Retrograde Pressure Research Articles

On the transition of liquid dispersion states and their physical-thermodynamic nature in the development of gas-condensate reservoirs in depletion mode

While the depletion regime for gas-condensate fields may be more cost-effective, it often results in the loss of hydrocarbon condensate, which is economically more valuable than gas, and leads to the inefficient exploitation of the field in terms of condensate production. Therefore, the development of effective exploitation systems for such fields is essential. Effective exploitation of gas-condensate fields involves achieving maximum hydrocarbon condensate production in addition to maximum gas production. From this aspect, managing the condensate factor of reservoir system during the depletion regime is a critical issue. The article experimentally and theoretically investigates the phase transitions or mutual dispersion occurrences between hydrocarbon liquid and gas mixtures that occur with a decrease in pressure at reservoir temperature during the natural depletion of gas-condensate fields. During the exploitation of gas-condensate fields, it has been observed that even at pressures higher than retrograde condensation pressure, the hydrocarbon system undergoes complex phase transitions, resulting in distinct transition points due to the mutual dispersion of hydrocarbon liquid and gas. Additionally, pVT studies conducted in the laboratory have made it possible to determine the transition points of the reservoir fluid in the “liquid in gas” and vice versa dispersion states. The research has demonstrated that dependance of gas condensate factor on pressure under given isothermal natural conditions more clearly reflects the retrograde and maximum condensation, also dispersion points of the liquid components. It was found that proportionality coefficient between condensate ratio and pressure of gas-condensate system is unique for each production facility under isothermal conditions and characterizes the stability of fluid’s dispersion state. The importance of considering such transition points when designing gas-condensate field development projects has been highlighted.

Endovascular treatment of spinal AVM: report of two cases with transvenous approach in combination with retrograde pressure cooker technique

PurposeEndovascular treatment of spinal AVMs is limited by low complete cure rates. Transarterial extensive treatment with liquid embolics carries the risk of clinically relevant ischemic complications. We report two cases of symptomatic spinal AVMs treated by a transvenous approach with retrograde pressure cooker technique.MethodsIn two selected cases, transvenous navigation aimed at retrograde pressure cooker embolization.ResultsRetrograde venous navigation was possible with two parallel microcatheters, and the pressure cooker technique with ethylenvinylalcohol-polymer was applicable in both cases. One AVM was occluded completely, and one subtotally due to a second draining vein. No clinical complications occurred.ConclusionA transvenous approach for embolization with liquid embolics may offer advantages in treating certain spinal AVMs.

Results of carotid endarterectomy with the use of temporary shunts with reduced retrograde pressure in the internal carotid artery - analysis of the multicenter Russian register.

The aim of the study was to assess the role of a temporary carotid shunt in patients undergoing carotid endarterectomy. This was a retrospective, multicentric (n = 159) study carried out between January 2005 and October 2020. The study included 3114 patients undergoing carotid endarterectomy who had a reduced retrograde internal carotid artery pressure (<60% of systolic blood pressure). A temporary carotid shunt was used in 1328 patients and 1786 patients underwent carotid endarterectomy without a shunt. The in-hospital outcomes were comparable in terms of the incidence of deaths, myocardial infarctions, and stroke between the two groups. However, asymptomatic strokes (confirmed on computed tomography) occurred more frequently in the group where the temporary shunt was used (34 (2.5%) vs. 10 (0.55%), p < 0.0001). The composite endpoints of adverse events were also higher in the group where a temporary shunt was used (44 (3.3%) vs. 28 (1.5%), p = 0.002). The risk of symptomatic stroke (both fatal and non-fatal) was higher in the group where a temporary shunt was not used, though this was statistically not significant. Logistic regression analysis identified diabetes mellitus and stenosis (81-90%) of the contralateral internal carotid artery to be important predictors for stroke. Temporary carotid shunts during carotid endarterectomy were associated with increased rates of asymptomatic stroke. There were no statistically significant differences in the incidence of non-fatal or fatal stroke, myocardial infarction, and mortality.

The Coronary Sinus Reducer Stent for the Treatment of Refractory Angina Pectoris: From the Conception of Innovation to Clinical Application.

The Neovasc Coronary Sinus Reducer Stent (CSRS) was developed for the treatment of patients who continue to suffer from disabling symptoms despite optimal medical therapy. This patient population with refractory angina symptoms is expected to grow, since life expectancy of individuals with atherosclerotic coronary artery disease is increasing. In this paper, we discussed the development of a novel device the CSRS and the upside-down strategy to rebuild a retrograde coronary pressure that was attenuated by the atherosclerotic disease.

Abstract 12468: Hemodynamic Validation of Echocardiographic Left Ventricular to Left Atrial Volumes Ratio Indices in Heart Failure With Preserved Ejection Fraction

Introduction: The assessment of mean left atrial (LA) pressure rather than Left Ventricular (LV) end-diastolic pressure reflects more accurately filling pressure which is pathophysiological landmark of Heart Failure with preserved Ejection Fraction (HFpEF). Hypothesis: We sought to test whether the measurement of LV to LA volume ratio at the specific cardiac phases can estimate resting LA pressure in patients with HFpEF. Methods: Fifty-three HFpEF patients (mean age 71+-10 years) who underwent cardiac catheterization including direct, at rest, retrograde LA pressure, were analysed. Echocardiographic data was obtained 1.5+-1.0 hours off cardiac catheterization. Patients were divided into: Group 1 (normal filling pressure) and Group 2 (elevated filling pressure, mean LA pressure &gt;12mmHg and/or pulmonary capillary wedge pressure 14mmHg). The ratio of LV/LA volume was measured in end-systole (LV ES /LA max ), end-diastole (LV ED /LA min ), diastasis (LV dias /LA dias ), and as both maximum (LV ED /LA max ), and minimum (LV ES /LA min ). Results: All measured LV/LA ratios were lower in Group 2 as compared to Group 1 and correlated inversely with an increased LA pressure (LV ED /LA min , r=-0.54, p&lt;0.001; LV ES /LA min , r=-0.53, p&lt;0.001; LV ED /LA max , r=-0.52, p&lt;0.001; LV dias /LA dias , r=-0.50, p&lt;0.001; LV ES /LA max , r=-0.37, p=0.013. The following ratios, LV dias /LA dias , LV ED /LA max , LV ED /LA min , and LV ES /LA min , were the most accurate echocardiographic indices to differentiate HFpEF patients between Group 2 and Group 1 (independently off the presence atrial fibrillation), with the area under the curve &gt;0.75 and statistically noninferior to the following a new LA function parameters such as: LA reservoir strain, index LA reservoir strain, LA total emptying fraction and LA active emptying fraction. The cut-off values for LV ES /LA min &lt;1.45 and LV dias /LA dias &lt;1.30 had the sensitivity 78%, 74% and specificity 71%, 71%, respectively, to differentiate patients between Group 2 and Group 1. Conclusions: Among all studied echocardiographic indices the LV ES /LA min and LV dias /LA dias were the most accurate parameters to assess the level of LA pressure in HFpEF.

Experimental investigation of transvenous embolization of arteriovenous malformations using different in vivo models

BackgroundTransvenous embolization (TVE) is an emerging technique for the endovascular treatment of cerebral arteriovenous malformations (AVMs). The aim of this study was to investigate two in vivo AVM models and...

Temporary shunt and carotid endarterectomy (review of literature)

The main idea of this article is based on the uncertainty of the current recommendations, according to which a temporary shunt (TS) during carotid endarterectomy (CEE) can be used selectively, routinely, and even completely abandon its use. This statement is supported by the low level of evidence (class B) of the conclusion that indications for the use of TS are established only on the basis of a decrease in retrograde pressure in the internal carotid artery (ICA) and/or indicators of cerebral oximetry. Thus, the low efficiency of these procedures makes it possible not to use them at all.

Multicenter study: outcomes of carotid endarterectomy depending on configuration of circle of Willis

BACKGROUND: The circle of Willis (CW) is an important network of collaterals that provide compensatory redistribution of hemodynamic load. Several studies showed that the CW is open in approximately 50%90% of cases, and the number of missing segments correlates with low brain tolerance to ischemia in internal carotid artery (ICA) compression. Currently, studies dedicated to the relationship of different configurations of CW with the risk of ischemic brain damage.&#x0D; AIM: The analyze the immediate results of eversion carotid endarterectomy (CEA) in patients with different configurations of the structure of the CW.&#x0D; MATERIALS AND METHODS: We included 641 patients with hemodynamically significant stenosis of the internal carotid arteries (ICA) in a study period from 2010 to 2020. All patients underwent multispiral computed tomography with angiography of the extracranial and CW arteries. Based on the structural variants of the CW, six groups of patients were studied: group 1 (64.9%, n = 416) closed posterior part (CPP) with the existence of posterior communicative artery (PCA) and P1 segment of the posterior cerebral artery (PCerA); group 2 (27%, n = 173) an intermediate structure of the posterior part (IPP) with hypoplasia of the PCA or PCerA; group 3 (8.1%, n = 52) open posterior part (OPP) with the absence of PCA or PCerA; group 4 (85.95%, n = 551) closed anterior part (CAP) with the presence of the anterior communicating artery (ACA) and A1 segment of the anterior cerebral artery (ACerA); group 5 (7.95%, n = 51) an intermediate structure of the anterior part (IAP) with hypoplasia of ACA or ACerA; group 6 (6.1%, n = 39) open anterior part (OAP) with the absence of ACA or ACerA. To assess the compensatory potentials of the brain, all patients underwent measurement of the retrograde pressure in the ICA and intraoperative cerebral oximetry.&#x0D; RESULTS: In the postoperative period, 1 death was recorded in group 4 (CAP) due to a hemorrhagic transformation in the zone of ischemic stroke, on the background development of hyperperfusion syndrome. The largest number of ischemic strokes of the cardioembolic subtype was diagnosed in the ACerA territory in the presence of an unstable atherosclerotic plaque: group 1 (CPP) 0%; group 2 (IPP) 0%; group 3 (OPP) 0.24%, n = 1; group 4 (CAP) 0.18%, n = 1; group 5 (IAP) 1.96%, n = 1; group 6 (OAP) 5.1%, n = 2; p 0.9999. The probable cause was embolization against the background increase in the arterial pressure before ICA clamping. In turn, the majority of ischemic strokes of the hemodynamic subtype developed in the territory of PCerA: group 1 (CPP) 0%; group 2 (IPP) 1.73%, n = 3; group 3 (OPP) 3.8%, n = 2; group 4 (CAP) 0.18%, n = 1; group 5 (IAP) 0%; group 6 (OAP) 2.56%, n = 1; p 0.9999. This pattern coincided with the largest number of patients with CW of the IPP and OPP types among all open variants of the structure.&#x0D; CONCLUSION: Parameters of retrograde pressure in the ICA and intraoperative cerebral oximetry do not always demonstrate the need for a temporary shunt (TS). Due to the opened structure of CW, the redistribution of blood flow occurs with the formation of zones of hypo- and hyperperfusion, causing ischemic alterations in the brain matter. Thus, in order to maintain adequate cerebral hemodynamics, to mitigate the effect of hypo- and hyperperfusion, and reduce the risk of ischemic stroke, the open variant of the CW structure should be considered as an indication for a TS.

Design optimization of bidirectional arterial perfusion cannula

ObjectivesDetermine if shortening the covered section of a self-expanding bidirectional arterial cannula, can enhance retrograde flow and thus reduce the risk of lower limb ischemia.MethodsOutlet pressure vs flow rate was determined for three cannulas types: a 15F self-expanding bidirectional cannula having a covered section of 90 mm, the same cannula but with a shorter covered section of 60 mm, and a Biomedicus cannula as control. The performances of all the cannulas were compared using a computerized flow-bench with calibrated sensors and a centrifugal pump. Water retrograde flow was determined using a tank timer technique. Anterograde and retrograde flow rate versus outlet pressure were determined at six different pump speed.ResultsFor each of the six pump speed, both bidirectional cannulas, 60-mm covered and 90-mm covered respectively, showed higher performance than Biomedicus cannula control, as demonstrated by higher flow rate and lower pressure. We also observed that for the bidirectional cannula with shorter covered section, i.e. 60 mm coverage, provides enhanced performance as compared to a 90-mm coverage. Finally, the flow rate and the corresponding pressure can be consistently measured by our experimental set-up with low variability.ConclusionsThe new configuration of a shorter covered section in a bidirectional self-expanding cannula design, may present an opportunity to overcome lower leg ischemia during extra-corporal life support with long term peripheral cannulation.

Comparative Results of Emergency Carotid Endarterectomy and Emergency Carotid Angioplasty With Stenting in the Acute Period of Ischemic Stroke. Multicenter Study Results

AIM OF STUDY Study of hospital results of emergency carotid endarterectomy (CEE) and carotid angioplasty with stenting (CAS) in the acute period of acute cerebrovascular accident (ACVA). MATERIAL AND METHODS From January 2008 to August 2020, the study included 615 patients with hemodynamically significant stenosis of the internal carotid arteries (ICA), operated on in the acute period of ischemic stroke (within 3 days from the onset of stroke). Depending on the type of revascularization implemented, all patients were divided into 2 groups: group 1 — CAS (n=312); 2nd group — CEE (n=357). Inclusion criteria were as follows: 1. Mild neurological disorders: NIHSS score 3–8; Modified Rankin Scale score 2 of less; Barthel Scale &gt; 61; 2. Indications for CEE / CAS according to the current national recommendations; 3. Ischemic focus in the brain not more than 2.5 cm in diameter. Exclusion criteria: 1. Presence of con-traindications to CEE / CAS. Carotid angioplasty with stenting was performed according to the standard technique; in all cases, distal embolism protection systems were used. Carot-id endarterectomy was performed according to the classical and eversion techniques. When the retrograde pressure in the ICA was less than 60% of the systemic pressure, a temporary shunt (TS) was installed. In the postoperative period, all patients underwent multispiral computed tomography (MSCT) of the brain. In the absence of negative dynam-ics in the neurological status, MSCT was performed on the 7th day after the operation, if available, it was performed urgently. The checkpoints were the development of such unfa-vorable cardiovascular events as death, myocardial infarction (MI), stroke / transient is-chemic attack (TIA), “mute” stroke, “mute” hemorrhagic transformations, combined end-point (death + all strokes / TIA + MI). Strokes were mute if diagnosed according to MSCT, without symptoms. RESULTS In 69% of diabetic patients with anterior myocardial infarction and in 63% of patients with posterolateral MI 12 months after PCI, signs of LV inferiority were revealed in the form of an increase in the indices of end-diastolic and systolic volumes of the LV and low ejection fraction (≤45%). In patients without diabetes, these figures were 18% and 31%, respectively. High concentrations of NT-proBNP on the first day of myocardial infarction after PCI were of the greatest value in the diagnosis and prognosis of LV UR after 12 months. RESULTS When analyzing hospital complications, significant differences in the frequency of lethal outcome were not obtained (group 1: n=6 (1.92%); group 2: n=8 (2.24%); p=0.98; OR=0.85; 95% CI 0.29–2.49); MI (group 1: n=5 (1.6%); group 2: n=5 (1.4%); p=0.91; OR=1.14; 95% CI 0.32–3.99 ); ACVA (ischemic type) / TIA (group 1: n=5 (1.6%); group 2: n=6 (1.7%); p=0.82; OR=0.95; 95% CI 0.28–3.15), as well as “mute” ACVA (group 1: n=7 (2.2%); group 2: n=15 (4.2%); p=0.23; OR=0.52; 95% CI 0.21–1.3). However, the vast majority of hemorrhagic transformations (group 1: n=2 (0.64%); group 2: n=13 (3.6%); p=0.018; OR=0.17; 95% CI 0.03–0.76) and all “mute” hemorrhagic transformations (group 1: n=0; group 2: n=26 (7.3%); p=0.001; OR=0.02; 95% CI 0.001–0.33) were observed only in the CEE group, which was reflected in the maximum values of the combined end point: group 1: n=22 (7.05%); group 2: n=73 (20.4%); p&lt;0.0001; OR=0.29; 95% CI 0.17–0.48). Thus, in the CEE group, every 5th patient had a complication. CONCLUSION Carotid angioplasty with stenting is the safest method of revascularization for patients in the acute period of ACVA. This is largely due to the reduction in the risk of reperfusion syndrome and the prevention of embolism due to the use of modern protection systems. Carotid endarterectomy can be performed with comparable efficiency only when a tempo-rary shunt is placed in the internal carotid arteries in the absence of unstable atheroscle-rotic plaque.

Pressure‐to‐Depth Conversion Models for Metamorphic Rocks: Derivation and Applications

AbstractPressure‐to‐depth conversion is a crucial step toward geodynamic reconstruction. The most commonly used pressure‐to‐depth conversion method assumes that pressure corresponds to the lithostatic pressure. However, deviatoric stresses can cause pressure to deviate from the lithostatic case strongly, thus adding considerable uncertainty to pressure to‐depth conversion. First, we rederive formulas of pressure‐to‐depth conversion that take into account deviatoric stresses. Then, we estimate the range of possible depth independently for each point in a data set containing peak and retrograde metamorphic pressure data (one‐point method). In a second time, we use both the peak and retrograde pressure of a rock sample together, assuming that both pressures were recorded at the same depth (two‐point method). We explore different cases to explain the transition from peak to retrograde pressure by varying the direction and magnitude of stresses. This alternative model is consistent with all data points but for a more restricted range of stress state and depth than the one‐point model. Our results show that (1) even small deviatoric stresses have a significant impact on depth estimates, (2) the second principal stress component σ2 plays an essential role, (3) several models can explain the pressure evolution of the data but lead to different depth estimates, and (4) strain data offer a mean to falsify our proposed two‐point pressure‐to‐depth conversion. The maximum predicted depth at peak pressure is 170 km using the assumption that pressure is lithostatic, compared to &lt;75 km for our two‐point model, which could correspond to the crustal root Moho's depth.

Percutaneous coronary intervention and carotidal endarterectomy: hospital and long-term outcomes of hybrid interventions and predictors of complications

Goal. Analysis of hospital and long-term results with the identification of predictors of complications after combined interventions on the coronary and carotid arteries in the volume of percutaneous coronary intervention + carotid endarterectomy (PCI + CEE). Materials and methods. From 2010 to 2016, 64 patients underwent hybrid revascularization of the brain and myocardium in the volume of PCI + CEE. Initially, PCI was performed, then the patient was transported to the vascular operating room, where he underwent CEE was performed according to the classical technique with modeling the reconstruction zone with a patch made of diepoxy-treated xenopericardium. Brain protection was achieved by invasive measurement of retrograde pressure. After CEE, the patient received a loading dose of clopidogrel 600 mg. The average follow-up period in the long-term period was 53.04 ± 17.1 months. Results. In the hospital period, only hemorrhagic complications were noted (n = 3; 4.68 %) while taking double antiplatelet therapy (acetylsalicylic acid + clopidogrel) and intraoperative heparin. In the long-term period, the leading position was occupied by a lethal outcome (n = 9; 16.6 %). Despite taking double antiplatelet therapy, in 6 (11.1 %) cases, stroke development was noted, in 1 (1.8 %) — MI. In 3 (5.5 %) patients, repeated unplanned revascularization was performed — CABG as a result of restenosis in the stent. The combined endpoint (death + stroke + myocardial infarction) was 29.6 % (n = 16). Significant risk factors for the development of complications in the hospital postoperative period were chronic renal failure (OR 3.7165; 95 % CI 1.2032–11.4800), III–IV functional class of angina (OR 21.9; 95 % CI 2.29–208, 8), a history of stroke (OR 6.82; 95 % CI 1.04–44.7). In the long term, the predictors of adverse events were bleeding (OR 2.02; 95 % CI 1.15–3.55), ejection fraction less than 50 % (OR 2.9; 95 % CI 1.47–5.7) and lesion trunk of the left coronary artery and more than three additional coronary arteries (OR 2.67; 95 % CI 1.27–5.59), and two or less affected coronary arteries (OR 0.34; 95 % CI 0.19–0.62). Conclusion. The efficiency and safety of hybrid revascularization in the volume of PCI + CEE has been proven in view of the minimum number of complications at different stages of follow-up.

Comparison of admission lung ultrasound and left ventricle end diastolic pressure in patients with ST-segment elevation myocardial infarction submitted to primary percutaneous coronary intervention

Abstract Background/Introduction Elevated left ventricle end diastolic pressure (LVEDP) is related to diastolic dysfunction, increased retrograde pulmonary capillary pressure and pulmonary congestion. Diastolic dysfunction precedes the onset of systolic dysfunction in acute ischemia, and the prognostic utility of LVEDP in ST-segment elevation myocardial infarction (STEMI) is well known. Bedside lung ultrasound (LUS) is a simple and sensitive method for evaluating pulmonary congestion. Purpose The aim of this study was to assess the correlation between LVEDP and LUS and to evaluate their prognostic capacity in STEMI patients submitted to primary percutaneous coronary intervention (PPCI). Methods This was a prospective cohort of STEMI patients treated in a tertiary care hospital. LUS was performed by two independent operators before coronary angiography. Our protocol consisted of eight scanning zones; a zone was considered positive in case it presented three or more B lines. LVEDP was recorded before coronary angiography, assessed offline and blinded to LUS results. Results We have included 217 patients with mean age of 60 (±12.1) years and 63% were male. Killip 4 on admission was diagnosed in 16.5% of patients and total in-hospital mortality was 14.7%. Median LVEDP and LUS positive sites were 19 mmHg [13, 28] and 1 [0, 5], and spearman correlation between them was 0.33. LUS and LVEDP c-statistics for in-hospital mortality were 0.69 (0.58–0.79) and 0.60 (0.49–0.71), respectively. LUS and LVEDP c-statistics for in-hospital cardiogenic shock were 0.75 (0.67 – 0.83) and 0.65 (0.57–0.74), respectively. A multivariate analysis was performed including 4 or more positive LUS zones, LVEDP &amp;gt;22 mmHg, diabetes and admission creatinine. In patients with 4 or more positive LUS zones, odds ratios of cardiogenic shock and in-hospital mortality were 7.04 (2.89–18.30, p&amp;lt;0.001) and 4.52 (1.92–11.12, p=0.001), respectively. In patients with LVEDP higher than 22 mmHg, odds ratios for cardiogenic shock and in-hospital mortality were 1.43 (0.57–3.54, p=0.437) and 0.88 (0.36–2.09, p=0.768), respectively. Conclusion We found no significant correlation between LVEDP and LUS in a STEMI patient's cohort. Unlike LVEDP, LUS had a significant AUC to predict in-hospital mortality. LUS had a great magnitude hazard ratio for cardiogenic shock and in-hospital mortality when 4 or more scanning zones were positive. A high LVEDP did not predict cardiogenic shock or in-hospital mortality on this subset of STEMI patients. LUS and LVEDP correlation Funding Acknowledgement Type of funding source: Public Institution(s). Main funding source(s): Hospital de Clinicas de Porto Alegre and Universidade Federal do Rio Grande do Sul

Results of carotidal endarterectomy in different age group

Background. Carotid endarterectomy is an effective and safe operation aimed at treating patients with hemo-dynamically significant stenosis of the carotid arteries, the outcomes of which are well studied, and the permissible levels of postoperative complications are presented in the current recommendations. Nevertheless, the issues related to the incidence of cardiovascular accidents in different age groups of patients have not been sufficiently studied. Objective. Analysis of hospital outcomes of carotid endarterectomy in different age groups. Design and methods. The study included 1416 patients who were operated on for stenotic lesions of the internal carotid arteries. According to the WHO classification, patients were divided into groups depending on age: up to 44 years — young age (n = 76); 45-59 years old — average age (n = 291); 60-74 — old age (n = 835); over 75 years old — old age (n = 214). The compensatory capabilities of cerebral blood flow were assessed by invasive measurement of the retrograde pressure in the internal carotid artery. The endpoints were death, myocardial infarction, acute cerebrovascular accident, transient ischemic attack, hemorrhagic complications, cranial nerve damage, combined endpoint. Results. There were no significant differences in the incidence of all cardiovascular events. In the group of young patients, no lethal outcomes, myocardial infarction, acute cerebrovascular accident, or transient ischemic attack were recorded. All deaths were caused by the development of ischemic stroke as a result of distal embolization. In cases of non-fatal acute disorders of cerebral circulation, transient ischemic attacks in 1 patient of the 60-74 year group, the catastrophe developed against the background of thrombosis of the internal carotid arteries. In other 3 cases, on the background of the development of hyperperfusion syndrome. In 1 patient of the 60-74 year group, hemorrhagic transformation of the old ischemic focus with the development of intracerebral hematoma was recorded. There was also no significant intergroup difference in the incidence of hemorrhagic complications. The total number of all cardiovascular events in each group and the sample as a whole did not exceed one and a half percent, which corresponded to the standards described in the current recommendations. Conclusion. There was no statistically significant difference in the development of adverse cardiovascular events depending on the patient’s age.

The transvenous retrograde pressure cooker technique for the curative embolization of high-grade brain arteriovenous malformations

BackgroundTransvenous embolization of brain arteriovenous malformations (AVMs) can be curative. We aimed to evaluate the cure rate and safety of the transvenous retrograde pressure cooker technique (RPCT) using coils and...

Критерії використання тимчасового шунта у хворих із стенозами сонних і церебральних артерій

Вивчено особливості нейропротективної тактики хірургічного лікування атеросклеротичного стенозу внутрішньої сонної артерії. В аналіз включено 108 пацієнтів з поєднаним атеросклеротичним ураженням церебральних і каротидних артерій, яким була зроблена оцінка резервних можливостей головного мозку. На підставі результатів, які були отримані під час проведення ішемічних проб, пацієнтів розподілили на дві групи. До 1-ї групи увійшло 68 осіб, яким була виконана каротидна ендартеректомія без використання тимчасового шунта, 2-гу групу склали 40 пацієнтів, яким дана операція виконувалася з використанням ТШ (тимчасового шунта). Рішення про використання шунта приймали за сукупністю показників ретроградного тиску, неврологічного дефіциту, кровотоку по середній мозковій артерії. У пацієнтів з оклюзією сонних артерій з контрлатеральної сторони використання ТШ показано незалежно від показників оксиметрії, ретроградного тиску, швидкості по середній мозковій артерії. При поєднаному атеросклеротичному ураженні сонних і церебральних артерій тактика хірургічного лікування повинна ґрунтуватися на оцінці функціональних резервів головного мозку. Результати проведеної проби гіпоксії слугували додатковим критерієм щодо рішення про накладення внутрішнього шунта (ВШ). Це дозволяє уникнути додаткових можливих ускладнень в ранньому післяопераційному періоді. Розімкнене Вілізієве коло не вимагає використання тимчасового шунта у 32 випадках

Rupture of aneurysm of the middle cerebral artery along with stenosis of the internal carotid and coronary arteries

This article presents the results of treatment of a patient with rupture of a giant intracerebral aneurysm of the left middle cerebral artery (MCA), hemodynamically significant stenosis of the internal carotid artery on the left and the trunk of the left coronary artery with multiple lesions of the coronary arteries (anterior descending artery, diagonal branch, right coronary artery). A phased surgical correction was performed, with the time period between stages being 2 months, as follows:Stage 1 — open microsurgical clipping of the aneurysm of the left MCA and removal of intracerebral hematoma. The usage of the standard treatment volume in the form of 3H therapy (hypertension, haemodilution and hypervolemia), as well as slow calcium channel blockers in the postoperative period, was associated with a high risk of developing cardiovascular complications due to the presence of occlusal–stenotic lesions of the coronary and brachiocephalic channels. In the postoperative period, the patient received antiplatelet therapy (acetylsalicylic acid 100 mg at lunch), lipid-lowering therapy (rosuvastatin 20 mg in the evening) and anti-hypertensive therapy (bisoprolol 2.5 mg in the morning; perindopril 2.5 mg in the evening; spironolactone 25 mg in the morning; torasemide 10 mg in the morning; valparin XP 500 mg 2 times a day). On day 14, the patient was transferred from the intensive care unit, and on day 20, the patient was discharged from the hospital in satisfactory condition.Stage 2 — a combined operation in the amount of carotid endarterectomy (CEE) with plastic surgery of the biological patch on the left with plastic reconstruction of the reconstruction zone with a patch from the xenopericardium and coronary bypass grafting (CABG). Tactics were confirmed as optimal, taking into account the stratification of the risk of complications in the postoperative period when applying the new interactive program ‘Program support for the decision-making process for choosing a surgical re-vascularisation strategy for multifocal atherosclerosis’ (certificate of registration of a computer program RU 2017619457). Brain protection during CEE was achieved by invasive measurement of retrograde pressure (60 % of systemic blood pressure (BP)) and intraoperative increase in blood pressure to 180/90 mm Hg. CABG was performed using cardiopulmonary bypass. An epiaortic ultrasound scan was used to select the position of the implantation of a venous shunt into the aortic wall. Intraoperative flowmetry was used to regulate the quality of the implanted shunts.The patient was discharged 10 days after the surgery from the hospital in satisfactory condition. Conservative therapy, initiated after stage 1 of re-vascularisation, was continued.Clipping of intracerebral arterial aneurysm during its rupture and reconstructive interventions on the internal carotid artery and coronary arteries could be performed combined with the possibility of endovascular correction. However, due to the presence of an unstable atherosclerotic plaque, the possibility of interventional correction of the internal carotid artery was excluded, and the condition of the coronary bed at the time of stage 1 remained unknown. An additional argument in favour of open microsurgical clipping of the aneurysm was the need for the removal of intracerebral hematoma.The treatment strategy chosen here was found to be safe and effective. Satisfactory outcome of the surgery was achieved due to a complete range of perioperative examinations. The implemented tactics prevented the development of complications. The data obtained here would form the basis for the development of recommendations for selecting the optimal tactics of re-vascularisation in combined lesions of intracranial, extracranial and coronary arteries. Received 21 April 2020. Revised 27 April 2020. Accepted 28 April 2020. Funding: The study did not have sponsorship. Conflict of interest: Authors declare no conflict of interest. Author contributionsConception and design: А.N. Kazantsev, R.S. TarasovLiterature review: K.P. Chernykh, N.E. Zarkua, R.Y. Leader, G.Sh. BagdavadzeDrafting the article: А.N. KazantsevIllustrations: А.N. Kazantsev, K.P. Chernykh, N.E. Zarkua, R.Y. Leader, G.Sh. BagdavadzeCritical revision of the article: N.E. Zarkua, R.S. Tarasov, Y.P. LinetsFinal approval of the version to be published: А.N. Kazantsev, R.S. Tarasov, K.P. Chernykh, N.E. Zarkua, R.Y. Leader, G.Sh. Bagdavadze, Y.P. Linets

Study the effect of nitrogen gas on phase behavior of gas condensate systems and dispersion of retrograde condensate

The effect of nitrogen gas on the phase transformation of gas condensate systems and its efficiency as a «working agent» for the production of precipitated retrograde condensate has been analyzed. Experimental studies on the pVT bomb based on a special methodology have clarified some contradictions that still exist in this area. Thus, the physical-thermodynamic nature of the different ways effect of nitrogen gas on the retrograde condensation pressure of the formation system or the stability of its dispersed state depending on the temperature range is explained. The research surveys are also studied the effect of nitrogen gas on gas phase dispersion in the precipitated retrograde condensate and liquid-gas interfacial exchange processes under different thermo-baric conditions. It was defined that if nitrogen gas is used to develop the wellbore zone of a gas condensate well, its efficiency should be specified depending on the degree of wellbore saturation with retrograde condensate, the amount of nitrogen in the working agent, formation temperature and number of cycles affecting the wellbore.

Is pre-operative urodynamic bladder function the true predictor of outcome of male sling for post prostatectomy incontinence?

PurposeTo investigate pre-operative urodynamic parameters in male sling patients to ascertain whether this might better predict surgical outcomes and facilitate patient selection.MethodsWe performed a retrospective, case notes and video-urodynamics, review of men who underwent AdVanceXP male sling in three London hospitals between 2012 and 2019. Urodynamics were performed in all centres, while retrograde leak point pressure (RLPP) was performed in one centre.ResultsSuccessful outcome was seen in 99/130 (76%) of men who required one pad or less per day. The dry rate was 51%. Pad usage was linked to worse surgical outcomes, mean 2.6 (range 1–6.5) for success vs 3.6 (range 1–10) although the ranges were wide (p = 0.002). 24 h pad weight also reached statistical significance (p = 0.05), with a mean of 181 g for success group versus 475 g for the non-successful group. The incidence of DO in the non-successful group was significantly higher than in successful group (55% versus 29%, p = 0.0009). Bladder capacity less than 250 ml was also associated with worse outcomes (p = 0.003). Reduced compliance was not correlated with outcomes (31% for success groups vs 45% for non-successful group, p = 0.15). Preoperative RLPP was performed in 60/130 patients but did not independently reach statistical significance (p = 0.25).ConclusionUrodynamic parameters related to bladder function—detrusor overactivity and reduced maximum cystometric capacity predict male sling outcomes and may help in patient selection for male sling (or sphincter) surgery; whereas urodynamic parameters of sphincter incompetency (RLPP) were not predictive. Further larger scale studies are required to confirm these findings.

PD37-12 URODYNAMIC PREDICTORS OF SURGICAL OUTCOMES FOLLOWING MALE SLING IMPLANTATION

You have accessJournal of UrologyUrodynamics/Lower Urinary Tract Dysfunction/Female Pelvic Medicine: Male Incontinence: Therapy II (PD37)1 Apr 2020PD37-12 URODYNAMIC PREDICTORS OF SURGICAL OUTCOMES FOLLOWING MALE SLING IMPLANTATION Bogdan Toia*, Lap Yan Leung, Raveen Saigal, Eskinder Solomon, Sachin Malde, Claire Taylor, Arun Sahai, Rizwan Hamid, Tamsin Greenwell, Jai Seth, Davendra Sharma, and Jeremy Ockrim Bogdan Toia*Bogdan Toia* More articles by this author , Lap Yan LeungLap Yan Leung More articles by this author , Raveen SaigalRaveen Saigal More articles by this author , Eskinder SolomonEskinder Solomon More articles by this author , Sachin MaldeSachin Malde More articles by this author , Claire TaylorClaire Taylor More articles by this author , Arun SahaiArun Sahai More articles by this author , Rizwan HamidRizwan Hamid More articles by this author , Tamsin GreenwellTamsin Greenwell More articles by this author , Jai SethJai Seth More articles by this author , Davendra SharmaDavendra Sharma More articles by this author , and Jeremy OckrimJeremy Ockrim More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000000908.012AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: The surgical options for post prostatectomy incontinence are implantation of an artificial sphincter or male sling. Outcomes for artificial sphincters, and predictive values for good outcome have been documented. However, the criteria for patient selection and the likelihood of a good outcome for male slings are limited. Most authors have relied on pad number/weight as their primary parameter, despite poor correlation with success rates. It remains unclear whether pre-operative urodynamic parameters might better predict surgical outcomes and facilitate patient selection. METHODS: We performed a retrospective case notes and video-urodynamics review of men who underwent AdVanceXP male mid-urethral sling insertion in three London hospitals between 2012 and 2019. Collected data included demographics, postoperative continence and urodynamic parameters. Video-urodynamics were performed in all centres, while retrograde leak point pressure (RLPP) was only performed in one centre. Analysis was performed using chi-squared and independent t tests, with p<0.05 is considered significant. RESULTS: 114 men were identified. 89/114 (78%) patients were cured of their incontinence requiring 1 pad per day or less for reassurance (59/114 (52%) did not use any pads), whilst 25/114 (22%) patients remained significantly wet. Success by urodynamic parameters is shown in Figure 1. 43/114 (38%) had detrusor overactivity (DO) on preoperative urodynamics, with a mean pressure of 41cmH2O (range 15-78). The rate of DO demonstrated in the wet group was significantly higher than in dry group (60% vs 31%, p=0.009), but the peak DO pressure did not correlate with outcomes (p = 0.778). 31/114 (27%) had abnormal compliance, with higher incidence in the wet group (48% vs. 21%, p= 0.008). Having a bladder capacity less than 400ml was also associated with worse outcomes (p=0.001). Preoperative RLPP did not correlate with surgical outcomes (p=0.495), but was only was performed in 55 men (48%). CONCLUSIONS: Urodynamic parameters can be used to predict outcome for male sling. The predictors of significance are detrusor overactivity, reduced compliance and reduced bladder capacity (<400mls). Further study is required to accurately define urodynamic parameters that will differentiate outcomes and criteria for sling (and sphincter) selection. Source of Funding: No funding required © 2020 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 203Issue Supplement 4April 2020Page: e732-e733 Advertisement Copyright & Permissions© 2020 by American Urological Association Education and Research, Inc.MetricsAuthor Information Bogdan Toia* More articles by this author Lap Yan Leung More articles by this author Raveen Saigal More articles by this author Eskinder Solomon More articles by this author Sachin Malde More articles by this author Claire Taylor More articles by this author Arun Sahai More articles by this author Rizwan Hamid More articles by this author Tamsin Greenwell More articles by this author Jai Seth More articles by this author Davendra Sharma More articles by this author Jeremy Ockrim More articles by this author Expand All Advertisement PDF downloadLoading ...