This study presents the technology of developing a universal stent graft for endovascular treatment of aneurysms and aortic dissection of various localizations, without considering the vessel diameter. A self-expanding nitinol stent was used as the frame of the main trunk of the stent graft. During the study, several variants of the aortic linear graft were manufactured and tested. The optimal stiffness and diameter of the nitinol wire were selected based on the results. When creating a bifurcation module, special attention was paid to simplifying the positioning and intravascular assembly of the structure. Implantable modules have been developed for the prosthetics of the main branches of the aorta. Dacron, optimal in terms of fiber structure, was chosen as the material of the woven shell of the graft. Linear extensibility, compactness of the pile, and tensile strength during fenestration were evaluated. To determine the heparin-controlled surgical porosity, experimental samples of stent grafts were tested on a stand simulating arterial blood flow. The wall material of the developed device had a heparin-controlled surgical porosity of 50150 mL/min/cm2 at 120 mm Hg with the possibility of maintaining a controlled endolic. The graft wall created a pressure gradient of no more than 3 mm Hg, and the flow velocity indicators were quite sufficient for adequate perfusion of vital organs. After the inactivation of heparin, blood permeability became zero. The implantation technique of the developed product was implemented on a silicone aortic phantom simulating aneurysm expansion with and without dissection. The phantom contour was filled with a solution simulating the rheological properties of native blood. Pulsating blood flow was simulated using a perfusion pump. Under X-ray control, a stent graft was installed on five large biological samples (sheep). Implantation was performed in the aortic arch with prosthetics of the brachiocephalic trunk and the suprarenal aorta with prosthetics of the visceral branches. With the experiment, we hope that the result will allow us to minimally invasively help patients suffering from aneurysms of any localization.

A technique and a prototype of a mobile test bench for conducting experiments on uniaxial compression of biological tissue samples have been developed. The test bench consists of high-precision scales, an electronic caliper with modified grips, and a video camera. With the help of the test bench, a series of experiments (120 in total) was carried out to determine Young's modulus of atherosclerotic plaques and vascular walls removed from the human body no later than a few hours. A database of plaques and artery walls' mechanical characteristics, as close as possible to their real strength properties, has been formed. In addition, regression dependencies linking Hounsfield units and Young’s moduli of atherosclerotic plaques were constructed. The uniaxial compression technique has been verified on the Instron 3342 universal testing machine. Also, to demonstrate the applicability of the developed technique and test bench for uniaxial compression of hard tissues, experiments were conducted with 14 samples of bovine spongy bone.

The sequence of determining determination of the critical value of blood pressure for the occurrence of dissection of atherosclerotic intima of the internal carotid artery according to the experimental study. Atherosclerotic lesion of the brachiocephalic arteries was modeled on a vascular silicone phantom of the carotid arteries, in which the surgical material (intact annular area of atherosclerotic intima with plaque), obtained after eversion endarterectomy in a patient with atherosclerotic lesions, was placed and fixed in the region of the mouth of the internal carotid artery. A total of 30 models were created. To determine the critical values of the pressure on the intima with the plaque, at which it ruptures, balloon catheters were used, controlling the pressure with a manometer. The results were compared with the preoperative data of ultrasound and computed tomography examinations of patients. Dissection of the intima in the area of the plaque occurred in 6 cases at a pressure of 150180 mm Hg; in 9 cases at 180200 mm Hg, in 3 cases at a pressure of more than 200 mmHg, in 12 when exposed to more than 300 mm Hg. All patients, whose intima ruptured at a pressure of less than 200 mm Hg, had a fluid component of the plaque on preoperative examination, and in 6 patients, the critical pressure on the plaque was 150 mm Hg., there was also a thinned "cover" of the plaque. In the rest of the cases, the plaques were stable without a liquid component. Dissection of the intima in these cases did not occur when the exposure value was more than 300 mm Hg. The presence of a fluid component in an atherosclerotic plaque of the carotid artery in combination with a thinned cover of the plaque indicates the extreme danger of its destruction and embolism during a hypertensive crisis. The degree of stenosis of the carotid artery was found to be a less significant risk factor for unstable plaque rupture than the presence of a fluid component.

The paper describes a case of the rare complication of orthotopic liver transplantation - steal syndrome successfully controlled by interventional radiology techniques.

Objective: to assess the first results of transjugular intrahepatic portocaval shunting (TIPS) as a technique for preventing portal hypertension complications in patients in the period of waiting for a donor liver.Subjects and methods. TIPS was performed in 6 patients on the list of waiting for orthotopic liver transplantation (OLT). The indications for TIPS were current (n=1) or high-risk recurrent hemorrhages from the esophageal varices and stomach (n=4) and diuretic-resistant ascitis (n=1).Results. TIPS was successfully carried out in all the patients. The portovenous gradient was reduced by 2—3 times (to 9—12 mm Hg). A further follow-up revealed recurrent varicose hemorrhage or ascitis in none patients. Doppler study indicated that the shunt showed a good function. OLT was successfully made in 3 patients 2, 8, and 19 months after TIPS; one female patient had been waiting for OLT for 5 months; 2 patients died from sepsis and hepatic failure following 1 and 5 months, respectively.Conclusion. The first results suggest that in patients with hepatic cirrhosis complicated with portal hypertension, TIPS can be regarded as a safety bridge while waiting for a donor liver.

The paper describes a case of the rare complication of orthotopic liver transplantation - steal syndrome successfully controlled by interventional radiology techniques.

The article analyzed the results of surgical treatment of 140 patients with surgery of abdominal aortic aneurism. The comparison group consisted of 80 patients with aortic aneurism more than 4,5 cm, who didn’t undergo surgery. The conventional method of Khardi-Pokrovskiy resection was complemented by a number of surgical methods in these cases. The results of surgery were improved due to application of these methods. All the patients (100%), who didn’t undergo surgery, passed away during 5 years, though 70% of them died because of aneurysm rupture. The early postoperative lethality was 5% in the main group, but 5-year survival was 81%.

The authors analysed the immediate outcomes of implanting stents with bioactive coating in treatment of patients presenting with atherosclerotic lesions of the superficial femoral artery. Over the period from January 2014 to December 2015, endovascular interventions on the superficial femoral artery were carried out in a total of 18 patients (mean age 61.3±9.2 years). The implants inserted were stents with bioactive coating based on titanium oxinitride, measuring 6 to 8 mm in diameter and being from 50 to 200 mm long. Prior to operation and 7 days after implantation of the stent, the immunoenzymatic assay was used to determine the level of nitrogen nitric oxide (NO) in blood. The stents' patency was assessed by the findings of ultrasound duplex scanning performed at 30 days, and then 6 and 12 months after the intervention. There were no complications either during the operation or in the early postoperative period. An increase in the ankle-brachial index was observed in all patients: with the average value prior to treatment amounting to 0.4±0.3 and equalling 1.1±0.2 after stenting (p<0.0001). Normalization of the blood NO level was revealed (was noted to normalize): the mean value prior to operation amounted to 18.9±2.3 µmol/L and after operation to 28.9±4.1 µmol/L (p<0.05). Primary patency rate of the stents was 100% at 30 days, 94.5% (1 occlusion) at 6 months and 88.8% (1 restenosis and 1 occlusion) at 12 months. The patients with occlusion or restenosis were subjected to repeat endovascular interventions, with restoration of patency of the construction (with the construction's patency restored). By now all the 18 patients show preserved patency (currently patency was preserved) of lower-limb arteries, with no evidence of restenosis in the zones of operations. It was concluded that using stents with bioactive coating based on titanium oxinitride results in normalization of the level of NO in blood, which may contribute favourably to prolongation of the period of functioning of endovascular constructions. The first data concerning primary patency of stents of this type make it possible to count on betterment of the remote results of treatment of patients presenting with atherosclerotic lesions of the superficial femoral artery.

The article presents an analysis of treatment results of 91 patients with iliac-femoral segment artery occlusion at the period from 2008 to 2014. Patients were divided into 2 groups: main group (n=30) consisted of patients who undergoing a half-closed loop endarterectomy with following implantation of stent-grafts in this area and control group (n=61) had patients whom were performed routine half-closed loop endarterectomy. The II degree of ischemia of lower extremities was in 88 (96,7%) patients and III degree had 3 (3,3%) patients. The areas of abnormalities of intravascular pattern were detected in 100% of cases in intraoperative angiography. They were modified using stent-grafts. A primary vascular patency was 100% in the first group and it numbered 65% in the second group during 5 years. The intraoperative angiography control with stent-graft implantation to the area of endarterectomy allowed reliable improvement of treatment results.

The authors analyzed the single-center experience of treatment of 72 patients with abdominal aortic aneurisms and severe accompanied pathology. The aneurisms were repaired by stentgrafts. All the patients had abdominal aortic aneurisms with the diameters from 41 to 84 mm against the background of severe somatic pathology. It was a contraindication to planned open surgery. An installation of stent-graft was successful in all 72 follow-ups. It wasn’t necessary to use a conversion to open surgery. The follow-up period consisted of 44,6±2,1 months. Control ultrasound and computer tomography studies hadn’t revealed an increase of aneurism sack sizes or «leakages». A reduction of abdominal aortic aneurism sizes was noted in 37 patients on 4-5% during first year after operation. The stentgraft implantation extends the possibilities of abdominal aortic aneurism treatment for patients from a high surgical risk group.