Embolic Microspheres Research Articles

Embolic Microspheres Within Ovarian Arterial Vasculature After Uterine Artery Embolization

Embolic Microspheres Within Ovarian Arterial Vasculature After Uterine Artery Embolization

Initial Experience with Use of Tris-acryl Gelatin Microspheres for Uterine Artery Embolization for Leiomyomata

To assess the safety and effectiveness of tris-acryl gelatin microspheres (Embospheres) in the treatment of leiomyomata by uterine artery embolization. This was a Phase I study of 30 patients with symptomatic leiomyomata. Each patient underwent ultrasound imaging and completed questionnaires regarding symptoms and health status at baseline and 3 and 6 months after treatment. Bilateral embolization was performed with use of tris-acryl gelatin microspheres. Summary statistics were used to characterize the demographic and procedure data. Paired t-tests were used to assess change in the severity of menstrual bleeding and health-related quality of life. Bilateral embolization was technically successful in all patients. Three months after treatment, menstrual bleeding was markedly improved as assessed by menorrhagia questionnaire (P <.0001) and menstrual calendar (P <.0001). Pelvic pain and discomfort was improved in 92% of cases. Physical component summary scores of the SF-12 also increased from baseline at 3 months (P =.02) and at 6 months (P =.01). Minor complications occurred in nine patients; there were no major complications. Although limited, this initial experience suggests that tris-acryl gelatin microspheres are an effective and safe embolic agent for the treatment of uterine leiomyomata.

Preparation and preclinical evaluation of bioresorbable hydroxyethylstarch microspheres for transient arterial embolization

Hydroxyethylstarch microspheres were prepared using an emulsion-heat denaturation technique. In order to achieve short-term embolization of arteries, several sizes of microparticles were needed and could be adjusted, within the range 25–400 μm, by the speed of agitation during the emulsion step. In vitro, degradation of microspheres in aqueous physiologic medium was preceded by swelling and occurred at rates inversely proportional to the temperature of preparation. In vivo in rabbits, the duration of embolization of the renal artery after selective catheterism also depended on the temperature of microsphere preparation, and could be easily adjusted within the range 5–45 min.

Tantalum-loaded polyurethane microspheres for particulate embolization: preparation and properties

Polyurethane microspheres having diameters in the range 150–1500 μm were prepared by condensation polymerization of toluene diisocyanate (TDI) with poly(tetramethylene glycol) (PTMG) of average mol wt 990 in an aqueous dispersion medium containing dioctyl sulphosuccinate (DOS) as the suspension stabilizer and 1,4-diazabicyclo[2.2.2]octane (DA6CO) as the catalyst for polymerization. Incorporation of tantalum powder in the polymerizing phase led to the formation of Ta-loaded microspheres with good radiopacity. Microspheres were surface-modified by grafting methacrylic acid (MA) on to them using γ-radiation from a Co 60 source. Conversion of the grafted MA into its sodium salt imparted hydrophilicity and slipperiness to the microspheres enabling them to pass through Teflon® catheters without obstructing the catheter lumen. These microspheres may find application as radiopaque embolization agents.

The Bronchial Arteries and Their Anastomoses in the Human Lung

Haemoptysis is a life-threatening complication of cystic fibrosis (CF). One treatment is bronchial artery embolisation (BAE) using embolic-microspheres (EMs). During BAE, pulmonary arteries can be seen on digital subtracted angiography while iodine containing contrast material injection is performed in the bronchial artery. This suggests that EMs could go from bronchial to nontarget pulmonary arteries. The aim was to evaluate if EMs could be found inside pulmonary arteries on lung explants after BAE in transplanted CF patients.Retrospective observational study including patients with CF who underwent lung transplantation and had previously needed BAE. Clinical, chest CT angiography, and angiographic data were reviewed from medical records. Pathology examination of lung explants was performed to analyze the EMs anatomical localisation.Eight patients were included between 2013 and 2015, four males with a mean age of 29 (19-45) years. All patients had bronchial artery hypertrophy on CT and bronchial-to-pulmonary artery shunting during BAE. On pathology examination, EM ≤800 µm were found in the pulmonary arteries in all patients and were responsible for distal branch occlusions. Two pulmonary infarcts were observed on CT angiography after BAE and confirmed histopathologically.EM migration from the bronchial to pulmonary arteries is a common occurrence after BAE in patients with advanced stage CF. Although BAE is a highly effective means of controlling haemoptysis in CF, studies on the optimal particle size are needed to preserve pulmonary artery circulation, because these results suggest that low size EMs could lead to nontarget embolisation.