American Journal of Neuroradiology 27:148-150, January 2006
© 2006 American Society of Neuroradiology
CASE REPORT
INTERVENTIONAL
Occlusion of the Middle Cerebral Artery due to Synthetic Fibers
R. Chapota,
M. Wassefb,
A. Bisdorffa,
A. Rogopoulosa,
J.-J. Merlanda and
E. Houdarta
a Department of Interventional Neuroradiology, Hôpital Lariboisière, Paris, France
b Department of Pathology, Hôpital Lariboisière, Paris, France
Address correspondence to: René Chapot, Unité de Neuroradiologie Interventionnelle, Hôpital Universitaire Dupuytren, 2 avenue Martin Luther King, 87042 Limoges, France
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Abstract
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SUMMARY: We report an unusual etiology for a thromboembolic
complication. Occlusion of the middle cerebral artery occurred
before embolization of an intracranial aneurysm. Attempts to
recanalize the artery failed by using both fibrinolytics and
IIb/IIIa inhibitors but succeeded with mechanical thrombectomy
with a microsnare. Pathologic analysis of the thrombus showed
numerous synthetic fibers that were determined to have originated
from unsealed gauzes that were used during the procedure.
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Introduction
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Thromboembolic events are the most frequent complications of
endovascular treatment of intracranial aneurysms, seen on angiography
in 9%.
1 These may be due to inadequate flushing of the guiding
catheter or thrombus extension from the aneurysm. Embolic events
are more frequently recognized when diffusion-weighted MR imaging
is performed following treatment with one series reporting an
incidence of 61%.
2 Most of these events remain clinically silent
and are not visible on angiography. The exact etiology for these
lesions is usually unknown. We report an unusual cause of thromboembolic
occlusion of the middle cerebral artery due to inadvertent injection
of synthetic fibers.
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Case Report
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A 43-year-old woman with a recent episode of subarachnoid hemorrhage
was referred for endovascular treatment of 2 intracranial aneurysms
located at the right carotid bifurcation and left posterior
communicating artery.
Embolization was achieved by using standard anticoagulation protocol with a bolus of 50 IU/kg of heparin followed by a continuous infusion of 25 IU/kg/h. Continuous flushing of the guiding catheter (Envoy 6F; Cordis, Miami Lakes, Fla) and microcatheter (Prowler 14, Cordis) with saline was achieved throughout the procedure. Both aneurysms were intended to be treated in the same session. After uneventful embolization of the right carotid bifurcation aneurysm, the 6F guiding catheter was displaced from the right to the left internal carotid artery. Injection of the left internal carotid artery was initially normal but showed an abrupt occlusion of the left middle cerebral artery after insertion of the microcatheter (Fig 1). Embolization of the posterior communicating artery aneurysm was rapidly achieved followed by intra-arterial fibrinolysis with 900,000 IU of urokinase. Fibrinolysis remained unsuccessful so that intra-arterial abciximab (ReoPro, Centocor, Malvern, Pa) was progressively added, with a total injected bolus of 8 mL. A slight reduction of the thrombus was found, but the middle cerebral artery remained partially occluded. Mechanical thrombectomy was therefore attempted by using a 2-mm microsnare (Microvena, EV3, Irvine, Calif). The thrombus was caught at the third attempt and could be removed, allowing complete recanalization of the middle cerebral artery (Figs 2 and 3). On wakening, the patient had no motor deficit but a mild aphasia that progressively resolved within 6 months.
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Fig 1. Lateral projection of the left internal carotid artery after insertion of the microcatheter showing an acute occlusion of the middle cerebral artery.
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Fig 2. Immediate angiographic control after removal of the thrombus with a goose-neck microsnare. The thrombus can be seen at the level of the carotid siphon (arrow).
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The thrombus was sent to pathology for analysis. Numerous synthetic fibers were found within the thrombus. Confirmation of foreign bodies was achieved with polarized light examination (Fig 4). All possible sources for spillage of synthetic fibers were checked. Unsealed gauzes were found within the angiography vascular set (Cardinal Health, McGaw Park, Ill). These gauzes consisted of a double-layer gauze containing cotton-like material. The layer was disrupted on one side, allowing spontaneous spillage of the fibers (Fig 5). These fibers were found to be widespread in the entire vascular set. Microscopic examination and chromatographic analysis confirmed that fibers found in the gauzes, vascular set, and thrombus were similar. This led to withdrawal from the vascular set of these unsealed gauzes by the manufacturer.
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Fig 4. A, Macroscopic view of the thrombus showing fibers inside the platelets aggregates.
B, Polarized light showing the presence of foreign bodies inside the thrombus.
C, Regular oval-shaped fibers suggesting a synthetic origin.
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Fig 5. Unsealed gauze furnished in the vascular set. Spontaneous leakage of unattached fibers may be seen after minimal handling of the gauze.
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Discussion
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Thromboembolic events may occur during intracranial endovascular
procedures despite adequate anticoagulation. Intra-arterial
injection of fibrinolytic drugs and/or IIb/IIIa inhibitors may
be achieved, allowing a high recanalization rate when the thrombus
is fresh and unorganized.
3,
4 In our patient, the thromboembolic
occlusion was initially presumed to be platelet derived, but
inefficiency of the fibrinolytic agents led us to attempt a
mechanical thrombectomy. Thrombectomy may be achieved by using
either thromboaspiration as reported in the basilar artery
5 or a dedicated device.
6,
7 In our patient, the goose-neck microsnare
allowed rapid recanalization without thrombus fragmentation
and capture of the thrombus so that further histologic analysis
could be achieved and the synthetic fibers found.
Intravascular embolism related to foreign material has rarely been described. Fragmentation of the hydrophilic coating from microcatheters has been reported.8 Leakage of synthetic fibers due to fragmentation of vascular dacron prostheses9 have also been reported.
In our patient, the embolus was made of numerous synthetic fibers that migrated and blocked the middle cerebral artery. It may be argued that the fibers were secondarily incorporated into a pre-existing thrombus originating from the guiding catheter. The fibers, however, were numerous and evenly distributed throughout the entire thrombus. This is more likely to occur if the thrombus formed around the fibers and not if the fibers were secondarily mechanically incorporated into a pre-existing thrombus. Moreover, the number and volume of these thrombogenic fibers was sufficient to occlude an artery. Besides, if the middle cerebral artery would have been primarily occluded by a pre-existing thrombus, the flow would have been reduced making secondary migration and incorporation of fibers in the thrombus less likely. These fibers originated from unsealed gauzes, as confirmed by spectrometric analysis. These fibers were disseminated within the vascular set. It may therefore be presumed that some fibers were mixed in the saline and contrast and were directly injected in the guiding catheter. This kind of embolic complication may be underestimated, because histologic analysis of a thrombus is usually not achieved as this requires mechanical retrieval. Individual similar fibers may, however, occasionally be observed in arterial lumen of histologic specimens of tumors and arteriovenous malformations operated on after embolization. Silent thromboembolic events are frequently diagnosed on MR diffusion sequences after cerebral or cardiac angiography with an incidence 
62%.2 These lesions may be attributed to inadvertent injection of micro bubbles of air- or platelet-derived thrombi. The incidence of such lesions can be significantly reduced by using a filter placed at the proximal part of the catheter, as shown in a prospective randomized study.10 This kind of filter may also be used to prevent inadvertent injection of foreign material such as synthetic fibers.
Simultaneously, unsealed gauzes must be withdrawn, as well as gauzes that are likely to fragment and deliver synthetic fibers. Such kinds of fragmentation may be induced by maneuvers of catheterization such as the use of gauzes to manipulate hydrophilic guidewires. Torquing of hydrophilic guidewires may be facilitated by gauze, though this promotes drying of the hydrophilic coating with subsequent sticking of the gauze to the guidewire and detachment of fibers when removing the gauze.
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Acknowledgments
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Special thanks to Dr. Hubert L’Hôpital for his expert
review of the manuscript.
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References
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Received December 28, 2004;
accepted after revision February 17, 2005.
TOP
Abstract
Introduction