Daniel Hoit

Distal aspiration with retrievable stent assisted thrombectomy for the treatment of acute ischemic stroke

Objective Flexible large lumen aspiration catheters and stent retrievers have recently become available in the USA for the revascularization of large vessel occlusions presenting within the context of acute ischemic stroke (AIS). We describe a multicenter experience using a combined aspiration and stent retrieval technique for thrombectomy. Design A retrospective analysis to identify patients receiving combined manual aspiration and stent retrieval for treatment of AIS between August 2012 and April 2013 at six high volume stroke centers was conducted. Outcome variables, including recanalization rate, post-treatment National Institutes of Health Stroke Scale (NIHSS) score, symptomatic intracranial hemorrhage, discharge 90 day modified Rankin Scale (mRS) score, and mortality were evaluated. Results 105 patients were found that met the inclusion criteria for this retrospective study. Successful recanalization (Thrombolysis in Cerebral Infarction score 2B) was achieved in 92 (88%) of these patients. 44% of patients had favorable (mRS score 0–2) outcomes at 90 days. There were five (4.8%) symptomatic intracerebral hemorrhages and three procedure related deaths (2.9%). Conclusions Mechanical thrombectomy utilizing combined manual aspiration with a stent retriever is an effective and safe strategy for endovascular recanalization of large vessel occlusions presenting within the context of AIS.

A safe and effective management strategy for blunt cerebrovascular injury: Avoiding unnecessary anticoagulation and eliminating stroke.

BACKGROUND Few injuries have produced as much debate with respect to management as have blunt cerebrovascular injuries (BCVIs). Recent work (American Association for the Surgery of Trauma 2013) from our institution suggested that 64-channel multidetector computed tomographic angiography (CTA) could be the primary screening tool for BCVI. Consequently, our screening algorithm changed from digital subtraction angiography (DSA) to CTA, with DSA reserved for definitive diagnosis of BCVI following CTA-positive study results or unexplained neurologic findings. The current study was performed to evaluate outcomes, including the potential for missed clinically significant BCVI, since this new management algorithm was adopted. METHODS Patients who underwent DSA (positive CTA finding or unexplained neurologic finding) over an 18-month period subsequent to the previous study were identified. Screening and confirmatory test results, complications, and BCVI-related strokes were reviewed and compared. RESULTS A total of 228 patients underwent DSA: 64% were male, with mean age and Injury Severity Score (ISS) of 43 years and 22, respectively. A total of 189 patients (83%) had a positive screening CTA result. Of these, DSA confirmed injury in 104 patients (55%); the remaining 85 patients (45%) (false-positive results) were found to have no injury on DSA. Five patients (4.8%) experienced BCVI-related strokes, unchanged from the previous study (3.9%, p = 0.756); two were symptomatic at trauma center presentation, and three occurred while receiving appropriate therapy. No patient with a negative screening CTA result experienced a stroke. CONCLUSION This management scheme using 64-channel CTA for screening coupled with DSA for definitive diagnosis was proven to be safe and effective in identifying clinically significant BCVIs and maintaining a low stroke rate. Definitive diagnosis by DSA led to avoidance of potentially harmful anticoagulation in 45% of CTA-positive patients (false-positive results). No strokes resulted from injuries missed by CTA. LEVEL OF EVIDENCE Diagnostic study, level III.

Blood pressure levels post mechanical thrombectomy and outcomes in large vessel occlusion strokes

Objective: There are limited data evaluating the effect of post mechanical thrombectomy (MT) blood pressure (BP) levels on early outcomes of patients with large vessel occlusions (LVO). We sought to investigate the association of BP course following MT with early outcomes in LVO. Methods: Consecutive patients with LVO treated with MT during a 3-year period were evaluated. Hourly systolic BP (SBP) and diastolic BP (DBP) values were recorded for 24 hours following MT and maximum SBP and DBP levels were identified. LVO patients with complete reperfusion following MT were stratified in 3 groups based on post-MT achieved BP goals: <140/90 mm Hg (intensive), <160/90 mm Hg (moderate), and <220/110 mm Hg or <180/105 mm Hg when pretreated with IV thrombolysis (permissive hypertension). Three-month functional independence was defined as modified Rankin Scale score of 0–2. Results: A total of 217 acute ischemic stroke patients with LVO were prospectively evaluated. A 10 mm Hg increment in maximum SBP documented during the first 24 hours post MT was independently (p = 0.001) associated with a lower likelihood of 3-month functional independence (odds ratio [OR] 0.70; 95% confidence interval [CI] 0.56–0.87) and a higher odds of 3-month mortality (OR 1.49; 95% CI 1.18–1.88) after adjusting for potential confounders. In addition, achieving a BP goal of <160/90 mm Hg during the first 24 hours following MT was independently associated with a lower likelihood of 3-month mortality (OR 0.08; 95% CI 0.01–0.54; p = 0.010) in comparison to permissive hypertension. Conclusions: High maximum SBP levels following MT are independently associated with increased likelihood of 3-month mortality and functional dependence in LVO patients. Moderate BP control is also related to lower odds of 3-month mortality in comparison to permissive hypertension.

Rupture of giant vertebrobasilar aneurysm following flow diversion: mechanical stretch as a potential mechanism for early aneurysm rupture

A patient with a giant symptomatic vertebrobasilar aneurysm was treated by endoscopic third ventriculostomy for obstructive hydrocephalus followed by treatment of the aneurysm by flow diversion using a Pipeline Embolization Device. After an uneventful procedure and initial periprocedural period, the patient experienced an unexpected fatal subarachnoid hemorrhage 1 week later. Autopsy demonstrated extensive subarachnoid hemorrhage and aneurysm rupture (linear whole wall rupture). The patent Pipeline Embolization Device was in its intended location, as was the persistent coil occlusion of the distal left vertebral artery. The aneurysm appeared to rupture in a linear manner and contained a thick large expansile clot that seemed to disrupt or rupture the thin aneurysm wall directly opposite the basilar artery/Pipeline Embolization Device. We feel the pattern of aneurysm rupture in our patient supports the idea that the combination of flow diversion and the resulting growing intra-aneurysmal thrombus can create a mechanical force with the potential to cause aneurysm rupture.

Implications of limiting mechanical thrombectomy to patients with emergent large vessel occlusion meeting top tier evidence criteria

Background Recent guidelines for endovascular management of emergent large vessel occlusion (ELVO) award top tier evidence to the same selective criteria in recent trials. We aimed to understand how guideline adherence would have impacted treatment numbers and outcomes in a cohort of patients from a comprehensive stroke center. Methods A retrospective observational study was conducted using consecutive emergent endovascular patients. Mechanical thrombectomy (MT) was performed with stent retrievers or large bore clot aspiration catheters. Procedural outcomes were compared between patients meeting, and those failing to meet, top tier evidence criteria. Results 126 patients receiving MT from January 2012 to June 2015 were included (age 31–89 years, National Institutes of Health Stroke Scale (NIHSS) score 2–38); 62 (49%) patients would have been excluded if top tier criteria were upheld: pretreatment NIHSS score <6 (10%), Alberta Stroke Program Early CT score <6 (6.5%), premorbid modified Rankin Scale (mRS) score ≥2 (27%), M2 occlusion (10%), posterior circulation (32%), symptom to groin puncture >360 min (58%). 26 (42%) subjects had more than one top tier exclusion. Symptomatic intracerebral hemorrhage (sICH) and systemic hemorrhage rates were similar between the groups. 3 month mortality was 45% in those lacking top tier evidence compared with 26% (p=0.044), and 3 month mRS score 0–2 was 33% versus 46%, respectively (NS). After adjusting for potential confounders, top tier treatment was not associated with neurological improvement during hospitalization (β −8.2; 95% CI −24.6 to −8.2; p=0.321), 3 month mortality (OR=0.38; 95% CI 0.08 to 1.41), or 3 month favorable mRS (OR=0.97; 95% CI 0.28 to 3.35). Conclusions Our study showed that with strict adherence to top tier evidence criteria, half of patients may not be considered for MT. Our data indicate no increased risk of sICH and a potentially higher mortality that is largely due to treatment of patients with basilar occlusions and those treated at an extended time window. Despite this, good functional recovery is possible, and consideration of MT in patients not meeting top tier evidence criteria may be warranted.

Admission systolic blood pressure and outcomes in large vessel occlusion strokes treated with endovascular treatment

Background and purpose High admission blood pressure (BP) levels have been associated with lower recanalization rates after endovascular treatment (EVT) for patients with acute ischemic stroke (AIS) with emergent large vessel occlusion (ELVO). We sought to evaluate the association of admission BP with early outcomes in patients with ELVO treated with EVT. Methods Consecutive patients with AIS presenting with ELVO in a tertiary stroke center during a 4-year period were prospectively evaluated. Admission systolic blood pressure (SBP) and diastolic blood pressure (DBP) were measured using automated cuff recordings. A blinded neuroradiologist calculated the final infarct volume (FIV) using standardized ABC/2 methodology. A favorable functional outcome (FFO) at 3 months was defined as modified Rankin Scale score of 0–2. Results Our study population consisted of 116 patients with AIS (mean age 63±13 years, median NIH Stroke Scale score 17 points (IQR 14–21), median FIV 30 cm3 (IQR 8–94)). Higher admission SBP correlated with higher FIV (r +0.225; p=0.020). Patients with FFO had lower admission SBP (151±24 mm Hg vs 165±28 mm Hg; p=0.010), while admission SBP levels were higher in patients who died during hospitalization (169±34 mm Hg vs 156±24 mm Hg; p=0.043). A 10 mm Hg increment in admission SBP was independently (p=0.010) associated with an increase of 12 cm3 in FIV (95% CI 3 to 21) in multiple linear regression models adjusting for potential confounders. A 10 mm Hg increment in admission SBP was independently (p=0.012) associated with a lower likelihood of FFO at 3 months (OR 0.64; 95% CI 0.45 to 0.91) in multiple logistic regression models adjusting for potential confounders. Conclusions Higher admission SBP is an independent predictor of increased FIV and lower likelihood of 3-month FFO in patients with ELVO treated with EVT.

A multicenter study of the safety and effectiveness of mechanical thrombectomy for patients with acute ischemic stroke not meeting top-tier evidence criteria.

Background While mechanical thrombectomy (MT) has become the standard of care for patients with acute ischemic stroke (AIS) with emergent large-vessel occlusions (ELVO), recently published guidelines appropriately award top-tier evidence to the same selective criteria that were employed in completed clinical trials. We sought to evaluate the safety and effectiveness of MT in patients with AIS with ELVO who do not meet top-tier evidence criteria (TTEC). Methods We conducted an observational study on consecutive patients with AIS with ELVO who underwent MT at six high-volume endovascular centers. Standard safety outcomes (3-month mortality, symptomatic intracranial hemorrhage) and effectiveness outcomes (3-month functional independence: modified Rankin Scale scores of 0–2) were compared between patients meeting and failing TTEC. Results The sample consisted of 349 (60%) controls fulfilling TTEC and 234 (40%) non-TTEC patients. Control patients meeting TTEC for MT tended to have higher functional independence rates at 3 months (47% vs 39%; p=0.055), while the rates of symptomatic intracerebral hemorrhage (sICH) were similar (9%) in both groups (p=0.983). In multivariable logistic regression models, adherence to TTEC for MT was not independently related to any safety outcome (sICH: OR 0.71, 95% CI 0.30 to 1.68, p=0.434; 3-month mortality: OR 1.27, 95% CI 0.69 to 2.33, p=0.448) or effectiveness outcome (3-month functional independence: OR 0.81, 95% CI 0.48 to 1.37, p=0.434; 3-month functional improvement: OR 0.73, 95% CI 0.48 to 1.11, p=0.138) after adjusting for potential confounders. Conclusions Approximately 40% of patients with AIS with ELVO offered MT do not fulfill TTEC for MT. Patients who did not meet TTEC had high rates of good clinical outcome and low complication rates.

Prevention of stent thrombosis with reduced dose of prasugrel in two patients undergoing treatment of cerebral aneurysms with pipeline embolisation devices.

Prevention of intracranial stent thrombosis with dual-antiplatelet therapy is widely used in neuroendovascular procedures. However, the rising incidence of inadequate platelet inhibition with clopidogrel may increase complications following stent placement, especially with newer devices that possess a larger total metal surface area. While there are recent reports of prasugrel as an alternative to clopidogrel, there is no clinical evidence in neurointerventional patients regarding the use of a lower maintenance dose as an alternative strategy to gain adequate platelet inhibition while possibly reducing the risk of bleeding. We present 6-month efficacy and safety outcomes of two patients undergoing elective pipeline embolisation that were found to have inadequate platelet response to clopidogrel and subsequently transitioned to prasugrel 5 mg daily for the prevention of stent thrombosis.

The first North American use of the Pipeline Flex flow diverter

Flow diversion for the management of intracranial aneurysms represents a paradigm shift in how aneurysms are managed. The Pipeline embolization device (PED) is, to date, the only flow diverter approved for use in the USA by the Food and Drug Administration. Limitations and complications with new treatment strategies are inevitable, and with the PED there have been reports of complications, most commonly with challenging deployments. Once deployment has been initiated, the device is ‘one-way’; it can only be deployed further or removed. Yet, situations arise in which the ability to recapture or reposition the device would be advantageous. A second-generation Pipeline has been developed that addresses these concerns. We report the first use in North America of this second-generation Pipeline device: the Pipeline Flex. We discuss our rationale for using the device, our impressions of its operation, and the relevant literature concerning the current state of flow diversion.

Comparative safety and efficacy of combined IVT and MT with direct MT in large vessel occlusion

Objective In this multicenter study, we sought to evaluate comparative safety and efficacy of combined IV thrombolysis (IVT) and mechanical thrombectomy (MT) vs direct MT in emergent large vessel occlusion (ELVO) patients. Methods Consecutive ELVO patients treated with MT at 6 high-volume endovascular centers were evaluated. Standard safety and efficacy outcomes (successful reperfusion [modified Thrombolysis in Cerebral Infarction IIb/III], functional independence [FI] [modified Rankin Scale (mRS) score of 0–2 at 3 months], favorable functional outcome [mRS of 0–1 at 3 months], functional improvement [mRS shift by 1-point decrease in mRS score]) were compared between patients who underwent combined IVT and MT vs MT alone. Additional propensity score–matched analyses were performed. Results A total of 292 and 277 patients were treated with combination therapy and direct MT, respectively. The combination therapy group had greater functional improvement (p = 0.037) at 3 months. After propensity score matching, 104 patients in the direct MT group were matched to 208 patients in the combination therapy group. IVT pretreatment was independently (p < 0.05) associated with higher odds of FI (odds ratio [OR] 1.75; 95% confidence interval [CI] 1.02–2.99) and functional improvement (common OR 1.64; 95% CI 1.05–2.56). Combination therapy was independently (p < 0.05) related to lower likelihood of 3-month mortality (0.50; 95% CI 0.26–0.96). Conclusions This observational study provides preliminary evidence that IVT pretreatment may improve outcomes in ELVO patients treated with MT. The question of the potential effect of IVT on ELVO patients treated with MT should be addressed with a randomized controlled trial. Classification of evidence This study provides Class III evidence that for stroke patients with emergent large vessel occlusion, combined IVT and MT is superior to direct MT in improving functional outcomes.