logo
Introduction
Vascular Smooth Muscle Enhances Functionality of Tissue Engineered Blood Vessels In Vivo
Evolution of Operative Strategies in Open Thoracoabdominal Aneurysm Repair (TAA)
In Situ Rifampin-Soaked Grafts Are Durable With Low Reinfection Rates in Patients With Aortic Graft Enteric Erosion or Fistula
Para-visceral Aortic Endarterectomy: Treatment of Choice for Coral-reef Aortic Plaque
Secondary Vascular Interventions After EVAR
A Comparison of Indirect Radiation Dose Estimates With Directly Measured Radiation Dose for Patients and Operators During Complex Endovascular Procedures
Venous Specific Eph-B4 Regulates Vein Graft Thickening via Caveolin-1
Asymptomatic Internal Carotid Artery Stenosis and Cerebrovascular Risk Stratification
Effects of Statins on Early and Late Results of Carotid Stenting
Long-term Results of Endovascular Treatment of Subclavian and Innominate Arterial Stenosis
Urgent Carotid Endarterectomy in Mild-to-Moderate Acute Strokes: Preventing Recurrence and Improving Neurological Outcome
Carotid Endarterectomy by the Eversion Technique With and Without Shunt
Duplex-Guided Dialysis Access Angioplasty Can Be Performed Safely in the Office Setting: Techniques, Advantages and Results
Fistula First: A Timely Approach for Successful Dialysis Access?
Creating Functional Autogenous Vascular Access in Older Patients
Prior Failed Ipsilateral Percutaneous Vascular Intervention (PVI) in Patients With Critical Limb Ischemia Predicts Poor Outcome After Lower Extremity Bypass
Sustained 5 Years Performance Analysis of Sequential Compression Biomechanical Device (SCBD) in Critical Limb Ischaemia (CLI) Patients with Un-reconstructable Peripheral Vascular Disease (PVD) vs Primary Amputation in a Tertiary Referral Vascular Centre With Quality of Time Without the Symptoms or Toxicity of the Disease (QTWiST)
A Comparison of Endovascular Revascularization and Bypass in Regards to Healing Rates of Ischemic Wounds
Popliteal to Dorsalis Pedis Translocated Vein Graft
Vacuum-Assisted Closure (VAC) Therapy for the Treatment of Deep (Szilagyi Grade III-Infection) in the Groin
Low Rehospitalization Rate for Vascular Surgery Patients at a Single University Hospital
Differential Expression of ERK and Akt Following Nitric Oxide Exposure in Type 1 and Type 2 Diabetic Rats
Renal Volume and Blood Pressure Response to Renal Artery Stenting
The Contemporary Management of Splenic Artery Aneurysms
Late Outcomes Following Open and Endovascular Repair of Blunt Thoracic Aortic Injury
Video Presentation Left Renal Vein Transposition for the Treatment of Nutcracker Syndrome
Minimal Aortic Injury: Which Patients Can Be Observed?
The Post-Exercise Common Femoral Artery Doppler Waveform: A Powerful NonInvasive Vascular Laboratory Test to Detect Aortoiliac Disease
Critical Appraisal of the Carotid Duplex Consensus Criteria in the Diagnosis of Carotid Artery Stenosis
Thrombus Volume Is Associated With Cardiovascular Events and Aneurysm Growth in Patients Who Have Abdominal Aortic Aneurysm
Is Endovascular Aortic Repair (EVAR) an Effective Initial Therapy for All Infected Aortic Aneurysms?
Percutaneous Endovascular Aortic Aneurysm Repair Using Ultrasound-guided Access: The Key to Expand Selection Criteria
A 3-Dimensional Analysis of Juxtarenal, Pararenal, and Suprarenal Abdominal Aortic Aneurysms
Endovascular Chimney (Snorkel) Technique vs Open Surgery for Repair of Juxtarenal and Suprarenal Aneurysms
Midterm Outcomes of the Zenith Renu Ancillary Graft: Results From a Post-market Registry
Effect of Gender on Long-term Survival After Abdominal Aortic Aneurysm (AAA) Repair: Results From Medicare National Database
Percutaneous Verus Femoral Cutdown Access for EVAR in ACS NSQIP
Surgical Revascularization for Aorto-Iliac Occlusive Disease (AIOD): Current Indications and Outcomes
Frailty, Sarcopenia, and Mortality in Aortic Surgery Patients
Arterial Evaluation by Ultrasound for Dialysis Access
Protein Kinase C-delta Contributes to the Development of Abdominal Aortic Aneurysm Through Stimulation of Apoptosis and Inflammation
Continued Expansion of EVAR for Intact and Ruptured Abdominal Aortic Aneurysm in the Medicare Population 1995-2008
The Proximal Aneurysm Neck Distension in Patients With Stentgraft Migration Is Significantly Larger Than in Patients Without Migration
The Effect of Injectable Biocompatible Elastomer (PDMS) on the Strength of the Proximal Fixation of EVAR-grafts
Aortic Neck Changes and Sac Shrinkage After Anaconda™ Stent-graft: Midterm Results
Hypogastric Preservation With Branch Endograft Versus Exclusion for Aorto-iliac Aneurysms
When Is Conservative Management of Primary Type Ia Endoleaks Justified?
In Vivo Assessment of Thoracic Aortic Compliance: Implications for Endograft Design
Female and Elderly AAA Patients More Commonly Develop Concurrent Thoracic Aortic Aneurysm
Long-term Results of Talent Endografts for Endovascular Abdominal Aortic Aneurysm Repair
Hardman Index and Glasgow Aneurysm Score in Predicting Survival Following Open Repair of Ruptured Abdominal Aortic Aneurysms (AAA): Are They Practical?
Inhomogenous Wall Stress Distribution in the Normal Human Thoracic Aorta: A Potential Etiology of Type B Aortic Dissections
Fenestrated Stent Graft Improves Clinical Results of Thoracic Aortic Emergency
Clinical Utility and Safety of Noncontrast Computed Tomography for Follow-Up After Endovascular Abdominal Aortic Aneurysm Repair
The Impact of Co-morbid Abdominal Aortic Aneurysm on Outcomes After Coronary Artery Bypass Grafting
Evidence That Statins Protect Renal Function During Endovascular Repair of AAAs
Comparative Mortality of Ruptured Abdominal Aortic Aneurysm After Endovascular Versus Open Repair
Short- and Long-term Results After Fascial Closure Technique of Femoral Artery Access Sites After Endovascular Aortic Aneurysm Repair (EVAR)
One-Year Results of a New Endograft for AAA Treatment: Real-life Experience with the Endurant Stentgraft System
Abdominal Aortic Aneurysms: Challenging Neck and Difficult Access (How to Solve a Real Problem With A New Hydrophilic and Low-profile Device)
Infected Abdominal Aortic and Iliac Artery Aneurysm: A Single Center 25-Year Experience
The Incidence of Pulmonary Neoplasms Discovered by Serial CT Scanning Following Endovascular AAA Repair
Elephant Trunk Repair of the Transverse Arch and Descending Thoracic Aorta: Long-term Experience With the Hybrid Technique
Lower Extremity Ischemia Complicating Acute Type A Dissection: A Ten-Year Single-Center Experience
Aortic Customize: A New Alternative Endovascular Approach to Aortic Aneurysm Repair Using Injectable Biocompatible Elastomer
Relationship of Aneurysm Sac Regression and Type II Endoleak: Role of the Inferior Mesenteric Artery
Type IV Thoracoabdominal Aortic Aneurysm Repair: A Large Single-Center Experience
Endovascular Salvage of Collapsed Thoracic Endografts - A Multicenter Review
Reanastomosis of Divided Left Renal Vein During Aneurysm Repair Is Not Necessary
The Impact of CardioMEMS EndoSure on Longitudinal Axial Imaging Studies
Intensive Statin Therapy Is Associated With a Decrease in Adverse Events and Death Following Carotid Revascularization
Coronary Artery Disease May Increase the Risk of Cerebrovascular Accidents During Carotid Angioplasty and Stenting
Superior Nationwide Outcomes of Carotid Endarterectomy Compared to Carotid Artery Stenting: 10-Year Analysis
Carotid Endarterectomy in Diabetic Patients: Are the Results Worth the Effort?
Carotid Artery Plaque Burden and Calcification in ≥ 50% NASCET Stenosis in Relation to Symptomatic Outcome
Post Carotid Endarterectomy Hyperperfusion Syndrome- Is It Predictable by Lack of Cerebral Reserve?
Coronary Bypass and Carotid Endarterectomy (CEA): Does a Combined Operative Approach Offer Better Outcome? - Outcome of Different Management Strategies in Patients With Carotid Stenosis Undergoing Coronary Artery Bypass Grafting (CABG)
Predictors of Cerebral Ischemia During Carotid Endarterectomy Performed in Awake Patients
Staged Versus Synchronous Carotid Endarterectomy and Coronary Artery Bypass Grafting: Analysis of 10-year Nationwide Outcomes
Systematic Review of Randomized Controlled Trials of Patch Angioplasty Versus Primary Closure and Different Types of Patch Materials During Carotid Endarterectomy
Retrograde Supra-aortic Stent Placement Combined With Open Carotid or Subclavian Artery Revascularization
Aspirin vs Aspirin/Plavix in the Prevention of Stroke: A Meta-analysis
Hybrid Procedures for the One-stage Treatment of Multi-focal Ipsilateral Internal Carotid and Proximal Common Carotid/Innominate Artery Lesions
Proximal Vertebral Artery Disease: Surgical Reconstruction or Stenting?
Carotid Artery Endarterectomy (CEA) for Stroke in Evolution (SIE): Technical and Long-term Clinical Outcome in a Tertiary Referral Vascular Centre. When to Master Silence?
Transradial Approach for the Treatment of Non-maturing Hemodialysis Fistulae May Have Better Patency Than Standard Direct Fistula Approach
The Use of Subclavian-Atrial Bypass for the Treatment of Central Venous Hypertension Induced by Dialysis Access Procedures
Screening for Carotid & Renal Stenosis in Patients Undergoing Tesio Catheter Placement
Technical Feasibility, Safety, and Efficacy of a Novel Anastomotic Device (Optiflow™) for the Creation of Arteriovenous Fistulae (AVF) for Hemodialysis
Transradial Approach for the Treatment of Non-maturing Hemodialysis Fistulae: An Alternative Percutaneous Approach
Development of an Endovascular Training Curriculum: Role of Simulation in Medical Student Education
Live Cadavers for Laboratory Training in Vascular Surgery
Time of Year Does Not Influence Mortality in Vascular Operations at Academic Centers
Recent Trends in the Publications of the U. S. Vascular Surgery Program Directors
Analysis of Computerized Tomographic Angiography in the Evaluation of Carotid Artery Stenosis in Patients With Equivocal Duplex Findings
Duplex Brachial Vein Velocities Can Predict Central Stenosis
Magnetic Resonance Imaging of Abdominal Aortic Aneurysms (AAA) Using Ultrasmall Superparamagnetic Particles of Iron Oxide (USPIO)
Electronic Ordering of Vascular Laboratory Studies for DVT in Symptomatic Patients Is Less Specific and Increases the Number of Bilateral Scans
Preoperative Rise in N-Terminal Pro-brain Natriuretic Peptide and High-sensitive C-Reactive Protein Is Associated With Increased Rates of Cardiac Complications and Poor Surgical Outcome After Vascular Surgery
Comparison of BNP to Traditional Preoperative Risk Factors
Long-term Outcomes of Internal Carotid Artery Dissection
Improved Hemodynamic Outcomes with Glycopyrrolate Over Atropine in Carotid Angioplasty and Stenting
Geometric and Morphological Analyses of the Superficial Femoral Artery by IVUS
National Outcomes and Charges for Claudication and Limbthreat: Angioplasty Versus Bypass Graft
Management of Dialysis-Dependent Patients With Critical Limb Ischemia
Socioeconomic and Hospital-Related Predictors of Amputation for Critical Limb Ischemia
Genetic Influences on Peripheral Arterial Disease in a Twin Population
Carotid Artery Disease and Peripheral Vascular Disease Are Both Independent Predictors of Long-term Mortality After Coronary Artery Bypass Grafting
Limb Salvage and Survival Rate After Endovascular Treatment of Infrapopliteal Artery Occlusion in Diabetic Patients With Critical Limb Ischemia
Outcomes of Excimer Laser Atherectomy for the Treatment of Infrainguinal Occlusive Disease in Patients With Critical Limb Ischemia
The 6L Irish Pivotal Trial Comparing Three-Year Outcomes of Cool Excimer Laser Assisted Angioplasty (CELA) and Tibial Balloon Angioplasty (TBA) in Management of Infragenicular Tibial Arterial Occlusion in Critical Lower Limb Ischaemia (CLI) TASC D E
Vascular Surgery in the Elderly Patient—Should Age Affect Treatment Strategy?
Durability of Endovascular Treatment of Iliac Artery Occlusions
Etiological Analysis and Experience of Diagnosis and Treatment in Young Patients Who Had Peripheral Arterial Disease
Surgical Implications of Failed Stenting of the Superficial Femoral Artery
Isolated Endarterectomy of Femoral Bifurcation in Critical Limb Ischemia (CLI): Is Restoration of Inline Flow Essential?
Do Objective Performance Goals (OPGs) for Critical Limb Ischemia (CLI) Apply to Everyday Vascular Surgery Practice?
The Use of Distal Arterial Access for Difficult Femoropopliteal Subintimal Angioplasty
Infrainguinal Bypass vs Endovascular Interventions for Primary Treatment of Claudication
Long-term Outcome After Surgical Intervention for Common Femoral Artery (CFA) Occlusive Disease
The Gore PROPATEN® Vascular Graft, a Prosthetic Conduit for all Arterial Bypass Positions
Comparison of Endovascular and Open Popliteal Artery Aneurysm Repair
Outcome of Leg Bypasses Using Less Than 3 mm Vein Conduit in Critical Leg Ischemia
Short-term Patient-Reported Outcomes of Open and Endovascular Treatment of Peripheral Arterial Disease
Patient Awareness on Vascular Disease Risk Factors? A Study of 916 Volunteers
Management of Median Arcuate Ligament Syndrome (MALS) with Decompression and Coeliac Ganglion Sympathectomy (CGS) for Chronic Mesenteric Ischaemia (CMI). Procedural, Clinical and Enduring Results With Quality-Adjusted Time Spent Without Symptoms of Disease and Toxicity of Treatment (Q-TWiST)
Intravascular Ultrasound Is More Sensitive Than Angiography in the Diagnosis of Blunt Traumatic Aortic Injury
National Outcomes of Open and Endovascular Repair of Traumatic Transection of the Thoracic Aorta
Role of Intravenous Ultrasound in Assessment of Iliac-Femoral Vein Stenosis
Postoperative Morbidity and Mortality of Venous Thrombectomy: A Review of the NSQIP Database
Deep Venous Thrombosis (DVT) in Critically Ill Trauma Patients: There Are No Low-Risk Patients
Does Topical Wound Oxygen (TWO2) Offer an Improved Outcome Over Conventional Compression Dressings (CCD) in the Management of Refractory Non-healing Venous Ulcers (RVU)? Three-Year Technical and Clinical Outcome and Midterm Results With Quality-Adjusted Time Spent Without Symptoms of Disease and Toxicity of Treatment (Q-TWiST)
A Systematic Review on the Effectiveness of Knee Versus Thigh Length Graduated Compression Stockings in Thromboprophylaxis for Surgical Patients
Clinical Outcome Analyses of Radio-Frequency Ablation (RFA) in the Treatment of Incompetent Greater Saphenous Vein (GSV): Differences Between ClosurePlus and ClosureFast Catheters
Value and Limitations of Repeat VNUS Closure of the GSV
The Role of Ultrasound to Identify Non-thrombotic Lower Extremity Pathology
Clinically Significance Incidental Computed Tomographic (CT) Finding in Patients Undergoing Endovascular Aortic Aneurysm Repair
Spectrum of Presentation of Thoracic Outlet Syndrome in Adolescents
The Cranial Radiation Exposure of Vascular Interventionalists
Effects of Anesthesia Versus Regional Nerve Block on Major Leg Amputation Mortality Rates
The Comparison of Continuous Electrocardiography Monitoring Devices for the Detection of New-Onset Arrhythmias During Vascular Surgery
Effectiveness of Vascular Sealant® Compared With GELFOAM®/Thrombin for Control of Anastomosis Suture Line Bleeding: A Prospective, Randomized, Multi-center Trial
Radiation Dose Optimization for Endovascular Aneurysm Repair (EVAR)
Ultrasonic Debridement for the Treatment of Infected Grafts
Presentation, Management and Outcome of Femoral Anastomotic Pseudoaneurysms in the Era of Endovascular Interventions
Post-Discharge 30-Day Mortality After Vascular Surgery
Durable Effect of Nitric Oxide at Inhibiting Neointimal Hyperplasia Is due to Modulation of Cellular Populations Throughout the Arterial Wall
Toll-like Receptors 2 and 4, but Not RAGE Deficiency Results in Greater Muscle Necrosis 2 Weeks After Hind-limb Ischemia: Implications for Muscle Recovery After Ischemic Injury
A Specific Inhibitor of IGF-1 Receptor - Picropodophyllin Can Suppress Atheroma Progression and Has a Stabilizing Effect on Atherosclerotic Lesions in ApoE Deficient Mice
Cytostatic Gene Therapy: RNAi-Mediated Survivin Knockdown Induces Cell Cycle Arrest, Polyploidy, and Reduced Migration of Vascular Smooth Muscle Cells (VS MC)
Surgical Restoration of Flow Following Prolonged Ischemia Inhibits Neuromuscular Recovery in a Porcine (Sus Scrofa) Model of Extremity Vascular Injury
Human Adult Stem Cells Restore Endothelial Migratory Dysfunction in a Hypoxic Environment
Estrogen Stimulates the Cellular Processes of Intimal Hyperplasia Development via ERK1/2 Dependent Signaling Cascades
Short-term Diet Induced Obesity Drives Negative Vein Graft Remodeling
Effect of Remote Ischemic Preconditioning in Liver Ischemia—Reperfusion Injury Produced by Supraceliac Aortic Cross-clamping in a Swine Model of Open Repair of Thoracoabdominal Aortic Aneurysm
Peroxiredoxin-2 as Circulating Biomarkers for Small Abdominal Aortic Aneurysm Progression: A Proteomic View
An Aortic Model for Physiological Assessment of Aortic Stent-grafts and In Vitro Compliance Measurement
Nogo-B Protein Modulates Intimal Thickening During Vein Graft Adaptation
Nitric Oxide Decreases the Expression of the 11S Proteasome Activator In Vivo
Cilostazol Causes Angiogenesis Mediated Through the Enhancement of Nitric Oxide Production in Athe Ischemic Hindlimb of Mouse
A Novel In Vitro Model of Chronic Venous Insufficiency
Expression of the Heat Shock Protein HSPB1 Is Associated With Impaired Smooth Muscle Relaxation
A Mouse Model of Vascular Grafting
Hydrophilic Surface Treatment of Thin Film Nickel Titanium Reduces Bacterial Biofilm Production Compared to Commercially Available Endograft Materials
Regulation of Endothelin-1 and Endothelin Receptors by Shear Stress in Vascular Smooth Muscle Cells
Edaravone Suppresses Reperfusion Injury After Leg Ischemia in Rat Models
Ethyl Pyruvate Prevents Delayed Paralysis in a Murine Model of Spinal Cord Ischemic Injury
Long-term Results of Aorto-Arterial Surgery in Children With Renovascular Hypertension From Mid Aortic Syndrome With and Without Involvement of Renal and Mesenteric Arteries: Single-Center Experience in 44 Cases
Sudden Death During Follow-up After New-onset Ventricular Tachycardia's in Vascular Surgery Patients
Combined Endovascular and Surgical Treatment of Severe (TASC D) Aortoiliac Occlusive Disease
A Regional Quality Improvement Effort to Increase Preoperative Beta-Blocker Utilization
Peripherally Inserted Central Catheter (PICC) Usage Patterns and Associated Upper Extremity Venous Thrombosis
Vascular Surgery Board Analysis of the Surgical Operative Experience of Trainees and Practicing Vascular Surgeons
Technique for Supraceliac Balloon Aortic Control During EVAR for Ruptured Abdominal Aortic Aneurysms
Standardization Is Superior to Traditional Methods of Teaching Simulated Vascular Anastomoses
Acute Mesenteric Ischemia: A Comparison of Endovascular Revascularization to Traditional Therapy
Routine Venography Following Transaxillary First Rib (FRRS) Resection for Subclavian Vein Thrombosis Ensures Excellent Outcomes and Vein Patency
Open Surgical and Hybrid Reconstructions for Non-malignant Occlusion of the Iliofemoral (IF) Veins and the Inferior Vena Cava (IVC): Factors Affecting Long-term Outcome
Endovascular Solutions to Arterial Complications Resulting from Posterior Spine Surgery
Derivation and Validation of a Practical Risk Score for Mortality After Repair of Ruptured Abdominal Aortic Aneurysms and Comparison to Existing Models in a U. S. Regional Cohort
Outcome of EVAR for Small Abdominal Aortic Aneurysms: Results From a 5-Year Prospective Clinical Trial
Left Subclavian Artery Coverage During Endovascular Thoracic Aortic Repair and Risk of Perioperative Stroke or Death
Sideways Movement of the Endograft Within the Aneurysm Sac Is Associated With Late Adverse Events
Continued Favorable Results With Type IV Thoracoabdominal Aortic Aneurysm Repair
Five-Year Experience with Pararenal Endovascular Aortic Repair (PEVAR) Without Fenestration. Clinical Efficacy, Reintervention Rates & Cost-effectiveness Compared With Open Surgical Repair (OSR) in a High Deliberare Practice Volume Centre
Accommodating Complex Aortic Neck Morphology During EVAR: A Prospective Analysis of Stentgrafts With Suprarenal Fixation
Long-term Results of Endovascular Repair of Paraanastomotic Aneurysms After Previous Conventional Aortic Prosthetic Reconstruction
Success of Type 2 Endoleak Embolization for Abdominal Aortic Aneurysm (AAA) Sac Enlargement
Aneurysmal Iliac Arteries Do Not Portend Future Iliac Aneurysmal Enlargement After EVAR for AAA
A Population-Based Study of Polymorphisms in Genes Related to Sex Hormones and Abdominal Aortic Aneurysm
Disease Progression Following Initial Surgical Intervention for Takayasu's Arteritis
Comparison of Percutaneous Versus Open Repair of Femoral Arteries During Aortic Endovascular Aortic Repair
In Vivo Displacement Force (DF) Is Higher in Patients Who Experience Aortic Endograft Migration: A 3D Computational Analysis
Outcomes of Carotid Artery Stenting Versus Historical Surgical Controls in Patients With Radiation-Induced Carotid Stenosis, With or Without Prior Neck Dissection
Changing Trends in Assessment and Management of Carotid Body Tumors: A 35-Year Experience
Learning Curve Associated With the Use of the Carotid Flow Reversal System
Open AAA Repair Is Feasible and Can Be Done With Excellent Results in Octogenarians
Carotid Artery Disease: Risk Factor Analysis in a Cohort of 3.9 Million Individuals
Influence of Vascular Access Type on Gender and Ethnicity Related Mortality in Hemodialysis Patients
Duplex-Guided Balloon-Assisted Mturation (BAM) of Arteriovenous Fistulas (AVF) in the Office
Medical Student Career Survey: Vascular Surgery Awareness Initiative
Comparison of Patient Characteristics Between Spontaneous Isolated Superior Mesenteric Artery Dissection and Combined Aortic and Superior Mesenteric Artery Dissection
Infrainguinal Bypass Is Associated Wth Higher Survival Tan Major Amputation in Patients With Severe Comorbidities
Iliac Artery Stenting Combined With Open Femoral Endarterectomy Is As Effective As Open Surgical Reconstruction for Severe Aortoiliac and Common Femoral Occlusive Disease
Longitudinal Outcomes After Tibioperoneal Angioplasty in the US Medicare Population: In-hospital and 30-Day Outcomes
Effect of Physician and Hospital Experience on Patient Outcomes for Endovascular Treatment of Aortoiliac Occlusive Disease
Wall Composition of Popliteal Artery Aneurysms Differs From Abdominal Aortic Aneurysms
LEAP Classification Predicts Lower Extremity Amputation and Mortality in Diabetic Patients
Intraoperative DynaCT During Endovascular Aneurysm Repair
Peak Perioperative Troponin I Levels With The Revised Cardiac Risk Index Predict Outcomes Following Vascular Surgery
Positional Compression of the Axillary Artery in the Thoracic Outlet: The Spectrum of Lesions in the Overhead Athlete
Iatrogenic Arterial Complications of Spine and Orthopedic Operations
Inflammatory Biomarkers and Clinical Characteristics Diagnose Deep Venous Thrombosis
Endovenous Ablation of the Greater Saphenous Vein—Significance of Proximal Venous Tributaries