Klemens H. Barth

Therapeutic embolization with long-term occluding agents and their effects on embolized tissues.

The effects of long-term occlusion of branches of the celiac and renal arteries were studied in 13 pigs, using isobutyl 2-cyanoacrylate (ibc), the Gianturco-Anderson-Wallace wool coil, and lvalon. IBC permanently occluded 2- to 8-cm lengths of both vessels, including their branches so that collateral circulation was not able to preserve the tissue supplied by the occluded artery. Gastric ulcers, splenic and hepatic infarcts, and large, sterile biliary cysts were observed on postmortem examination. Permanent occlusion was also observed with the wool coil and lvalon, but the pathological results were much less deleterious. The authors conclude that IBC is presently unsafe for use in branches of the celiac artery.

Long term follow-up of transcatheter embolization with autologous clot, oxycel and gelfoam in domestic swine.

Transcatheter embolization of the distal gastrosplenic artery as well as the distal right renal artery or one of its bifurcational branches was performed in 9 domestic swine. The animals were embolized with fresh autologous clot, oxycel or gelfoam in groups of 3. The embolic material was opacified with tantalum in several animals. At 4 months, none of the initial occlusions was sustained and recanalization without residuals was found in the left gastroepipolic artery with only one minor exception. Organized thrombi as sole vascular residuals regardless of embolic substance were found in both the terminal splenic artery as well as in the right renal artery distribution in various degrees together with infarcts in both organs. No trace of either oxycel or gelfoam remained, nor tissue reaction against either material. All 3 agents are therefore regarded equivalent in their long term effects and are not suitable for permanent vascular occlusion.

Pulmonary Arteriovenous Malformations: Physiologic Observations and Results of Therapeutic Balloon Embolization

Pulmonary arteriovenous malformations can result in severe hypoxemia and dyspnea. We measured pulmonary function, arterial blood gases, and hemodynamics in 10 patients with such malformations. Pulmonary-function tests were normal, but hypoxemia was associated with chronic hyperventilation at rest (mean, 12 liters per minute; mean carbon dioxide tension, 28 mm Hg). With exercise, ventilation increased more than expected for the level of carbon dioxide production. Balloon embolization of 58 of the 71 visible vascular malformations in the 10 patients resulted in an increase in arterial oxygen tension (43 vs. 64 mm Hg; P less than 0.001) and hemoglobin saturation (79 vs. 92 per cent; P less than 0.001). Nine patients had improved exercise tolerance. Forty-eight to 72 hours after correction of the hypoxemia, resting ventilation had decreased but was still above normal (mean, 9.3 liters per minutes; mean carbon dioxide tension, 29 mm Hg). We conclude that ventilatory responses in these patients are similar to those of people from sea-level areas who are acclimated to high altitudes and that dyspnea is due to inappropriately high levels of ventilation for a given workload under hypoxic conditions.

Embolotherapy with detachable silicone balloons: technique and clinical results.

Catheter techniques and early clinical results of therapeutic embolization with detachable silicone rubber balloons are described in 13 patients. Effective control of post-traumatic or spontaneously occurring hemorrhage or preoperative devascularization of neoplasms was achieved in 10 patients. Three additional patients, one each with pelvic arteriovenous malformation. pulmonary arteriovenous malformation, and hemangioendothelioma of the liver, were partially treated by balloon occulsion. Therapeutic embolization with detachable silicone balloons provides a method of long-term, extremely selective arterial occlusion with reduced risks from inadvertent embolization of neighboring circulations.

Hemodynamic significance of iliac artery stenosis: pressure measurements during angiography.

Peak systolic pressure gradients were obtained before and after vasodilatation in 42 patients (50 limbs) with arteriographic iliac artery stenosis of questionable significance. Patients were divided into three groups according to per cent narrowing of the iliac artery. Pressure gradients across the site of stenosis tended to be significant in patients with greater than 75% stenosis (greater than or equal to 20 mm Hg) but not in patients with less than 50% stenosis; patients in the middle group (50-75% stenosis) demonstrated a wide variance. Thus the arteriogram is not an accurate indicator of hemodynamically significant lesions, particularly in patients with 50-75% stenosis where pressure measurements are of greatest value. Variations in the aortic and femoral artery systolic peak pressure occurred following vasodilatation, indicating the importance of simultaneous pressure recording.

Balloon embolization for treatment of pulmonary arteriovenous fistulas.

Pulmonary arteriovenous malformations associated with hereditary hemorrhagic telangiectasia are often multiple and may enlarge with time.1 Shunt-induced hypoxemia is surgically correctable when the...

Transcatheter embolization with microfibrillar collagen in swine

Transcatheter embolization of the gastrosplenic and renal arteries was performed in 7 domestic swine with suspensions of microfibrillar collagen (MFC), a recently developed topical hemostatic agent. Embolized vessels remained occluded 2 days following embolization. Recanalization occurred by 14 days, although some occlusion in distal vessel persisted at 3 months. Pathologically a marked granulomatous arteritis was noted at 14 days which resolved by 3 months. Gastric ulcers or infarcts were present in two animals. The severe vasculitis and gastric pathology observed with MFC in this study would seem to preclude its use as a general embolic agent. It may be useful, however, in the preoperative embolization of neoplasms, especially in pediatric patients since its physical characteristics allow it to be easily injected through small diameter catheters.

Therapeutic embolization with detachable silicone balloons: Long-term effects in swine

Twenty-one embolizations were performed in 12 swine using a detachable silicone balloon-catheter system. In 11 embolizations, balloons were filled with 60% meglumine sodium diatrizoate (R-60); 30% meglumine sodium diatrizoate (R-30) was used in 10 embolizations. Serial radiographs were obtained to determine the duration of balloon inflation. Repeat angiography and autopsy examinations were performed three to six months following embolization. Eighty percent of balloons filled with R-30 were still inflated after 10 days, as opposed to 27% of the balloons filled with R-60. Balloons which remained inflated for more than 10 days caused permanent occlusion of the embolized arteries. The vessels were occluded precisely at the point at which the balloons were initially attached. Pathologically, the occluded vessels exhibited organized thrombi with minimal inflammation. Detachable balloons appear to be an effective, safe method of performing selective vascular occlusion in many circulatory systems. Careful control of the volume and osmolarity of the contrast medium used to inflate the balloons produces permanent arterial occlusion.

Treatment of traumatic renal arteriovenous fistulas by detachable silicone balloon embolization

A new technique of detachable balloon arterial embolization allowed non-operative occlusion of 2 patients with post-traumatic arteriovenous fistulas in the kidney. This approach was successful in controlling hemorrhage with minimal loss of renal tissue.

Therapeutic embolization with detachable balloons. Physical factors influencing permanent occlusion

Twenty-one detachable Silastic 3 balloon embolizations were performed in 12 swine. Late balloon rupture was associated in vivo with increased size and decreased radiopacity of the balloons. Variables affecting the permanency of occlusion by the Silastic balloons were the osmolarity of the contrast medium and the size of the balloon relative to its uninflated size.