Felix Zibold

Thrombectomy of calcified emboli in stroke. Does histology of thrombi influence the effectiveness of thrombectomy

Background and purpose Thrombus composition has been postulated to affect the success of endovascular therapy. Calcified clots are composed of large amounts of calcium phosphate which influences their mechanical properties and may serve as a model for testing this hypothesis. The aim of this study was to evaluate the recanalization and complication rates of calcified thromboemboli in patients with acute ischemic stroke who underwent thrombectomy. Material and methods A retrospective analysis was performed of all calcified intracranial thromboemboli in patients suffering an acute ischemic stroke, referred for endovascular therapy at two centers between January 2013 and July 2016. Results Eight patients with a calcified intracranial clot underwent stent retriever thrombectomy (five women; mean age 80 years). Mean clot attenuation was 305 HU (range 150–640 HU). Successful reperfusion defined, as Thrombolysis in Cerebral Infarction grade 2b–3 was achieved in only one patient (12.5%). Two periprocedural adverse events occurred: one peripheral vessel perforation which was coiled and one inadvertent stent retriever detachment due to fracture of the stent retriever wire. Conclusion Stent retriever thrombectomy of calcified thromboemboli seems less effective than with other types of clots. Different mechanical properties of calcified clots may render them stiffer and less accessible for stent retrievers. When faced with a calcified intracranial thromboembolus in clinical practice, a more contained approach may be warranted in view of low recanalization rates, and the potential for periprocedural adverse events.

Improving mTICI2b reperfusion to mTICI2c/3 reperfusions: A retrospective observational study assessing technical feasibility, safety and clinical efficacy

BackgroundRecent studies suggested that modified Thrombolysis in Cerebral Infarction grade (mTICI) 3 reperfusions are associated with superior outcome to mTICI2b reperfusions, questioning if neurointerventionalists should generally strive to achieve mTICI3.MethodsRetrospective analysis of successfully reperfused MCA occlusions (n=246) with available angiography runs between every manoeuvre was performed. Final reperfusion success and those between all single manoeuvres were evaluated applying the modified version of the TICI score (including TICI2c). Final TICI2c/3 reperfusions were dichotomized as ‘direct’ (reperfusion before final manoeuvre ≤mTICI2a) or ‘secondary improved’ (mTICI2b was achieved).ResultsPatients with mTICI2c reperfusion had similar outcome to patients with mTICI3 rather than mTICI2b reperfusions. Compared with mTICI2c/3-patients, mTICI2b-patients had lower rates of neurological improvement (33.3% vs. 61.2%, p<0.001) and good functional outcome (28.7% vs. 46.5%, p=0.008). In 28 patients, mTICI2b reperfusion was improved to mTICI2c/3 without complications. Outcome of patients with ‘direct’ or ‘secondary improved’ mTICI2c/3 did not differ (p>0.5).ConclusionImproving mTICI2b reperfusions to mTICI2c/3 reperfusions is sometimes technically feasible and safe, and associated with clinical benefit comparable to ‘direct’ mTICI2c/3 reperfusions. If confirmed, a more aggressive treatment approach in cases of already achieved mTICI2b may be justified, although proper patient selection is needed.Key Points• Patients with mTICI2c or 3 reperfusions have a comparable clinical course.• mTICI2c/3 are associated with a larger therapeutic benefit than are mTICI2b reperfusions.• Improving reperfusion from mTICI2b to mTICI2c/3 is sometimes feasible and reasonably safe.• Outcome of patients with ‘secondary improved’ and ‘direct’ mTICI2c/3 is not different.

Endovascular Treatment of Dural Arteriovenous Fistulas of the Transverse and Sigmoid Sinuses Using Transarterial Balloon-Assisted Embolization Combined with Transvenous Balloon Protection of the Venous Sinus

BACKGROUND AND PURPOSE: Combined transarterial balloon-assisted endovascular embolization with double-lumen balloon microcatheters and concomitant transvenous balloon protection was described as a promising treatment technique for dural arteriovenous fistulae of the transverse and sigmoid sinus. The purpose of this study was to evaluate the technical efficacy and safety of this combined treatment technique. MATERIALS AND METHODS: Nine consecutive patients presenting with dural arteriovenous fistulas of the transverse and sigmoid sinuses underwent combined transarterial and transvenous balloon-assisted endovascular embolization. Prospectively collected data were reviewed to assess the technical success rate, complication rate, and clinical outcome. RESULTS: Six patients presented with clinically symptomatic Borden type I, and 3 patients, with Borden type II dural arteriovenous fistulas of the transverse and sigmoid sinuses (3 men, 6 women; mean age, 50.4 years). Transarterial embolization was performed with a double-lumen balloon with Onyx and concomitant transvenous sinus protection with a dedicated venous remodeling balloon. Complete angiographic occlusion at the latest follow-up (mean, 4.8 months) was achieved in 6 patients, and near-complete occlusion, in 2 patients. Clinical cure or remission of symptoms was obtained in 6 and 2 patients, respectively. One patient with a residual fistula underwent further treatment in which the dural arteriovenous fistula was cured by sinus occlusion. Complete occlusion of the dural arteriovenous fistula was visible on the follow-up angiography after final treatment in 8 patients. One patient refused follow-up angiography but was free of symptoms. There were no immediate or delayed postinterventional complications. CONCLUSIONS: Transarterial balloon-assisted embolization of dural arteriovenous fistulas of the transverse and sigmoid sinuses with combined transvenous balloon protection is safe and offers a high rate of complete dural arteriovenous fistula occlusion and remission of clinical symptoms.

Rates and Quality of Preinterventional Reperfusion in Patients With Direct Access to Endovascular Treatment.

Background and Purpose— Preinterventional reperfusion before endovascular treatment (ET) is a benefit of bridging with intravenous tPA (tissue-type plasminogen activator). However, detailed data on reperfusion quality and rates of obviating ET in a cohort of patients with immediate access to ET is lacking. Purpose of this analysis was to evaluate prevalence and quality of preinterventional reperfusion in mothership patients. Methods— All mothership patients (n=627) from a prospective registry subjected to angiography with an intention to perform ET were reviewed. Preinterventional change of occlusion site (COS) was categorized into COS with Thrombolysis in Cerebral Infarction (TICI) 0/1, COS with TICI ≥2a, COS with TICI ≥2b, and COS with perfusion worsening. Predictors and clinical relevance were evaluated using multivariable logistic regression and results are displayed as adjusted odds ratios (aOR) and corresponding 95% confidence intervals (95% CI). Results— Prevalence of COS in all patients was 10.7% (95% CI, 8.3%–13.1%), subdividing into 2.7% COS with TICI 0/1, 6.2% COS with ≥TICI 2a (including 2.9% with TICI ≥2b), and 1.8% COS with perfusion worsening. Factors related to COS with ≥TICI 2a were intravenous tPA (aOR, 11.98; 95% CI, 4.5–31.6), cardiogenic thrombus origin (aOR, 2.3; 95% CI, 1.1–4.6), and thrombus length (aOR per 1 mm increase 0.926; 95% CI, 0.87–0.99). Additional ET was performed despite COS with ≥TICI 2a in 51.3%. COS with ≥TICI 2a showed a tendency for favorable outcomes (modified Rankin Scale, ⩽2; aOR, 2.65; 95% CI, 0.98–7.17). Rates of COS with ≥TICI 2a were particularly low in internal carotid artery and proximal M1 occlusions (2.2%; 95% CI, 0.9%–5%), where intravenous tPA was associated with perfusion worsening (aOR, 4.33; 95% CI, 1.12–16.80). Conclusions— Prevalence of preinterventional reperfusion is non-negligible in patients with direct access to ET and is clearly favored by intravenous tPA treatment. However, it is often incomplete and often requires additional ET. Preinterventional reperfusion of internal carotid artery and proximal M1 occlusions is rare and usually of low quality, where intravenous tPA may also promote perfusion worsening.

Multivessel Occlusion in Patients Subjected to Thrombectomy: Prevalence, Associated Factors, and Clinical Implications

Background and Purpose— Patients with embolic large-vessel occlusion may present with additional coincidental acute occlusions within or distant from the involved territory, referred to as multivessel occlusion (MVO). Purpose of this study was to assess prevalence of MVO, associated factors, and clinical relevance in patients undergoing endovascular stroke treatment. Methods— Image data of consecutive endovascular candidates (n=720) with direct access to angiography were extracted from a prospective registry. Prevalence of MVO was assessed with multimodal magnetic resonance imaging/computed tomography and confirmed by intra-arterial angiography. Explorative analysis of associated factors and clinical relevance was evaluated using multivariable logistic regression including variables with P<0.15 in univariate comparison. Good functional outcome was defined as modified Rankin Scale score ⩽2 at day 90. Results— MVO was present in 10.7% of patients (95% confidence interval [CI], 6.4%–13.0%). Two, 3, and 4 concomitant occlusions were found in 80.5%, 16.9%, and 2.6% of MVO cases, respectively. Detection rate on initial radiological report was 54.5%. Downstream MVO was present in around one third of MVO (n=27/77, 35.1%), whereas all other MVO (n=50/77, 64.9%) occurred in different territories. Independent factors related to MVO were statin treatment (adjusted odds ratio [aOR], 0.477; 95% CI, 0.276–0.827), higher systolic blood pressure (aOR per mmu2009Hg increase, 1.014; 95% CI, 1.005–1.023), and primary occlusion site M2 (aOR, 1.870; 95% CI, 1.103–3.170). MVO was related to lower rates of successful reperfusion (aOR, 0.549; 95% CI, 0.316–0.953) and lower rates of good functional outcome (aOR, 0.437; 95% CI, 0.207–0.923). Conclusions— Every tenth patient subjected to angiography for endovascular stroke treatment experienced MVO in our series, and only half were prospectively identified on preinterventional diagnostic imaging. Patients with MVO had higher baseline systolic blood pressure and were less often medicated with statins, an observation that warrants external validation and evaluation regarding causality. Occurrence of MVO has implication for treatment decisions, negatively affects endovascular treatment success, and is predictive of worse clinical outcome.

Cryptogenic Cerebrospinal Fluid Leaks in Spontaneous Intracranial Hypotension: Role of Dynamic CT Myelography

Purpose To propose a modified dynamic CT myelographic technique to locate cerebrospinal fluid (CSF) leaks, also known as cryptogenic leaks, in patients with spontaneous intracranial hypotension (SIH) in whom previous imaging did not show the dural breach. Materials and Methods This retrospective analysis included 74 consecutive patients with SIH and a myelographically proven CSF leak who were evaluated between February 2013 and October 2017. In 14 patients, dynamic CT myelography in the prone or lateral position showed the exact leakage point after unsuccessful previous imaging. During image analysis, the first time point showing extrathecal contrast material was defined as the site of dural breach point. Results Mean population age was 44 years (range, 25-65 years [nine women; mean age, 44 years; age range, 25-65 years] [five men; mean age, 46 years; age range, 29-61 years]). All patients had previously undergone spine MRI, conventional dynamic myelography, and CT myelography. Subsequent dynamic CT myelography covered a mean range of seven vertebral levels. The leak was caused by a calcified microspur in 10 patients and by a dural tear at the axilla of a spinal nerve root in the remaining four. The mean volume CT dose index of dynamic CT myelography was 107 mGy (range, 12-246 mGy), and the mean dose-length product was 1347 mGy·cm (range, 550-3750 mGy·cm). Conclusion Dynamic CT myelography is a valuable adjunctive tool with which to identify the precise location of a dural tear when other examinations are unsuccessful.

Safety of the Solitaire 4 × 40 mm Stent Retriever in the Treatment of Ischemic Stroke.

PurposeStent retrievers apply mechanical force to the intracranial vasculature. Our aim was to evaluate the safety and efficacy of the long Solitaire 4xa0×xa040xa0mm stent retriever for large vessel occlusion in stroke patients.MethodsWe conducted a retrospective analysis of all patients treated for acute ischemic large vessel occlusion stroke with the Solitaire 2 FR 4xa0×xa040 device between May and October 2016 at our institution. Patient-specific data at baseline and at discharge were documented. Reperfusion was graded with the thrombolysis in cerebral infarction (TICI) classification. Postinterventional angiograms and follow-up cross-sectional imaging were used to evaluate complications.ResultsTICI 2b/3 recanalization was achieved in 20 of 23 patients (87.0%), in 17 patients with the first retriever pass. NIHSS improved from a mean score at presentation of 16 (range 4–36) to 11 (range 0–41) at discharge. Mean mRS score at discharge was 3 (range 0–6) and 3 (range 0–6) at 90xa0days post-treatment. No infarcts in other territories were observed. One patient showed a (reversible) vasospasm in the postinterventional angiogram and another a small contrast extravasation in follow-up imaging.ConclusionThe Solitaire 2 FR 4xa0×xa040 stent retriever is a safe and efficient device for large vessel occlusion acute ischemic stroke with a high recanalization rate and a low peri- and postinterventional complication rate together with a good clinical outcome. Despite potentially higher friction and shearing forces, no increased incidence of visible damage to the vessel wall was observed.

Reasons for Reperfusion Failures in Stent-Retriever-Based Thrombectomy: Registry Analysis and Proposal of a Classification System

An intention-to-treat single-center cohort (n= 592) was re-evaluated for all patients in whom no reperfusion could be achieved (n = 63). Baseline characteristics were compared between patients with and without reperfusion failures. After qualitative review of all cases with reperfusion failures, a classification system was proposed and relative frequencies were reported. Reasons for reperfusion failure in stent-retriever thrombectomy are heterogeneous. The failure to establish intracranial or cervical access is almost as common as stent-retriever failure after establishing intracranial access. Systematic reporting standards of reasons may help to further estimate relative frequencies and thereby guide priorities. BACKGROUND AND PURPOSE: In 5%–10% of patients with acute ischemic stroke with an intention to treat with mechanical thrombectomy, no reperfusion can be achieved (Thrombolysis in Cerebral Infarction score = 0/1). Purpose of this analysis was a systematic assessment of underlying reasons for reperfusion failures. MATERIALS AND METHODS: An intention-to-treat single-center cohort (n = 592) was re-evaluated for all patients in whom no reperfusion could be achieved (n = 63). Baseline characteristics of patients were compared between patients with and without reperfusion failures. After qualitative review of all cases with reperfusion failures, a classification system was proposed and relative frequencies were reported. In a second step, occurrence of delayed recanalization at 24 hours after reperfusion failure and dependency on IV-tPA were evaluated. RESULTS: In 63/592 patients with an intention to perform stent-retriever thrombectomy, no reperfusion was achieved (TICI 0/1, 10.6%, 95% CI, 8.2%–13.1%). Older patients (adjusted OR per yr = 1.03; 95% CI, 1.01–1.05) and patients with M2 occlusion (adjusted OR = 3.36; 95% CI, 1.82–6.21) were at higher risk for reperfusion failure. In most cases, no reperfusion was a consequence of technical difficulties (56/63, 88.9%). In one-third of these cases, reperfusion failures were due to the inability to reach the target occlusion (20/63, 31.7%), while “stent-retriever failure” occurred in 39.7% (25/63) of patients. Delayed recanalization was very rare (18.2%), without dependence on IV-tPA pretreatment status. CONCLUSIONS: Reasons for reperfusion failure in stent-retriever thrombectomy are heterogeneous. The failure to establish intracranial or cervical access is almost as common as stent-retriever failure after establishing intracranial access. Systematic reporting standards of reasons may help to further estimate relative frequencies and thereby guide priorities for technical development and scientific effort.

Balloon-assisted coil embolization and large stent delivery for cerebral aneurysms with a new generation of dual lumen balloons (Copernic 2L)

Introduction Dual coaxial lumen balloon microcatheters through which small stents can be delivered have recently been described. We report a series of a new type of dual lumen balloon catheter with a parallel lumen design enabling enhanced inflation and deflation properties through which larger stents may be deployed, including flow diverters (FD). Methods All aneurysms that were treated with a Copernic 2L (COP2L) dual lumen balloon catheter at our institution between February 2014 and December 2016 were assessed. Patient demographics, aneurysm characteristics, clinical and angiographic follow-up, as well as adverse events were analyzed. Results A total of 18 aneurysms in 16 patients (14 women) were treated with the COP2L. Mean maximal aneurysm diameter was 6.4u2009mm, mean neck size was 3.3u2009mm (min 1; max 6.3), and mean aneurysm height/width was 1.1 (min 0.5; max 2.1). The COP2L was used for balloon-remodeled coiling exclusively in 2 aneurysms; coiling and FD stenting in 8; coiling and braided stent delivery in 3; coiling, braided and FD stenting in 1; and FD stenting without coiling in 4 (stenting alone). The rate of Roy–Raymond 1 (complete occlusion) changed from 22% in the immediate postoperative period to 100% at 3 months (mean imaging follow-up 8.2 months). There were three technical complications (3/16, 18.7%), including a perforation and two thromboembolic asymptomatic events that were rapidly controlled with the COP2L. There was no immediate or delayed morbidity or mortality (modified Rankin Scale score 0–1 in 100% of patients). Conclusion The COP2L is a new type of dual lumen balloon catheter that may be useful for balloon and/or stent-assisted coiling of cerebral aneurysms. The same device can be used to deliver stents up to 4.5u2009mm and to optimize stent/wall apposition or serve as a life-saving tool in case of thromboembolic or hemorrhagic events. Long-term efficacy and safety need to be further assessed with larger case-controlled cohorts.