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Biomedical subjects

A Ferko

Publications and source records attributed to A Ferko.

31 records · Page 2Linked to original sources
PubMed2000

[Preservation of venous grafts].

The objective of the work was to find an optimal preservation medium for short-term preservation of venous grafts which could be subsequently used to line metal stents. The external jugular vein of dogs (n = 15) was removed surgically, divided into portions and immersed into preservation media. For hypothermic preservation (+4 degrees C) solutions of Optisol (Chiron, USA), University of Wisconsin (Baxter, USA), Eurocollins (Fresenius, GFR) and saline (Bieffe Medital, Italy) were used. For normothermic preservation (+37 degrees C) in an atmosphere with 5% CO2 Dulbecc's medium for tissue cultures (Sigma, USA) was used. During hypothermic preservation the specimens were kept for 24 hours, 3 and 7 days, during normothermic preservation in Dulbecc s medium also for 24 hours, 3 and 7 days. The specimens were evaluated by light microscopy and raster electron microscopy. The results revealed that minimal changes on the endothelia of venous grafts occurred during normothermic preservation in Dulbecc's medium where after 7 days the endothelium did not become detached and the vitality of cells did not change. During hypothermic preservation the solution of Wisconsin University proved most suitable. By addition of 5% human albumin to this solution it proved possible moreover to reduce pyknosis of the endothelial cell nuclei. The specimens kept in saline displayed deformities of the nuclei, oedema and loss of endothelia incl. incipient oedema of the cellular wall already after 24 hours of hypothermic preservation. The authors consider the use of this solution unsuitable for preservation.

Animals↗
PubMed2000

[The spiral Z-stent with a knit dacron coating in endoluminal therapy of aneurysms of the abdominal aorta].

The authors present their own experience with construction, experimental testing and clinical application of endoluminal grafts. In the first part of the project, a new selfexpandable stentgraft was constructed on the basis of spiral Z stent. Spiral Z stent was covered by ultrathin polyester sleeve. Next, stentgraft was tested on animal model of abdominal aortic aneurysm. On the basis of experimental results endoluminal grafting of AAA was started in Czech Republic.

Aged↗
PubMed1999

[Complications of endovascular therapy of abdominal aortic aneurysms. Analysis and possible treatment].

The required result of correctly implemented endovascular treatment is bridging and elimination of the aneurysmatic sac from the blood flow in the aorta. Perfusion of the sac after release of the endovascular prosthesis is one of the most frequent complications of endovascular treatment. The majority of these perfusions is caused by a leak of the endovascular prosthesis at the site of the stented anastomosis, or more rarely by a collateral flow into the aneurysmatic sac or rupture of the endoprosthesis. Perfusion of the sac "endoleak" complicates endovascular treatment in cca 30%. During the postoperative period about half the perfusions recede spontaneously and about half require further treatment. Based on their own experience the author submits suggestions for the classification of leakage of endovascular prostheses with regard to the method of their treatment.

Aortic Aneurysm, Abdominal↗
PubMed1998

Dissection of the infrarenal aorta treated by stent graft placement.

Aortic dissection is primarily localized in the thoracic aorta. Dissection of the abdominal aorta is exceedingly rare, especially in the absence of a blunt abdominal trauma. Two cases of a primarily infrarenal aortic dissection were diagnosed by US, CT and angiography. The patients were treated by stent graft placement. The stent grafts were introduced via a femoral arteriotomy through the introducer sheath and were placed so that they occluded entry and reentry of aortic dissection. The stent graft placement caused total obliteration of a false channel of the dissection immediately after endoprosthesis deployment. The patients were followed-up by CT and angiography at 16 and 3 months after surgery without complication.

Aged↗
PubMed1997

Juxtarenal aortic aneurysm associated with a horseshoe kidney. Transfemoral endoluminal repair.

Horseshoe kidney complicates aortic aneurysm surgery in 1 of 200 cases. A patient with asymptomatic juxtarenal aortic aneurysm associated with a horseshoe kidney was successfully treated by stent graft placement. The kidney was supplied by 4 renal arteries. The proximal uncovered part of the stent graft was anchored across the origin of 1 renal artery. Another renal artery, arising from the aneurysmal sac, was occluded by the covered part of the stent graft. A kidney infarction developed postoperatively, which did not affect renal function or blood pressure. The patient was discharged from the hospital in good condition. Follow-up computed tomography and angiography confirmed a satisfactory result of the endovascular treatment.

Aged↗
PubMed1997

Juxtarenal aortic aneurysm: endoluminal transfemoral repair?

Endoluminal transfemoral repair of an abdominal aortic aneurysm by a stent graft placement requires a segment of the nondilated infrarenal aorta of at least 15 mm long for safe stent graft attachment. The possibility of endoluminal treatment of a juxtarenal abdominal aortic aneurysm with partially covered spiral Z stent was assessed in experiment and in three clinical cases. In the experiment, the noncovered spiral Z stent was placed into the abdominal aorta, across the origins of renal arteries and mesenteric arteries, in six dogs. In the clinical cases, a partially covered stent graft was attached in 3 patients with the juxtarenal abdominal aortic aneurysm (of the group of 12 patients with abdominal aortic aneurysm). The stent grafts were attached with proximal uncovered parts across the origins of the renal arteries. In experiment, the renal artery occlusions or stenoses were not observed 36 months after stent placement, and in clinic, 3 patients with the juxtarenal aortic aneurysm were successfully treated by stent graft placement. There were no signs of flow impairment into the renal arteries 14 months after stent graft implantation. This approach can possibly expand the indications for endoluminal grafting in the treatment of juxtarenal aortic aneurysms in patients who are at high risk for surgery.

Aged↗
PubMed1997

[Endovascular treatment of abdominal aortic aneurysms. Morphology of aneurysms as one of the deciding indicating factors].

Endovascular treatment of aneurysms of the abdominal aorta is based on intravascular bridging of the aneurysm using of an endovascular prosthesis. The prosthesis must be safely anchored above and below the sac of the aneurysm in the non-dilated artery. Therefore the indication of endovascular treatment depends on the morphology of the aneurysm. The objective of the work was to analyse the morphology of the aneurysm with regard to the possibility of endovascular treatment. The morphology of the aneurysm was evaluated with regard to the angiographic examination and examination by computed tomography. The following parameters were investigated: diameter and length of the proximal and distal neck, diameter of the sac in two planes, diameter and tortousity of the iliac arteries, tortousity of the infrarenal aorta. A total of 70 patients with aneurysms of the abdominal aorta were examined. The patients were divided into three groups according to the morphology of the aneurysm. I. infrarenal aneurysms not affecting common iliac artery (n = 20) 28.5%, II. infrarenal aneurysms affecting common iliac artery (n = 38) 54.2%, III. juxtarenal aneurysms regardless of the affection of common iliac arteries (n = 12) 17.1%. Of the total of 70 examined patients 24 (34.2%) with infrarenal aneurysm and 6 (8.57%) with juxtarenal aneurysm were suitable for endovascular treatment.

Angiography, Digital Subtraction↗
PubMed1996

[Polyester-covered spiral Z stent. Initial clinical experience with endovascular treatment of aortic aneurysms].

The authors present their initial clinical experience with endovascular treatment of an aneurysm of the abdominal aorta using of a polyester covered spiral Z stent. Since May 1995 they treated by the endoluminal route 13 patients with aneurysms of the abdominal aorta and 1 patient with thoracic aneurysm. In patients with a subrenal aneurysm (n = 10) the stent graft was anchored below renal arteries origins. In patients with a juxtarenal aneurysm (n = 3) the stent graft was anchored across the renal arteries origins. All patients were followed up by angiography, computed tomography and ultrasonography. In one patient with a subrenal aneurysm dislocation of the stent graft during implantation occurred. In the remaining patients it proved possible to exclude the aneurysm successfully. One patient with an juxtarenal aneurysm died 6 days after surgery. The cause of death was not associated with the aneurysm or surgery. In patients with juxtarenal aneurysms the authors did not observe changes of renal functions or occlusion of the renal artery in the course of 12 months.

Aged↗
PubMed1995

[Endoluminal grafts in the therapy of aneurysms of the abdominal aorta. Experimental results].

In 1991 a new method of treatment of aneurysms of the abdominal aorta was published. The method is based on bridging the sac of the aneurysm by an endoluminal graft. The graft is a stent provided with a special vascular prosthesis. The endoprosthesis is inserted by means of a catheter from arteriotomy of the common femoral artery. The objective of the submitted work was to test the possibility to use a polyester covered spiral Z stent in the treatment of aneurysms of the abdominal aorta. For experiments six dogs were used weighing 12-18 kg. In the experimental animals an artificial aneurysm of the abdominal aorta was induced. Then the authors interposed surgically into the subrenal section of the abdominal aorta a special polyester knitted prosthesis imitating the shape of the aneurysm. Two weeks after surgery angiography of the abdominal aorta was performed. After angiography the authors introduced from arteriotomy of the superficial femoral artery an endoluminal graft into the artificial aneurysm. The graft bridged the aneurysm on the inside and this led to thrombosis of the sac of the aneurysm. The state of the graft and aneurysm was checked sonographically and angiographically. The graft was successfully used in all experimental animals. Angiographic check-up examinations revealed that application of the graft led to immediate exclusion of the sac of the aneurysm. In two experimental animals the graft was inserted in an excessively cranial position. It did not bridge the aneurysm throughout its length. Reflux of blood in the distal part persisted and filled the residual cavity of the sac of the aneurysm.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

[A new approach to modelling prehepatic portal hypertension. Preliminary experimental results].

The generally used model of prehepatic portal hypertension is based on stenosis of the portal vein closely before it enters the hepatic parenchyma. The modelling is performed in the open abdominal cavity, which distorts the subsequent development of the modelled disease. The objective of the presented work was to elaborate a new approach to modelling of PPH where the rise of pressure in the portal vein will be separated from the surgery and the pressure in the portal circulation will rise gradually. Equipment for external compression of the portal vein was used in sic minipigs. The equipment comprised an inflatable balloon fitted to a silicone clamp. The balloon was connected by means of a polyurethane catheter to a chamber (ELLA Port CS). The compression set was attached before operation to the portal vein. The second cannula attached to the chamber (ELLA Port CS) was inserted into the lienal vein. Seven days after surgery the authors began to model portal hypertension percutaneously without laparotomy by inflating the balloon inserted into the portal vein. The value of the portal pressure seven days after the onset of modelling was 17.69 +/- 0.76 mm Hg, as compared with 9.0 +/- 1.3 mm Hg before modelling was started. In all experimental animals prehepatic portal hypertension was induced, as was proved angiographically and by direct assessment of the portal pressure.

Animals↗
PubMedDate not supplied

Intrahepatic portal vein branches after extrahepatic portal vein occlusion. Experimental study.

BACKGROUND/AIMS: Prehepatic portal hypertension caused by extrahepatic portal vein occlusion is a situation in which hepatocytes are not damaged by disease despite the fact that portal blood is unable to reach them due to portal vein occlusion. We explored the patency of intrahepatic portal vein branches after extrahepatic portal vein occlusion for the possibility of revascularization by splenoportal shunt. METHODOLOGY: Prehepatic portal hypertension was induced in 8 mini-pigs by external compression of the portal vein with a device consisting of an inflatable silicone balloon mounted on a silicone cuff and attached to a subcutaneous chamber. Another device consisting of cannula and a subcutaneous chamber was placed into the splenic vein for portal pressure monitoring and portal venograms. Both devices were placed during laparotomy with their chambers positioned subcutaneously. Portal vein compression was initiated one week later and was accomplished in two steps. Extrahepatic portal vein occlusion and the patency of intrahepatic portal vein branches were confirmed by direct portal venography. Alteration of the intrahepatic portal bed was examined at necropsy after 4 weeks, checking for the presence of occlusion or thrombosis. RESULTS: Portal vein occlusion was achieved in 5 animals, while severe stenosis was demonstrated in the remaining three. Portal venograms demonstrated patency of the lobar portal vein branches filled by hepatopetal collaterals around the occluded portal vein. All intrahepatic branches were free of thrombus at gross examination. CONCLUSIONS: In the absence of the hepatic parenchymal disease, lobar intrahepatic portal vein branches remain patent despite truncal portal vein occlusion and are supplied by rapidly developed hepatopetal collaterals.

Animals↗
PubMedDate not supplied

Extrahepatic portal venous laceration in TIPS treated with stent graft placement.

Three cases of intraperitoneal bleeding from extrahepatic portal vein laceration were observed in a series of 104 patients with TIPS. In one patient, bleeding continued after Wallstent placement and the patient died during an emergency laparotomy. Bleeding was stopped in the other two patients by using a stent graft rather than a regular stent. One shunt remained patent and outflow stenosis developed in 3 months. The other shunt thrombosed in 5 months. Both shunts were fully reopened.

Adolescent↗