] to 6 [death]) in all patients treated as randomized. Safety outcomes included rate of symptomatic intracranial hemorrhage and death.

RESULTS

The study was terminated early for inability to maintain placebo availability and enrollment rate because of the COVID-19 pandemic. Of 1825 patients with acute ischemic stroke treated with thrombectomy at the 7 study sites, 748 (41%) patients fulfilled the angiographic criteria, 121 (7%) patients were randomized (mean age, 70.6 [SD, 13.7] years; 57 women [47%]), and 113 (6%) were treated as randomized. The proportion of participants with a modified Rankin Scale score of 0 or 1 at 90 days was 59.0% (36/61) with alteplase and 40.4% (21/52) with placebo (adjusted risk difference, 18.4%; 95% CI, 0.3%-36.4%; P = .047). The proportion of patients with symptomatic intracranial hemorrhage within 24 hours was 0% with alteplase and 3.8% with placebo (risk difference, -3.8%; 95% CI, -13.2% to 2.5%). Ninety-day mortality was 8% with alteplase and 15% with placebo (risk difference, -7.2%; 95% CI, -19.2% to 4.8%).

CONCLUSIONS AND RELEVANCE

Among patients with large vessel occlusion acute ischemic stroke and successful reperfusion following thrombectomy, the use of adjunct intra-arterial alteplase compared with placebo resulted in a greater likelihood of excellent neurological outcome at 90 days. However, because of study limitations, these findings should be interpreted as preliminary and require replication.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT03876119; EudraCT Number: 2018-002195-40.

Effectiveness of Thrombectomy in Stroke According to Baseline Prognostic Factors: Inverse Probability of Treatment Weighting Analysis of a Population-Based Registry

Background and Purpose

 In real-world practice, the benefit of mechanical thrombectomy (MT) is uncertain in stroke patients with very favorable or poor prognostic profiles at baseline. We studied the effectiveness of MT versus medical treatment stratifying by different baseline prognostic factors.

Methods

 Retrospective analysis of 2,588 patients with an ischemic stroke due to large vessel occlusion nested in the population-based registry of stroke code activations in Catalonia from January 2017 to June 2019. The effect of MT on good functional outcome (modified Rankin Score ≤2) and survival at 3 months was studied using inverse probability of treatment weighting (IPTW) analysis in three pre-defined baseline prognostic groups: poor (if pre-stroke disability, age >85 years, National Institutes of Health Stroke Scale [NIHSS] >25, time from onset >6 hours, Alberta Stroke Program Early CT Score <6, proximal vertebrobasilar occlusion, supratherapeutic international normalized ratio >3), good (if NIHSS <6 or distal occlusion, in the absence of poor prognostic factors), or reference (not meeting other groups’ criteria).

Results

 Patients receiving MT (n=1,996, 77%) were younger, had less pre-stroke disability, and received systemic thrombolysis less frequently. These differences were balanced after the IPTW stratified by prognosis. MT was associated with good functional outcome in the reference (odds ratio [OR], 2.9; 95% confidence interval [CI], 2.0 to 4.4), and especially in the poor baseline prognostic stratum (OR, 3.9; 95% CI, 2.6 to 5.9), but not in the good prognostic stratum. MT was associated with survival only in the poor prognostic stratum (OR, 2.6; 95% CI, 2.0 to 3.3).

Conclusions

 Despite their worse overall outcomes, the impact of thrombectomy over medical management was more substantial in patients with poorer baseline prognostic factors than patients with good prognostic factors.

Combined Approach to Stroke Thrombectomy Using a Novel Short Flexible Aspiration Catheter with a Stent Retriever : Preliminary Clinical Experience

BACKGROUND

Large-bore aspiration catheters enabling greater flow rates and suction force for mechanical thrombectomy might improve outcomes in patients with stroke secondary to large-vessel occlusion. Complete or near-complete reperfusion after a single thrombectomy pass (first-pass effect) is associated with improved clinical outcomes. We assessed the efficacy and safety of novel MIVI Q™ aspiration catheters in combination with stent-retriever devices.

METHODS

We retrospectively analyzed demographics, procedure characteristics, and clinical data from consecutive patients with acute anterior large-vessel occlusion treated with a combined approach using MIVI Q™ aspiration catheters and stent retrievers. Reperfusion was defined according to the modified thrombolysis in cerebral infarction (mTICI) score. Clinical outcomes were measured by the National Institute of Health Stroke Scale (NIHSS) and modified Rankin scale (mRS) scores.

RESULTS

We included 52 patients (median age, 75 y IQR: 64-83); 31 (59.6%) women; 14 (26.9%) with terminal internal carotid artery occlusions, 26 (50%) middle cerebral artery (MCA) segment M1 occlusions, and 12 (23.1%) MCA segment M2 occlusions; median NIHSS score at admission was 19 (IQR: 13-22). After the first pass, 25 (48%) patients had mTICI ≥ 2c. At the end of the procedure, 47 (90.4%) had mTICI ≥ 2b and 35 (67.3%) had mTICI ≥ 2c. No serious device-related adverse events were observed. Symptomatic intracranial hemorrhage developed in 1 patient. Mean NIHSS score was 13 at 24 h and 5 at discharge. At 90 days, 24 (46.2%) patients were functionally independent (mRS 0-2).

CONCLUSION

This preliminary study found good efficacy and safety for MIVI Q™ aspiration catheters used in combination with stent-retriever devices.

Mediation of the Relationship Between Endovascular Therapy and Functional Outcome by Follow-up Infarct Volume in Patients With Acute Ischemic Stroke

Importance

The positive treatment effect of endovascular therapy (EVT) is assumed to be caused by the preservation of brain tissue. It remains unclear to what extent the treatment-related reduction in follow-up infarct volume (FIV) explains the improved functional outcome after EVT in patients with acute ischemic stroke.

Objective

To study whether FIV mediates the relationship between EVT and functional outcome in patients with acute ischemic stroke.

Design, Setting, and Participants

Patient data from 7 randomized multicenter trials were pooled. These trials were conducted between December 2010 and April 2015 and included 1764 patients randomly assigned to receive either EVT or standard care (control). Follow-up infarct volume was assessed on computed tomography or magnetic resonance imaging after stroke onset. Mediation analysis was performed to examine the potential causal chain in which FIV may mediate the relationship between EVT and functional outcome. A total of 1690 patients met the inclusion criteria. Twenty-five additional patients were excluded, resulting in a total of 1665 patients, including 821 (49.3%) in the EVT group and 844 (50.7%) in the control group. Data were analyzed from January to June 2017.

Main Outcome and Measure

The 90-day functional outcome via the modified Rankin Scale (mRS).

Results

Among 1665 patients, the median (interquartile range [IQR]) age was 68 (57-76) years, and 781 (46.9%) were female. The median (IQR) time to FIV measurement was 30 (24-237) hours. The median (IQR) FIV was 41 (14-120) mL. Patients in the EVT group had significantly smaller FIVs compared with patients in the control group (median [IQR] FIV, 33 [11-99] vs 51 [18-134] mL; P = .007) and lower mRS scores at 90 days (median [IQR] score, 3 [1-4] vs 4 [2-5]). Follow-up infarct volume was a predictor of functional outcome (adjusted common odds ratio, 0.46; 95% CI, 0.39-0.54; P < .001). Follow-up infarct volume partially mediated the relationship between treatment type with mRS score, as EVT was still significantly associated with functional outcome after adjustment for FIV (adjusted common odds ratio, 2.22; 95% CI, 1.52-3.21; P < .001). Treatment-reduced FIV explained 12% (95% CI, 1-19) of the relationship between EVT and functional outcome.

Conclusions and Relevance

In this analysis, follow-up infarct volume predicted functional outcome; however, a reduced infarct volume after treatment with EVT only explained 12% of the treatment benefit. Follow-up infarct volume as measured on computed tomography and magnetic resonance imaging is not a valid proxy for estimating treatment effect in phase II and III trials of acute ischemic stroke.

Transfer to the Local Stroke Center versus Direct Transfer to Endovascular Center of Acute Stroke Patients with Suspected Large Vessel Occlusion in the Catalan Territory (RACECAT): Study protocol of a cluster randomized within a cohort trial

RATIONALE

Optimal pre-hospital delivery pathways for acute stroke patients suspected to harbor a large vessel occlusion have not been assessed in randomized trials.

AIM

To establish whether stroke subjects with rapid arterial occlusion evaluation scale based suspicion of large vessel occlusion evaluated by emergency medical services in the field have higher rates of favorable outcome when transferred directly to an endovascular center (endovascular treatment stroke center), as compared to the standard transfer to the closest local stroke center (local-SC).

DESIGN

Multicenter, superiority, cluster randomized within a cohort trial with blinded endpoint assessment.

PROCEDURE

Eligible patients must be 18 or older, have acute stroke symptoms and not have an immediate life threatening condition requiring emergent medical intervention. They must be suspected to have intracranial large vessel occlusion based on a pre-hospital rapid arterial occlusion evaluation scale of ≥5, be located in geographical areas where the default health authority assigned referral stroke center is a non-thrombectomy capable hospital, and estimated arrival at a thrombectomy capable stroke hospital in less than 7 h from time last seen well. Cluster randomization is performed according to a pre-established temporal sequence (temporal cluster design) with three strata: day/night, distance to the endovascular treatment stroke center, and week/week-end day.

STUDY OUTCOME

The primary endpoint is the modified Rankin Scale score at 90 days. The primary safety outcome is mortality at 90 days.

ANALYSIS

The primary endpoint based on the modified intention-to-treat population is the distribution of modified Rankin Scale scores at 90 days analyzed under a sequential triangular design. The maximum sample size is 1754 patients, with two planned interim analyses when 701 (40%) and 1227 patients have completed follow-up. Hypothesized common odds ratio is 1.35.

Penumbral imaging and functional outcome in patients with anterior circulation ischaemic stroke treated with endovascular thrombectomy versus medical therapy: a meta-analysis of individual patient-level data

BACKGROUND

CT perfusion (CTP) and diffusion or perfusion MRI might assist patient selection for endovascular thrombectomy. We aimed to establish whether imaging assessments of irreversibly injured ischaemic core and potentially salvageable penumbra volumes were associated with functional outcome and whether they interacted with the treatment effect of endovascular thrombectomy on functional outcome.

METHODS

In this systematic review and meta-analysis, the HERMES collaboration pooled patient-level data from all randomised controlled trials that compared endovascular thrombectomy (predominantly using stent retrievers) with standard medical therapy in patients with anterior circulation ischaemic stroke, published in PubMed from Jan 1, 2010, to May 31, 2017. The primary endpoint was functional outcome, assessed by the modified Rankin Scale (mRS) at 90 days after stroke. Ischaemic core was estimated, before treatment with either endovascular thrombectomy or standard medical therapy, by CTP as relative cerebral blood flow less than 30% of normal brain blood flow or by MRI as an apparent diffusion coefficient less than 620 μm²/s. Critically hypoperfused tissue was estimated as the volume of tissue with a CTP time to maximum longer than 6 s. Mismatch volume (ie, the estimated penumbral volume) was calculated as critically hypoperfused tissue volume minus ischaemic core volume. The association of ischaemic core and penumbral volumes with 90-day mRS score was analysed with multivariable logistic regression (functional independence, defined as mRS score 0-2) and ordinal logistic regression (functional improvement by at least one mRS category) in all patients and in a subset of those with more than 50% endovascular reperfusion, adjusted for baseline prognostic variables. The meta-analysis was prospectively designed by the HERMES executive committee, but not registered.

FINDINGS

We identified seven studies with 1764 patients, all of which were included in the meta-analysis. CTP was available and assessable for 591 (34%) patients and diffusion MRI for 309 (18%) patients. Functional independence was worse in patients who had CTP versus those who had diffusion MRI, after adjustment for ischaemic core volume (odds ratio [OR] 0·47 [95% CI 0·30-0·72], p=0·0007), so the imaging modalities were not pooled. Increasing ischaemic core volume was associated with reduced likelihood of functional independence (CTP OR 0·77 [0·69-0·86] per 10 mL, p_interaction=0·29; diffusion MRI OR 0·87 [0·81-0·94] per 10 mL, p_interaction=0·94). Mismatch volume, examined only in the CTP group because of the small numbers of patients who had perfusion MRI, was not associated with either functional independence or functional improvement. In patients with CTP with more than 50% endovascular reperfusion (n=186), age, ischaemic core volume, and imaging-to-reperfusion time were independently associated with functional improvement. Risk of bias between studies was generally low.

INTERPRETATION

Estimated ischaemic core volume was independently associated with functional independence and functional improvement but did not modify the treatment benefit of endovascular thrombectomy over standard medical therapy for improved functional outcome. Combining ischaemic core volume with age and expected imaging-to-reperfusion time will improve assessment of prognosis and might inform endovascular thrombectomy treatment decisions.

FUNDING

Medtronic.

eTICI reperfusion: defining success in endovascular stroke therapy

Background

Revascularization after endovascular therapy for acute ischemic stroke is measured by the Thrombolysis In Cerebral Infarction (TICI) scale, yet variability exists in scale definitions. We examined the degree of reperfusion with the expanded TICI (eTICI) scale and association with outcomes in the HERMES collaboration of recent endovascular trials.

Methods

The HERMES Imaging Core, blind to all other data, evaluated angiography after endovascular therapy in HERMES. A battery of TICI scores (mTICI, TICI, TICI2C) was used to define reperfusion of the initial target occlusion defined by non-invasive imaging and conventional angiography.

Results

Angiography of 801 subjects was available, including 797 defined by non-invasive imaging (154 internal carotid artery (ICA), 583 M1, 60 M2) and 748 by conventional angiography (195 ICA, 459 M1, 94 M2). Among 729 subjects in whom the reperfusion grade could be established, using eTICI (3=100%, 2C=90–99%, 2b67=67–89%, 2b50=50–66%) of the conventional angiography target occlusion, there were 63 eTICI 3 (9%), 166 eTICI 2c (23%), 218 eTICI 2b67 (30%), 103 eTICI 2b50 (14%), 100 eTICI 2a (14%), 19 eTICI 1 (3%), and 60 eTICI 0 (8%). Modified Rankin Scale shift analyses from baseline to 90 days showed that increasing TICI grades were linked with better outcomes, with significant distinctions between TICI 0/1 versus 2a (p=0.028), 2a versus 2b50 (p=0.017), and 2b50 versus 2b67 (p=0.014).

Conclusions

The benefit of endovascular therapy in HERMES was strongly associated with increasing degrees of reperfusion defined by eTICI. The eTICI metric identified meaningful distinctions in clinical outcomes and may be used in future studies and routine practice.

Evaluation of white matter hypodensities on computed tomography in stroke patients using the Fazekas score

PURPOSE

To assess the reliability of the Fazekas score on brain CT in acute stroke patients.

METHODS

Two raters evaluated the Fazekas score in 157 CT scans from consecutive patients with acute stroke.

RESULTS

The Fazekas scores on brain CT scans showed consistent (weighted κ, 0.73) and moderate (weighted κ, 0.56) interobserver agreement for periventricular and deep white matter areas, respectively. Intraobserver reliability was substantial for both areas (weighted κ, 0.85 and 0.8).

CONCLUSION

The Fazekas score on CT can be used to reliably grade white matter changes, and can be a useful tool when MRI is not available.

Safety and efficacy of thrombectomy in acute ischaemic stroke (REVASCAT): 1-year follow-up of a randomised open-label trial

BACKGROUND

The REVASCAT trial and other studies have shown that the neurovascular thrombectomy improves outcomes at 90 days post stroke. However, whether the observed benefit is sustained in the long term remains unknown. We report the results of the prespecified 12-month analysis of the REVASCAT trial.

METHODS

Patients with acute ischaemic stroke who could be treated within 8 h of symptom onset were randomly assigned to medical therapy (including intravenous alteplase when eligible) and neurovascular thrombectomy with Solitaire FR or medical therapy alone. The main secondary outcome measure at 1 year follow-up was disability, measured using the modified Rankin Scale (mRS), ranging from 0 (no symptoms) to 6 (death) with categories 5 (severe disability) and 6 (death) collapsed into one category (severe disability or death), analysed as the distribution of the mRS. Additional prespecified secondary outcome measures included health-related quality of life measured with the EuroQol five dimensions questionnaire (EQ-5D) utility index (ranging from -0·3 to 1, higher values indicate better quality of life), the rate of functional independence (mRS 0-2), and cognitive function measured with the Trail Making Test (reported elsewhere). Treatment allocation was open label but endpoints at 12 months were assessed by masked investigators. The trial was registered at ClinicalTrials.gov, number NCT01692379.

FINDINGS

From Nov 24, 2012, to Dec 12, 2014, 206 patients were randomly assigned to medical therapy plus endovascular treatment (n=103) or medical treatment alone (n=103), at four centres in Catalonia, Spain. At 12 months post randomisation, based on 205 of 206 outcomes available at 12 months, thrombectomy reduced disability over the range of the mRS (common adjusted odds ratio [aOR] 1·80, 95% CI 1·09-2·99), and improved functional independence (mRS=0-2; 45 [44%] of 103 patients vs 31 [30%] of 103 patients; aOR 1·86, 95% CI 1·01-3·44). Health-related quality of life was superior in the thrombectomy group (mean EQ-5D utility index score, 0·46 [SD 0·38] in the thrombectomy group vs 0·33 [0·33] in the control group, difference 0·12 [95% CI 0·03-0·22]; p=0·01). 1-year mortality was 23% (24 of 103 patients) in the thrombectomy group versus 24% (25 of 103 patients) in the control group.

INTERPRETATION

At 12 months follow-up, neurovascular thrombectomy reduced post-stroke disability and improved health-related quality of life, indicating sustained benefit. These findings have important clinical and public health implications for evaluating the cost-effectiveness of the intervention in the long term.

FUNDING

Fundació Ictus Malaltia Vascular through an unrestricted grant from Medtronic.

Abstract 176: HERMES: Collaterals at Angiography Guide Clinical Outcomes

Background: Collateral circulation is a key factor in the pathophysiology of ischemic stroke. We conducted detailed analyses of angiography acquired immediately prior to endovascular therapy in the HERMES collaboration of recent landmark thrombectomy trials to determine predictors of collateral status and assess impact on clinical outcomes.

Methods: The HERMES Imaging Core, blind to all other clinical and imaging data, independently interpreted conventional angiography acquired immediately prior to endovascular therapy. Collaterals were graded with the ASITN scale, based on available data for the site of arterial occlusion defined on initial injections. The statistical core analyzed the association of collateral grade with demographics, baseline NIHSS, site of arterial occlusion and clinical outcomes of day 90 mRS.

Results: Angiography of collaterals was available in 376/605 (62%), including ASITN grades 0 in 7 (2%), 1 in 40 (10%), 2 in 182 (48%), 3 in 129 (34%) and 4 in 18 (5%). Elevated blood glucose (p=0.011) and diabetes (p=0.048) were associated with worse collateral grades, but age and NIHSS were unrelated. Better collateral grade was strongly associated with the degree of subsequent TICI reperfusion (p<0.001). The limited numbers of symptomatic intracranial hemorrhage (14/376 or 3.7%) or parenchymal hematomas (18/376 or 4.8%) precluded analysis of association with collateral status. Collaterals had strong impact on mRS shift from baseline to 90 days (p<0.001).

Multivariable regression revealed that better collateral status was a potent determinant (OR 1.37 per grade, p=0.028) of outcomes, equivalent to 4.5 points of NIHSS and 14 years of age in terms of impact on mRS outcomes.

Conclusions: Collaterals at angiography were a potent determinant of clinical outcomes in recent landmark thrombectomy trials.

Abstract 128: TICI Reperfusion in HERMES: Success in Endovascular Stroke Therapy

Background: Successful revascularization after endovascular therapy for acute ischemic stroke is measured by TICI score, yet variability exists in scale definitions and use. We examined the degree of reperfusion and association with outcomes in the HERMES collaboration of recent endovascular trials.

Methods: An independent reader of the HERMES Imaging Core, blind to all other data, evaluated the angiography of subjects treated with endovascular therapy in HERMES. A battery of various TICI scores (mTICI, oTICI, oTICI2C) was used to define reperfusion of the initial target occlusion on noninvasive imaging (ITO) and conventional angiography (CATO). Statistical analyses examined all TICI reperfusion metrics and correlation with clinical outcomes.

Results: Angiography of 593 subjects was analyzed, including ITO (124 ICA, 413 M1, 47 M2) and CATO (161 ICA, 329 M1, 62 M2). Across the entire scale range (0-3), the mTICI (AUC 0.61), oTICI (AUC 0.61) and oTICI2C (AUC 0.62) revealed similar ROC characteristics (p=0.450) in discriminating that more reperfusion is associated with better clinical outcomes. Using oTICI2C (3=100%, 2C=90-99%, o2B=67-89%, m2B=50-66%) of CATO, there were 44 TICI 3 (8%), 125 TICI 2C (22%), 178 TICI o2B (32%), 80 TICI m2B (14%), 85 TICI 2A (15%), 15 TICI 1 (3%) and 35 TICI 0 (6%). mRS shift analyses from baseline to 90 days revealed increasing TICI grades were linked with better outcomes (Figure), with significant distinctions of m2B vs. 2C (p=0.023) and all 2B combined vs. 3 (p=0.045).

Conclusions: The benefit of endovascular therapy in HERMES was strongly associated with increasing degrees of TICI reperfusion. The oTICI2C metric reveals important distinctions in clinical outcomes that should be used in future studies.

Abstract 31: The Association Between Baseline Ischemic Core Volume and Benefit of Endovascular Thrombectomy in Pooled Data from Six Randomized Trials

Background and purpose: Patients estimated to have a large irreversibly injured ischemic core are sometimes excluded from reperfusion therapies. We examined the association between estimated core volume and thrombectomy outcomes.

Methods: Patient-level CT perfusion (CTP) and clinical data were pooled from trials comparing endovascular thrombectomy with standard care in anterior circulation ischemic stroke: MR CLEAN, EXTEND IA, ESCAPE, SWIFT PRIME, REVASCAT and PISTE. Ischemic core volume was estimated using relative cerebral blood flow <30% of normal brain (RAPID automated software, IschemaView). The primary outcome was the 90 day modified Rankin scale (mRS), adjusted for baseline prognostic variables. To account for between-trial variance we used mixed-effects modeling with a random effect for trial incorporated in all models.

Results: Of 1352 patients, pre-treatment CTP was assessable in 539 after exclusion of 27 patients (12 severe motion, 2 no lesion within coverage, 2 contrast bolus failure, 11 data corruption during transfer from site). There were 264 allocated to endovascular thrombectomy and 275 to control. Baseline characteristics were similar between endovascular and control patients with CTP, median core 9.6 mL (IQR 2.4-26 mL) and with the overall trial demographics. Larger estimated core volume was associated with lower probability of independent outcome (mRS 0-2) in endovascular (OR 0.87 95%CI 0.80-0.95) and control patients (OR 0.85 95%CI 0.77-0.93, core*treatment interaction p=0.62) and increased disability: utility scores derived from mRS reduced by 2% (95%CI 1-4%) per 10mL increase in core volume for both endovascular and control patients (core*treatment interaction p=0.79). However, patients with >70mL core (median 100 mL, IQR 82-144mL) still benefitted from thrombectomy: ordinal mRS cOR 7.0 (2.6 -18.9) and the number needed to treat (NNT) remained stable across the spectrum of core volumes (point estimate NNT<10 for mRS 0-2 and NNT<3 for improvement in at least 1 mRS level).

Conclusions: Increasing estimated core volume was independently associated with worse outcome but endovascular thrombectomy remained effective versus standard care even in patients with large core who otherwise met eligibility for these trials.

Endovascular thrombectomy after large-vessel ischaemic stroke: a meta-analysis of individual patient data from five randomised trials

BACKGROUND

In 2015, five randomised trials showed efficacy of endovascular thrombectomy over standard medical care in patients with acute ischaemic stroke caused by occlusion of arteries of the proximal anterior circulation. In this meta-analysis we, the trial investigators, aimed to pool individual patient data from these trials to address remaining questions about whether the therapy is efficacious across the diverse populations included.

METHODS

We formed the HERMES collaboration to pool patient-level data from five trials (MR CLEAN, ESCAPE, REVASCAT, SWIFT PRIME, and EXTEND IA) done between December, 2010, and December, 2014. In these trials, patients with acute ischaemic stroke caused by occlusion of the proximal anterior artery circulation were randomly assigned to receive either endovascular thrombectomy within 12 h of symptom onset or standard care (control), with a primary outcome of reduced disability on the modified Rankin Scale (mRS) at 90 days. By direct access to the study databases, we extracted individual patient data that we used to assess the primary outcome of reduced disability on mRS at 90 days in the pooled population and examine heterogeneity of this treatment effect across prespecified subgroups. To account for between-trial variance we used mixed-effects modelling with random effects for parameters of interest. We then used mixed-effects ordinal logistic regression models to calculate common odds ratios (cOR) for the primary outcome in the whole population (shift analysis) and in subgroups after adjustment for age, sex, baseline stroke severity (National Institutes of Health Stroke Scale score), site of occlusion (internal carotid artery vs M1 segment of middle cerebral artery vs M2 segment of middle cerebral artery), intravenous alteplase (yes vs no), baseline Alberta Stroke Program Early CT score, and time from stroke onset to randomisation.

FINDINGS

We analysed individual data for 1287 patients (634 assigned to endovascular thrombectomy, 653 assigned to control). Endovascular thrombectomy led to significantly reduced disability at 90 days compared with control (adjusted cOR 2.49, 95% CI 1.76-3.53; p<0.0001). The number needed to treat with endovascular thrombectomy to reduce disability by at least one level on mRS for one patient was 2.6. Subgroup analysis of the primary endpoint showed no heterogeneity of treatment effect across prespecified subgroups for reduced disability (pinteraction=0.43). Effect sizes favouring endovascular thrombectomy over control were present in several strata of special interest, including in patients aged 80 years or older (cOR 3.68, 95% CI 1.95-6.92), those randomised more than 300 min after symptom onset (1.76, 1.05-2.97), and those not eligible for intravenous alteplase (2.43, 1.30-4.55). Mortality at 90 days and risk of parenchymal haematoma and symptomatic intracranial haemorrhage did not differ between populations.

INTERPRETATION

Endovascular thrombectomy is of benefit to most patients with acute ischaemic stroke caused by occlusion of the proximal anterior circulation, irrespective of patient characteristics or geographical location. These findings will have global implications on structuring systems of care to provide timely treatment to patients with acute ischaemic stroke due to large vessel occlusion.

FUNDING

Medtronic.

Mechanical thrombectomy in acute basilar artery occlusion: A safety and efficacy single centre study

OBJECTIVES

The objective of this study was to add more evidence about the efficacy and safety of mechanical thrombectomy in patients with basilar artery occlusion and secondarily to identify prognostic factors.

METHODS

Twenty-two consecutive patients (mean age 60.5 years, 15 men) with basilar artery occlusion treated with mechanical thrombectomy were included. Clinical, procedure and radiological data were collected. Primary outcomes were the modified Rankin scale score with a good outcome defined by a modified Rankin scale score of 0-2 and mortality rate at three months.

RESULTS

The median National Institutes of Health stroke scale at admission was 24 (interquartile range 11.5-31.25). Twelve patients (54.5%) required tracheal intubation due to a decreased level of consciousness. Successful recanalisation (modified treatment in cerebral ischaemia scale 2b-3) was achieved in 20 patients (90.9%). A favourable clinical outcome (modified Rankin scale score 0-2) was observed in nine patients (40.9%) and the overall mortality rate was 40.9% (nine patients). Haemorrhagic events were observed in three patients (13.63%). A decreased level of consciousness requiring intubation in the acute setting was more frequent in patients with poor outcomes (84.6%) than in patients with favourable outcomes (11.1%), and in patients who died (100%) compared with those who survived (23.1%), with a statistically significant difference (P = 0.002 and P = 0.001, respectively).

CONCLUSION

Mechanical thrombectomy is feasible and effective in patients with acute basilar artery occlusion. A decreased level of consciousness requiring tracheal intubation seems to be a prognostic factor and is associated with a poor clinical outcome and higher mortality rate. These initial results must be confirmed by further prospective studies with a larger number of patients.

Thrombectomy within 8 hours after symptom onset in ischemic stroke

BACKGROUND

We aimed to assess the safety and efficacy of thrombectomy for the treatment of stroke in a trial embedded within a population-based stroke reperfusion registry.

METHODS

During a 2-year period at four centers in Catalonia, Spain, we randomly assigned 206 patients who could be treated within 8 hours after the onset of symptoms of acute ischemic stroke to receive either medical therapy (including intravenous alteplase when eligible) and endovascular therapy with the Solitaire stent retriever (thrombectomy group) or medical therapy alone (control group). All patients had confirmed proximal anterior circulation occlusion and the absence of a large infarct on neuroimaging. In all study patients, the use of alteplase either did not achieve revascularization or was contraindicated. The primary outcome was the severity of global disability at 90 days, as measured on the modified Rankin scale (ranging from 0 [no symptoms] to 6 [death]). Although the maximum planned sample size was 690, enrollment was halted early because of loss of equipoise after positive results for thrombectomy were reported from other similar trials.

RESULTS

Thrombectomy reduced the severity of disability over the range of the modified Rankin scale (adjusted odds ratio for improvement of 1 point, 1.7; 95% confidence interval [CI], 1.05 to 2.8) and led to higher rates of functional independence (a score of 0 to 2) at 90 days (43.7% vs. 28.2%; adjusted odds ratio, 2.1; 95% CI, 1.1 to 4.0). At 90 days, the rates of symptomatic intracranial hemorrhage were 1.9% in both the thrombectomy group and the control group (P=1.00), and rates of death were 18.4% and 15.5%, respectively (P=0.60). Registry data indicated that only eight patients who met the eligibility criteria were treated outside the trial at participating hospitals.

CONCLUSIONS

Among patients with anterior circulation stroke who could be treated within 8 hours after symptom onset, stent retriever thrombectomy reduced the severity of post-stroke disability and increased the rate of functional independence. (Funded by Fundació Ictus Malaltia Vascular through an unrestricted grant from Covidien and others; REVASCAT ClinicalTrials.gov number, NCT01692379.).

Relevance of blood-brain barrier disruption after endovascular treatment of ischemic stroke: dual-energy computed tomographic study

BACKGROUND AND PURPOSE

Computed tomographic (CT) high attenuation (HA) areas after endovascular therapy for acute ischemic stroke are a common finding indicative of blood-brain barrier disruption. Dual-energy CT allows an accurate differentiation between HA areas related to contrast staining (CS) or to brain hemorrhage (BH). We sought to evaluate the prognostic significance of the presence of CS and BH after endovascular therapy.

METHODS

A prospective cohort of 132 patients treated with endovascular therapy was analyzed. According to dual-energy CT findings, patients were classified into 3 groups: no HA areas (n=53), CS (n=32), and BH (n=47). The rate of new hemorrhagic transformations was recorded at follow-up neuroimaging. Clinical outcome was evaluated at 90 days with the modified Rankin Scale (poor outcome, 3-6).

RESULTS

Poor outcome was associated with the presence of CS (odds ratio [OR], 11.3; 95% confidence interval, 3.34-38.95) and BH (OR, 10.4; 95% confidence interval, 3.42-31.68). The rate of poor outcome despite complete recanalization was also significantly higher in CS (OR, 9.7; 95% confidence interval, 2.55-37.18) and BH (OR, 15.1; 95% confidence interval, 3.85-59.35) groups, compared with the no-HA group. Patients with CS disclosed a higher incidence of delayed hemorrhagic transformation at follow-up (OR, 4.5; 95% confidence interval, 1.22-16.37) compared with no-HA patients.

CONCLUSIONS

Blood-brain barrier disruption, defined as CS and BH on dual-energy CT, was associated with poor clinical outcomes in patients with stroke treated with endovascular therapies. Moreover, isolated CS was associated with delayed hemorrhagic transformation. These results support the clinical relevance of blood-brain barrier disruption in acute stroke.

Risk factors for the development of chronic back pain after percutaneous vertebroplasty versus conservative treatment

In a recent randomized controlled trial comparing vertebroplasty (VP) versus conservative treatment (CT) in patients with symptomatic vertebral fractures (VF), we observed the development of chronic back pain (CBP) in nearly one-quarter of patients. The aim of this study was to identify the risk factors related to the development of severe CBP in these subjects. We evaluated risk factors including visual analog scale (VAS) at baseline and during the 1-year follow-up, age, gender, symptom onset time, number, type and severity of VF at baseline, number of vertebral bodies treated, incident VF, and antiosteoporotic treatment, among others. CBP was considered in patients with VAS ≥ 7 at 12 months. 91/125 patients completed the 12-months follow-up. CBP was observed in 23% of VP-treated patients versus 23% receiving CT. Patients developing CBP after VP showed a longer symptom onset time (82% ≥ 4 months in VP vs. 40% in CT, P = 0.03). On univariate analysis, female gender (OR 1.52; 95% CI 1.47-1.57, P < 0.0001), multiple acute VF (OR 1.79; 95% CI 1.71-1.87, P < 0.0001), VAS ≥ 7 two months after treatment (OR 11.04; 95% CI 6.71-18.17, P < 0.0001), and type of antiosteoporotic drug (teriparatide) (OR 0.12; 95% CI 0.03-0.60, P = 0.0236) were risk factors of CBP development in both groups. In the multivariate analysis, the main risk factors were baseline and post-treatment VAS ≥ 7, longer symptom onset time, and type of antiosteoporotic treatment. In conclusion, 23% of patients with symptomatic osteoporotic VF developed severe CBP independently of the type of treatment. Symptom onset time before VP and persistence of severe CBP after treatment were the main factors related to CBP with teriparatide treatment decreasing the risk of this complication.

Medical and endovascular treatment of patients with large vessel occlusion presenting with mild symptoms: an observational multicenter study

BACKGROUND

A significant proportion of stroke patients presenting with mild symptoms does not have a successful recovery, especially when a large vessel is occluded. IV thrombolysis is safe and may benefit patients presenting with mild symptoms. In this study, we tested whether endovascular therapy (ET) is superior to medical therapy in these patients.

METHODS

Observational, prospectively collected, multicenter study of 78 consecutive patients admitted from 2009 to 2012 within 6 h of stroke, with NIHSS≤5 at presentation or during initial diagnostic work-up and large vessel occlusion. Data for patients undergoing ET and/or IV thrombolysis were taken from the SONIIA registry of reperfusion therapies in Catalonia, or from our local stroke registry if no reperfusion therapy was delivered. We compared risk factors, clinical course, collateral circulation, revascularization rates, hemorrhagic complications, infarct volume, and the functional outcome at 3 months of patients treated with ET and those not receiving ET. Ordinal regression was used to assess the independent effect of ET on functional outcome.

RESULTS

Baseline characteristics were similar for ET (n=34) and medically (n=44) treated patients, except for older age in the latter. The occlusions were located in the terminal internal carotid artery (1%), M1 segment of the middle cerebral artery (33%), M2 segment (30%), posterior circulation (31%), and 5% of the patients had tandem lesions, with no significant differences between groups. Most patients in both treatment groups had good collateral flow. The rate of successful revascularization (91.2 vs. 63.4%; p=0.006) and the risk of symptomatic intracranial hemorrhage (11.8 vs. 0%; p=0.033) were higher in the ET group. The NIHSS scores were similar at hospital arrival, after initial neuroimaging, and at 24 h in both treatment groups and there were no significant differences in the infarct volume in a follow-up MRI. At 3 months, 35.9% of the patients had some disability. The functional outcome was similar in both treatment groups in univariate analysis and also in models adjusted for age and initial NIHSS or for variables associated to functional outcome on univariate comparison. Conversely, IV thrombolysis was associated with significantly greater chances of full recovery after adjusting for baseline differences (OR 3.70, p=0.015).

CONCLUSIONS

One third of stroke patients with mild symptoms and large vessel occlusions do not have a successful recovery. ET is effective to recanalize the occluded vessel but increases the risk of serious bleeding significantly without improving the functional outcome, and is therefore not justified routinely in these patients.

Anatomical labeling of the Circle of Willis using maximum a posteriori probability estimation

Anatomical labeling of the cerebral arteries forming the Circle of Willis (CoW) enables inter-subject comparison, which is required for geometric characterization and discovering risk factors associated with cerebrovascular pathologies. We present a method for automated anatomical labeling of the CoW by detecting its main bifurcations. The CoW is modeled as rooted attributed relational graph, with bifurcations as its vertices, whose attributes are characterized as points on a Riemannian manifold. The method is first trained on a set of pre-labeled examples, where it learns the variability of local bifurcation features as well as the variability in the topology. Then, the labeling of the target vasculature is obtained as maximum a posteriori probability (MAP) estimate where the likelihood of labeling individual bifurcations is regularized by the prior structural knowledge of the graph they span. The method was evaluated by cross-validation on 50 subjects, imaged with magnetic resonance angiography, and showed a mean detection accuracy of 95%. In addition, besides providing the MAP, the method can rank the labelings. The proposed method naturally handles anatomical structural variability and is demonstrated to be suitable for labeling arterial segments of the CoW.

Risk factors for the development of vertebral fractures after percutaneous vertebroplasty

We have recently observed an increased risk for vertebral fractures (VF) in a randomized controlled trial comparing the analgesic effect of vertebroplasty (VP) versus conservative treatment in symptomatic VF. The aim of the present study was to evaluate the risk factors related to the development of VF after VP in these patients. We evaluated risk factors including age, gender, bone mineral density, the number, type, and severity of vertebral deformities at baseline, the number of vertebral bodies treated, the presence and location of disk cement leakage, bone remodeling (determining bone turnover markers) and 25 hydroxyvitamin D [25(OH)D] levels at baseline in all patients. Twenty-nine radiologically new VF were observed in 17 of 57 patients undergoing VP, 72% adjacent to the VP. Patients developing VF after VP showed an increased prevalence of 25(OH)D deficiency (<20 ng/mL) and higher P1NP values. The principal factor related to the development of VF after VP in multivariate analysis was 25(OH)D levels < 20 ng/mL (RR, 15.47; 95% CI, 2.99-79.86, p < 0.0001), whereas age >80 years (RR, 3.20; 95% CI, 1.70-6.03, p = 0.0007) and glucocorticoid therapy (RR, 3.64; 95% CI, 1.61-8.26, p = 0.0055) constituted the principal factors in the overall study population. Increased risk of VF after VP was also associated with cement leakage into the inferior disk (RR, 6.14; 95% CI, 1.65-22.78, p = 0.044) and more than one vertebral body treated during VP (RR, 4.19; 95% CI, 1.03-34.3, p = 0.044). In conclusion, nearly 30% of patients with osteoporotic VF treated with VP had a new VF after the procedure. Age, especially >80 years, the presence of inferior disk cement leakage after the procedure, the number of cemented vertebrae, and low 25(OH)D serum levels were related to the development of new VF in these patients, with the latter indicating the need to correct vitamin D deficiency prior to performing VP.

A virtual coiling technique for image-based aneurysm models by dynamic path planning

Computational algorithms modeling the insertion of endovascular devices, such as coil or stents, have gained an increasing interest in recent years. This scientific enthusiasm is due to the potential impact that these techniques have to support clinicians by understanding the intravascular hemodynamics and predicting treatment outcomes. In this work, a virtual coiling technique for treating image-based aneurysm models is proposed. A dynamic path planning was used to mimic the structure and distribution of coils inside aneurysm cavities, and to reach high packing densities, which is desirable by clinicians when treating with coils. Several tests were done to evaluate the performance on idealized and image-based aneurysm models. The proposed technique was validated using clinical information of real coiled aneurysms. The virtual coiling technique reproduces the macroscopic behavior of inserted coils and properly captures the densities, shapes and coil distributions inside aneurysm cavities. A practical application was performed by assessing the local hemodynamic after coiling using computational fluid dynamics (CFD). Wall shear stress and intra-aneurysmal velocities were reduced after coiling. Additionally, CFD simulations show that coils decrease the amount of contrast entering the aneurysm and increase its residence time.

Performance assessment of isolation methods for geometrical cerebral aneurysm analysis

Geometrical aneurysm quantification is considered an important topic for the study of aneurysm formation, growth, risk of rupture and also in treatment planning. Usually, quantification involves aneurysm isolation, consisting in the operation of detecting the boundary between the aneurysm dome and its feeding arteries. This operation is sometimes performed manually, but it is a tedious task, subject to user variability. To obtain reproducible measurements, automatic techniques have been proposed. In this paper, we compare different aneurysm isolation techniques, two automatic and one manual-based on a cutting plane. All of them are compared against the results obtained by manual delineations of 26 real cases. We show from the results that automatic methods have good performance, providing results similar to manual methods in average. We also show that automatic methods improve reproducibility compared to direct measurements performed on volume rendering views. Each automatic method presents strengths and weaknesses in particular cases such as small aneurysms, aneurysms with multiple parent vessels or terminal aneurysms, but their reproducibility makes them suitable for robust population studies. Finally, based on this study, we have proposed a criterion that allows to use a combination of the two methods studied and that outperforms each of them individually.

Single-center experience of cerebral artery thrombectomy using the TREVO device in 60 patients with acute ischemic stroke

BACKGROUND AND PURPOSE

We sought to explore the safety and efficacy of the new TREVO stent-like retriever in consecutive patients with acute stroke.

METHODS

We conducted a prospective, single-center study of 60 patients (mean age, 71.3 years; male 47%) with stroke lasting <8 hours in the anterior circulation (n=54) or <12 hours in the vertebrobasilar circulation (n=6) treated if CT perfusion/CT angiography confirmed a large artery occlusion, ruled out a malignant profile, or showed target mismatch if symptoms >4.5 hours. Successful recanalization (Thrombolysis In Cerebral Infarction 2b-3), good outcome (modified Rankin Scale score 0-2) and mortality at Day 90, device-related complications, and symptomatic hemorrhage (parenchymal hematoma Type 1 or parenchymal hematoma Type 2 and National Institutes of Health Stroke Scale score increment ≥ 4 points) were prospectively assessed.

RESULTS

Median (interquartile range) National Institutes of Health Stroke Scale score on admission was 18 (12-22). The median (interquartile range) time from stroke onset to groin puncture was 210 (173-296) minutes. Successful revascularization was obtained in 44 (73.3%) of the cases when only the TREVO device was used and in 52 (86.7%) when other devices or additional intra-arterial tissue-type plasminogen activator were also required. The median time (interquartile range) of the procedure was 80 (45-114) minutes. Good outcome was achieved in 27 (45%) of the patients and the mortality rate was 28.3%. Seven patients (11.7%) presented a symptomatic intracranial hemorrhage. No other major complications were detected.

CONCLUSIONS

The TREVO device was reasonably safe and effective in patients with severe stroke. These results support further investigation of the TREVO device in multicentric registries and randomized clinical trials.

Automated segmentation of cerebral vasculature with aneurysms in 3DRA and TOF-MRA using geodesic active regions: an evaluation study

PURPOSE

To evaluate the suitability of an improved version of an automatic segmentation method based on geodesic active regions (GAR) for segmenting cerebral vasculature with aneurysms from 3D x-ray reconstruction angiography (3DRA) and time of flight magnetic resonance angiography (TOF-MRA) images available in the clinical routine.

METHODS

Three aspects of the GAR method have been improved: execution time, robustness to variability in imaging protocols, and robustness to variability in image spatial resolutions. The improved GAR was retrospectively evaluated on images from patients containing intracranial aneurysms in the area of the Circle of Willis and imaged with two modalities: 3DRA and TOF-MRA. Images were obtained from two clinical centers, each using different imaging equipment. Evaluation included qualitative and quantitative analyses of the segmentation results on 20 images from 10 patients. The gold standard was built from 660 cross-sections (33 per image) of vessels and aneurysms, manually measured by interventional neuroradiologists. GAR has also been compared to an interactive segmentation method: isointensity surface extraction (ISE). In addition, since patients had been imaged with the two modalities, we performed an intermodality agreement analysis with respect to both the manual measurements and each of the two segmentation methods.

RESULTS

Both GAR and ISE differed from the gold standard within acceptable limits compared to the imaging resolution. GAR (ISE) had an average accuracy of 0.20 (0.24) mm for 3DRA and 0.27 (0.30) mm for TOF-MRA, and had a repeatability of 0.05 (0.20) mm. Compared to ISE, GAR had a lower qualitative error in the vessel region and a lower quantitative error in the aneurysm region. The repeatability of GAR was superior to manual measurements and ISE. The intermodality agreement was similar between GAR and the manual measurements.

CONCLUSIONS

The improved GAR method outperformed ISE qualitatively as well as quantitatively and is suitable for segmenting 3DRA and TOF-MRA images from clinical routine.

Pharmacological profile of 5-hydroxytryptamine-induced inhibition on the pressor effect elicited by sympathetic stimulation in long-term diabetic pithed rats

We analysed the type and/or subtype of 5-hydroxytryptamine (5-HT) receptors involved in the inhibitory mechanisms of 5-HT on the pressor responses induced by stimulation of sympathetic vasopressor outflow in long-term diabetic pithed rats. Diabetes was induced in male Wistar rats by a single subcutaneous injection of alloxan. Eight weeks later, rats were anaesthetized, pre-treated with atropine, and pithed. The effect of 5-HT on the pressor responses elicited by stimulation of the sympathetic outflow was analysed in eight-week alloxan-induced diabetic pithed rats. 5-HT (20 microg/kg/min) reduced the pressor action obtained by electrical stimulation of the sympathetic outflow. However, there was no effect on exogenous noradrenaline-induced pressor responses. 5-CT (5 microg/kg/min), 8-OH-DPAT (5 microg/kg/min), and alpha-methyl-5-HT (5 microg/kg/min), selective 5-HT(1), 5-HT(1A) and 5-HT(2) receptor agonists, respectively, reproduced the 5-HT inhibitory action. Nevertheless, infusion of 5 microg/kg/min of 1-phenylbiguanide, CGS-12066B, L-694,247, BW273C86 or MK212 (5-HT(3), 5-HT(1B), 5-HT(1D), 5-HT(2B) and 5-HT(2C) receptor agonists, respectively) had no effect on the pressor responses elicited by stimulation of the sympathetic outflow. Methiothepin (100 microg/kg) and a cocktail of WAY-100,635 (100 microg/kg) and spiperone (125 microg/kg) blocked the 5-HT inhibitory effect on the pressor action obtained by sympathetic stimulation. Moreover, WAY-100, 635 abolished the 8-OH-DPAT inhibitory effect and spiperone blocked alpha-methyl-5-HT action. In conclusion, this study revealed that long-term experimental diabetes induces changes in the receptor type/subtype involved in the 5-HT inhibitory action on the sympathetic pressor responses produced by electrical stimulation. This is mainly mediated by pre-junctional 5-HT(1A) and 5-HT(2A) receptors.

Characterization of contractile 5-hydroxytryptamine receptor subtypes in the in situ autoperfused kidney in the anaesthetized rat

Using several 5-hydroxytryptamine (5-HT) agonists and antagonists, we attempted to characterize the receptor subtypes involved in the contractile response to 5-HT in the in situ autoperfused rat kidney. An intra-arterial (i.a.) bolus injection of 5-HT (0.00000125 to 0.1 microg/kg) increased renal perfusion pressure in a dose-dependent way but did not affect the systemic blood pressure. The selective 5-HT2 receptor agonist alpha-methyl-5-HT (alpha-methyl-5-hydroxytryptamine) and the non-selective 5-HT2C receptor agonist (1-(3-chlorophenyl)piperazine), m-CPP, caused a local vasoconstrictor effect in the autoperfused rat kidney, whereas BW723C86, a selective 5-HT2B receptor agonist, the 5-HT1 receptor agonist 5-carboxamidotryptamine, 5-CT, and the selective 5-HT3 receptor agonist m-CPBG (1-(m-chlorophenyl)-biguanide) did not modify the renal perfusion pressure. The vasoconstrictor effect elicited by alpha-methyl-5-HT and m-CPP was significantly decreased by ritanserin (a 5-HT2 receptor antagonist), SB 206553 (3,5-Dihydro-5-methyl-N-3pyridinylbenzo[1,2.b:4,5-b']dipyrrole(1H)-carboxamide hydrochloride), a selective 5-HT2B/2C receptor antagonist and enalapril, but was not modified by pretreatment with spiperone (a 5-HT2A receptor antagonist). The results of protein expression analyses allow us to postulate that 5HT-SRC (a 5-HT2C receptor protein) is expressed in renal tissue and differentially expressed in renal artery. Our data suggest also that the serotonergic vasoconstrictor response induced in the in situ autoperfused rat kidney would be mediated by local 5-HT2C receptor activation.

Diabetes-induced changes in 5-hydroxytryptamine modulation of vagally-induced bradycardia in rat heart

1. In the present study, we investigated how alloxan-induced diabetes affects the ability of 5-hydroxytryptamine (5-HT) to modulate bradycardia induced in vivo by electrical stimulation of the vagus nerve in pithed rats. We also analysed the type and/or subtype of 5-HT receptors involved. 2. Diabetes was induced in male Wistar rats with a single injection of alloxan (150 mg/kg, s.c.). Four weeks later, rats were anaesthetized, pretreated with atenolol and pithed. Electrical stimulation (3, 6 and 9 Hz) of the vagus nerve resulted in frequency dependent decreases in heart rate (HR). 3. In diabetic rats, intravenous bolus administration of high doses of 5-HT (100 and 200 microg/kg) increased the bradycardia induced by vagal electrical stimulation. Similarly, low doses (10 microg/kg) of the 5-HT(1/7) receptor agonist 5-carboxamidotryptamine (5-CT), increased vagally induced bradycardia. However, at high doses (50, 100 and 150 microg/kg), 5-CT reduced the bradycardia. Attenuation of the vagally induced bradycardia evoked by the higher doses of 5-CT was reproduced by L-694,247 (50 microg/kg), a selective agonist for the non-rodent 5-HT(1B) and 5-HT(1D) receptors. Enhancement of the vagally induced bradycardia elicited by low doses of 5-CT was reproduced by the selective 5-HT(1A) receptor agonist 8-hydroxydipropylaminotretalin hydrobromide (8-OH-DPAT; 50 microg/kg). These stimulatory and inhibitory actions on vagal stimulation-induced bradycardia in diabetic rats were also observed after administration of exogenous acetylcholine. 4. Vagally induced bradycardia in diabetic rats was not affected by administration of the selective 5-HT(2) receptor agonist alpha-methyl-5-HT (150 microg/kg), the selective 5-HT(3) receptor agonist 1-phenylbiguanide (150 microg/kg) or the selective 5-HT(1B) receptor agonist CGS-12066B (50 microg/kg). 5. Enhancement of the electrical stimulation-induced bradycardia in diabetic rats caused by 5-CT (10 microg/kg) or 8-OH-DPAT (50 microg/kg) was abolished by the selective 5-HT(2/7) receptor antagonist mesulergine (1 mg/kg) and the selective 5-HT(1A) receptor antagonist WAY-100,635 (100 microg/kg), respectively. Similarly, pretreatment with the non-selective 5-HT(1) receptor antagonist methiothepin (0.1 mg/kg) blocked the inhibitory effect of 5-CT (50 microg/kg) on the bradycardia induced by vagal electrical stimulation in diabetic rats. BRL-15572 (2 microg/kg), a selective 5-HT(1D) receptor antagonist, inhibited the action of L-694,247 (50 microg/kg), a selective agonist for the non-rodent 5-HT(1B) and 5-HT(1D) receptors, on the vagally induced bradycardia. 6. In conclusion, in the present study, experimental diabetes evoked changes in both the nature and 5-HT receptor types/subtypes involved in vagally induced bradycardia.

Frequency and Predictors of Symptomatic Intracerebral Hemorrhage in Patients with Ischemic Stroke Treated with Recombinant Tissue Plasminogen Activator outside Clinical Trials

BACKGROUND

To determine the frequency and predictors of symptomatic intracerebral hemorrhage (SICH) in patients treated with recombinant tissue plasminogen activator (rt-PA).

METHODS

We reviewed the databases of 7 tertiary hospitals that treated ischemic stroke patients with intravenous rt-PA. We recorded demographic data, vascular risk factors, time between onset and treatment, dose, the NIHSS score, body temperature, blood pressure, platelet count, blood glucose, antiplatelet treatment, and CT data. We also registered the study protocol used for treatment and deviations from the accepted protocol. A control CT was performed on all patients. SICH was diagnosed if a parenchymal hematoma was detected within the 36 h after rt-PA and was associated with an increase of > or =4 in the NIHSS score. Bivariate analyses were performed followed by a logistic regression analysis.

RESULTS

A total of 347 patients were studied, whose mean age was 68 +/- 10.9 years; 56% were men. Thirty-two patients (9.2%) exhibited a parenchymal hematoma, and 8 patients (2.3%) suffered a SICH. Patients with SICH had a higher frequency of previous transient ischemic attack (p = 0.04), early signs of ischemia (p = 0.003), hyperdense arterial sign (p = 0.008), and deviations (p = 0.002). Early signs of ischemia (OR 8.5, 95% CI 1.6-45.4, p = 0.01) and deviation from the protocol (OR 11.1, 95% CI 2.4-50, p = 0.002) were independent predictors of SICH.

CONCLUSIONS

SICH is infrequent in patients with ischemic stroke treated with rt-PA outside of a clinical trial. Its frequency increases in the presence of early signs of ischemia on the non-contrast CT scan and deviations from the recommended protocol.

The nitric oxide synthesis/pathway mediates the inhibitory serotoninergic responses of the pressor effect elicited by sympathetic stimulation in diabetic pithed rats

We investigated the involvement of the nitric oxide pathway in the inhibitory mechanisms of 5-hydroxytryptamine (5-HT) in the pressor responses induced by stimulation of sympathetic vasopressor outflow in diabetic pithed rats. Diabetes was induced in male Wistar rats by a single s.c. injection of alloxan. Four weeks later, the animals were anaesthetized, pretreated with atropine, and pithed. Electrical stimulation of the sympathetic outflow from the spinal cord (0.1, 0.5, 1 and 5 Hz) resulted in frequency-dependent increases in blood pressure. The inhibition of electrically induced pressor responses by 5-HT (10 microg/kg/min) in diabetic pithed rats could not be elicited after i.v. treatment with 1H-[1,2,4]Oxadiazolo[4,3-a]quinoxalin-1-one (ODQ) (10 microg/kg), a guanylyl cyclase inhibitor, or N-omega-L-Arginine methyl ester hydrochloride (L-NAME) (10 mg/kg), a nitric oxide synthase (NOS) inhibitor. The inhibitory effect produced by infusion of the selective 5-HT(1A) receptor agonist 8-hydroxydipropylaminotretalin hydrobromide (8-OH-DPAT) (20 microg/kg/min) was abolished in the presence of ODQ (10 microg/kg), or L-NAME (10 mg/kg) in diabetic pithed rats. The administration of L-Arginine (100 mg/kg) 30 min after L-NAME reproduced the inhibitory effect caused by 5-HT (10 microg/kg/min) and 8-OH-DPAT (20 microg/kg/min) on the electrically induced pressor responses, whereas in the presence of D-Arginine (100 mg/kg)+L-NAME the 5-HT or 8-OH-DPAT inhibitory effect on the pressor responses was abolished. In conclusion, in diabetic pithed rats, the inhibition produced by prejunctional 5-HT(1A) activation on electrically induced sympathetic pressor responses is mediated by the NO synthesis/pathway.

Diabetes-induced changes in the 5-hydroxytryptamine inhibitory receptors involved in the pressor effect elicited by sympathetic stimulation in the pithed rat

1. We investigated the effect of alloxan-induced diabetes on the inhibitory mechanisms of 5-hydroxytryptamine (5-HT) in the pressor responses induced by stimulation of sympathetic vasopressor outflow in pithed rats, and analysed the type and/or subtype of 5-HT receptors involved. 2. Diabetes was induced in male Wistar rats by a single s.c. injection of alloxan, then 4 weeks later, they were anaesthetized, pretreated with atropine and pithed. Electrical stimulation of the sympathetic outflow from the spinal cord (0.1, 0.5, 1 and 5 Hz) resulted in frequency-dependent increases in blood pressure. 3. Intravenous infusions of 5-HT (1-80 microg kg(-1) min(-1)) reduced the pressor effects obtained by electrical stimulation. The 5-HT(1) receptor agonist 5-carboxamidotryptamine, 5-CT (5 microg kg(-1) min(-1)), caused an inhibition of the pressor response, whereas the selective 5-HT(2) receptor agonist, alpha-methyl-5-HT (5 microg kg(-1) min(-1)) and the selective 5-HT(3) receptor agonist, 1-phenylbiguanide (40 microg kg(-1) min(-1)), did not modify the sympathetic pressor responses. 5-HT had no effect on exogenous noradrenaline (NA)-induced pressor responses. 4. The inhibition of electrically induced pressor responses by 5-HT (10 microg kg(-1) min(-1)) was unable to be elicited after i.v. treatment with methiothepin (100 microg kg(-1)) because of the marked inhibition produced by methiothepin alone. The 5-HT-induced inhibition was blocked after i.v. administration of WAY-100,635 (100 microg kg(-1)) and not affected by ritanserin (1 mg kg(-1)), MDL 72222 (2 mg kg(-1)). 5. The selective 5-HT(1A) receptor agonist, 8-hydroxydipropylaminotretalin hydrobromide (8-OH-DPAT) (5-20 microg kg(-1) min(-1)) but neither the rodent 5-HT(1B) receptor agonist, CGS-12066B (5 microg kg(-1) min(-1)), nor the selective nonrodent 5-HT(1B) and 5-HT(1D) receptor agonist, L-694,247 (5 and 40 microg kg(-1) min(-1)), inhibited the electrically induced pressor response. The selective 5-HT(1A) receptor antagonist, WAY-100,635 (100 microg kg(-1)), blocked the inhibition induced by 8-OH-DPAT (10 microg kg(-1) min(-1)). 8-OH-DPAT had no effect on exogenous NA-induced pressor responses. 6. Experimental diabetes produces changes in the inhibitory effect induced by 5-HT on electrically induced sympathetic pressor responses, such that the inhibitory action induced by 5-HT in diabetic pithed rats is mediated by prejunctional 5-HT(1A) receptors.

Amlodipine decreases fibrosis and cardiac hypertrophy in spontaneously hypertensive rats: persistent effects after withdrawal

Our objective was to examine the effect of chronic treatment with amlodipine on blood pressure, left ventricular hypertrophy, and fibrosis in spontaneously hypertensive rats and the persistence of such an effect after drug withdrawal. We investigated the effects of treatment with 2, 8 and 20 mg/kg/day of amlodipine given orally for six months and at three months after drug withdrawal. Systolic blood pressure was measured using the tail-cuff method. At the end of the study period, the heart was excised, the left ventricle was isolated, and the left ventricle weight/body weight ratio was calculated as a left ventricular hypertrophy index. Fibrosis, expressed as collagen volume fraction, was evaluated using an automated image-analysis system on sections stained with Sirius red. Age-matched untreated Wistar-Kyoto and SHR were used as normotensive and hypertensive controls, respectively. Systolic blood pressure was reduced in the treated SHR in a dose-dependent way and after amlodipine withdrawal it increased progressively, without reaching the values of the hypertensive controls. Cardiac hypertrophy was reduced by 8 and 20 mg/kg/day amlodipine, but when treatment was withdrawn only the group treated with 8 mg/kg/day maintained significant differences versus the hypertensive controls. All three doses of amlodipine reduced cardiac fibrosis and this regression persisted with the two highest doses after three months without treatment. We concluded that antihypertensive treatment with amlodipine is accompanied by a reduction in left ventricular hypertrophy and regression in collagen deposition. Treatment was more effective in preventing fibrosis than in preventing ventricular hypertrophy after drug withdrawal.

Neo-clerodane diterpenoids from Croton schiedeanus

Two new neo-clerodane type furano diterpenoids were isolated from the aerial part of Croton schiedeanus, besides the clerodane diterpenes cis- and trans-dehydrocrotonin, previously isolated from other species of Croton. Structural elucidation was achieved on basis of extensive NMR experiments, including X-ray diffraction analysis and molecular mechanics calculations. The previously known flavonoids ayanin and quercetin-3,7-dimethyl ether were also obtained from the extract of this plant.

Focal myositis of the thigh: unusual MR pattern

Focal myositis is a commonly referenced, infrequently reported and poorly documented benign inflammatory pseudotumor which may be misdiagnosed clinically as a malignant tumor. We report the clinicopathologic features and magnetic resonance imaging findings in a case of focal myositis in the thigh of a 55-year-old woman. A different radiologic presentation of this disorder is described. The gross appearance of the lesion, previously undescribed, appears to be rather specific for such a pseudoneoplastic disorder, and correlates very well with the magnetic resonance imaging features.

Effects of P5, a novel oxazolo(3,2-a)pyridine derivative with a long-acting antihypertensive activity, on different agonist-mediated pressor responses in pithed rats

1. An oxazolo(3,2-a)pyridine derivative P5, described chemically as (+/-)-ethyl-7-(3-nitrophenyl)-5,8a-dimethyl-6-methoxycarbonyl-2,3,8,8a-tetrahydro-7H-oxazolo[3,2-a]pyridin-8-carboxylate, is a novel compound that has been synthesized as a possible antihypertensive prodrug of the 1,4-dihydropyridine type. Its antihypertensive activity was described in a previous study by the authors (Morán, Martin, Velasco, Martin, San Roman, Caballero, Puebla, Medarde & San Feliciano, 1997). 2. The aim of this work was to establish in vivo, the possible mechanisms participating in this antihypertensive action. Accordingly, we examined the effect of P5 on the pressor responses induced in pithed rats by noradrenaline (an alpha1-, alpha2- and beta-adrenoceptor agonist), xylazine (an alpha2-adrenoceptor agonist), methoxamine (an alpha1-adrenoceptor agonist), angiotensin I, angiotensin II, L-NAME (a nitric oxide synthase inhibitor) and BayK 8644 (a calcium channel agonist) and compared them with those of nifedipine, used as the reference drug. 3 Intravenous (i.v.) administration of P5 (2.5-10 mg kg(-1)) inhibited the pressor responses to noradrenaline (1 microg kg(-1)), xylazine (80 microg kg(-1)), angiotensin I (0.5 microg kg(-1)), angiotensin II (0.5 microg kg(-1)), BayK 8644 (30 microg kg(-1)) and L-NAME (10 mg kg(-1)). Nifedipine (10 microg kg(-1), i.v.) reduced the pressor responses to all these agonists and also to methoxamine (2 microg kg(-1)). 4. However, P5 was more effective than nifedipine in inhibiting these responses and its inhibitory effect lasted longer. Intravenous infusion of calcium gluconate (1 ml kg(-1) min(-1)) reversed the reduction in the pressor responses as a result of nifedipine. The effects of P5 were only reversed at 2-3 h after administration. 5 These results suggest that P5 has a strong capacity to inhibit the pressor responses to several agonists after its i.v. administration and that such effects are related to its potent antihypertensive activity.

MR-14134, a new benzothiazepine with central hypotensive action

Structural changes introduced into the benzothiazepine molecule have led to a compound, MR-14134 (3-[(3-dimethylamino)propyl]-2,3,4,5- tetrahydro-2[4-methoxyphenyl]-1,5-benzothiazepin-4-one oxalate). We have compared the effects of MR-14134 and diltiazem on blood pressure and heart rate in anaesthetized and pithed rats following intravenous administration as well as in anaesthetized rats after intracerebroventricular administration and on the binding of [3H]clonidine in the rat cerebral cortex. MR-14134 (0.1-5.0 mg/kg, i.v.) produced a dose-dependent hypotensive and bradycardic effect similar in intensity but lasting longer than that of diltiazem. These effects were antagonized by previous administration of yohimbine but not by atropine, propranolol or ICI 118,551. Doses of 1 mg/kg i.v. of MR-14134 did not modify either blood pressure or heart rate in pithed rats and did not affect the hypertensive response elicited by electrical sympathetic stimulation or by exogenous administration of norepinephrine in pithed rats. Intracerebroventricular administration of MR-14134 (60 micrograms/kg) decreased blood pressure and heart rate in rats. This effect was antagonized by yohimbine and prazosin. [3H]Clonidine-binding experiments in the rat cortex showed that neither MR-14134 nor diltiazem have affinity for alpha 2A-adrenoceptors. These results confirmed that MR-14134 has a hypotensive and bradycardic effect in which, unlike diltiazem, the central nervous system is involved. These effects were mediated, at least partly, by alpha 2B-adrenoceptors and I1 imidazoline receptors.

JB-9322, a new selective histamine H2-receptor antagonist with potent gastric mucosal protective properties

1. JB-9322 is a selective histamine H2-receptor antagonist with gastric antisecretory activity and mucosal protective properties. 2. The affinity of JB-9322 for the guinea-pig atria histamine H2-receptor was approximately 2 times greater than that of ranitidine. 3. In vivo, the ID50 value for the inhibition of gastric acid secretion in pylorus-ligated rats was 5.28 mg kg-1 intraperitoneally. JB-9322 also dose-dependently inhibited gastric juice volume and pepsin secretion. In gastric lumen-perfused rats, intravenous injection of JB-9322 dose-dependently reduced histamine-, pentagastrin- and carbachol-stimulated gastric acid secretion. 4. JB-9322 showed antiulcer activity against aspirin and indomethacin-induced gastric lesions and was more potent than ranitidine. 5. JB-9322 effectively inhibited macroscopic gastric haemorrhagic lesions induced by ethanol. Intraperitoneal injection was effective in preventing the lesions as well as oral treatment. The oral ID50 value for these lesions was 1.33 mg kg-1. By contrast, ranitidine (50 mg kg-1) failed to reduce these lesions. In addition, the protective effect of JB-9322 was independent of prostaglandin synthesis. 6. These results indicate that JB-9322 is a new antiulcer drug that exerts a potent cytoprotective effect in addition to its gastric antisecretory activity.