Biomedical subjects

I Szikora

Publications and source records attributed to I Szikora.

6 recordsLinked to original sources

PubMed2006

Endovascular treatment of intracranial aneurysms with parent vessel reconstruction using balloon and self expandable stents.

BACKGROUND AND PURPOSE: To assess the feasibility and results of parent vessel stent reconstruction with balloon expandable and self-expandable stents in the treatment of intracranial aneurysms. METHODS: In a total of 18 aneurysms balloon expandable (group A) and self expandable (group B) stents were used in 9 cases each. Stent implantation alone was used in 3 cases, and additional coil packing in the other 15. RESULTS: Stents were successfully deployed in 8 out of 9 in group A and in 9 out of 9 cases in group B. Nearly complete occlusion was achieved in all but one case. At 3 or 6 months stable occlusion was found in 4 group A and 2 group B patients, progressive thrombosis in 3 cases in both groups, and recanalisation in 1 case in group B. Late follow up at 1-4 years demonstrated one progressive thrombosis one recanalisation and 1 stable occlusion in 3 group A, and 2 stable occlusions in 2 group B. patients. Complications included one aneurysm perforation in group A, one in-stent thrombosis and a distal arterial perforation in group B and one groin hematoma in both groups. CONCLUSION: Stent reconstruction of intracranial arteries harbouring aneurysms is feasible and may result in aneurysm thrombosis without coil packing in some cases. Self expanding stents seem to provide a higher rate of success. Aggressive antiplatelet treatment increases the risk of hemorrhagic complications.

Adult↗

PubMed2006

Histopathologic evaluation of aneurysms treated with Guglielmi detachable coils or matrix detachable microcoils.

BACKGROUND AND PURPOSE: The purpose of this study was to evaluate the degree of organization and fibrocellular tissue development in aneurysms treated with bare platinum or biologically active microcoils. METHODS: Twelve aneurysms were removed at autopsy between 1-18 days and another 2 between 2-3 months posttreatment. Four aneurysms were surgically removed between 6 months and 3 years following treatment. One aneurysm removed at 8 days and another at 6 months were treated with bioactive (Matrix) coils; the other 16 with bare platinum (Guglielmi detachable coils; GDCs). All specimens were embedded in plastic, stained with hematoxilin-eosin and elastin and examined by light microscopy. RESULTS: All specimens removed within 3 weeks demonstrated intra-aneurysmal thrombus, without signs of organization or fibrotic tissue formation over the neck regardless of the type of coils used. In the GDC-treated aneurysms, evidence of early thrombus organization was observed within 2-3 months, and completed yet imperfect fibrocellular reaction together with residual thrombus at 2-3 years. In the Matrix-treated specimens, the aneurysm cavity was completely filled with granulation tissue corresponding to still ongoing fibrocellular reaction at 6 months, including newly formed blood vessels, smooth muscle cells, and collagen deposition without signs of residual thrombus. CONCLUSIONS: Our results indicate that in aneurysms treated with bare platinum coils thrombus organization does not occur until late after treatment and may remain imperfect for years. In one aneurysm studied 8 days following treatment with Matrix coils, no difference was noted compared to aneurysms treated with bare platinum coils. In another aneurysm examined 6 months following packing with Matrix coils, the histologic changes support the hypothesis that the biologically active polymer may accelerate aneurysm healing.

Adolescent↗

PubMed1997

Rapid saccular aneurysm induction by elastase application in vitro.

OBJECTIVE: To develop a new saccular aneurysm model in vitro using elastase to study aneurysm initiation, growth, and rupture and to create a new in vivo aneurysm model to test endovascular therapies. METHODS: Seventeen common carotid arteries excised from freshly killed pigs and sheep were treated with seven different methods of elastase delivery. The arteries were mounted in a saline-filled flow chamber. They received pulsatile flow for 48 hours, or until the resulting aneurysms ruptured. Changes were continuously monitored with video camera recordings and validated with histological sections. RESULTS: All eight arteries treated topically, either on the intimal or on the adventitial surface, with elastase concentrations greater than 1 U/mm2, developed saccular aneurysms; five of them ruptured within 48 hours. All four arteries treated with surface concentrations of 0.1 U/mm2 via microcatheter infusion into the lumen developed fusiform aneurysms. None of the arteries that received surface concentrations less than 0.1 U/mm2 developed aneurysms. Histological sections revealed a reduced number of cellular element in a stretched collagen matrix at the dome of the saccular aneurysms. CONCLUSION: After empirically testing several methods of elastase delivery, we were able to induce saccular, bifurcation-type aneurysms in animal arterial specimens. These aneurysms are histologically similar and more authentic than surgical models. The procedure is easy and reproducible. Our results suggest a possible enzymatic role in aneurysm formation and highlight the dramatic effects of selective arterial elastic damage. Also, the rapid growth of our experimental aneurysms may reflect the speed of the natural process.

Aneurysm, Ruptured↗

PubMed1997

Initial experience with collagen-filled Guglielmi detachable coils for endovascular treatment of experimental aneurysms.

PURPOSE: To evaluate the effectiveness of Guglielmi detachable coils (GDCs) filled with collagen threads in the permanent treatment of experimental aneurysms. METHODS: Seventeen side-wall aneurysms were surgically constructed in the canine common carotid artery; six were treated with conventional GDCs and 11 with collagen-filled GDCs. One aneurysms was removed at 1 week, the others were studied by digital subtraction angiography for a period of 8 to 12 weeks. Longitudinal sections of all aneurysms were examined by light microscopy. RESULTS: Angiograms obtained throughout the follow-up period showed no significant difference between aneurysms treated with conventional GDCs and those treated with collagen-filled GDCs. Light microscopy revealed a dense meshwork of newly formed collagen and fibroblasts near the collagen-filled GDCs, whereas a loose cellular meshwork surrounded the conventional GDCs at 8 and 12 weeks after treatment. CONCLUSION: Collagen threads within GDCs do not noticeably improve angiographic treatment of experimental aneurysms; however, these threads did induce local proliferation of fibroblasts and production of collagen within the aneurysmal cavities.

Aneurysm↗

PubMed1996

Endovascular treatment of experimental aneurysms with liquid polymers: the protective potential of stents.

Liquid polymers have previously been used to treat experimental and human aneurysms. However, the delivery of a liquid embolic material into the cerebral circulation involves a high risk of irreversible vessel occlusion and stroke. To evaluate methods for the safe and effective treatment of experimental aneurysms with liquid polymer injection, we tested four different techniques to deliver cellulose acetate polymer (CAP) or N-hexyl-cyanoacrylate into canine side-wall carotid artery aneurysms. The animals were observed for 1 to 10 weeks after treatment. Two aneurysms were treated without protection of the distal circulation, one with CAP and another with N-hexyl-cyanoacrylate. In four cases, an angioplasty balloon was inflated within the parent artery during endosaccular injection of CAP. In two of these cases, the balloon was placed adjacent to the aneurysm orifice, resulting in simultaneous occlusion of both the aneurysm and the parent artery, and in the other two cases, the balloon was positioned proximal to the aneurysm, resulting in temporary flow arrest. Three aneurysms were treated with either CAP or N-hexyl-cyanoacrylate after implantation of a balloon-expandable tantalum stent within the parent artery across the aneurysm orifice. Complete angiographic obliteration was achieved in all but one case. One aneurysm ruptured. Another partially occluded aneurysm reopened 10 weeks after treatment. In all cases treated without stents, distal migration of the polymer resulted in either stenosis or occlusion of the parent arteries. The combination of stent implantation and polymer injection resulted in permanent aneurysm occlusion without detectable polymer migration. An intravascular stent deployed within the parent artery across the aneurysm orifice acted as a safety net during endosaccular polymer injection by allowing blood to flow from the aneurysm cavity while preventing distal migration of liquid polymer.

Aneurysm↗

PubMed1994

Combined use of stents and coils to treat experimental wide-necked carotid aneurysms: preliminary results.

PURPOSE: To develop a new technique to treat wide-necked side-wall aneurysms, combining the implantation of intraarterial stents with the endosaccular placement of coils. METHODS: Bilateral side-wall aneurysms were surgically created on the carotid arteries of four dogs. In each animal, Guglielmi detachable coils were introduced into one of the aneurysms after implantation of a balloon-expandable Strecker stent within the parent artery, adjacent to the aneurysm orifice. The contralateral aneurysms were treated with coils alone. RESULTS: In two dogs, one of the stented and both nonstented aneurysms remained partially open for 4 weeks after subtotal packing with coils. In another two dogs, tight aneurysm packing with coils resulted in complete occlusion of all four aneurysms. Bulging of the coil mass resulted in 30% to 75% narrowing of the nonstented parent arteries. At 4 and 5 weeks, significant stenosis resulting from reactive hyperplasia was observed in all stented carotid arteries. CONCLUSION: Based on these preliminary results, we conclude that Guglielmi detachable coils can be introduced into an aneurysm cavity through Strecker stents. The stents allow tighter packing of wide-necked aneurysms by preventing coils from migrating or bulging into the parent arteries.

Aneurysm↗