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Introduction/Objective. Circle of Willis (CoW) provides the most significant collateral flow in the presence of significant stenosis or occlusion of internal carotid artery. In terms of collateral flow ?incomplete? type and ?complete? type of CoW can be recognized. Patients with carotid artery disease with incomplete CoW have lower cerebrovascular reactivity and higher risk for stroke. Cerebrovascular reactivity refers to the residual capacity of dilatation of cerebral blood vessels in the condition of insufficient blood flow. In this study we analyzed changes in cerebrovascular reactivity after carotid endarterectomy in asymptomatic patients with respect to complete and incomplete CoW morphology. Methods. In this study in 97 patients with asymptomatic carotid artery disease we measured cerebrovascular reactivity before and after carotid endarterectomy by using method of ?apnea test? and ?breathholding index? (BHI). Patients were divided into two following groups: patients with ?complete? CoW and ?incomplete? CoW based on non-contrast magnetic resonance angio performed previously to the operation. Descriptive statistics, univariate analysis, and ANOVA for comparison of BHI values between groups were used. Results. The results showed significant increase in cerebrovascular reactivity at the side of stenosis in both groups of patients with complete CoW (BHI value increased from 0.897 to 1.090; F (1.65) = 30.788, p < 0.0005, parc. ?2 = 0.321) and incomplete CoW (BHI value increased from 0.690 to 1.010; F (1.27) = 62.318, p < 0.0005, parc. ?2 = 0.698) and the more significant increase in the group of incomplete CoW compared to the group with complete CoW (F (1.92) = 4.557, p = 0.035, parc. ?2 = 0.047) Conclusion. In most asymptomatic patients, cerebrovascular reactivity restores to normal following carotid endarterectomy. Parameters of cerebrovascular reactivity are lower in patients with incomplete CoW and the increase after carotid endarterectomy is more significant in such patients.

Introduction. Carotid endarterectomy is an efficient surgical procedure of primary and secondary prevention of ischemic stroke in asymptomatic and symptomatic patients with extracranial carotid artery disease. Material and Methods. In this paper we analyzed incidence, risk factors, potential causes and preventive measures for early stroke after carotid endarterectomy in patients (809) who underwent surgery for carotid artery stenosis at the Clinic of Vascular and Endovascular Surgery of the Clinical Center of Vojvodina in Novi Sad during a five year period (April 2013 - March 2018). Results and Discussion. Early operative stroke was registered in 12 patients with no significant difference between symptomatic (2.8%) and asymptomatic (1.1%) patients (odds ratio - 2,56, 95% confidence interval - 0.8063 to 8.1770 standard deviation 1,596; p = 0,11). Contralateral carotid occlusion (odds ratio - 3.1154, 95% confidence interval - 1.1620 to 8.3522, p = 0.0239) and no dual antiplatelet therapy (odds ratio - 3.1154, 95% confidence interval - 1.8537 to 526.4871; p = 0.0169) were pointed out as risk factors for operative stroke. Most of the perioperative and early postoperative strokes after carotid endarterectomy were due to arterial-arterial thromboembolism, intracerebral hemorrhage and acute carotid occlusion that developed rarely and were associated with severe neurological deficit. Conclusion. Even though our results are in agreement with the literature data, additional measures for surgical quality control would further decrease the incidence of operative stroke.

Background Cerebral hyperperfusion syndrome is a rare but potentially severe complication of carotid artery revascularisation that develops under conditions of resistant postoperative hypertension and impaired cerebrovascular autoregulation. Objective Was to determine which preoperative and operative factors affect the development of cerebral hyperperfusion syndrome after carotid endarterectomy. Methods This prospective observational study enrolled 93 asymptomatic patients who underwent carotid endarterectomy. Cerebral hyperperfusion was registered in patients who had 100% postoperative increase in mean flow in middle cerebral artery registered by Transcranial Doppler ultrasound. Cerebral hyperperfusion syndrome was diagnosed in patients with cerebral hyperperfusion who postoperatively developed at least one of the symptoms. Pre-operative and operative risk factors for cerebral hyperperfusion syndrome were analysed by multivariate binary logistic regression. Results Out of 93 operated patients, cerebral hyperperfusion was registered in 23 and cerebral hyperperfusion syndrome in 18 patients. Risk factors for cerebral hyperperfusion syndrome were included in the binary logistic regression model. Incomplete Circle of Willis morphology on 3D TOF magnetic resonance image (p = 0.002), Breath holding index below the 0.69 cut-off (p = 0.006), positive criteria for insufficient collateral flow through circle of Willis registered by TCD (p = 0.03), and poorly controlled hypertension (p = 0.023) showed statistically significant independent predictive value for cerebral hyperperfusion syndrome. The model was statistically significant (p = 0.012) and correctly classified 90.3 % of patients. Conclusions Incomplete circle of Willis and insufficient collateral flow, low cerebrovascular reserve, and poorly regulated hypertension are significant predictors of post- carotid endarterectomy hyperperfusion development.

Introduction. This research has been aimed at determining whether incomplete Circle of Willis in patients with significant extracranial carotid stenosis is associated with a higher incidence of neurological symptomatology and/or ischemic cerebral lesions. Material and Methods. The research was conducted as a prospective study which comprised 211 patients who underwent surgical treatment of extracranial carotid disease at the Department of Vascular Surgery in Novi Sad and 102 patients in the control group. Each patient underwent preoperative magnetic resonance imaging and magnetic resonance angiography with visualization of cerebral parenchyma, extracranial and intracranial cerebral circulation. Assessment of Circle of Willis morphology was performed by 3D time-of-flight magnetic resonance angiogram sequence analysis. The patients were divided into two groups: group I - the patients with complete Circle of Willis and group II - the patients with incomplete Circle of Willis i.e. with the disruption of anterior and/or ipsilateral posterior circulation - regarding the side of significant carotid stenosis. Results. Out of 211 patients who were operated during a two-year period, 133 had the complete Circle of Willis, while 78 patients had the incomplete Circle of Willis. Out of 111 patients with symptomatic carotid disease or silent cerebral infarction, 52.5% (58) had the complete Circle of Willis and 47.5% (53) had the incomplete Circle of Willis. It was shown to be statistically different (P = 0.0146) in relation with the asymptomatic group of patients (100), where the frequency of the complete Circle of Willis was 75% (75) while the insufficiency of anterior or ipsilateral posterior collateralization was found in 25% (25). In the control group there were significantly fewer cases of developed collateral flow and the complete Circle of Willis (41%) compared to the operated patients with extracranial carotid stenosis (63%) (P = 0.0003). Conclusion. Incompleteness of Circle of Willis is associated with more frequent occurrence of neurological symptomatology or ischemic lesions of brain parenchyma in operated patients with significant extracranial carotid stenosis. The control group without extracranial carotid stenosis had less developed collaterals of Circle of Willis compared to extracranial carotid patients.

Introduction. Due to the ever-present lack of kidney transplant grafts, more and more organs obtained from the so-called ?marginal donors? group are accepted, which can provide suboptimal effect of transplantation, depending on their characteristics and/or implantation techniques. Case report. We presented a case with successful variation of kidney position with modified approach of kidney transplantation from an infant to an adult female patient with normal postoperative recovery. Urethral anastomosis was performed without antireflux procedure and this has not led to the development of reflux disease at an early stage. Conclusion. The position of a pair of kidneys proved to be satisfactory despite the growth of the kidney to the expected size and relatively small pelvis. There were no problems with venous stasis and kidney function from the very beginning was good.

Background/Aim. A certain percentage of patients with asymptomatic carotid stenosis have an unstable carotid plaque. For these patients it is possible to register by modern imaging methods the existence of lesions of the brain parenchyma - the silent brain infarction. These patients have a greater risk of ischemic stroke. The aim of this study was to analyze the connection between the morphology of atherosclerotic carotid plaque in patients with asymptomatic carotid stenosis and the manifestation of silent brain infarction, and to analyze the influence of risk factors for cardiovascular diseases on the occurrence of silent brain infarction and the morphology of carotid plaque. Methods. This retrospective study included patients who had been operated for high grade (> 70%) extracranial atherosclerotic carotid stenosis at the Clinic for Vascular and Transplantation Surgery of the Clinical Center of Vojvodina over a period of 5 years. The patients analyzed had no clinical manifestation of cerebrovascular insufficiency of the carotid artery territory up to the time of operation. The classification of carotid plaque morphology was carried out according to the Gray-Weale classification, after which all the types were subcategorized into two groups: stable and unstable. Brain lesions were verified using preoperative imaging of the brain parenchyma by magnetic resonance. We analyzed ipsilateral lesions of the size > or = 3 mm. Results. Out of a 201 patients 78% had stable plaque and 22% unstable one. Unstable plaque was prevalent in the male patients (male/female ratio = 24.8% : 17.8%), but without a statistically significant difference (p > 0.05). The risk factors (hypertension, nicotinism, hyperlipoproteinemia, and diabetes mellitus) showed no statistically significant impact on carotid plaque morphology and the occurrence of silent brain infarction. Silent brain infarction was detected in 30.8% of the patients. Unstable carotid plaque was found in a larger percentage of patients with silent brain infarction (36.4% : 29.3%) but without a significant statistical difference (p > 0.05). Conclusions. Even though silent brain infarction is more frequent in patients with unstable plaque of carotid bifurication, the difference is of no statistical significance. The effects of the number and type of risk factors bear no statistical significance on the incidence of morphological asymptomatic carotid plaque.

Introduction. Acute critical lower limb ischemia refers to the state of severely impaired vitality of lower limbs due to acute occlusion of arterial blood vessel by a thrombus or emboli. Surgical revascularization in the first 6-12 hours after the onset of symptoms gives the best results. However, a high mortality rate and probability of limb loss make this problem more debatable, and can be related with associated diseases. Material and Methods. This research included 95 patients who had been operated within the first 12 hours after the onset of symptoms of critical limb ischemia. We collected the following data: age and sex of patients, etiology of limb ischemia, type of operation, associated diseases and outcome of treatment. Results and Discussion. Most of the patients were 70 to 80 years old, both sexes being equally represented. There was significantly more arterial embolism (70%) than thrombosis on the prior arterial lesion. Most of the embolizations were treated with Fogarty balloon catheter embolectomy (98%); however, a great number of arterial thrombosis demanded more complex ”inflow” and ”outflow” ensuring procedures such as thromboendarterectomy and bypass (33%). The performed surgical procedures showed no statistical differences when final outcome was analyzed. Amputation had to be performed in about 3% of the patients and all of them were diabetics. Mortality rate in this research was 10.5% and 7/10 with this outcome had severe form of chronic myocardiopathy and metabolic decompensation. Conclusion. Acute critical lower limb ischemia should be treated surgically as soon as possible. Negative outcomes are associated with comorbidity and general condition of the patient.