Thrombolysis In Myocardial Ischemia Research Articles

Impact of Diabetes on Outcomes in Patients Hospitalized With Acute Myocardial Infarction: Insights From the Atherosclerosis Risk in Communities Study Community Surveillance.

Background Diabetes is associated with increased risk of acute myocardial infarction (AMI). The demographic trends, clinical presentation, management, and outcomes of patients with diabetes who are hospitalized with AMI have not been recently reported. Methods and Results The ARIC (Atherosclerosis Risk in Communities) study conducted hospital surveillance of AMI in 4 US communities. AMI was classified by physician review using a validated algorithm. Medications and procedures were abstracted from the medical record. From 2000 to 2014, 21 094 weighted hospitalizations for AMI were sampled. The prevalence of diabetes steadily increased, from 35% to 41% to 43% (P-trend<0.0001) across 2000 to 2004, 2005 to 2009, and 2010 to 2014, respectively. Patients with diabetes were older (61 versus 59 years of age), more often Black (44% versus 31%), and more commonly women (42% versus 34%). The burden of cardiovascular comorbidities was higher with diabetes and increased temporally. Patients with diabetes less often presented with ST-segment elevation (9% versus 17%) or acute chest pain (72% versus 80%), and had higher mean GRACE (Global Registry of Acute Coronary Syndrome) score (123 versus 109), Thrombolysis in Myocardial Ischemia (TIMI) score (4.3 versus 4.0), and Killip class (1.9 versus 1.5). Patients with diabetes had a lower adjusted probability of receiving aspirin (relative probability, 0.95 [95% CI, 0.91-0.99]), nonaspirin antiplatelets (0.93 [95% CI, 0.86-0.99]), coronary angiography (0.85 [95% CI, 0.78-0.92]), and coronary revascularization (0.85 [95% CI, 0.76-0.92]). Diabetes was associated with a 52% higher hazard of all-cause 1-year mortality (hazard ratio, 1.52 [95% CI, 1.23-1.89]). Conclusions Diabetes is associated with higher risk of death in patients hospitalized with AMI, highlighting the need for adherence to evidence-based therapies in this high-risk population.

Creatine kinase during non-ST-segment elevation acute coronary syndromes is associated with major bleeding

BackgroundIt was recently reported that highly elevated plasma activity of the ADP-scavenging enzyme creatine kinase (CK), to >10 times the upper reference limit (URL), is independently associated with fatal or...

North American Solitaire Stent Retriever Acute Stroke registry: post-marketing revascularization and clinical outcome results

BackgroundLimited post-marketing data exist on the use of the Solitaire FR device in clinical practice. The North American Solitaire Stent Retriever Acute Stroke (NASA) registry aimed to assess the real...

Runoff Detected by Magnetic Resonance Angiography as an Indicator for Better Recanalization Outcomes in Below-the-Knee Chronic Total Occlusions in Diabetic Patients

Purpose: To compare the feasibility and efficacy of recanalizing below-the-knee (BTK) chronic total occlusions (CTOs) between patients with good or poor distal runoff based on magnetic resonance angiography (MRA) scans. Methods: Two hundred long-segment BTK CTOs in 171 limbs of 113 diabetic patients (58 men; mean age 69.8±1.9 years) were divided into good distal runoff (GDR: 119 lesions, 98 limbs) or poor distal runoff groups (PDR: 81 lesions, 73 limbs) based on baseline MRA findings. After angioplasty, modified thrombolysis in myocardial ischemia (mTIMI) grades and ankle-brachial index (ABI) were used to assess immediate outcomes. Regularly scheduled duplex or MRA imaging was performed in follow-up. The restenosis and limb salvage rates were compared. Results: The success rates were 93.3% and 87.7% in the GDR and PDR groups, respectively (p=0.21); subintimal angioplasty was more common in the PDR group (93.0% vs. 63.1%, p<0.01). Completion angiography indicated an mTIMI grade 3 blood flow in 71.2% lesions in the GDR patients and in 52.1% in the PDR (p=0.01) group. Improvement in the ABI was greater in the GDR limbs (p<0.001 vs. PDR). Mean imaging follow-up was 10.8±6.9 months in the GDR group and 11.1±6.6 months in the PDR group. Kaplan-Meier analysis showed a better restenosis-free rate in the GDR group (80.6% vs. 61.7%; p=0.02) at 12 months and for lesions with mTIMI grade 3 flow (p<0.01). At 24 months, Kaplan-Meier analysis revealed a better limb salvage rate in the GDR group (84.2% vs. 54.6%; p=0.02). Conclusion: Distal runoff detected using MRA could be a predictor for successful intraluminal recanalization, better distal tissue perfusion, improved long-term patency, and better limb salvage for patients with BTK CTOs.

Prediction of recanalization in acute stroke patients receiving intravenous and endovascular revascularization therapy.

The study aims to assess the recanalization rate in acute ischemic stroke patients who received no revascularization therapy, intravenous thrombolysis, and endovascular treatment, respectively, and to identify best clinical and imaging predictors of recanalization in each treatment group. Clinical and imaging data were collected in 103 patients with acute ischemic stroke caused by anterior circulation arterial occlusion. We recorded demographics and vascular risk factors. We reviewed the noncontrast head computed tomographies to assess for hyperdense middle cerebral artery and its computed tomography density. We reviewed the computed tomography angiograms and the raw images to determine the site and degree of arterial occlusion, collateral score, clot burden score, and the density of the clot. Recanalization status was assessed on recanalization imaging using Thrombolysis in Myocardial Ischemia. Multivariate logistic regressions were utilized to determine the best predictors of outcome in each treatment group. Among the 103 study patients, 43 (42%) received intravenous thrombolysis, 34 (33%) received endovascular thrombolysis, and 26 (25%) did not receive any revascularization therapy. In the patients with intravenous thrombolysis or no revascularization therapy, recanalization of the vessel was more likely with intravenous thrombolysis (P = 0·046) and when M1/A1 was occluded (P = 0·001). In this subgroup of patients, clot burden score, cervical degree of stenosis (North American Symptomatic Carotid Endarterectomy Trial), and hyperlipidemia status added information to the aforementioned likelihood of recanalization at the patient level (P < 0·001). In patients with endovascular thrombolysis, recanalization of the vessel was more likely in the case of a higher computed tomography angiogram clot density (P = 0·012), and in this subgroup of patients gender added information to the likelihood of recanalization at the patient level (P = 0·044). The overall likelihood of recanalization was the highest in the endovascular group, and higher for intravenous thrombolysis compared with no revascularization therapy. However, our statistical models of recanalization for each individual patient indicate significant variability between treatment options, suggesting the need to include this prediction in the personalized treatment selection.

North American Solitaire Stent Retriever Acute Stroke registry: post-marketing revascularization and clinical outcome results

BackgroundLimited post-marketing data exist on the use of the Solitaire FR device in clinical practice. The North American Solitaire Stent Retriever Acute Stroke (NASA) registry aimed to assess the real...

SOLITAIRE™ with the Intention for Thrombectomy (SWIFT) Trial: Design of a Randomized, Controlled, Multicenter Study Comparing the SOLITAIRE™ Flow Restoration Device and the MERCI Retriever in Acute Ischaemic Stroke

Self-expanding stent retrievers are a promising new device class designed for rapid flow restoration in acute cerebral ischaemia. The SOLITAIRE™ Flow Restoration device (SOLITAIRE) has shown high rates of recanalization in preclinical models and in uncontrolled clinical series. (1) To demonstrate non-inferiority of SOLITAIRE compared with a legally marketed device, the MERCI Retrieval System®; (2) To demonstrate safety, feasibility, and efficacy of SOLITAIRE in subjects requiring mechanical thrombectomy diagnosed with acute ischaemic stroke. DESIGN : Multicenter, randomized, prospective, controlled trial with blinded primary end-point ascertainment. Key entry criteria include: age 22-85; National Institute of Health Stroke Scale (NIHSS) ≥8 and <30; clinical and imaging findings consistent with acute ischaemic stroke; patient ineligible or failed intravenous tissue plasminogen activator; accessible occlusion in M1 or M2 middle cerebral artery, internal carotid artery, basilar artery, or vertebral artery; and patient able to be treated within 8 h of onset. Sites first participate in a roll-in phase, treating two patients with the SOLITAIRE device, before proceeding to the randomized phase. In patients unresponsive to the initially assigned therapy, after the angiographic component of the primary end-point is ascertained (reperfusion with the initial assigned device), rescue therapy with other reperfusion techniques is permitted. The primary efficacy end-point is successful recanalization with the assigned study device (no use of rescue therapy) and with no symptomatic intracranial haemorrhage. Successful recanalization is defined as achieving Thrombolysis In Myocardial Ischemia 2 or 3 flow in all treatable vessels. The primary safety end-point is the incidence of device-related and procedure-related serious adverse events. A major secondary efficacy end-point is time to achieve initial recanalization. Additional secondary end-points include clinical outcomes at 90 days and radiologic haemorrhagic transformation.

Revascularization grading in endovascular acute ischemic stroke therapy

Recanalization and angiographic reperfusion are key elements to successful endovascular and interventional acute ischemic stroke (AIS) therapy. Intravenous recombinant tissue plasminogen activator (rt-PA), the only established revascularization therapy approved by the US Food & Drug Administration for AIS, may be less effective for large artery occlusion. Thus, there is enthusiasm for endovascular revascularization therapies, which likely provide higher recanalization rates, and trials are ongoing to determine clinical efficacy and compare various methods. It is anticipated that clinical efficacy will be well correlated with revascularization of viable tissue in a timely manner. Reporting, interpretation, and comparison of the various revascularization grading methods require agreement on measurement criteria, reproducibility, ease of use, and correlation with clinical outcome. These parameters were reviewed by performing a Medline literature search from 1965 to 2011. This review critically evaluates current revascularization grading systems. The most commonly used revascularization grading methods in AIS interventional therapy trials are the thrombolysis in cerebral ischemia (TICI, pronounced "tissy") and thrombolysis in myocardial ischemia (TIMI) scores. Until further technical and imaging advances can incorporate real-time reliable perfusion studies in the angio-suite to delineate regional perfusion more accurately, the TICI grading system is the best defined and most widely used scheme. Other grading systems may be used for research and correlation purposes. A new scale that combines primary site occlusion, lesion location, and perfusion should be explored in the future.

The Penumbra system for mechanical thrombectomy in endovascular acute ischemic stroke therapy

Efficacy of IV systemic thrombolysis is limited in patients with severe acute ischemic stroke and large-vessel occlusion. Mechanical thrombectomy has been the mainstay therapy in large-vessel occlusion. This review focuses on the Penumbra aspiration device. Literature review. The Penumbra prospective studies were reviewed and results are presented. The pivotal single-arm prospective trial that led to its approval by the US Food and Drug Administration enrolled 125 patients within 8 hours of symptom onset and demonstrated an 82% recanalization rate, to Thrombolysis in Myocardial Ischemia (TIMI) scores of 2 and 3. The risk of symptomatic intracranial hemorrhage was 10%, and modified Rankin Scale (mRS) score of ≤ 2 was 25%. In the postmarketing registry, 157 vessels were treated, with 87% achieving TIMI 2 and 3 recanalization and 41% having an mRS score of ≤ 2. The Penumbra aspiration system is an effective tool to safely revascularize large-vessel occlusions in patients within 8 hours of onset of acute ischemic stroke who are either refractory to or excluded from IV thrombolytic therapy. Further prospective, randomized controlled trials will be needed to address whether this ability translates into neurologic improvement and better functional outcomes for our patients.

Solitaire flow restoration device versus the Merci Retriever in patients with acute ischaemic stroke (SWIFT): a randomised, parallel-group, non-inferiority trial

The Solitaire Flow Restoration Device is a novel, self-expanding stent retriever designed to yield rapid flow restoration in acute cerebral ischaemia. We compared the efficacy and safety of Solitaire with the standard, predicate mechanical thrombectomy device, the Merci Retrieval System. In this randomised, parallel-group, non-inferiority trial, we enrolled patients from 18 sites (17 in the USA and one in France). Patients were eligible for inclusion if they had acute ischaemic stroke with moderate to severe neurological deficits and were treatable by thrombectomy within 8 h of stroke symptom onset. We used a computer-generated randomisation sequence to randomly allocate patients to receive thrombectomy treatment with either Solitaire or Merci (1:1; block sizes of four and stratified by centre and stroke severity). The primary endpoint was Thrombolysis In Myocardial Ischemia (TIMI) scale 2 or 3 flow in all treatable vessels without symptomatic intracranial haemorrhage, after up to three passes of the assigned device, as assessed by an independent core laboratory, which was masked to study assignment. Primary analysis was done by intention to treat. A prespecified efficacy stopping rule triggered an early halt to the trial. The study is registered with ClinicalTrials.gov, number NCT 01054560. Between February, 2010, and February, 2011, we randomly allocated 58 patients to the Solitaire group and 55 patients to the Merci group. The primary efficacy outcome was achieved more often in the Solitaire group than it was in the Merci group (61%vs 24%; difference 37% [95% CI 19-53], odds ratio [OR] 4·87 [95% CI 2·14-11·10]; p(non-inferiority)<0·0001, p(superiority)=0·0001). More patients had good 3-month neurological outcome with Solitaire than with Merci (58%vs 33%; difference 25% [6-43], OR 2·78 [1·25-6·22]; p(non-inferiority)=0·0001, p(superiority)=0·02). 90-day mortality was lower in the Solitaire group than it was in the Merci group (17 vs 38; difference -21% [-39 to -3], OR 0·34 [0·14-0·81]; p(non-inferiority)=0·0001, p(superiority)=0·02). The Solitaire Flow Restoration Device achieved substantially better angiographic, safety, and clinical outcomes than did the Merci Retrieval System. The Solitaire device might be a future treatment of choice for endovascular recanalisation in acute ischaemic stroke. Covidien/ev3.

Late Drug-Eluting Stent Thrombosis

Late stent thrombosis (LST) after drug-eluting stent (DES) implantation remains a dreadful complication.1–4 Intravascular ultrasound (IVUS) and optical coherence tomography (OCT) provide unique insights on the results of DES implantation.1–3 We describe the value of a “combined” use of these intracoronary diagnostic techniques in a patient with DES LST. A 51-year-old man with unstable angina and a severe lesion in the proximal left anterior descending coronary artery was successfully treated with an everolimus-eluting stent. Despite excellent initial angiographic results, OCT disclosed malapposed struts and protrusion (2 mm) of the proximal edge of the DES across the ostium of the left circumflex coronary artery. With additional dilation (3.5-mm balloon, 12-bar), results improved, but malapposition was not completely resolved (Figure 1 ). At 9-month scheduled coronary angiography, an excellent result was maintained at the DES site. However, 2 months later, at the time the patient was still taking dual antiplatelet therapy, he presented with an extensive anterior myocardial infarction and pulmonary edema. Urgent angiography revealed LST with total occlusion of the proximal left anterior descending coronary artery. A Thrombolysis in Myocardial Ischemia 2 flow was obtained after …

Manual Aspiration Thrombectomy

We evaluated recanalization rates, clinical outcomes, and safety when manual aspiration thrombectomy is used in conjunction with other thrombolytic modalities in a consecutive case series of patients with large vessel intracranial occlusion. We conducted a retrospective review of a prospectively acquired acute endovascular stroke database. Manual aspiration thrombectomy was carried out with Distal Access and Penumbra reperfusion catheters of different sizes placed in the thrombus and aspirated with a syringe. We identified 191 patients: Occlusion locations were as follows: M1% to 50%, M2% to 10%, internal carotid artery terminus 25%, and vertebrobasilar 15%. Median treatment duration was 90 minutes. Recanalization results were Thrombolysis in Myocardial Ischemia 2/3 93%, Thrombolysis in Myocardial Ischemia 3 27%, Thrombolysis In Cerebral Infarction 2a/2b/3 91%, Thrombolysis In Cerebral Infarction 2b/3 71%, and Thrombolysis In Cerebral Infarction 3 25%. Larger catheters were associated with higher recanalization rates. Parenchymal hematoma rate was 13.6%. The favorable outcome (90-day modified Rankin Scale ≤ 2) rate was 54%. Mortality at 90 days was 25%. Manual aspiration thrombectomy is a useful addition to the armamentarium of endovascular treatment modalities for acute stroke.

Abstract 77: Beyond TIMI: Recanalization and Reperfusion with Endovascular Thrombectomy for Acute Ischemic Stroke in Multi MERCI

Background: Angiographic definitions for revascularization of arterial occlusion often vary in endovascular stroke trials. Thrombolysis in Myocardial Ischemia (TIMI) scores continue to be used despite inconsistent methods and limited correlation with clinical outcome after stroke. Novel recanalization and reperfusion scores, including the Arterial Occlusive Lesion (AOL) and Thrombolysis in Cerebral Infarction (TICI) scales respectively, have been advanced with limited data on scale metrics. We conducted a prospective analysis of central core lab angiography scores with local site reads in Multi MERCI to establish AOL and TICI metrics of recanalization and reperfusion, linking revascularization with clinical outcomes. Methods: Core lab AOL and TICI scores of two central readers were compared and analyzed with respect to local TIMI grade in Multi MERCI (n=164). In Multi MERCI, a modified TIMI was used, where the final TIMI score was the lowest of the TIMI scores in target vessel and the downstream vasculature. Recanalization and reperfusion were analyzed with respect to baseline clinical variables and 90-day outcomes. Results: Local site TIMI score showed only modest, but statistically significant correlation with AOL recanalization (0.50, p&lt;0.001) and TICI reperfusion (0.65, p&lt;0.001). Inter-rater reliabilities of central readers were excellent for AOL (κ=0.987) and TICI (κ=0.826). AOL and TICI were moderately correlated (0.83, p&lt;0.001). AOL recanalization was associated with time from symptom onset to procedure (-0.23, p=0.005), platelet count (0.16, p=0.043) and SBP &lt; 150 (0.18, p=0.022). TICI reperfusion was also associated with time from symptom onset to procedure (-0.17, p=0.029), current smoking (0.17, p=0.042), CHF (-0.18, p=0.031) and SBP &lt; 150 (0.20, p=0.013). Across all grades, TICI reperfusion was inversely associated with 90-day death (-0.22, p=0.007) and positively associated with good outcomes (0.24, p=0.003). AOL recanalization showed the same trend, though the association was weaker (-0.12, p=0.129; 0.16, p=0.047). TICI 2b/3 strongly predicted 90-day mRS 0-2 (OR 2.73, p=0.004) and decreased mortality (OR 0.29, p&lt;0.001) beyond AOL 2/3 (OR 2.78, p=0.020; 0.56, p=0.125). AOL and TICI exhibited similar relationships across various sites of arterial occlusion. Conclusions: AOL recanalization and TICI reperfusion core lab readings in Multi MERCI revealed excellent reliability and strong predictive value for 90-day clinical outcomes. AOL and TICI scores may discriminate recanalization from reperfusion, allowing further consideration of these distinct aspects of revascularization in future trials.

Endovascular Treatment of Tandem Extracranial/Intracranial Anterior Circulation Occlusions

Acute ischemic stroke due to tandem occlusions of the extracranial internal carotid artery and intracranial arteries has a poor natural history. We aimed to evaluate our single-center experience with endovascular treatment of this unique stroke population. Consecutive patients with tandem occlusions of the internal carotid artery origin and an intracranial artery (ie, internal carotid artery terminus, M1 middle cerebral artery, or M2 middle cerebral artery) were studied retrospectively. Treatment consisted of proximal revascularization with angioplasty and stenting followed by intracranial intervention. Endpoints were recanalization of both extracranial and intracranial vessels (Thrombolysis In Myocardial Ischemia ≥2), parenchymal hematoma, and good clinical outcome (modified Rankin Scale ≤2) at 3 months. We identified 77 patients with tandem occlusions. Recanalization occurred in 58 cases (75.3%) and parenchymal hematoma occurred in 8 cases (10.4%). Distal embolization occurred in 3 cases (3.9%). In 18 of 77 patients (23.4%), distal (ie, intracranial) recanalization was observed after proximal recanalization, obviating the need for distal intervention. Good clinical outcomes were achieved in 32 patients (41.6%). In multivariate analysis, Thrombolysis In Myocardial Ischemia ≥2 recanalization, baseline National Institutes of Health Stroke Scale score, baseline Alberta Stroke Programme Early CT score, and age were significantly associated with good outcome. Endovascular therapy of tandem occlusions using extracranial internal carotid artery revascularization as the first step is technically feasible, has a high recanalization rate, and results in an acceptable rate of good clinical outcome. Future randomized, prospective studies should clarify the role of this approach.

Emergent Endovascular Recanalization for Cervical Internal Carotid Artery Occlusion in Patients Presenting With Acute Stroke

Acute proximal (cervical) internal carotid artery (ICA) occlusion may cause ischemia of an entire hemisphere or no ischemia at all, depending on the presence of intracranial collaterals. To retrospectively analyze the clinical results for emergent endovascular carotid recanalization in patients with acute proximal (cervical) ICA occlusion and to assess predictors of recanalization and clinical, neurological, and functional outcome. Emergent endovascular revascularization was attempted in 22 patients presenting with acute stroke secondary to complete cervical ICA occlusion. Patients with pseudo-occlusion were excluded. Recanalization was assessed with the Thrombolysis in Myocardial Ischemia (TIMI) system: grade 0 (no flow) to grade 3 (normal flow). The median age of the patients was 65 years; mean admission National Institutes of Health Stroke Scale (NIHSS) score was 14. Recanalization (TIMI grade 2/3) occurred in 17 patients (77.3%). Ten patients (45.5%) demonstrated significant clinical improvement during hospitalization (NIHSS improved ≥4 points). Fifty percent of patients had good outcomes (modified Rankin Scale ≤2) after a median follow-up of 3 months. Patient age <70 years and successful recanalization (TIMI grade 2/3) predicted a good outcome (P ≤ .01). Presence of atrial fibrillation, admission NIHSS score ≥20, and complete ICA occlusion at all levels (cervical, petrocavernous, and intracranial) were associated with poor outcomes (P ≤ .05). Patients with complete cervical ICA occlusion but partial distal preservation of the vessel were most likely to benefit from the intervention (recanalization in 88.2%; good outcome in 64.7%). Attempts at emergent endovascular carotid recanalization for acute stroke are encouraged, particularly in younger patients with partial distal preservation of the ICA.

Collateral Flow Predicts Response to Endovascular Therapy for Acute Ischemic Stroke

Collaterals sustain the penumbra before recanalization and offset infarct growth, yet the influence of baseline collateral flow on recanalization after endovascular therapy remains relatively unexplored. We analyzed consecutive patients who received endovascular therapy for acute cerebral ischemia from 2 distinct study populations. We assessed the relationship between pretreatment collateral grade and vascular recanalization (Thrombolysis In Myocardial Ischemia [TIMI] scale). In addition, we assessed infarct growth on serial MRI. A total of 222 patients was included, 138 from the United States and 84 from South Korea. Complete revascularization occurred in 14.1% (11 of 78) patients with poor pretreatment collateral grades, whereas it was observed in 25.2% (26 of 103) patients with good collaterals and 41.5% (17 of 41) patients with excellent collaterals (P<0.001). This relationship was consistently observed in both study populations, although the mode of endovascular therapy was different between them. After adjustment for other factors, including mode of endovascular therapy, prior use of intravenous tissue plasminogen activator, and site of occlusion, pretreatment collateral grade was independently associated with recanalization. When revascularization was achieved, greater infarct growth occurred in patients with poor collaterals than in those with good collaterals (P=0.012). Our data indicate that angiographic collateral grade determines the recanalization rate after endovascular revascularization therapy. When therapeutic revascularization was achieved, beneficial effects were not observed in patients with poor collaterals. Angiographic collateral grade may therefore help guide treatment decision-making in acute cerebral ischemia.

Collateral Circulation in Symptomatic Intracranial Atherosclerosis

Collateral circulation in intracranial atherosclerosis has never been systematically characterized. We investigated collaterals in a multicenter trial of symptomatic intracranial atherosclerotic disease. Baseline angiography was reviewed for information on collaterals in stenoses of the internal carotid, middle cerebral, vertebral, and basilar arteries. A battery of angiographic scales was utilized to evaluate lesion site, arterial patency, antegrade flow, downstream territorial perfusion, and collateral circulation, blinded to all other data. Collateral circulation was adequately available for analysis in 287/569 (50%) subjects with proximal arterial stenoses ranging from 50% to 99%. Extent of collaterals was absent or none in 69%, slow or minimal in 10%, more rapid, yet incomplete perfusion of territory in 7%, complete but delayed perfusion in 11%, and rapid, complete collateral perfusion in 4%. Extent of collateral flow correlated with percentage of stenosis (P<0.0001), with more severe stenoses exhibiting greater compensation via collaterals. Overall, collateral grade increased with diminished antegrade flow across the lesion (thrombolysis in myocardial ischemia) and resultant downstream perfusion (thrombolysis in cerebral infarction) (both P<0.001). Our findings provide the initial detailed description of collaterals across a variety of stenoses, suggesting that collateral perfusion is a pivotal component in pathophysiology of intracranial atherosclerosis and implicating the need for further evaluation in ongoing studies.

Endovascular Treatment of Acute Ischemic Stroke May Be Safely Performed With No Time Window Limit in Appropriately Selected Patients

The traditional time window for acute ischemic stroke intra-arterial therapy (IAT) is <6 hours, which is based on pharmacological thrombolysis without penumbral imaging. This study was conducted to determine the safety of patient selection for IAT based on perfusion mismatch rather than time. A cohort of consecutive patients treated with IAT was identified by database review. Patients were selected for IAT based on the presence of perfusion mismatch using CT perfusion or MRI regardless of stroke duration. Thrombolytics were minimized after 6 hours in favor of mechanical embolectomy or angioplasty+/-stenting. Outcomes (National Institutes of Health Stroke Scale, modified Rankin Scale) were assessed by independent examiners. A multivariate analysis was performed to compare those treated <6 hours (early) with those treated >6 hours (late). Fifty-five patients (mean National Institutes of Health Stroke Scale=19.7+/-5.7) were treated, 34 early and 21 late, with mean time-to-intervention of 3.4+/-1.6 hours and 18.6+/-16.0 hours, respectively. Thrombolysis In Myocardial Ischemia 2 or 3 recanalization was achieved in 82.8% early and 85.7% late patients (P=1.0). Intracerebral hemorrhage occurred in 25.5% overall, but symptomatic intracerebral hemorrhage occurred in 8.8% of the early and 9.5% of the late patients (P=1.0). Thirty-day mortality was similar (29.4% versus 23.8%, P=0.650). At 3 months, 41.2% and 42.9%, respectively, achieved a modified Rankin Scale <or=2 (P=0.902). Only presenting National Institutes of Health Stroke Scale was a predictor of modified Rankin Scale <or=2 (OR 0.794[95% CI 0.68 to 0.92], P=0.009) and death (adjusted OR 1.29[95% CI 1.04 to 1.59], P=0.019). In appropriately selected patients, IAT for acute ischemic stroke can be performed safely regardless of stroke duration. The concept of an acute ischemic stroke treatment window for IAT should be re-evaluated with a clinical trial selecting patients with perfusion mismatch.

Need to Clarify Thrombolysis In Myocardial Ischemia (TIMI) Scale Scoring Method in the Penumbra Pivotal Stroke Trial

To the Editor: We congratulate the Penumbra Investigators on the successful completion of the Penumbra Pivotal Stroke Trial.1 The addition of the Penumbra System to the therapeutic armamentarium is an important advance in acute stroke care. A major defect of the report is the investigators do not specify how they measured the primary trial outcome, angiographic revascularization. They state without further elaboration that the core laboratory used the Thrombolysis In Myocardial Ischemia (TIMI) scale to assess revascularization. However, the TIMI scale was developed for the myocardial circulation and cannot be applied in the more complex cervicocephalic arterial tree without the creation of additional operational rules. A recent review found no fewer than 7 different operationalized versions of the TIMI scale being used across different stroke trials.2 The Stroke Therapy Academic Industry Roundtable (STAIR) has for this reason recommended abandonment of the TIMI in future cerebral revascularization clinical trials and use of one or more of the more transparent …

Predictors of Good Clinical Outcomes, Mortality, and Successful Revascularization in Patients With Acute Ischemic Stroke Undergoing Thrombectomy

The Mechanical Embolus Removal in Cerebral Ischemia (MERCI) and Multi MERCI trials evaluated the safety and efficacy of thrombectomy in the treatment of intracranial arterial occlusions within 8 hours of symptom onset. We sought to determine the predictors of clinical and angiographic outcomes in these patients. The trial cohorts were combined in a data set of 305 patients. Twenty-eight baseline variables were included in univariate and multivariate analyses to define the independent predictors of good outcomes (modified Rankin Scale score </=2), mortality, and successful revascularization (Thrombolysis In Myocardial Ischemia 2 to 3 flow). In the univariate analysis, final revascularization, baseline National Institutes of Health Stroke Scale, age, and systolic blood pressure were associated with both good outcomes and mortality at 90 days (P<0.0018 for all). In the multivariate analysis, final revascularization (OR, 20.4; 95% CI, 7.7 to 53.9; P<0.0001), baseline National Institutes of Health Stroke Scale (OR, 0.86; 95% CI, 0.81 to 0.92; P<0.0001), and age (OR, 0.96; 95% CI, 0.95 to 0.98; P=0.0004) were independent predictors of good outcome. Final revascularization (OR, 0.28; 95% CI, 0.16 to 0.50; P<0.0001), baseline National Institutes of Health Stroke Scale score (odds ratio, 1.09; 95% CI, 1.04 to 1.14; P=0.0001), age (OR, 1.05; 95% CI, 1.03 to 1.07; P<0.0001), and internal carotid artery occlusion (OR, 2.17; 95% CI, 1.22 to 3.86; P=0.0084) were the strongest predictors of mortality. Systolic blood pressure (<150 versus >or=150 mm Hg; OR, 0.42; 95% CI, 0.26 to 0.70; P=0.0007) and M2 occlusion (OR, 3.86; 95% CI, 1.28 to 11.67; P=0.0168) were independent predictors of revascularization. Final recanalization status represents the strongest predictor of clinical outcomes in patients undergoing thrombectomy. The ability to remove the clot is negatively influenced by systolic blood pressure on presentation perhaps because of the hydraulic forces imposed by higher blood pressures. Although internal carotid artery occlusions are associated with increased mortality, they do not appear to influence the chances of good outcomes. This finding supports the inclusion of internal carotid artery occlusions in future efficacy trials.