Considerations beyond Stenosis for Carotid Endarterectomy in Treating Free-Floating Thrombus of the Carotid Artery.

BACKGROUND: Free-floating thrombus (FFT) of the carotid artery is an uncommon condition that can present with neurologic symptoms, often in the setting of ischemic stroke. The literature pertaining to the incidence and optimal treatment of this condition is limited. Herein, we report our contemporary experience with FFT across a range of degrees of carotid stenosis. METHODS: Medical records and imaging studies from a single academic medical center from January 2016 to July 2018 were retrospectively reviewed. Patient demographics, presentation, treatment, and follow-up were abstracted. RESULTS: Six cases of FFT of the carotid artery with and without hemodynamically significant atherosclerotic disease were identified. All cases presented with ischemic stroke; one case had a hemorrhagic conversion. In each case, the FFT was visualized by at least one imaging modality including computed tomography angiography, magnetic resonance angiography, and duplex ultrasound. Three patients had >50% carotid stenosis and three had <50%. All cases were treated with endarterectomy. Four of the six patients received preoperative anticoagulation. There were no postoperative complications. Median follow-up was 252 days, with one case lost to follow-up. Four of the six patients have been without restenosis, recurrence of the thrombus, nor worsening or recurrent stroke on follow-up. The fifth patient developed restenosis but remained clinically stable. CONCLUSIONS: Although current society guidelines do not recommend carotid endarterectomy as first-line treatment for symptomatic patients with <50% stenosis, it may be indicated in the context of FFT.

Influence of luminal stenosis in aneurysmal and non-aneurysmal blunt cerebrovascular injury.

BACKGROUND: Current blunt cerebrovascular injury (BCVI) grading grossly differentiates injury characteristics such as luminal stenosis (LS) and aneurysmal disease. The effect of increasing degree of LS beyond the current BCVI grading scale on stroke formation is unknown. STUDY DESIGN: BCVI over a 3-year period were retrospectively reviewed. To investigate influence of LS beyond the BCVI grading scale within aneurysmal and non-aneurysmal BCVI, grade 2 BCVI were subdivided into BCVI with ≥ 25% and ≤ 50% LS and BCVI with > 50% and ≤ 99% LS. Grade 3 BCVI were subdivided into BCVI with pseudoaneurysm (PSA) without LS and BCVI with PSA and LS. We hypothesized increased LS beyond the current BCVI grade distinctions would be associated with higher rates of stroke formation. RESULTS: 312 BCVI were included, of which 140 were carotid BCVI and 172 vertebral BCVI. Sixteen carotid BCVI underwent endovascular intervention (EI) and 19 suffered a stroke. In carotid BCVI stroke rates increased sequentially with BCVI grade except in grade 3. There was a stroke rate of 12% in grade 1 carotid BCVI, 18% in grade 2, 6% in grade 3, and 31% in grade 4. In subgroup analysis for grade 2 carotid BCVI, BCVI with > 50% and ≤ 99% LS had higher rates of stroke (22% vs. 15%, p = 0.44) than BCVI with ≥ 25% and ≤ 50% LS. In subgroup analysis of grade 3 carotid BCVI, BCVI with PSA and LS had higher rates of stroke (9% vs. 4%, p = 0.48) than BCVI with PSA without LS. Higher rates of EI in grade 2 carotid BCVI with > 50% and ≤ 99% LS (22% vs. 5%, p = 0.14) and grade 3 carotid BCVI with PSA and LS (35% vs. 4%, p = 0.01) were noted in subgroup analysis. CONCLUSION: Higher percentage LS beyond the currently used BCVI grading scale has a non-significantly increased rate of stroke in both aneurysmal and non-aneurysmal BCVI. Grade 3 BCVI with PSA and LS seems to be a high-risk subgroup. Use of EI confounds modern measurement of stroke risk in higher LS BCVI.

Organization of microtubule assemblies in Dictyostelium syncytia depends on the microtubule crosslinker, Ase1.

It has long been known that the interphase microtubule (MT) array is a key cellular scaffold that provides structural support and directs organelle trafficking in eukaryotic cells. Although in animal cells, a combination of centrosome nucleating properties and polymer dynamics at the distal microtubule ends is generally sufficient to establish a radial, polar array of MTs, little is known about how effector proteins (motors and crosslinkers) are coordinated to produce the diversity of interphase MT array morphologies found in nature. This diversity is particularly important in multinucleated environments where multiple MT arrays must coexist and function. We initiate here a study to address the higher ordered coordination of multiple, independent MT arrays in a common cytoplasm. Deletion of a MT crosslinker of the MAP65/Ase1/PRC1 family disrupts the spatial integrity of multiple arrays in Dictyostelium discoideum, reducing the distance between centrosomes and increasing the intermingling of MTs with opposite polarity. This result, coupled with previous dynein disruptions suggest a robust mechanism by which interphase MT arrays can utilize motors and crosslinkers to sense their position and minimize overlap in a common cytoplasm.