Delayed Complications Due to Polymer Coating Embolism after Endovascular Treatment

Foreign Body Granuloma After Embolization of Internal Iliac Artery Aneurysm Using N-Butyl-2-Cyanoacrylate: A Case Report

Foreign body granulomas following endovascular treatment are rare complications and are mostly reported in the brain or cutaneous vascular tissues. To the best of our knowledge, no study to date has reported on foreign body granulomas in the abdomen after injection of N-butyl-2-cyanoacrylate (NBCA)-lipiodol mixture into the abdominal arteries. This study reports a case of foreign body granuloma that appeared 12 months after the embolization of a right internal iliac artery aneurysm using an NBCA-lipiodol mixture, which posed challenges in differentiation from malignant tumors. We present a 77-year-old man who underwent embolization of a right internal iliac artery aneurysm and open surgical repair of an abdominal aortic aneurysm. A contrast-enhanced CT performed 12 months postoperatively revealed a right-sided retroperitoneal mass surrounding the iliopsoas muscle. The mass contained multiple, small, hyperdense areas, suggesting the migration of the NBCA-lipiodol mixture casts from the embolized right internal iliac artery aneurysm. The differential diagnosis included foreign body granuloma, lymphoma, and sarcoma. A biopsy of the lesion revealed a granuloma with various stages of inflammation, no hemosiderin deposition, multinucleated giant cells, and foam cells containing fat, and was diagnosed with a foreign body granuloma. Special staining for microorganisms revealed no findings suggestive of infection. Because the patient was asymptomatic, no treatment was administered. Contrast-enhanced CT at 24 months postoperatively showed shrinkage of the mass, with no change in size noted at 48 months postoperatively. This report highlights a foreign body granuloma that mimicked malignant tumors. Extravascular migration of the NBCA-lipiodol mixture casts likely contributed to granuloma formation. Radiologists should consider foreign body granulomas after embolization using NBCA into the abdominal arteries.

Fragmentation of Hydrophilic Guidewire Coatings During Neuroendovascular Therapy

PURPOSE

Cerebral polymer coating embolism from intravascular devices may cause serious complications after endovascular therapy (EVT) for neurovascular diseases. Although polymer fragments are often created during endovascular procedures, exact mechanisms of their formation, especially if of small size, are largely unknown.

METHODS

In this study eight microguidewires (Asahi Chikai 200 cm (Asahi Intecc, Aichi, Japan), Asahi Chikai Black (Asahi Intecc), Fathom™ (Boston Scientific, Marlborough, MA, USA), Hybrid (Balt Extrusion, Montmorency, France), Radifocus® Guide Wire GT (Terumo, Leuven, Belgium), Synchro2® (Stryker, Kalamazoo, MI, USA), Transend™ EX (Boston Scientific), and Traxcess™ (MicroVention®, Tustin, CA, USA)) frequently used during EVT were investigated ex vivo using their dedicated metal or plastic insertion tools to assess for coating delamination after backloading of the microguidewires.

RESULTS

Backloading caused damage to the coating of all microguidewires especially when the main body of the guidewires was bent in front of the insertion tool. All studied microguidewires produced microscopic filamentous and/or band-like coating fragments. Few larger irregular fragments were observed, but also very small fragments measuring 1-3 µm in diameter were found. Spectroscopic measurements of polymer fragments and microguidewires identified various polymers.

CONCLUSION

Backloading of polymer-coated microguidewires during EVT should be minimized if possible. More stable hydrophilic coatings on microguidewires and less traumatic insertion tools are desirable.

Cerebral foreign body granulomas after mechanical thrombectomy: Two case reports and a review of the literature

OBJECTIVES

A foreign body granuloma after an endovascular intervention is a rare complication. Some cases of foreign body granulomas, especially after coil embolization, have been reported. However, only four cases of foreign body granulomas after mechanical thrombectomy (MT) have previously been reported. The current study reports two cases of post-MT foreign body granulomas, including a biopsy-proven case.

MATERIAL AND METHODS

Case 1: A 73-year-old woman presented with complete occlusion of the right middle cerebral artery. Cerebral angiography and MT were successfully performed with improvement in clinical symptoms. Left hemiparesis and a disturbance in attention appeared after discharge and progressed slowly. She was re-admitted to our hospital 120 days after cerebral infarction owing to foreign body granulomas diagnosed on biopsy. Case 2: A 78-year-old man presented with occlusion of the left cervical internal carotid artery and the left middle cerebral artery. Cerebral angiography, percutaneous transluminal angioplasty, and MT were successfully performed. On the 34th day, he experienced progressive consciousness disorder because of foreign body granulomas. Both cases were successfully treated with steroid therapy.

RESULTS

MRI after steroid treatment showed the disappearance of most nodular lesions and improvement of the encephalopathy.

CONCLUSIONS

The cause of the granuloma may be an allergic reaction to the hydrophilic polymers that peel from endovascular devices. Steroid therapy is an effective treatment; therefore, neurologists should consider this complication when neurological symptoms or signs on image appears or worsens. A reliable diagnosis is important for prompt treatment.

Embolized Hydrophilic Coating Polymers Found in Left Ventricular Assist Device Apical Core Specimen

Left ventricular assist devices are increasingly used in patients with advanced heart failure. Gross and histologic evaluation of myocardial apical core specimens, extracted during device placement, can provide important insights. Herein, we describe a case of hydrophilic polymer embolization with associated foreign-body giant cell reaction discovered during apical core evaluation. (Level of Difficulty: Advanced.)

Polytetrafluoroethylene coating fragments during neuroendovascular therapy: An analysis of two damaged microguidewires

Cerebral polymer coating embolism from intravascular devices represents a potentially serious complication to endovascular therapy (EVT). We report two cases of neuroendovascular treatment where filamentous polymer fragments were noted possibly due to damage of the surface coating during manipulation and backloading of microguidewires. As the exact origin of the debris was initially not known, microguidewires and fragments were examined with light microscopy, stereomicroscopy, scanning electron microscopy and attenuated-total-reflection Fourier transform infrared spectroscopy. Fragments consisted of polytetrafluoroethylene and silicone oil stemming from the proximal shaft of a standard microguidewire. To our knowledge, this is the first report of polytetrafluoroethylene coating fragments created during EVT. Future studies should assess the mechanism of polymer coating delamination and its potential consequences during EVT including inadvertent fragment migration into the cerebral circulation.

Delayed Multiple Non-ischemic Cerebral Enhanced Lesions After Endovascular Therapy For Left Internal Carotid Aneurysm: A Case Report

INTRODUCTION

Endovascular therapy (EVT) for intracranial arterial aneurysms is depicted with several complications. Very recently, delayed non-ischemic cerebral enhanced (NICE) lesions have been identified as a rare complication associated with EVT. This complication always stands a higher chance of being missed in asymptomatic patients. We report a case of multiple NICE lesions in a known chronic hepatitis B infection and chronic gastritis patient with left internal carotid aneurysm (ICA) treated with detachable coils.

CASE PRESENTATION

A 52 years old female with left ICA was treated with detachable coils via the endovascular route. Three weeks after the operation, she presented with numbness of her right limbs which was persistent and waked her up from sleep each night. She admitted skin allergies after wearing metals except for gold and silver since childhood. MRI revealed multiple abnormal lesions in the left temporal lobe, hippocampus, insula, and parietal lobe and some perifocal edema which were consistent with the diagnosis of delayed NICE lesions.

CONCLUSION

It is very important to report the occurrences of these lesions in literature because of their allergic origin. We advocate that allergy to metals especially those used in coating endovascular equipment should be evaluated before every EVT for intracranial aneurysms.

Medical treatment of polymeric cerebral granulomatous reactions following endovascular procedures

BACKGROUND

Endovascular procedures are standard of care for an increasing range of cerebrovascular diseases. Many endovascular devices contain plastic and are coated with a hydrophilic polymer which has been rarely described to embolize, resulting in distal granulomatous inflammatory lesions within the vascular territory.

METHODS

We reviewed three cases of cerebral granulomatous reactions that occurred after endovascular intervention for internal carotid aneurysms. The patient procedure details, presentation, relevant investigations, and treatment course are described. We also provide a literature review on endovascular granulomatous reactions.

RESULTS

These three cases represent the largest biopsy proven series of cerebral granulomatosis following endovascular intervention. We highlight the variable clinical presentation, with two of the three cases having an unusually delayed onset of up to 4 years following the intervention. We show the characteristic histological findings of granulomatous lesions with foreign body material consistent with a type IV reaction, radiological abnormalities of enhancing lesions within the vascular territory of the intervention, and the requirement of prolonged immunosuppression for maintenance of clinical remission, with two of the three patients requiring a corticosteroid sparing agent. In comparison with the available literature, in addition to hydrophilic gel polymer, we discuss that plastic from the lining of the envoy catheter may be a source of embolic material. We also discuss the recommendations of the Food and Drug Administration and the implementation of novel biomaterials for the prevention of these reactions in the future.

CONCLUSIONS

There is a need for increased awareness of this severe complication of cerebral endovascular procedures and further longitudinal studies of its prevalence, optimal management and preventative measures.