Flow Diversion Research Articles

Assessing the efficacy of VerifyNow platelet-function testing in predicting postoperative hemorrhagic complications of neuroendovascular surgery: A systematic review and meta-analysis (part 2).

Dual antiplatelet therapy is used to reduce the risk of thromboembolic complications in neuroendovascular surgery. However, the predictive utility of preoperative platelet-sensitivity testing for decreasing bleed risk in patients undergoing endovascular neurointervention remains unclear. We conducted a systematic review and meta-analysis to illustrate the association between platelet response and risk of hemorrhagic complications from neuroendovascular surgery, examine the efficacy of the VerifyNow platelet reactivity unit (PRU) assay in predicting hemorrhagic outcomes, and assess whether a clinically useful threshold for platelet response can be defined to standardize guidelines. PubMed, Embase, and Scopus were searched. Articles were screened for relevance by title and abstract, followed by full text. Of 735 resultant articles, 17 studies of 2084 patients undergoing neuroendovascular intervention were included. Diagnoses included both intracranial and extracranial pathologies, of which 37.8% were treated with flow diversion, 22.4% with stent-assisted coil embolization, 14.3% with intracranial stenting, 12.8% with simple coil embolization, 5.8% with balloon-assisted coil embolization, 2.0% with extracranial stenting, and 4.8% with an alternate method. Precisely, 52.9% (9 out of 17) of studies determined platelet hyperresponse to be an independent predictor of postoperative hemorrhagic complications, with 11.8% (2 out of 17) of studies reporting a similar but non-statistically significant trend. 35.3% (6 out of 17) of studies found no relationship between platelet response and postoperative hemorrhagic complications. The estimated clinical threshold for PRU to prevent hemorrhagic complications varied considerably across studies (range: <46-118 PRU). Meta-analysis found platelet hyperresponse to have more than a 3-fold increased risk of hemorrhagic complications compared to normoresponders (relative risk = 3.2, p = 0.001). Although this meta-analysis shows the predictive utility of the P2Y12 assay for postoperative hemorrhagic complications in neuroendovascular surgery, the optimal therapeutic threshold for minimizing bleeding risk is still uncertain. To better understand the utility of the P2Y12 assay in the perioperative period, further prospective research is needed.

Assessing the efficacy of VerifyNow platelet-function testing in predicting postoperative thromboembolic complications of neuroendovascular surgery: A systematic review and meta-analysis (part 1).

Despite the heavily debated use of routine platelet-function testing, the VerifyNow Platelet Reactivity Unit (PRU) assay has been increasingly adopted as standard of care for assessing risk of postoperative thromboembolic complications of neuroendovascular surgery. We conducted a systematic review and meta-analysis to examine the relationship between platelet response and risk of ischemic events from neuroendovascular surgery, assess the efficacy of point-of-care platelet-function testing in predicting thromboembolic outcomes, and assess whether a clinically useful threshold for platelet response can be defined in order to standardize guidelines. PubMed, Embase, and Scopus were searched. Following deduplication, articles were first screened for relevance by title and abstract, followed by full text. Of 735 resultant articles, 22 studies consisting of 3266 patients undergoing neuroendovascular intervention were included. Diagnoses included both intracranial and extracranial pathologies, of which 45.8% were treated with flow diversion, 16.4% with stent-assisted coil embolization, 15.8% with intracranial stenting, 12.0% with simple coil embolization, 3.4% with balloon-assisted coil embolization, 3.6% with extracranial stenting, and 3.0% with an alternate method. 54.5% (12/22) of studies determined platelet hyporesponse to be an independent predictor of postoperative thromboembolic complications, with 27.3% (6/22) of studies reporting a similar, but non-statistically significant trend. 18.2% (4/22) of studies found no relationship between platelet response and postoperative thromboembolic complications. The estimated clinical threshold for PRU to prevent thromboembolic complications varied greatly across studies (Range: > 144-295 PRU). Meta-analysis found platelet hyporesponse to have a 2.23-fold increased risk of thromboembolic complications compared to normoresponders (RR = 2.23, P = 0.03). While PRU demonstrates a significant predictive value for postoperative thromboembolic complications of neuroendovascular surgery, the target therapeutic threshold for minimizing ischemic events remains unclear. Further studies, such as large multicenter cohorts of the existing data, are needed to standardize guidelines.

Evaluating Efficacy and Complications of Contour Intrasaccular Device in Cerebral Aneurysm Management: A Multicenter Analysis

IntroductionIntrasaccular devices provide a method for treating complex aneurysms without leaving metallic materials in the parent artery. Compared to other well-studied devices in neurointervention, the Contour device is relatively new as an intrasaccular flow diverter. This study examines its use in cases of incidental aneurysms and its application in the acute treatment of ruptured aneurysms. Additionally, it covers potential complications that may arise and methods for prevention. MethodsWe conducted a retrospective analysis of 25 patients who underwent treatment with the Contour device at three hospital centers. We collected data related to age, gender, baseline modified Rankin Scale (mRS), personal habits, medical history, procedure details, and angiographic results according to the WEB occlusion scale (WOS). ResultsA total of 15 patients (65.5%) achieved a satisfactory angiographic result (grade 0-0’) one year after embolization. Contrast stagnation was observed in 14 patients (58.3%). Intraprocedural complications, such as device displacement, were documented in 3 patients (12%), while 2 patients (8%) had aggregates attached to the device. Regarding late complications, 5 patients (20%) experienced device displacement, and 1 patient had a minor stroke (4%). Retreatment was necessary for 3 patients (12%), involving a flow diverter, stenting, and coiling. Discussion and ConclusionIn summary, the Contour device offers a viable option for treating complex aneurysms. While initial results are promising, it's crucial to acknowledge a learning curve to minimize complications and achieve satisfactory angiographic results without the need for additional treatments.

Postmarket Surveillance of Neuroendovascular Devices

Endovascular devices have catalyzed a global industry for advanced technologies such as flow diverters and stent retrievers. Though adoption of these devices has skyrocketed over the past 30 years, the regulatory landscape for real‐world monitoring is constantly under revision. Postmarket surveillance is an area of Medical Device Regulation that monitors how devices perform in the real world after regulatory approval. This area of research is underdeveloped globally, with most surveillance relying on passive adverse event data collection from health care systems. The US Food and Drug Administration has not yet established a comprehensive postmarket surveillance strategy for neuroendovascular devices. Postmarket clinical surveillance data are rare; only 4 mandated 522 postmarket neuroendovascular trials exist, and 4 of 14 endovascular registries have published results per ClinicalTrials.gov. The European Union 2017 Medical Device Regulation describes a comprehensive regulatory strategy to address postmarket surveillance, yet it has faced difficult implementation due to resource constraints and concerns such as increased costs and reliance on foreign devices and regulators. More than 50% of manufacturers are planning portfolio reductions, with 33% of the devices from these manufacturers planned for discontinuation. As of April 2022, &gt;85% of 500 000+ previously certified devices were without new certification. In this article, we describe the current regulatory landscape for postmarket surveillance and support the need for a comprehensive, cost‐efficient postmarket strategy for neurovascular devices while proposing several solutions and considerations. An effective postmarket strategy has numerous benefits, such as promoting patient safety, expanding real‐world data collection, and increased efficiency for approving future devices.

A membrane photobioreactor with flashing light for enhancing biomass and lipid production by a benthic diatom mutant Nitzschia sp. L8

In this work, a membrane photobioreactor integrating with a flashing light (MFLPBR) has been developed for dense culture of a fast growing and oil-rich benthic diatom mutant Nitzschia sp. L8. Under 45 μmol/m2/s light intensity, 0.5 Hz flashing light (FL) could obviously improve the photosynthetic activity, specific growth rate and biomass yield of L8, with the increments by 18.5 %, 32.2 % and 137.6 % comparing to the continuous illumination culture. The total lipid content of L8 reached up to 53.5 % of dry weight, indicating a diversion of carbon flow from carbohydrates to lipids, resulting in increased biomass and lipid accumulation under FL. When L8 was subject to attached growth on the membrane surface in MFLPBR, cell growth was further improved, reaching the biomass yield and lipid productivity of 0.423 g/L and 30.35 mg/L/d in MFLPBR. The MFLPBR was proved to be a feasible strategy to promote the growth of benthic diatom for biomass and lipid production.

Indications for alternative endovascular techniques in carotid-cavernous fistulas: A 20-year single-center experience.

While coiling is considered the standard treatment for carotid-cavernous fistulas (CCFs), studies demonstrating excellent results using new materials, especially flow diverter (FD) stents and liquid embolisates, are becoming more frequent. The indications and effectiveness of these alternative endovascular techniques remain unclear. A total of 22 direct and 20 indirect CCFs were included in the study. These were further subdivided based on the embolic material used: coils versus FD stents for direct and coils versus liquid embolisates for indirect CCFs. The subgroups were subjected to statistical analysis. An angiographic cure was achieved in 88% of all CCFs, 93% of patients' experienced clinical improvement or remained stable. Direct CCFs were treated with coiling (41%) or with both coils and FD stents (55%). One (4%) patient with a direct CCF was treated with FD stent alone. Statistical analysis comparing these subgroups revealed a significantly higher complete occlusion rate immediately after treatment in the coiling subgroup (67% vs. 23%, p = 0.0409). The occlusion rates at the last follow-up were similar (89% vs. 85%). Indirect CCFs were treated with coiling (35%) or liquid embolisates (65%). All three periprocedural ischemic complications were recorded within the liquid subgroup, resulting in a significantly higher clinical deterioration rate (p = 0.0333). FD stents in direct and liquid embolisates in indirect fistulas did not demonstrate better angiographic or clinical outcomes compared to convetional coiling. Liquid agents carried a higher risk of ischemic complications. Alternative embolization materials should be reserved for CCFs that cannot be treated with simple coiling.

A hybrid deep learning model for detecting DDoS flooding attacks in SIP-based systems

The Session Initiation Protocol (SIP) is widely used for multimedia communication as a signaling protocol to manage, establish, maintain, and terminate multimedia sessions among participants. However, SIP is vulnerable to attacks due to its text-based nature and the lack of adequate security measures. One of the most damaging attacks is the Distributed Denial of Service (DDoS) attack, which consumes resources and blocks legitimate users from accessing the available services. Although various machine learning-based schemes have been proposed to detect DDoS flooding attacks in SIP-based systems, most of them only address INVITE flooding attacks. REGISTER and ACK flooding attacks were not addressed. On the other hand, schemes based on statistical analysis are not sufficiently accurate. In this article, we propose a novel approach classifying DDoS flooding attacks in SIP-based systems using a combination of deep learning and entropy techniques. The proposed approach consists of two components: a hybrid deep learning model and an entropy-based model. The hybrid deep learning model combines convolutional neural networks and a stacked bidirectional long short-term memory network to extract features and classify traffic patterns. The entropy-based model measures the randomness and diversity of traffic flows using Shannon and Rényi entropies. To validate the proposed scheme, we built a balanced dataset of different types and intensities of DDoS flooding attacks. The results showed that the proposed scheme can effectively detect DDoS flooding attacks with high accuracy and low detection time for various attack intensities. Moreover, it surpasses other related schemes in terms of accuracy and detection time.

Construction and assessment of an indicator system of stream conditions in a typical mountain landscape in Northeast China.

Stream ecosystem health assessments are crucial for the effective management of aquatic ecosystem service functions and the assessment of anthropogenic and climatic impacts on aquatic ecosystems. However, there is still a lack of comprehensive assessment methods based on complete ecosystem structures. This study improved an ecological health assessment system, which consists of 13 indicators based on ecosystem structure. The assessment system was applied to 30 streams on Changbai Mountain. The results showed that the comprehensive index of stream health (ISH) in Changbai Mountain was relatively high, and the ISH increased with the elevation gradient. The dominant factors controlling the ecosystem health level were water pH, water flow, vegetation coverage, total phosphorus (TP), and vegetation diversity index. All these results indicated that the damage caused by excessive deforestation and farmland occupation in recent years has not been fully reversed and that human disturbance from tourism may be the main reason for the low stream health at lower elevations. Our results suggest that the key to future work is to increase quantitative research on disturbance sensitivity and to develop economically viable restoration measures.

Vanguard Study: Initial experience with the new fourth generation Pipeline Vantage Flow Diverter (PVFD): 6-month results, technical and clinical considerations

BackgroundThe Pipeline Embolization Device has proven to be a safe and effective device for the treatment of intracranial aneurysms. The Pipeline Vantage Flow Diverter (PVFD) with Shield Technology is the...

The Management of Intracranial Aneurysms: Current Trends and Future Directions.

Intracranial aneurysms represent a major global health burden. Rupture of an intracranial aneurysm is a catastrophic event. Without access to treatment, the fatality rate is 50% in the first 30 days. Over the last three decades, treatment approaches for intracranial aneurysms have changed dramatically. There have been improvements in the medical management of aneurysmal subarachnoid haemorrhage, and there has been an evolution of treatment strategies. Endovascular therapy is now the mainstay of the treatment of ruptured intracranial aneurysms based on robust randomised controlled trial data. There is now an expansion of treatment indications for unruptured intracranial aneurysms to prevent rupture with both microsurgical clipping and endovascular treatment. Both microsurgical and endovascular treatment modalities have evolved, in particular with the introduction of innovative endovascular treatment options including flow diversion and intra-saccular flow disruption. These novel therapies allow clinicians to treat more complex and previously untreatable aneurysms. We aim to review the evolution of treatment strategies for intracranial aneurysms over time, and discuss emerging technologies that could further improve treatment safety and functional outcomes for patients with an intracranial aneurysm.

Interception performance of intake structures with a flow diversion barrier under supercritical flow conditions

Intake structures are commonly used in drainage systems to redirect surface rainfall runoff into underground tunnels. The Hong Kong West Drainage Tunnel (HKWDT) system is designed to capture stormwater from steep upland catchments during periods of heavy rainfall, concurrently maintaining a minimal environmental flow downstream during dry weather. However, during heavy rainfall events, excess rainfall water is often directed into the drainage system, presenting a significant challenge to the urban drainage system. Undistorted Froude scale physical models and computational fluid dynamics (CFD) models are developed to investigate the flow performance. In this study, effects of various design parameters on water diversion performance are examined across a wide range of inflow conditions. Steeper channel bottom slopes leading to a larger proportion of water being directed downstream. Extending the length of the bottom rack effectively reduces adhering flow. Introducing a transverse barrier generates a hydraulic jump, which increases flow diversion into the LFC. With higher barrier heights, the hydraulic jump becomes stronger, facilitating greater water diversion into the downstream sewage system. The results indicate potential solutions to these challenges and provide valuable insights into optimizing flow diversion performance in intake structures, particularly in areas characterized by steep terrains and varying flow conditions.

Treatment Outcome of Flow Diverter Device for Medium-Sized Cerebral Aneurysms: A Single-Center Report.

Flow diverters (FDs), first introduced in Japan in 2015, were initially limited to wide-necked large cerebral aneurysms, which pose a high treatment risk. However, based on the results of the PREMIER study, the indications have expanded since 2020, and the number of treatment cases is increasing in Japan. At our hospital, FD placement with adjunctive coil embolization has been actively performed for medium-sized cerebral aneurysms, as indicated in the PREMIER study; herein, we report the outcomes of this treatment. Of the 25 patients with 28 aneurysms who underwent FD placement at our institution between April 2022 and June 2023, 15 with 17 wide-necked unruptured cerebral aneurysms with a maximum diameter of <12 mm in the internal carotid artery (ICA) or vertebral artery (VA) were included. Postoperative complications were investigated in each case, and the aneurysm occlusion status was assessed using ultrashort echo time (UTE)-MRA at 3 months postoperatively and angiography at 6 months postoperatively. Fifteen patients who underwent coiling or stent-assisted coiling (SAC) for the same criteria during the same period were compared. Baseline characteristics and treatment results were compared between FD and coiling/SAC cases. Four males and 11 females with a mean age of 61.7 ± 12.8 years were included, and the median follow-up period was 9 months (6-18 months). There were 14 aneurysms of the ICA and 3 of the VA, and the mean maximum aneurysm diameter was 7.9 ± 1.7 mm. All patients were treated using the Pipeline Flex with Shield Technology (Medtronic, Minneapolis, MN, USA), and 14 aneurysms (82.4%) were treated with adjunctive coil embolization. There were no symptomatic strokes in the perioperative period; only one patient receiving corticosteroid therapy for thyroid eye disease had asymptomatic ICA occlusion at 3 months. Fifteen aneurysms (88.2%) were not visible on UTE-MRA at 3 months postoperatively, and angiography at 6 months showed complete occlusion in 16 (94.1%) aneurysms. The coiling/SAC group had a smaller neck size and higher volume embolization ratio than the FD group; however, complete occlusion was higher in the FD group. FD placement with adjunctive coil embolization for medium-sized cerebral aneurysms is expected to result in good occlusion rates in the early postoperative period.

A Review of Current Flow Diverters.

Flow diverter (FD) devices are new-generation stents placed in the parent artery at the aneurysmal neck to obstruct intra-aneurysmal blood flow, thus favoring intra-aneurysmal thrombosis. In Japan, about eight years have passed since health insurance approval was granted for FD devices, and FD placement to treat aneurysms has become widespread. Treatment indications have also been expanded with the introduction of novel devices. At present, three types of FD (Pipeline, FRED, and Surpass Streamline) are available in Japan. This report represents a compilation of available FD technologies and describes the current consensus on this treatment.

Endovascular Treatments for Aneurysms Involving a Major Branch.

Remarkable advances have been made in the endovascular treatment of intracranial cerebral aneurysms. These advances include various adjunctive techniques, increased indications for endovascular treatment, and improved treatment results. Furthermore, the number of cerebral aneurysm treatments using flow diverters (FDs) is expected to increase. However, the reported long-term rate of branch artery occlusion after FD treatment has been reported is 15.8%. Moreover, the complete aneurysm obliteration rate is low if normal branches arise from an aneurysm neck or dome. Flow diverter placement for ophthalmic artery, posterior communicating artery, and anterior choroidal artery aneurysms is often difficult because these normal branches often arise from the aneurysm neck or dome. Therefore, in many cases, coil embolization, which can occlude the aneurysm while preserving branch vessels, should be selected. Although not yet established, various adjunctive techniques and other endovascular treatments that can be performed safely have been reported. Treatment must be planned after understanding the advantages and disadvantages of each treatment method.

Endovascular complications: Antiplatelet management for flow diversion

Up to 3−5% of the general population is affected by cerebral aneurysms that are associated with both modifiable as well as non-modifiable risk factors ranging from familial to acquired neurovascular conditions. The initial treatment option was aneurysm clipping and evolved to including primary or adjuvant endovascular treatment. Aneurysm re-rupture, although rare, can have devastating consequences such as intracranial bleeding and carotidcavernous fistula. Emergent surgery in view of delayed aneurysm rupture in patients maintained on dual antiplatelet therapy presents with the need to carefully assess the procedure-related risk factors and evaluate the patients’ platelet function. With the advent of novel technology, flow diverters came into play. These devices utilize the deployment of metallic stents into the parent artery that serves the diversion of blood flow away from the pouching aneurysm. Despite their efficacy, flow diverter insertion and catheter manipulation come with a risk of developing ischemia and stroke, hemorrhage and aneurysm re-rupture, in-stent thrombosis and stenosis, and aneurysmal occlusion amongst other complications. The prospect of thromboembolic events necessitates the use of aggressive antiplatelet regimen with the dual antiplatelet regimen utilizing clopidogrel and aspirin used most frequently. Prasugrel and Ticagrelor have been shown to be superior to Clopidogrel in terms of thromboembolic consequences in cardiovascular literature. Given their potential benefit over the current standard of treatment in this patient population, more extensive randomized-controlled studies are warranted for the evaluation of the efficacy and non-inferiority of Prasugrel and Aspirin or Ticagrelor and Aspirin to Clopidogrel and Aspirin.

Predictors of occlusion, long-term outcomes, and safety in a cohort of 674 aneurysms treated with the Pipeline embolization device.

By providing a more physiological approach to the treatment of intracranial aneurysms, the Pipeline embolization device (PED) has revolutionized the endovascular treatment of aneurysms. Although there are many flow diverters on the market, the authors report their experience with the PED, the first flow diverter to be approved by the Food and Drug Administration. They aimed to assess the efficacy and safety of PED flow diversion for the treatment of a wide range of aneurysms, as well as to look at factors affecting occlusion. This is a retrospective study of a prospectively maintained database of patients treated with the PED between January 2011 and December 2019. Charts were reviewed for patient, aneurysm, and procedure characteristics. The primary outcomes of interest were complication rates, occlusion outcomes (O'Kelly-Marotta grading scale), and functional outcomes (modified Rankin Scale [mRS]). Secondary outcomes included predictors of incomplete occlusion at 6 and 24 months of follow-up. The study cohort included 581 patients with 674 aneurysms. Most aneurysms (90.5%) were in the anterior circulation and had a saccular morphology (85.6%). Additionally, 638 aneurysms (94.7%) were unruptured, whereas 36 (5.3%) were acutely ruptured. The largest mean aneurysm diameter was 8.3 ± 6.1 mm. Complications occurred at a rate of 5.5% (n = 32). The complete occlusion rate was 89.3% at 24 months' follow-up, and 94.8% of patients had a favorable neurological outcome (mRS score 0-2) at the last follow-up. On multivariate analysis, predictors of incomplete aneurysm occlusion at 6 months were hypertension (OR 1.7, p = 0.03), previous aneurysm treatment (OR 2.4, p = 0.001), and increasing aneurysm neck diameter (OR 1.2, p = 0.02), whereas a saccular morphology was protective (OR 0.5, p = 0.05). Predictors of incomplete occlusion at 24 months were increasing aneurysm neck diameter (OR 1.2, p = 0.01) and previous aneurysm treatment (OR 2.3, p = 0.01). The study findings are corroborated by those of previous studies and trials. The complete occlusion rate was 89.3% at 24 months' follow-up, with 94.8% of patients having favorable functional outcomes (mRS score 0-2). Aneurysm treatment before PED deployment and an increasing aneurysm neck diameter increase the risk of incomplete occlusion at 6 and 24 months.

Periprocedural management of patients presenting for neurointerventional procedures using flow diverters for complex intracranial aneurysms: An anesthetist's perspective - A narrative review.

Complex intracranial aneurysms pose significant challenges in the realm of neurointervention, necessitating meticulous planning and execution. This article highlights the crucial roles played by anesthetists in these procedures, including patient assessment, anesthesia planning, and continuous monitoring and maintaining hemodynamic stability, which are pivotal in optimizing patient safety. Understanding these complex procedures and their complications will aid the anesthetist in delivering optimal care and in foreseeing and managing the potential associated complications. The anesthetist's responsibility extends beyond the procedure itself to postprocedure care, ensuring a smooth transition to the recovery phase. Successful periprocedural anesthetic management in flow diverter interventions for complex intracranial aneurysms hinges on carefully orchestrating these elements. Moreover, effective communication and collaboration with the interventional neuroradiologist and the procedural team are emphasized, as they contribute significantly to procedural success. This article underscores the essential requirement for a multidisciplinary team approach when managing patients undergoing neurointerventions. In this collaborative framework, the expertise of the anesthetist harmoniously complements the skills and knowledge of other team members, contributing to the overall success and safety of these procedures. By providing a high level of care throughout the periprocedural period, anesthetists play a pivotal role in enhancing patient outcomes and minimizing the risks associated with these intricate procedures. In conclusion, the periprocedural anesthetic management of neurointervention using flow diverters for complex intracranial aneurysms is a multifaceted process that requires expertise, communication, and collaboration.

Role of temporary portosystemic surgical shunt during liver resection to prevent a post-resection small for size-like syndrome

Liver resection stands as the gold-standard therapeutic approach for selected cases of hepatocellular carcinoma (HCC). The extent of resectable parenchyma hinges upon the underlying liver function and its regenerative potential. Consequently, cirrhosis may impede access to potentially curative interventions for HCC arising within this context. Cirrhotic patients undergoing liver resection face heightened susceptibility to post-hepatectomy liver failure (PHLF). The clinical profile of PHLF bears a resemblance to a well-documented syndrome within the liver transplant (LT) domain: Small-for-size syndrome (SFSS), a form of graft failure observed in the postoperative phase following LT with undersized or partial organs. Management of SFSS targets mitigating the overflow syndrome, achievable through diverse portal diversion techniques. Portal vein flow diversion encompasses procedures redirecting a variable proportion of portal vein flow towards systemic circulation. Consequently, derivative procedures aim to directly alleviate portal hypertension. Side-to-side portocaval shunts emerge as the most straightforward and efficacious means of decompressing the portal system. Furthermore, they afford flow calibration to diminish the incidence and severity of steal syndrome and hepatic encephalopathy, without compromising efficacy or hepatic function. Translating insights gleaned from LT complexities involving SFSS to liver resection, strategies involving portal flow diversion warrant consideration in efforts to forestall PHLF. This approach aims to extend the frontiers of liver surgery, broadening access to hepatectomy with curative intent, either as a standalone intervention or as part of a comprehensive treatment regimen where LT serves as a secondary option.

Functional Connectivity of the California Bulrush (Schoenoplectus californicus) in Central-Western Wetlands in Mexico

Wetlands are natural links between terrestrial and aquatic ecosystems maintaining biodiversity at regional and landscape levels. Wetland conservation in Mexico could benefit from understanding functional connectivity for aquatic plants. This is an ongoing research project aimed at identifying the landscape factors that determine gene flow and genetic diversity of Schoenoplectus californicus in the highland wetlands of Central-Western Mexico. Between 10 to 30 leaf tissue samples from S. californicus individuals were collected in natural and artificial wetlands in the states of Michoacán, Guanajuato, and Jalisco for genomic DNA extraction. A total of sixteen nuclear microsatellite markers developed for S. americanus will be transferred and genotyped to estimate genetic diversity and differentiation and to statistically test their relationship with landscape elements. To date, 419 individuals from 27 sites have been sampled from 11 wetlands. Six out of 16 microsatellites have been transferred. The results of this work will guide the design of wetland management and conservation strategies at the landscape scale, particularly in anthropogenic landscapes where wetlands are at high risk.

The role of turnover in structuring subterranean aquatic communities in Southeastern Brazil.

Similarly to other animal communities, the diversity of subterranean aquatic fauna is influenced by several factors and processes, such as habitat fragmentation, dispersion, environmental heterogeneity, and physical and chemical water characteristics. Here, we studied cave aquatic communities of the Alto Ribeira hydrographic basin, regarding troglobitic and non-troglobitic species, located in a single karst area to evaluate the influence of sub-basins in fauna differentiation. We investigated how abiotic variables (flow, electrical conductivity, temperature, pH, and substrate) influence the fauna composition and the contribution of beta diversity components (nestedness and turnover) in explaining communities' dissimilarities. Fauna composition differed between sub-basins, as most species did not co-occur in different caves. Caves with higher flow and substrate diversity were the richest. In addition, each cave community was influenced by a unique set of abiotic variables. Dissimilarity among caves was mainly explained by turnover, and our findings suggest the restricted species distribution could be due to ecological (e.g., limited dispersion capacity, tolerance to abiotic variables), hydrogeological (e.g., dispersion barriers, isolation of sub-basins), and historical (e.g., colonization, paleoclimatic events) factors and processes. Therefore, different elements are responsible for determining the composition of cave aquatic communities in different sub-basins, reflecting the variability within a single karst area.