Development and integration of photonic Doppler velocimetry as a diagnostic for radiation driven experiments on the Z-machine.

Plasma density measurements are key to a wide variety of high-energy-density (HED) and laboratory astrophysics experiments. We present a creative application of photonic Doppler velocimetry (PDV) from which time- and spatially resolved electron density measurements can be made. PDV has been implemented for the first time in close proximity, ∼6 cm, to the high-intensity radiation flux produced by a z-pinch dynamic hohlraum on the Z-machine. Multiple PDV probes were incorporated into the photoionized gas cell platform. Two probes, spaced 4 mm apart, were used to assess plasma density and uniformity in the central region of the gas cell during the formation of the plasma. Electron density time histories with subnanosecond resolution were extracted from PDV measurements taken from the gas cells fielded with neon at 15 Torr. As well, a null shot with no gas fill in the cell was fielded. A major achievement was the low noise high-quality measurements made in the harsh environment produced by the mega-joules of x-ray energy emitted at the collapse of the z-pinch implosion. To evaluate time dependent radiation induced effects in the fiber optic system, two PDV noise probes were included on either side of the gas cell. The success of this alternative use of PDV demonstrates that it is a reliable, precise, and affordable new electron density diagnostic for radiation driven experiments and more generally HED experiments.

[Prosthetic repair of the aorta with a cadaveric homograft for infection of bifurcated synthetic vascular prosthesis]. / Protezirovanie aorty trupnym gomograftom pri infitsirovanii bifurkatsionnogo sinteticheskogo sosudistogo proteza.

Infection of arterial vascular grafts is a rare but utterly severe complication in vascular surgery. Therapeutic policy in patients with graft infection has not been standardized, to be determined individually. One of the variants of surgical treatment is considered to be repeat aortic repair using a cadaveric graft. Presented in the article is a clinical case report concerning a 60-year-old male patient previously subjected to aortofemoral bifurcation bypass grafting with stage IV ischaemia of lower limbs according to the Pokrovsky-Fontaine classification. In the early postoperative period the events of critical ischaemia were not arrested. Due to the presence of a block of the femoropopliteal segment, as the second stage 3 days after the primary operation, the patient underwent autovenous femoropopliteal bypass grafting with a reversed autovein above the knee-joint fissure. The clinical course of critical ischaemia of the limb was relieved. During subsequent 8 months of follow up his state remained stable. Eight months after the primary operation he developed purulent discharge from the postoperative scar on the left femur. In the setting of the Purulent Surgery Department, the patient was emergently subjected to opening and drainage of the abscess of the postoperative scar. On the bottom of the wound there was a freely lying branch of a synthetic vascular prosthesis. Computed tomography revealed infection of the entire synthetic prosthesis and aneurysms of distal anastomoses. Given extremely high risk for the development of arrosive haemorrhage, a decision was made on operative treatment - repeat prosthetic repair of the abdominal aorta with a cadaveric allograft. At the Vascular Department of the Clinic of Faculty Surgery, laparotomy was performed, with removal of the infected graft, followed by debridement of the retroperitoneal space and repeat aortofemoral bifurcation prosthetic repair of the abdominal aorta with a cadaveric allograft. The wound healed with first intention. There was no evidence of infectious process relapse. The patient was discharged on postoperative day 15 in a satisfactory condition. The duration of follow up amounted to 6 months. The control examination showed that the pain-free walking distance was 500 m. Doppler ultrasonography demonstrated that the graft was functioning, with no signs of either anastomotic aneurysms or suppuration of the retroperitoneal space.

[Surgical treatment of a patient with a ruptured Crawford type III thoracoabdominal aortic aneurysm]. / Khirurgicheskoe lechenie bol'nogo s razryvom torakoabdominal'noi anevrizmy III tipa po E.S. Crawford.

Described herein is a clinical case report regarding surgical treatment of a patient presenting with a ruptured Crawford type III thoracoabdominal aortic aneurysm. The patient was subjected to prosthetic repair of the thoracoabdominal aorta by the Coselli technique, as well as reduction of the aneurysmal sac in the thoracic and abdominal portions according to the authors' technique. The operation was carried out with neither connecting the patient to a heart-lung machine nor use of pharmacological protection of the visceral organs. The sutures were removed on postoperative day 12 and the patient was discharged from hospital in a satisfactory condition.

[Optimal method of reconstruction in patients with pathology of the 1st segment of the subclavian artery]. / Optimal'nyi metod rekonstruktsii u patsientov s patologiei 1 segmenta podkliuchichnoi arterii.

The study enrolled a total of 318 patients presenting with lesions of the 1st segment of the subclavian artery and the clinical course of vertebrobasilar insufficiency. All patients prior to admission had been receiving the best course of medicamentous therapy under the supervision of a neurologist for more than 6 months but with no significant clinical improvement. According to the type of the reconstructive operation on the 1st segment of the subclavian artery, all patients were subdivided into three groups. Group I included 48 (15.1%) patients presenting with occlusion of the subclavian artery and undergoing carotid subclavian bypass grafting. Group II consisted of 224 (70.4%) patients who underwent endarterectomy from the subclavian artery and its transposition to the common carotid artery. Group III was composed of 46 (14.5%) patients presenting with local stenosis of the subclavian artery and subjected to stenting of the 1st segment of the subclavian artery. The main criteria for assessment of the results were patency of the zone of reconstruction and clinical improvement of the patient after surgery. RESULTS: Clinical improvement in the early postoperative period was observed in 301 (94%) patients. In Group I, in the early postoperative period, clinical improvement was achieved in 32 (66.7%) patients. Clinical improvement after 3 years persisted only in 16 (33.3%) patients. In Group II comprising patients with transposition of the subclavian artery to the common carotid artery, clinical improvement was observed in 223 (99.6%) patients. Within 3 years of follow-up, 13 (6.4%) patients were found to have a relapse of the clinical picture of vertebrobasilar insufficiency. Clinical improvement after transposition of the subclavian artery to the common carotid artery at 3 years persisted in 210 (93.6%) patients. In Group III patients after stenting of the 1st segment of the subclavian artery in the early postoperative period and during the follow-up period up to 1 year, the angiographic and clinical success amounted to 100%. After 3 years, 8 (17.3%) patients developed relapse of the clinical course because of restenosis, fracture, and thrombosis of the stent. Clinical improvement at 3 years persisted only in 38 (82.6%) patients after stenting. Comparing the remote results demonstrated that transposition of the subclavian artery to the common carotid artery turned out to be the most justified (p<0.05). CONCLUSION: For reconstruction of the 1st segment of the subclavian artery, an operation of choice is transposition of the subclavian artery to the common carotid artery.

[Cerebral protection from ischaemia during carotid endarterectomy]. / Zashchita golovnogo mozga ot ishemii pri operatsii karotidnoi éndarteréktomii.

The purpose of this study was to assess efficacy of cerebral protection during carotid endarterectomy by means of controlled systemic hypertension in patients presenting with various levels of retrograde pressure in the internal carotid artery. The study enrolled a total of 150 patients subjected to carotid endarterectomy. The operation was carried out under general anaesthesia with artificial pulmonary ventilation and was accompanied by haemodynamic monitoring with invasive control of arterial pressure, as well as primary and additional correction of central haemodynamics. Cerebral perfusion was assessed by measuring retrograde pressure in the internal carotid artery. The retrograde pressure index was calculated, according to which the patients were subdivided into three groups: those with values less than 30, with values from 30 to 39, and with values of 40 and more. Controlled systemic arterial hypertension was used as cerebral protection during the period of cross-clamping of the internal carotid artery, with phenylephrine and norepinephrine administered for this purpose. The parameters of central haemodynamics, time intervals of the operation, and the duration of internal carotid artery cross-clamping in the groups did not statistically differ (p>0.05). A statistically significant difference was revealed in the level of systolic arterial pressure necessary for cerebral protection (p<0.05). There were no cerebral circulation impairments, myocardial infarctions, nor lethal outcomes. A conclusion was drawn that individualized correction of central haemodynamics ensured a sufficient level of collateral compensation of the cerebral blood flow, thus making it possible to refuse from using intraluminal shunts.

[Comparative analysis of results of revascularization of the first segment of vertebral arteries]. / Sravnitel'nyi analiz rezul'tatov revaskuliarizatsii pervogo segmenta pozvonochnykh arterii.

Analysed herein is efficacy of various operations on the first segment of the vertebral artery (VA) during treatment of patients with vertebrobasilar insufficiency (VBI). The study enrolled a total of 194 patients with the clinical pattern of VBI induced by an atherosclerotic lesion of the first segment of the VA (stenosis >70%). All patients prior to admission had been receiving a course of medicamentous therapy under neurologist's supervision for more than 6 months with no significant effect. The patients were divided into two groups: Group A included 129 (66.5%) patients with VA tortuosity, subjected to 'open' operations, Group B was composed of 65 (33.5%) patients without VA tortuosity, subjected to stenting of the first segment of the VA. The main criteria of assessing the results were patency of the reconstructed zone and clinical improvement after surgery. In 189 (97.4%) patients we managed to attain stable clinical improvement which persisted after 1 year in 177 (91.2%) patients and after 3 years in 156 (80.2%). In the group of stenting, excellent immediate results were obtained - 100% technical and clinical success. However, in the remote period, the outcomes of 'open' operations turned out to be better as compared with those of stenting. Thus, 3-year clinical efficacy of 'open' and stenting operations amounted to 79.8% and 73.8%, respectively (p>0.05). After 'open' operations there was a significantly lower rate of restenosis of the reconstruction zone (1.6%) than after stenting - 15.4% (p<0.05). However, after 'open' operations the frequency of thrombosis of the reconstructed zone was higher than after stenting - 5.5 vs 1.5% (p>0.05). The incidence of stroke after open operations and after stenting amounted to 2.3 and 3.1%, respectively (p>0.05). Comparative assessment of relapse-free survival after all analysed methods of operations and interventions showed that the best techniques in the long-term perspective turned out to be 'open' operations, and amongst them the operation of transposition of the VA to the common carotid artery (median - 13 years) and the operation of reimplantation of the VA into its ostium (median not achieved in follow up observations for more than 18 years).

[Efficacy of carotid endarterectomy in patients with vertebrobasilar insufficiency without significant lesion of vertebral arteries]. / Éffektivnost' karotidnoi éndarteréktomii u bol'nykh s vertebro-baziliarnoi nedostatochnost'iu bez znachimogo porazheniia pozvonochnykh arterii.

The authors examined efficacy of carotid endarterectomy (CEA) in treatment of patients suffering from vertebrobasilar insufficiency (VBI) without significant involvement of the vertebral arteries. The study included a total of 297 patients with VBI and diagnosed as having stenosis of the bifurcation of the carotid arteries amounting to 70% and more, with no significant involvement of the vertebral arteries revealed. All patients underwent CEA: eversion CEA was performed in 226 (76.1%) cases and the classical one in 71 (23.9%) cases. On postoperative day 10, clinical improvement in the form of decreased severity of VBI was observed in 152 (51.2%) patients. One year after surgery, improvement persisted in 135 (45.5%) patients and after 3 years in 125 (42%) patients. Prognostic factors of unsatisfactory clinical outcomes were determined. It was demonstrated that in VBS, CEA is clinically efficient only if the circle of Willis is closed and there is no history of stroke in the vertebrobasilar basin. Besides, the outcome of the operation appeared to have been influenced by such factor as the duration of hypertension and diabetes mellitus. No effect of either cardiac arrhythmia or the technique of CEA on the results of treatment was observed.

[Clinical efficacy of reconstructive operations on the third (V3) segment of the vertebral artery]. / Klinicheskaia éffektivnost' rekonstruktivnykh operatsii na tret'em (V3) segmente pozvonochnoi arterii.

Presented herein are the results of a prospective cohort study of clinical efficacy of medicamentous treatment and operations of shunting to the third segment (V3) of the vertebral artery in patients with vertebrobasilar insufficiency (VBI). The study included a total of 60 patients with pronounced clinical manifestations of VBI and concomitant lesions of the V1 and V2 segments of the vertebral arteries. The patients were found to have no significant involvement of the carotid bifurcation. At the first stage, all patients during 12 months were receiving a course of optimal medicamentous therapy. Clinical improvement was observed in only 3 (5%) patients, and they were not subjected to surgery. The remaining 57 patients with no improvement after the course of conservative therapy underwent a second-stage treatment consisting in shunting to the third (V3) segment of the vertebral artery. Of these, 5 patients underwent arterial bypass grafting and 52 patients endured autovenous shunting. In the early postoperative period one patient developed thrombosis of the autovenous shunt. This patient died of repeat stroke into the trunk of the brain. In 56 patients the shunts were patent. Clinical improvement was observed in all 56 patients during 3-month follow-up. By month 12, all 5 patients with autoarterial shunts developed shunt thrombosis and were found to have a return of the clinical course of VBI, with no events of either acute impairment of cerebral circulation or transitory ischaemic attacks. We managed to mitigate the clinical course of VBI in 51 (85%) patients with autovenous shunts, with this effect persisting for 12 months and more after the operation. The differences between the results of medicamentous and surgical treatment were statistically significant (p≤0.01). During 3 years of follow up the achieved improvement persisted in 88.7% of the surgically treated patients and during 7 years in 78.3% of patients, with the 3- and 7-year shunt patency rate amounting to 90.2 and 88.2%, respectively.

The operative technique of shunting to the third (V3) segment of the vertebral artery. / Tekhnika vypolneniia operatsii shuntirovaniia v tretii (V3) segment pozvonochnoi arterii.

The authors provide a detailed description of the step-by-step technique of performing the operation of shunting to the V3 segment of the vertebral artery in patients with clinical manifestations of vertebrobasilar insufficiency (VBI). Reported are surgical outcomes in a total of 57 patients with VBI. Of these, 5 patients underwent arterial bypass grafting and 52 patients endured autovenous shunting. One patient developed shunt thrombosis in the early postoperative period and, unfortunately, died, with the remaining 51 shunts being patent. At 3 years of follow up, shunt thrombosis occurred in four (80%) patients with the arterial bypass and only in one (1.7%) of the 52 autovein-treated patients. The total duration of postoperative follow up amounted to 10 years. Long-term freedom from VBI clinical manifestations was achieved in 88.7 % of patients after 3 years and in 78.3% after 7 years, with the 3- and 7-year patency rate of the autovenous shunts amounting to 98.1 and 96.2%, respectively.

Treatment of vertebrobasilar insufficiency due to stenosis and aneurysm of the vertebral artery. / Lechenie vertebral'no-baziliarnoi nedostatochnosti, obuslovlennoi stenozom i anevrizmoi pozvonochnoi arterii.

A dissecting aneurysm of the vertebral artery in the extracranial portion is a rare pathology. It may either have a symptom-free course or induce a clinical picture of vertebrobasilar insufficiency. To the main methods of surgical treatment belong endovascular techniques and resection of an aneurysm with shunting of the V3 segment of the vertebral artery. Presented in the article is a clinical case report regarding successful surgical management of a dissecting aneurysm of the extracranial portion in a young woman presenting with a clinical course of vertebrobasilar insufficiency and treated by means of ligation of the vertebral artery in the V1 segment and autovenous shunting from the external carotid artery to the V3 segment of the vertebral artery.