Prevalence of Tinnitus in Patients Diagnosed with Cerebral Arteriovenous Fistula Treated with Endovascular Technique

Abstract Introduction Tinnitus is characterized as the conscious and involuntary perception of sound, and it affects ~ 30% of the population. Despite careful physical examination, the etiology of tinnitus can be established for only 30% of patients. Tinnitus is a common symptom of cerebral arteriovenous fistulas and results from increased blood flow through the dural venous sinuses, leading to turbulent arterial flow, mainly related to sigmoid and transverse sinus lesions. Objectives To analyze the frequency of tinnitus, patient profile, and endovascular treatment characteristics in individuals diagnosed with cerebral arteriovenous fistulas. Methods A retrospective and observational study based on reviewed data from medical records on the PHILIPS Tasy system (Philips Healthcare, Cambridge, MA, USA) at the neurosurgery and interventional neuroradiology service of Hospital Santa Isabel in Blumenau-state of Santa Catarina, Brazil. Results The profile of 68 individuals diagnosed with cerebral arteriovenous fistula who underwent endovascular treatment were analyzed. Most patients were female, aged 31 to 60. Tinnitus affected 18 individuals. Dural fistulas were the most prevalent in the sample, and computed tomography alone was the most used diagnostic method for initial investigation. Conclusion The prevalence of this symptom in patients diagnosed with cerebral arteriovenous fistula was found in 26.5% of this sample, mainly in women with associated comorbidities. Tinnitus remission was observed in all patients who underwent endovascular treatment to correct cerebral fistula.

Limb ischemia in patients with COVID-19 / Isquemia de membros em pacientes com COVID-19

Abstract This narrative review covers the life-threatening thromboembolic events associated with SARS-CoV-2 infection/COVID-19. It addresses the physical changes that cause vascular and arterial damage to limbs, laboratory management of coagulation, and management of anticoagulation. COVID-19's relationship with deep venous thrombosis and arterial thrombosis is also emphasized. The main thromboembolic events described in the literature are illustrated with examples from our experience with COVID-19 patients.

Resumo Esta revisão narrativa abrange os eventos tromboembólicos com risco de vida associados a infecção por SARS-CoV-2/COVID-19. Aborda as mudanças físicas que causam danos vasculares e arteriais aos membros, o manejo laboratorial da coagulação e o manejo da anticoagulação. A relação de COVID-19 com trombose venosa profunda e trombose arterial também é enfatizada. Os principais eventos tromboembólicos descritos na literatura são ilustrados a partir de nossa experiência com pacientes COVID-19.

Manejo endovascular de la estenosis ilíaca-bilateral mediante la técnica de kissing stent / Endovascular management of bilateral iliac stenosis using the kissing stent technique

La enfermedad aorto-ilíaca es una entidad que, por su localización y distribución, plantea un reto para el radiólogo intervencionista. Existen diferentes técnicas endovasculares que ofrecen una buena permeabilidad a mediano y largo plazos, a partir de una selección apropiada de los pacientes. Este artículo tuvo como objetivo caracterizar la técnica de kissing stent como una alternativa terapéutica más, mínimamente invasiva, en los pacientes con enfermedad aorto-ilíaca. En este sentido, se presenta el caso de una mujer de 60 años con claudicación intermitente de 3 meses de evolución, con cambios tróficos de la piel a predominio derecho, en quien se documentó una estenosis aorto-ilíaca bilateral según el Trans-Atlantic Inter-Society Consensus Working Group II tipo A. Se realizó angioplastia con balón y stent autoexpandibles de ambas ilíacas comunes mediante la técnica de kissing stent. En el seguimiento anual, la paciente toleró el ejercicio, y al examen físico, los pulsos periféricos estuvieron presentes. Además, el manejo endovascular de las lesiones estenótica aorto-ilíacas mediante la técnica de kissing stent resulta segura, menos cruenta y con buenos resultados a mediano plazo, que se debe sustentar en una selección apropiada de los pacientes(AU)

Aortoiliac disease is an entity that, due to its location and distribution, poses a challenge for the interventional radiologist. There are different endovascular techniques offering good permeability in the mid- and long terms, based on appropriate selection of patients. This article aimed at characterizing the kissing stent technique as another minimally-invasive therapeutic alternative in patients with aortoiliac disease. In this respect, the case is presented of a 60-year-old woman with intermittent claudication of three months of evolution, with trophic changes of the skin, predominantly on the right side, and in whom a bilateral aortoiliac disease was documented as type A according to the Trans-Atlantic Inter-Society Consensus Working Group II. Balloon angioplasty and self-expanding stenting of both common iliac arteries were performed using the kissing stent technique. At annual follow-up, the patient tolerated exercise; and, on physical examination, peripheral pulses were present. In addition, endovascular management of aortoiliac disease stenotic lesions using the kissing stent technique is safe, less invasive and present good outcomes in the midterm, which must be based on appropriate selection of patients(AU)

Invention of the Guide Catheter Irrigation Monitoring Device for Neuroendovascular Therapy

OBJECTIVE: The thromboembolic events during neuroendovascular therapy (NET) are the major complications of concern that can be occasionally fatal. The thrombotic occlusion of the guide catheter for NET is thought to be the risk of the thromboembolic events. We have developed an idea for inventing the monitoring system of the continuous irrigation through the guide catheter. We herein present a unique invention of the guide catheter irrigation monitoring device. METHODS: We have developed ideas for preventing the thrombotic occlusion of the guide catheter. In order to design a convenient device working in the practical use, we have consulted and shared the ideas with the electrical engineers about putting the invention. RESULTS: The guide catheter irrigation monitoring device (GCIMD) consisted of three parts of optical sensor, main body and electric adapter. In brief, the basic principles of working of the GCIMD are as follows. The optical sensor is attached to the dripping chamber of the line to irrigation solution. The main body had the small light and speaker to make an alarm sounds. The sensor monitors the dripping of flush solution. If the dripping stops more than three seconds, a warning alarm has been activated. So, the operating physicians can concentrate and check the guide catheter irrigation. After the use of the GCIMD, there was no major thromboembolic complication in conjunction with the thrombotic occlusion of the guide catheter in our institute. CONCLUSION: We have developed a brilliant invention of the GCIMD for NET.

Fusiform Superior Cerebellar Artery Aneurysm Treated with Endovascular Treatment

An aneurysm of the distal superior cerebellar artery (SCA) is a highly rare disease. Fusiform aneurysms of the distal SCA are particularly challenging to treat. Clipping, trapping with or without bypass using microsurgery or endovascular treatment (EVT) were used to treat this condition. We describe the case of fusiform distal SCA aneurysms treated successfully with endovascular coiling with a 3-month follow-up. A 39 year-old male was presented with subarachnoid hemorrhage (SAH) and a 15 mm fusiform aneurysm of the ambient segment of the left distal SCA. EVT for parent artery occlusion and packing of the aneurysm was done. Left sixth nerve palsy appeared after 1 day of EVT. The symptom completely recovered within 1 week of the post-procedural period. No neurological deficit was seen during the clinical 3-month follow-up. EVT of fusiform distal SCA aneurysms with coils is a safe and feasible option to manage this rare condition. However, the treatment options must be carefully selected depending on the neurologic condition, development of collateral circulation, and configuration of the dissection.

Open-cell Stent Deployment across the Wide Neck of a Large Middle Cerebral Aneurysm Using the Stent Anchor Technique

We describe a case of successful open-cell stent deployment across the wide neck of a large middle cerebral artery aneurysm using the stent anchor technique. A microcatheter was looped through the aneurysm and navigated into a distal vessel across the aneurysm neck. Although the loop of the microcatheter in the aneurysm straightened as it was gently withdrawn, the microcatheter again protruded into the aneurysm by open-cell stent navigation. The stent was partially deployed in a vessel distal to the aneurysm neck, withdrawn slowly to straighten the loop of the microcatheter in the aneurysm, and completely deployed across the aneurysm neck. After successful stent deployment, stent-assisted coil embolization was performed without complications. The stent anchor technique was successfully used to deploy an open-cell stent across the aneurysm neck in this case of microcatheter protrusion into the aneurysm during stent navigation.

Efficacy of minimally invasive endovascular techniques treatment of hydronephrosis with infection during pengnancy / 中国组织工程研究

To investigate the efficacy and safety of minimal y invasive endovascular techniques treatment of hydronephrosis in pregnancy complicated by infection. 65 cases of pregnancy hydronephrosis coinfected patients with minimal y invasive endovascular treatment. Patients were fol owed up for 3-12 months, compared with 48 patients with the same period of conservative treatment . Ureteral perforation and other surgery-related complications occurred in 65 patients in the observation group has not occurred. The patient's duration of hospitalization、the recurrence rate of postoperative infection, antibiotic duration of treatment, fever days were significantly lower than the control group(P Compared with conservative treatment, minimal y invasive endovascular technical treatment of gestational hydronephrosis co-infection with faster recovery, shorter hospital stay, can significantly reduce the number of days of fever patients and reduce the number of days of antibiotic use, can be used as conventional means of treatment of gestational hydronephrosis infection combined conventional.

Outcomes of Endovascular Mechanical Thrombectomy and Intravenous Tissue Plasminogen Activator for the Treatment of Vertebrobasilar Stroke

BACKGROUND AND PURPOSE: Aggressive treatment of posterior-circulation occlusions is important due to the high rates of morbidity and mortality associated with these infarctions. A large administrative database was evaluated to determine the outcomes of mechanical thrombectomy and intravenous tissue plasminogen activator (IV-tPA) for the treatment of posterior-circulation (vertebrobasilar) strokes. Outcomes were compared across age groups. METHODS: The United States Nationwide Inpatient Sample was used to evaluate the outcomes of patients treated for posterior-circulation acute ischemic stroke between 2006 and 2010. Patients who underwent endovascular mechanical thrombectomy and IV-tPA were selected. Primary outcomes were discharge status and mortality; secondary outcomes were length of stay, rate of intracranial hemorrhage, tracheostomy, and percutaneous endoscopic gastrostomy/jejunostomy tube placement. Outcomes were grouped according to age (i.e., or =65 years). Chi-squared test and Student's t-test were used for comparisons of categorical and continuous variables, respectively. RESULTS: During 2006-2010 there were 36,675 patients who had discharge International Classification of Diseases (9th edition) codes indicating posterior-circulation strokes. Of these, 631 (1.7%) underwent mechanical thrombectomy and 1554 (4.2%) underwent IV-tPA. The in-hospital mortality rate for mechanical thrombectomy patients was significantly lower for those aged or =65 years (30.4% versus 43.0%, p or =65 years (p=0.92). CONCLUSIONS: Patients requiring IV-tPA and/or mechanical thrombectomy for the treatment of posterior-circulation strokes suffer from high mortality rates. Increased age is associated with significantly higher mortality rates among posterior-circulation stroke patients who require mechanical thrombectomy.

Endovascular Repair of a Juxtarenal Abdominal Aortic Aneurysm Using a Chimney Graft / 대한내과학회지

An endovascular repair of an abdominal aortic aneurysm (AAA) is technically less invasive than open surgery, but gives results as effective as open surgery if the anatomy is adequate. Unfortunately, 20-30% of AAA patients are not suitable for endovascular repair because they lack a sufficient proximal landing zone. In an effort to broaden the applicability of endovascular repair, the chimney technique has been introduced. This refers to deployment of a covered or bare-metal stent parallel to the main aortic endograft within the aneurysm, creating a conduit that runs outside the main aortic endograft into the aortic branches. We report the case of a 75-year-old male with a juxtarenal abdominal aortic aneurysm and multiple comorbidities who was treated successfully with an endovascular aneurysm repair using a chimney graft.

Endovascular Repair of a Juxtarenal Abdominal Aortic Aneurysm Using a Chimney Graft / 대한내과학회지

An endovascular repair of an abdominal aortic aneurysm (AAA) is technically less invasive than open surgery, but gives results as effective as open surgery if the anatomy is adequate. Unfortunately, 20-30% of AAA patients are not suitable for endovascular repair because they lack a sufficient proximal landing zone. In an effort to broaden the applicability of endovascular repair, the chimney technique has been introduced. This refers to deployment of a covered or bare-metal stent parallel to the main aortic endograft within the aneurysm, creating a conduit that runs outside the main aortic endograft into the aortic branches. We report the case of a 75-year-old male with a juxtarenal abdominal aortic aneurysm and multiple comorbidities who was treated successfully with an endovascular aneurysm repair using a chimney graft.

Balloon Anchor Technique for Pipeline Embolization Device Deployment Across the Neck of a Giant Intracranial Aneurysm

Treatment of giant intracranial aneurysms, via either surgical or endovascular approaches, is associated with a high level of technical difficulty as well as a high rate of treatment-related morbidity and mortality. Flow-diverting stents, such as the Pipeline embolization device (PED), have drastically altered the therapeutic strategies for the treatment of giant aneurysms. Gaining endovascular access using a microcatheter to the portion of the parent artery distal to the aneurysm neck is requisite for safe and effective stent deployment. Giant aneurysms are often associated with vascular tortuosity, which necessitates significant catheter support systems to enable maneuvering of PEDs across the aneurysm neck. This is also required in order to reduce the probability of stent herniation within giant aneurysms. We report on a case of a giant supraclinoid internal carotid artery (ICA) aneurysm which was treated successfully with a PED utilizing a balloon anchor technique to facilitate direct microcatheter access across the aneurysm neck.

A Case of Abdominal Aortic Aneurysm with Short Angulated Proximal Neck Treated with the Chimney Graft Technique

Endovascular aneurysm repair (EVAR) using stent grafts has shown to be an effective alternative to surgical repair in treating an abdominal aortic aneurysm (AAA). EVAR is associated with shorter hospital stays, less blood loss, shorter operating times, and lower early morbidity and mortality compared to open surgical repair, although EVAR required a higher reintervention rate during a longer follow-up period. However, short or severely an angulated infrarenal proximal aortic neck is considered unsuitable for EVAR. The chimney graft technique is a modified procedure based on the deployment of a covered or bare-metal stent parallel to the main aortic endograft within the aneurysm, thereby creating a conduit that runs outside the aortic main endograft to preserve flow to the aortic branches. In this case report, we present a 78-year-old patient with an AAA with a short and severely angulated proximal neck who was successfully treated by EVAR using the chimney graft technique.

Cirugía abierta versus cirugía endovascular en el tratamiento de la patología de la aorta torácica descendente / Open Surgery versus Endovascular Surgery in the Treatment of the Descendent Thoracic Aortic Disease

Introducción: El reparo endovascular de la aorta torácica (REVAT) se ha incrementado en el mundo en los últimos años con relación al abierto. Objetivo: Comparar los resultados clínicos del REVAT frente al reparo abierto en la Fundación Cardio Infantil (Bogotá, Colombia) entre 2002 y 2011. Metodología: Análisis retrospectivo de la cohorte de pacientes sometidos a reparo abierto (grupo 1) en comparación de REVAT (grupo 2). En cada uno de los grupos se evaluó tiempo quirúrgico, tasa de morbilidad, mortalidad, reintervención y estancia hospitalaria. Resultados: Se incluyeron 57 pacientes en el análisis (26 % reparo abierto; 74 % REVAT). Se reintervinieron dos pacientes por endofugas tipo 1 en el grupo 2 y un caso por sangrado en el grupo 1. La mortalidad operatoria fue para el grupo 1 de 20 %, y para el grupo 2, de 2,3 %. El tiempo quirúrgico fue de 398 ± 180 min (grupo 1) versus 85,5 ± 35 min (grupo 2 (p = 0,0001) y el tiempo de estancia hospitalaria promedio fue de 9,8 días (grupo 1) y 5,3 días (grupo 2) [p = 0,01]). El tiempo promedio de seguimiento fue 4,8 ± 3,1 años. Conclusiones: El REVAT parece ofrecer menor morbilidad, mortalidad, tiempo quirúrgico y estancia hospitalaria respecto al reparo abierto, aunque las poblaciones de pacientes incluidos no fueron estrictamente comparables. Se requieren nuevos análisis en un diseño prospectivo, idealmente aleatorizado para documentar los beneficios a largo plazo de este tipo de reparo...

Introduction: Thoracic Endovascular Aortic Repair(TEVAR) has increased worldwide morethan open repair in the last few years. Objective:To compare clinical outcomes of TEVARversus open surgery at Fundación Cardio Infantil(Bogota, Colombia), between 2002 and 2011.Methods: Retrospective analysis of the cohort ofpatients with open repair (group 1) in comparisonto TEVAR (group 2). In each group, surgicaltime, morbidity rates (infection, hemorrhage,medular ischemia, cerebrovascular event, andpostoperative renal failure), mortality, reintervention,and hospital stay were evaluated. For comparisonsa univariate analysis was used, being a p< 0.05 statistically significant. Results: 57 patientswere included (26 % open repair; 74 % TEVAR).Two type 1 endoleaks on group 2 and 1 bleedingpatient in group 1 required a second surgery. Surgicalmortality was 20 % in group 1, and 2.3 % ingroup 2); surgical time was 398 ± 180 (group 1)versus 85.5 ± 35 min (group 2) (p = 0.0001); andhospital stay was 9,8 days (group 1) and 5.3 days(group 2). Average follow-up time was 4.8 ± 3.1years. Conclusions: TEVAR may be associatedwith less morbidity, mortality, surgical time, andhospital stay than open repair, although the populationsincluded were not strictly comparable.New, prospective studies, ideally randomized,are needed to support the long term benefits ofthis type of repair...

Direct Percutaneous Alcohol Sclerotherapy for Venous Malformations of Head and Neck Region without Fluoroscopic Guidance: Technical Consideration and Outcome / 신경중재치료의학

PURPOSE: Alcohol is not used directly to the vascular lesion without mixing with the contrast agent because alcohol itself cannot be seen on the fluoroscopy. Since we have used alcohol for the venous malformations in the head and neck area, we realized that alcohol can be safely and effectively used without using fluoroscopy. We present the method of direct sclerotherapy using absolute alcohol without using fluoroscopy. MATERIALS AND METHODS: After obtaining and carefully analyzing direct puncture venogram, we used this technique in 22 patients who underwent alcohol sclerotherapy. Because fluoroscopy was not used during alcohol injection, the angiotable can be placed outside of C-arm so that alcohol was comfortably injected without any obstacle around the patients. Venogram can also be obtained between the injections to detect whether there is any dangerous venous outflow drainage such as the superior ophthalmic vein to the cavernous sinus. To control the venous outflow, local compression to the draining vein was applied. The result and complication such as skin necrosis, infection, and nerve injury were evaluated during mean follow-up period of 13 months (range, 1-63 months). RESULTS: The frequency of sclerotherapy was one in 16 and 2-5 in 6 patients. The volume of alcohol used per treatment session ranged from 2 to 18 mL (mean, 8.5 mL). There was the minimum change in 1 (4.5%), moderately decreased lesion in 12 (54.5%), and markedly decreased lesion in 9 (41%) patients. The patients did not reveal any complications during 12.9 months follow-up period. CONCLUSION: Direct puncture alcohol sclerotherapy without using fluoroscopy can be a safe and effective technique for treating venous malformation of the head and neck areas. In addition, the procedure can be performed in the comfortable position because biplane fluoroscopy would not be necessary.

The Use of Protection Device in Landmark-wire Technique of Symptomatic Subclavian Artery Occlusion with Combined Approach via Trans-femoral vs. Trans-brachial Arteries: Technical note / 신경중재치료의학

PURPOSE: Since we reported about a landmark technique to reopen an occluded subclavian artery, we have faced difficulty in using protection devices in the vertebral artery to protect against thromboembolism from the reversed steal phenomenon after angioplasty and stenting. Therefore, we are presenting an optimal solution in using a protection device while recanalizing the occluded subclavian artery. MATERIALS AND METHODS: Among 21 cases of stenting for subclavian artery steno-occlusion, we applied the landmark technique at the opposite end of an occluded segment in 4 patients and used a protection device in two patients. Because the embolic protection device was placed in the vertebral artery via the brachial artery, optimal angioplasty and stenting via the brachial route were limited. Therefore, angioplasty via the trans-brachial approach was needed to be followed by stenting through a trans-femoral approach. We estimated the safe and optimal steps for placement and retrieval of the protection devices in addition to stenting. RESULTS: The procedure was safely performed when a stent was introduced via the femoral artery and a protection device was used via the brachial artery. However, in cases when a guidewire wasn't passed via the transfemoral route, simultaneous use of two systems via the brachial route could cause friction of devices or trapping of protection devices in a stent. When a protection device was trapped in a deployed stent, we retrieved the protection device with a 4F angiocatheter by selectively rotating the catheter tip. To avoid such procedural difficulty, we recommend using a transbrachial angioplasty followed by trans-femoral stenting while placing the protection device in the vertebral artery via the trans-brachial route. CONCLUSION: If a guidewire is not passed through using a trans-femoral approach while performing the landmark technique, changing the stenting route from brachial to the femoral artery can be useful after securing the lumen in the occluded subclavian artery after angioplasty via the brachial artery.

Z-Shaped Microcatheter Tip Shaping for Embolization of Aneurysms at the Proximal A1 Segment of the Anterior Cerebral Artery: A Technical Note / 신경중재치료의학

Embolization of an aneurysm at the proximal A1 segment of the anterior cerebral artery (ACA) is technically challenging. We treated four consecutive patients with unruptured aneurysms at the proximal portion of the A1 segment of the ACA. We tested various microcatheter tip shapes before we successfully embolized a lesion with a zigzag-shaped microcatheter tip, which was made by steam shaping. The shape of this microcatheter tip resembled the letter "Z", had a relatively long distal straight segment and was helpful in prompt catheterization of the aneurysm sac and stable placement of the catheter and delivery of coils.

Transvenous Embolization of Cavernous Sinus Dural Arteriovenous Fistula Using the Direct Superior Ophthalmic Vein Approach: A Case Report / 신경중재치료의학

Transvenous coil embolization has been successfully applied for the treatment of cavernous sinus dural arteriovenous fistula (CSDAVF). Unfortunately, the technique cannot be applied in cases of poor or absent inferior petrosal sinus or facial venous access route to the fistula. Recently, we experienced a successful embolization using direct superior ophthalmic vein approach in cases of CSDAVF which were no opacification of inferior petrosal sinus or facial vein.

Y-Stent–Assisted Coil Embolisation of Wide-Necked Aneurysms Using a New Fully Retrievable and Detachable Intracranial Stent: Report of Two Cases

Endovascular treatment of wide-necked aneurysms poses a challenge for the endovascular therapist. The Y-stent–assisted technique has been used for stent-assisted coil embolisation for wide-necked bifurcation aneurysms. This technique has been described for basilar tip aneurysms and middle cerebral artery bifurcation aneurysms using Neuroform and Enterprise stents. We report 2 cases of wide-necked bifurcation aneurysms that were treated with Y-stent–assisted coil embolisation using a new, fully retrievable and detachable intracranial stent (Solitaire ABTM). We describe the advantages of a fully retrievable and detachable stent and its feasibility of forming a Y configuration.

The Efficacy of Endovascular Treatment for Deep Vein Thrombosis / 대한흉부외과학회지

BACKGROUND: Deep vein thrombosis (DVT) is a serious disease that causes life-threatening pulmonary embolism and chronic venous insufficiency. Anticoagulation is the standard therapy for DVT. However, the results of standard anticoagulation for treating DVT have been disappointing, so endovascular treatment is commonly performed nowadays. The aim of this study was to evaluate the efficacy of an endovascular procedure for treating patients with DVT. MATERIAL AND METHOD: We retrospectively evaluated the clinical data of 29 DVT patients who underwent an endovascular procedure between December 2006 and July 2008. We compared the results of the 29 patients with the results of another 45 patients who were treated with only aspirin and heparin. RESULT: The patient's mean age was 55.4 years in the intervention group and 53.7 years in the control group. DVT occurred more frequently in the females. Catheter-directed thrombolysis was performed in 22 patients (75.8%). Aspiration thrombectomy was performed in 18 patients (62%) and a endovascular stent was placed in 25 patients (86.2%). Fifteen patients (51.7%) underwent percutaneous insertion of a retrievable IVC filter for the prevention of pulmonary embolism. In the control group, thirty nine patients (86.7%) were treated with low-molecular heparin, and seven patients (15.6%) who were contraindicated for warfarin were treated with aspirin. No bleeding complications occurred during thrombolysis or anticoagulation. We analyzed the statistical data according to recurrence of DVT and the incidence of post-thrombotic syndrome (PTS) during the follow-up period. The intervention group had a significantly lower incidence of PTS (p-value=0.008), but they had the same result as the control group for the recurrence of DVT. In addition, death from the DVT did not occur in the intervention group. Thus, we obtained better clinical outcomes in the intervention group as compared to those in the anticoagulation only group. CONCLUSION: Endovascular procedures are effective alternative modalities, as compared to systemic anticoagulation, for the treatment of DVT. But more studies are needed to determine the specific indications and to validate the long-term efficacy of endovascular procedures for the treatment of DVT.