Aspiration Thrombectomy as the Sole Treatment for Acute and Sub-acute Deep Venous Thrombosis (DVT) of the Lower Extremity: mid and long-term clinical results

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Aspiration Thrombectomy as the Sole

Treatment for Acute and Sub-acute

Deep Venous Thrombosis (DVT) of the

Lower Extremity: Mid and Long-term

Clinical Results

by

Anjali Basnyat Bista

Major in Medicine

Department of Medical Sciences

The Graduate School, Ajou University

Aspiration Thrombectomy as the Sole

Treatment for Acute and Sub-acute

Deep Venous Thrombosis (DVT) of the

Lower Extremity: Mid and Long-term

Clinical Results

by

Anjali Basnyat Bista

A Dissertation Submitted to The Graduate School of Ajou University

in Partial Fulfillment of the Requirements for The Degree of

Master of Medicine

Supervised by

Won Je Hwan, M.D., Ph.D.

Major in Medicine

Department of Medical Sciences

The Graduate School, Ajou University

This certifies that the dissertation

of Anjali Basnyat Bista is approved.

SUPERVISORY COMMITTEE

Won Je Hwan

Hong You Sun

Kim Jai Keun

The Graduate School, Ajou University

December 20th, 2011

ACKNOWLEDGEMENTS

I am heartily thankful to my supervisor, Prof. Dr. Won Je Hwan, who supported me throughout my years in Ajou University. It would have been impossible to accomplish this thesis without his help and guidance. His encouragement and help has led me to finish this thesis.

Thanks to my Professors and Colleagues at Ajou University Hospital who taught me a lot and guided me during my study period at Ajou University. I would like to give my special thanks to Nurse Ahn Hyejung for her invaluable help in telephone follow ups of the patients.

I am grateful to NIIED and KGSP for granting me the opportunity to study in Korea. Finally, I would like to thank my parents, Dr. Ramesh Bahadur Basnyat and Jayanti Basnyat, my father-in-law Hon. Keshar Bahadur Bista, and my mother-in-law Minerwa Bista, who have given me their unconditional love and encouragement throughout my life. Last but not least, I would like to thank my husband Biraj Bahadur Bista, and my dear son Kaibalya Bahadur Bista who have been with me through my ups and downs and inspired me to complete this thesis.

i - ABSTRACT -

Aspiration Thrombectomy as the Sole Treatment for Acute and

Sub-acute Deep Venous Thrombosis (DVT) of the Lower

Extremity: Mid and Long-term Clinical Results

Purpose: To determine the feasibility of aspiration thrombectomy as the sole treatment

for acute and sub-acute deep vein thrombosis of the lower extremity by evaluating the mid and long-term clinical results of aspiration thrombectomy treatment.

Patients and methods: During a five year period (2005-2010), 108 patients with acute

and sub-acute DVT of the lower-extremity underwent aspiration thrombectomy with 9-10 guiding catheters, after insertion of a temporary inferior vena cava (IVC) filter. The inclusion criteria were patients with acute or sub-acute iliofemoral or femoropopliteal DVT of less than 4 weeks duration, with or without IVC extension. If post procedure venography demonstrated persistent stenosis or residual thrombosis, adjunctive therapy was performed by balloon angioplasty, or stent placement. The aspirate was filtered and the amount of aspirated blood separated from the clot was measured. Adjuvant thrombolysis with urokinase was performed when the aspirated blood was over 400 ml or when the aspiration thrombectomy was incomplete.

ii

Results: Anatomical success was achieved in 92/108 (85%) patients after aspiration

thrombectomy treatment of the thrombosed veins. In 16 patients with residual thrombosis after thrombectomy (grade I to grade II lysis), additional thrombolysis was performed using urokinase. Seventy nine of 108 (73%) patients had residual venous stenoses post aspiration thrombectomy that were treated with stent placement and balloon angioplasty. There was no mortality associated with the procedure. On mid-term follow up, 61/75 patients (81.3%) had no recurrence of DVT and 14 patients (18.7%) demonstrated DVT recurrence. Fifty five patients (73.3%) were asymptomatic on mid-term follow-up and 20/75 (26.6%) had symptoms related to DVT. In the 52 patients who remained during long-term follow up, 41/52 (78.8%) had no recurrence of DVT and DVT recurrence was seen in 11/52 (21.1%). Thirty seven patients (71.1%) were asymptomatic on long-term follow-up and 15/52 (28.8%) were symptomatic.

Conclusion: Aspiration thrombectomy is a safe, effective and economic treatment for

acute proximal DVT. It showed similar clinical results with other treatment methods in mid and long term follow-up without any major complications.

Keywords: Deep venous thrombosis, Thrombolysis, thrombectomy, catheter, May Thurner syndrome

iii

TABLE

OF

CONTENTS

ABSTRACT ··· i

TABLE OF CONTENTS ··· iii

LIST OF FIGURES ··· iv

LIST OF TABLES ··· v

ABBREVIATIONS ··· vi

Ⅰ. INTRODUCTION ··· 1

Ⅱ. MATERIALS AND METHODS ··· 7

A. MATERIALS ··· 7

1. Study population ··· 7

B. METHODS ··· 10

1. Procedure notes ··· 11

2. Definitions and statistical analysis ··· 16

3. Follow up ··· 16 Ⅲ. RESULTS ··· 17 Ⅳ. DISCUSSION ··· 23 Ⅴ. CONCLUSION ··· 30 REFERENCES ··· 31 국문요약 ··· 36

iv

LIST OF FIGURES

Fig. 1.

Removal of the Günther Tulip filter

··· 12

Fig. 2.

Removal of the Cordis OptEase filter

··· 12

Fig. 3. May Thurner syndrome with DVT ··· 22

v

LIST OF TABLES

Table 1. Patient characteristics in the total study population ... 8

Table 2. DVT location in total study population ... 9

Table 3. Identified risk factors before the procedure in the study group ... 10

Table 4. Location of the stents ... 14

Table 5. Stented patient group characteristics ... 14

Table 6. Location of DVT in the stented patients ... 15

Table 7. Recurrence of DVT on mid-term follow up ... 18

Table 8. DVT recurrence and symptomatic patients on mid- and long-term follow up ... 19

Table 9. Recurrence of DVT on long-term follow up ... 19

vi

ABBREVIATIONS

ACCP - American College of Chest Physicians

AIDA- Assessment of the incidence of deep-vein thrombosis in Asia CaVenT - Catheter-directed Venous Thrombolysis

CDT - Catheter-Directed Thrombolysis CT - Computerized Tomography DVT - Deep Vein Thrombosis Hb- Hemoglobin

HIRA - Health Insurance Review and Assessment Service IFDVT - Iliofemoral Deep Vein thrombosis

INR - International Normalized Ratio IVC - Inferior vena cava

LMWH - Low Molecular Weight Heparin

MDCT- Multi-detector Computerized Tomography MTS- May Thurner Syndrome

PE - Pulmonary Embolism

PMT- Pharmacomechanical Thrombolysis PTA - Percutaneous Transluminal Angioplasty PTS - Post-thrombotic Syndrome

QOL- Quality of life

SIR- Society of Interventional Radiology UFH- Unfractioned Heparin

vii UK - Urokinase

VCHH- Valve Cusp Hypoxia Hypothesis VKA- Vitamin K antagonist

VT- Venous Thrombosis VTE - Venous Thromboembolism

1

I. INTRODUCTION

Deep vein thrombosis (DVT) is one of the entities that constitute the manifestations of venous thromboembolism (VTE), along with pulmonary embolism (PE). Deep vein thrombosis is a well recognized cause of morbidity, mortality, and a major public health concern worldwide. DVT causes considerable morbidity due to its recurrent nature and long term sequelae such as the post-thrombotic syndrome (PTS), as well as mortality if it progresses to pulmonary embolism. PTS is a symptom complex that commonly includes chronic limb edema, heaviness, pain, itching, cramps, paresthesia, lifestyle-limiting venous claudication, stasis dermatitis, and in advanced cases, venous ulcerations. Estimates of the 2-year cumulative incidence of PTS vary enormously ranging between 23% and 60% (Ashrani and Heit, 2009). In most cases, PTS develops within 1 to 2 years after DVT and severe PTS occurs in 5% to 10% of patients after DVT (Kahn and Ginsberg, 2004).

In 1856, Rudolf Virchow proposed a triad of abnormal vessel wall, abnormal blood flow, and abnormal blood constituents, as the three principal factors in the pathogenesis of emboli in his publication Thrombose und Embolie (Virchow, 1856). His findings were later extrapolated by Anning almost 100 years later in 1957 as the “Virchow’s triad” for DVT pathogenesis comprising of ‘stasis’, ‘hypercoagulability’ and ‘vessel wall injury’, also referred to as the consensus model (Anning, 1957; Malone and Agutter, 2006). There has been consequent substantiation to the initial theory by other scientists throughout the years as well as controversy regarding the fact that Virchow’s actual triad referred to the consequences of thrombosis rather than to its etiology (Brotman et al, 2004; Kyrle and

2

Eichinger, 2009; Agutter and Malone, 2011). The valve cusp hypoxia hypothesis (VCHH) holds thrombogenesis to be initiated in venous valve pockets under conditions of suffocating hypoxemia; given certain well-defined circumstances, these incipient nidi may develop into fully-fledged thrombi (Agutter and Malone, 2011).

A number of risk factors have been identified as contributing to the consequent development of DVT and a large number of clinical studies are available attempting to identify and assess the magnitude of risk associated with each factor and to recommend guidelines for the prophylaxis of DVT in the population at risk. The Sirius study, a multicenter case-control study to assess the clinical risk factors for DVT in medical patients identified that a history of DVT or PE, venous insufficiency, chronic heart failure, obesity, immobile standing position more than 6 hours per day and a history of 3 or more pregnancies were significantly more frequent in case patients than in control patients. In addition, the triggering factors that were identified more frequently in case patients than in controls were pregnancy, violent effort or muscular trauma, deterioration of the general condition, immobilization, long-distance travel, and infectious disease (Samama, 2000). A multicenter prospective study on symptomatic deep vein thrombosis (DVT) in geriatric inpatients identified the following factors as independently related to the development of DVT: restriction of mobility, limited mobility without immobilization, aged 75 and older, history of DVT or pulmonary embolism, acute heart failure, chronic edema of the lower limbs, and paresis or paralysis of a lower limb (Weill-Engerer et al, 2004). A systemic review of the publications on travel and venous thrombosis found that long-distance travel increases the risk of venous thrombosis (VT) 2- to 4- fold and that the risk of VT is not increased after travel shorter than 3–4 h. The risk of asymptomatic VT after long-haul flights ranged up to 12%. However, they were unable to draw any solid conclusions on the mechanisms

3

responsible for the association between VT and long-distance flight and concluded from the available evidence that the absolute risk of symptomatic VT in the general travelling population was not high enough to justify the widespread use of prophylaxis (Kuipers et al, 2007).

The most exhaustive review on the prevention of venous thromboembolism is provided by the American College of Chest Physicians (ACCP) Evidence-Based Clinical Practice Guidelines (8th Edition). It provides an in-depth description of the types, doses, and durations of prophylactic treatments tailored for each patient group. It recommends the implementation of group-specific thromboprophylaxis routinely for all patients who belong to each of the major target groups, for example patients undergoing major general surgery or major orthopedic surgery (Geerts et al, 2008).

The incidence of DVT, according to numerous scientific studies, shows widely varying results from around the world. It was initially reported in 1972 by Burkitt that DVT is less common in Asian patients compared to their African and Western counterparts and the claim has been recently reiterated by various other authors (Burkitt, 1972; White, 2003; Montagnana et al, 2010). The interplay of a variety of factors such as a difference in genetic predisposition, dietary factors, local climatic conditions, or seasonal variations in temperature were proposed as possible etiological factors for the difference in DVT incidence among the races (White, 2003). Recent scientific studies have focused on molecular studies in an attempt to solve the mystery of such varied DVT incidence rates in different populations. However, the exact cause remains yet to be ascertained and it is probably due to a complicated interaction of many variables (Vidaud et al, 1991; van Hylckama et al, 2000; Castoldi et al, 2010).

4

patient selection criteria, diagnostic tools, differentiation between first time diagnosis of DVT and recurrent DVT incidence, statistical analysis and presentation of data, rendering it extremely difficult to compare and contrast the reported incidence of DVT from around the world. In the US, the Worcester study reported that the average annual incidence of deep vein thrombosis alone was 48 per 100 000, while the incidence of pulmonary embolism with or without deep vein thrombosis was 23 per 100 000 (Anderson et al, 1991). The Olmsted Country, Minnesota study reported the overall average age- and sex-adjusted annual incidence of venous thromboembolism as 117 per 100 000 (deep vein thrombosis, 48 per 100 000; pulmonary embolism, 69 per 100 000) (Silverstein et al, 1998). In the Western world, the weighted mean incidence of first DVT in the whole general population was calculated to be 5.04 per 10 000 person years from pooled data of quality medical journal publications between 1976 and 2000 (Fowkes et al, 2002). VTE incidence in South Korea was calculated using the Korean Health Insurance Review and Assessment Service (HIRA) database and the respective age- and sex adjusted annual incidences of VTE, DVT and PE per 100 000 individuals in South Korea increased significantly from 8.83, 3.91 and 3.74 in 2004 to 13.8, 5.31 and 7.01 in 2008 (P = 0.0001), with successive increments each year (Jang et al, 2011). A retrospective study conducted in a hospital in India to determine the incidence of VTE among hospitalized patients calculated a VTE rate of 17.46 per 100 000 admissions (Lee et al, 2008). A review on the incidence of DVT and PE in the Chinese population reported a prevalence of DVT between 2.6% to 17% (Nandi et al, 1998). A review on the incidence of postoperative VTE in Asia revealed an incidence of postoperative DVT of 10% to 63% in orthopedic patients and an incidence of DVT ranging from 3% to 28% in general surgical patients. The incidence was slightly lower than the reported incidence of 40% to 80% following orthopedic surgery and 28% to 44% following general surgical operations in

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studies reporting on Caucasian populations (Liew et al, 2003). The Assessment of the incidence of deep-vein thrombosis in Asia (AIDA) study, a prospective epidemiological study in 19 centers across Asia, studied the incidence of deep-vein thrombosis (DVT) in Asian patients undergoing major orthopedic surgery of the lower limbs. They reported an incidence of total DVT of 25.6% in total hip replacement (THR) patients, 58.1% in total knee replacement (TKR) patients, and 42.0% in hip fracture surgery (HFS) patients without pharmacological thromboprophylaxis. The AIDA study further reported an apparent discrepancy in the incidence of post- operative DVT in Asian patients of different ethnicities, as the DVT rate in Koreans (29.8%) was lower than those in Chinese (45.0%) or in non-Korean–non-Chinese (46.3%) groups (Piovella et al, 2005). In another study in India, 60% incidence of DVT in patients not receiving prophylaxis and a 43.2% incidence in patients receiving prophylaxis with Low Molecular Weight Heparin (LMWH) after major lower limb surgery was reported (Agarwala et al, 2003). These figures appear to indicate that the incidence of DVT is increasing in Asian patients, although significant data from the native Asian population is still inadequate in the field of study of DVT and previous data is mostly from Asian patients in the Western world. Moreover, due to the abysmal paucity of substantial data on the incidence of DVT in the Asian population the true incidence of DVT in the Asian population cannot be properly validated without further research.

The treatment options for acute DVT include conventional pharmacologic therapy with anticoagulant agents such as heparin, warfarin, or low-molecular-weight heparins (LMWH). Anticoagulation halts propagation and formation of new thrombus but does not remove existing clots (Levine et al, 1996). Pharmacologic thrombolytic agents or tissue plasminogen activators such as streptokinase, urokinase, alteplase, duteplase, and reteplase have also been

6

used to treat acute DVT. The thrombolytic agents can be delivered by systemic thrombolysis, flow-directed thrombolysis, or catheter directed intrathrombus thrombolysis (CDT). Systemic thrombolysis or CDT carry the risk of bleeding and are contraindicated in patients with a high risk of bleeding (Mewissen, 2010; Schweizer et al, 2000; Comerota, 2010). The more commonly used interventional techniques of thrombus removal include catheter-directed thrombolysis, the pulse-spray technique, and pharmacomechanical thrombolysis (PMT) devices such as the Arrow Trerotola, AngioJet, and Trellis system that perform mechanical maceration and disruption of clot to facilitate removal. Pharmacomechanical thrombolysis is approved by the ACCP in preference to CDT alone to reduce treatment time, but it also carries the risk of bleeding (Kearon et al 2008; Karthikesalingam et al, 2011). Adjunctive mechanical thrombus removal techniques are by aspiration thrombectomy, balloon thrombectomy, or balloon maceration. In the endovascular treatment of lower extremity DVT concomitant treatment can also be performed by balloon angioplasty, stent placement, and Inferior Vena Cava filter placement. Surgical thrombectomy is rarely performed nowadays due to its invasive nature and is reserved for patients with extensive deep vein thrombosis involving the iliofemoral venous system, especially if other options are not available or have failed (Comerota and Gale, 2006).

In the background of recent internal bleeding, recent surgery, patients with bleeding disorders, severe hypertension, or recent cardiovascular accident, thrombolysis is contraindicated. The purpose of this study was to evaluate the mid- and long-term clinical results of aspiration thrombectomy as an effective and safe treatment for acute and sub-acute proximal DVT of the lower limb, especially in the sub-set of patients who have contraindications to thrombolytic treatment.

7

II. MATERIALS AND METHODS

A. MATERIALS

1. Study population

Between May 2005 and May 2010, a total of 108 patients with acute and sub-acute DVT of the lower-extremity underwent aspiration thrombectomy with 9-10 guiding catheters in the interventional radiology suite of Ajou University Hospital, Suwon, South Korea. The inclusion criteria were patients with acute or sub-acute femoropopliteal or iliofemoral DVT, of less than 4 weeks duration, with or without inferior vena cava (IVC) extension. The majority of the patients, 93/108 (86.1%), had acute DVT with only 15/108 (13.9%) patients having sub-acute DVT of between 2 to 4 weeks duration. Exclusion criteria consisted of isolated infrapopliteal DVT, chronic DVT more than 4 weeks, terminally ill patients, patients who could not take a proper prone position, severe anemia (Hb < 8 g/dl), or venous invasion by malignancy. All of the patients underwent the treatment during standard inpatient hospital bed admission status.

There were 65 female patients and 43 male patients enrolled in the study. The patients’ age ranged from 22 to 87 with a mean age of 58 years. The mean duration of symptoms from onset till procedure was 8.1 days with a range of (1-28) days. The left side was more commonly affected as 82/108 (75%) patients had left sided DVT, 23 had right sided DVT and 3 patients had bilateral DVT involvement. May Thurner syndrome (MTS) was present in 60/108 (55.5%) patients, out of which 42 (70%) were female and 18 (30%) were male. Seventy nine patients consequently underwent stent insertion after the procedure due to residual venous stenoses, out of which 57 had MTS. Therefore, 95% (57/60) of the patients

8

with MTS required stent placement post aspiration thrombectomy. The patient characteristics of the study group are shown in Table 1.

Table 1: Patient characteristics in the total study population (n=108).

Patient characteristic Values

Age, mean (range), years 58 (22 – 87) years

Sex (M/F) 43/65

DVT type (Sub-acute/ Acute) 15/93

Side of DVT (Right/Left/Bilateral) 23/82/3

Anatomical extent of DVT (Iliofemoral/ Femoropopliteal) 99/9

Symptoms duration (onset to procedure) mean (range), days 8.1 (1-28) days

MTS (M/F) 60 (18/42)

Stent insertion 79

Anatomical extent of the DVT was femoropopliteal DVT in 9/108 (8%) and iliofemoral DVT in the remaining 99/108 patients (92%). IVC extension of the iliofemoral DVT was present in 31/108 (29%) patients, whereas calf vein extension of DVT was seen in 57/108 (52%). The most common presentation was with left sided DVT extending from the tibial vein to the inferior vena cava (17.6%). Further sub-classification of the location of DVT is depicted in Table 2.

9

Table 2: DVT location in total study population (n = 108).

DVT location (n = 108) left side

right side

Bilateral Total Percentage %

1. IVC-Iliac-Femoral-Popliteal- Tibial 14 4 1 19 17.6% 2. IVC-Iliac-Femoral-Popliteal 5 2 0 7 6.5% 3. IVC-Iliac-Femoral 3 1 1 5 4.6% 4. Iliac-Femoral-Popliteal-Tibial 28 2 1 31 28.7% 5. Iliac-Femoral-Popliteal 20 6 0 26 24.1% 6. Iliac-Femoral 7 1 0 8 7.4% 7. Femoral-Popliteal-Tibial 5 2 0 7 6.5% 8. Femoral-Popliteal 0 2 0 2 1.85% 9. Isolated Femoral 0 2 0 2 1.85% 10. Isolated Iliac 0 1 0 1 0.9% Total 82 23 3 108 100%

The prevalence of risk factors for the first time incidence of DVT in this study group could not be identified in 8/108 patients. In the remaining 100 patients, 43 had 1 risk factor for DVT, 45 patients had 2 risk factors, 11 had 3 risk factors and one patient had 4 risk factors. The most common risk factors identified in these patients for the first time incidence of DVT were the presence of MTS and malignancy.

10

Table 3: Identified risk factors before the procedure in the study group (n=108).

Risk Factor Number of patients Total percentage %

1. May-Thurner syndrome 60 55.6%

2. Immobilization 4 3.7%

3. Previous DVT/ PTE 8 7.4%

4. Postoperative state/and or trauma 15 13.9%

5. Gravidity/ Post-partum 3 2.8%

6. IVC filters 3 2.8%

7. Malignancy 26 24.1%

8. Other factors (extreme obesity, varicose veins and congestive heart failure)

2 1.9%

9. Idiopathic DVT (no identified risk factors) 7 6.5% 10. Hormonal therapy* History not available NA 11. Inherited or acquired coagulation

abnormality*

History not available NA

Note.—The table shows numbers and percentages of identified risk factors in the 108 patients. NA (not available).

11 B. METHODS

1. Procedure notes

1.a. Initial heparinization, IVC filter placement and initial intravenous venography

procedure

Heparinization was started when DVT was diagnosed. Heparinization was started 1 to 193 hours (mean, 34.1 hours) before the procedure via a peripheral intravenous line with dose of Heparin between 750 to 165,000 units (mean, 25,459 units). The average rate of Heparin infusion was 746.5 units per hour. Heparin was administered at a therapeutic-level to attain an International Normalized Ratio (INR) in the range of 2.0-3.0.

As a prophylactic measure against the formation of pulmonary embolism retrievable IVC filters were inserted in 100/108 patients (92.6%) prior to aspiration thrombectomy, due to the invasive nature of the procedure, as per the Society of Interventional Radiology (SIR) guidelines (Vedantham et al, 2006). The types of filters deployed were Günther Tulip Filter (GTF; William Cook Europe, Bjaeverskov, Denmark) and Cordis OptEase IVC filter (Cordis Endovascular, Warren, NJ). Three of the patients had previously inserted IVC filters and five of the patients underwent aspiration thrombectomy without the insertion of an IVC filter. After the procedure, the IVC filters were removed in an average of 10 days, range (3-29 days), in 50/100 cases (50%). Filter retrieval was attempted only in patients with absent or minimal thrombus trapped in the filter as visualized on direct venography. Günther Tulip filters were retrieved via internal jugular vein access, whereas OptEase filters (Cordis) were retrieved by a common femoral vein access as demonstrated in figure 1 and figure 2 below. Fifty of the retrievable IVC filters were left in place due to various reasons, as well as the 3 permanent filters that were already present before the procedure.

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The patient was placed in prone position and the ipsilateral popliteal vein was accessed under ultrasonographic guidance with 12 to 14F sheath after local anesthesia. An initial ascending venography was performed to assess the extent of venous thrombosis.

Fig. 1. Removal of the Günther Tulip filter. Vena cavogram performed before filter

removal shows normal IVC and the filter is removed via the internal jugular vein access.

Fig. 2. Removal of the Cordis OptEase filter. Vena cavogram performed before filter

removal shows normal IVC and the filter is removed via the common femoral vein approach.

1.b. Aspiration thrombectomy procedure

Manual aspiration thrombectomy was done using a 9-10 F introducer sheath. The connecting hub of the 9 F braided introducer sheath was removed and connected to a 50cc

13

syringe for suction. The aspiration thrombectomy was performed by repeated pumping movement of the syringe plunger while maintaining a negative pressure within the barrel of the syringe and slowly withdrawing the introducer sheath along with the syringe. During the pumping action care was taken to maintain a negative pressure within the barrel by not allowing the plunger to retract to the end of the syringe barrel. The proper aspiration thrombectomy method is somewhat strenuous but manages to produce a high yield of thrombus extraction in each session.

The aspirate was filtered with 4 by 4 gauze pieces and the blood separated from the clot. The amount of aspirated blood separated from the clot was measured. Conversion to thrombolysis was done when the aspirated blood was over 400 cc or when the aspiration thrombectomy was incomplete. On completion of the procedure venography was performed to evaluate the success of the aspiration thrombectomy and to plan further treatment if required.

In case of significant residual venous stenosis post procedure we performed stent insertion and percutaneous transluminal angioplasty (PTA). Venous stenoses were noted in 79/108 patients (73.1%) located at the left common iliac vein (n=57), left external iliac vein (n=2), left common iliac vein and left external iliac vein (n=10), right common iliac vein (n=8), right external iliac (n=1), and right common femoral vein (n=1). The residual stenotic lesions were treated with stent placement and balloon angioplasty. The stents deployed were Smart nitinol bare stent (SMART; Cordis, Miami, FL), or ComVi stent (Taewoong Medical Inc., Seoul, Korea). The stent sizes most commonly used were 14mm x8cm and 12mm x8cm and they were mostly dilated with the help of a 10 mm balloon followed by a 12 mm balloon and up to 14 mm balloons in some cases. Nine of the patients required two overlapping stents in the left common iliac and left external iliac veins, so a total of 88 stents were placed.

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Seventy eight stents were placed on the left side and 10 stents were placed on the right side. The most common location of the stents was in the left common iliac vein. The locations of the stents were as tabulated in Table 4.

Table 4: Location of the stents (n=88).

Stent location Number (% of total)

Left common iliac vein 58 (65.9 %)

Left external iliac vein 2 (2.3 %)

Left common iliac vein + left external iliac vein 18 (20.5%)

Right common iliac vein 8 (9.1%)

Right external iliac vein 1 (1.1%)

Right common femoral vein 1 (1.1%)

Symptomatic relief was achieved in all patients. The characteristics of the stented patient group were as shown in Table 5. More female patients (65%) underwent stenting than male patients (35%). The majority of stents were placed in the left side and presence of MTS was seen in 72% of patients.

Table 5: Stented patient group characteristics (n=79)

Mean age (range) 59 (22-87) years

Sex (M/F) 28/51

Side of DVT (Right/Left/Bilateral) 9/69/1 DVT extent (Iliofemoral/ Femoropopliteal) 78/1

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IVC extension (%) 22 (27.8%)

Calf vein involvement (%) 41 (51.9%)

MTS (%) 57 (72%)

The most common location of DVT in the stented group was in the iliofemoral vein with extension to the IVC and the popliteal and tibial veins, 16.4%. The distribution of the location of DVT in the remaining stented patients are shown in Table 6.

Table 6: location of DVT in the stented patients (n=79).

DVT location (n = 78) left side

right side

Bilateral Total Percentage %

1. IVC-Iliac-Femoral-Popliteal- Tibial 12 1 0 13 16.4% 2. IVC-Iliac-Femoral-Popliteal 4 0 0 4 5.1% 3. IVC-Iliac-Femoral 3 1 1 5 6.4% 4. Iliac-Femoral-Popliteal-Tibial 27 0 0 27 34.6% 5. Iliac-Femoral-Popliteal 17 5 0 22 28.2% 6. Iliac-Femoral 5 0 0 5 6.4% 7. Femoral-Popliteal-Tibial 0 1 0 1 1.3% 8. Isolated Femoral 0 1 0 1 1.3% 9. Isolated Iliac 0 1 0 1 1.3% Total 68 10 1 79 100%

16 2. Definitions and Statistical analysis

The guidelines provided by Vedantham et al. in the “Reporting Standards for Endovascular Treatment of Lower Extremity DVT” were adhered to in the definitions and reporting of the findings of this study. Anatomical success was defined as a successful restoration of antegrade in-line flow in the treated vein with elimination of any underlying obstructive lesion as assessed on the procedural venogram. According to post-procedural venography, we defined technical success as over ninety five percent of thrombus extraction. The results were quantified as follows: minimal or no thrombolysis (grade I, < 50% thrombus removal), partial thrombolysis (grade II, 50–95% thrombus removal), or complete thrombolysis (grade III, 95–100% thrombus removal). Follow-up time after the procedure was graded as short-term (up to 1 y), mid-term (1–3 y), or long-term (>3 y) study (Vendantham et al, 2006).

3. Follow up

On follow-up there were 17 deaths unrelated to the procedure, 9 patients were lost to follow-up and 7 patients had less than one year of follow-up. The mean follow-up period in the remaining 75/108 (69%) patients was 45.3 months, range (12.6-77.3) months. Seventy five patients were assessed in the mid-term follow up (1-3 years after the procedure) and 52/108 (48%) patients remained in the long-term follow-up (>3 years after the procedure). Follow-up was performed by CT venography at 6 months, 12 months and 24 months, as well as by telephone interviews. The patients’ symptoms on telephone interviews were assessed by the Post-Thrombotic Syndrome VEINES-QOL/Sym scales (Kahn et al., 2006). The results were analyzed in combination with a prospectively registered database.

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III. RESULTS

Anatomical success was achieved in 92/108 (85%) patients after aspiration thrombectomy treatment of the thrombosed veins. In sixteen patients (15%) with residual thrombosis after thrombectomy (grade I to grade II lysis), additional thrombolysis was performed using urokinase (Vedantham et al, 2006). Seventy nine patients (73%) had residual venous stenoses post aspiration thrombectomy that were treated with stent placement and balloon angioplasty.

The amount of aspirated blood during the procedure ranged from 50 to 380 cc (mean, 158 cc) with decrease of mean hemoglobin level from 11.92.2 to 10.41.85 g/dL (mean, 1.5 g/dL). The mean hematocrit loss was 4.24. Total procedure time, excluding the time for urokinase infusion, ranged from 20-120 min (mean, 55.8 min). There was no major complication. No hemorrhagic complications occurred. There was no patient requiring transfusion. There was no patient mortality associated with the procedure and 30-day mortality rate was zero. Fever developed after the procedure in two patients, but subsided with antipyretics within 3 days.

On follow-up, 25 patients had recurrence of DVT and the findings were divided into mid-term follow-up and long-term follow-up categories. On mid-term follow-up, 61/75 patients (81.3%) had no recurrence of DVT and 14 patients (18.7%) demonstrated DVT recurrence. Fifty five patients (73.3%) were asymptomatic on mid-term follow-up and 20/75 (26.6%) had symptoms related to DVT. The most common risk factors associated with DVT recurrence were MTS and the presence of IVC filters. The details of the 14 patients with recurrence on mid-term follow up are shown in Table 7 below.

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Table 7: Recurrence of DVT on mid-term follow-up (n=14).

Patient characteristic Number (n)

Sex (M/F) 11/3

DVT type (Sub-acute/ Acute) 5/9

Original side of DVT (Right/Left/Bilateral) 4/10/0 DVT recur side (Same/opposite/bilateral) 10/1/3 Anatomical extent of DVT (Iliofemoral/ Femoropopliteal) 14/0 Risk factors (single risk factor/two risk factors) 6/5

MTS 6

IVC filters 4

Post-operative/trauma 3

Malignancy 2

Pregnancy 1

Out of the 52 patients who remained during long-term follow-up, 41/52 (78.8%) had no recurrence of DVT and DVT recurrence was seen in 11/52 (21.1%). Thirty seven patients (71.1%) were asymptomatic on long-term follow-up and 15/52 (28.8%) were symptomatic. The results are further elucidated in Table 8 below.

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Table 8: DVT recurrence and symptoms recurrence on mid-term and long-term follow-up.

Parameter Mid-term follow-up

(n=75) / (%) Long-term follow-up (n=52) / (%) No DVT recurrence Asymptomatic No DVT recurrence + asymptomatic 61 (81.3%) 55 (73.3%) 48 41 (78.8%) 37 (71.1%) 31 No DVT recurrence + symptomatic 13 10 DVT recurrence + asymptomatic 7 6 DVT recurrence + symptomatic 7 5

Out of the 11 cases of DVT recurrence on long-term follow-up, 4 were of sub-acute type and 7 were of acute type on initial presentation. The most common risk factors identified in DVT recurrence were MTS, IVC filters and post-operative state. Table 9 details the patient characteristics.

Table 9: Recurrence of DVT on long-term follow-up (n=11).

Patient characteristic Number (n)

Sex (M/F) 8/3

DVT type (Sub-acute/ Acute) 4/7

Original side of DVT (Right/Left/Bilateral) 3/8/0 DVT recur side (Same/opposite/bilateral) 9/0/2 Anatomical extent of DVT (Iliofemoral/ Femoropopliteal) 8/3 Risk factors (single risk factor/two risk factors) 4/4

20 MTS 5 IVC filters 3 Post-operative/trauma 3 Malignancy 1 Pregnancy 0

On follow-up of the 79 patients with stents, there were 14 deaths unrelated to the procedure and 12 patients were lost to up. In the remaining 53 patients, mean follow-up period was 1359 days (range 383 -2356) days and 35 patients remained during long-term follow-up. DVT recurrence was seen in a total of 10/53 (18.9%) patients, out of which 9 had intra-stent thrombi of the stented veins with 7 occlusions of the stents that required re-interventions. A total of 7/53 (13.2%) stents were found to be collapsed. Four of the stent collapses were between 50-75% of luminal diameter and occurred without recurrence of any DVT, due to wedging of the stent between the left common iliac artery and the spine. The remaining 3 stent collapses occurred in a background of DVT recurrence and were between 25-50% of the stent lumen.

Among the 10 patients with DVT recurrence in the stented group, 5 patients had a single risk factor for DVT recurrence and 5 had two risk factors present. The most common risk factors were identified to be May Thurner syndrome- 6 patients and inlaying IVC filters-3 patients. The other risk factors found were 2 malignancies, 2 operative statuses, 1 post-partum period and one case of idiopathic DVT. Table 10 depicts the characteristics of the stented patients in whom DVT recurrence occurred.

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Table 10: Recurrence of DVT in stented group (n=10).

Patient characteristic Number (n)

Sex (M/F) 6/4

DVT type (Sub-acute/ Acute) 5/5

Original side of DVT (Right/Left/Bilateral) 2/8/0 DVT recur side (Same/opposite/bilateral) 8/1/1 Anatomical extent of DVT (Iliofemoral/ Femoropopliteal) 10/0

MTS 6

Risk factors (single risk factor/two risk factors) 5/5

Four out of 108 patients underwent pulmonary CT angiography before the procedure and pulmonary thromboembolisms were detected in 3 of them, 2 of which resolved after treatment and one patient was lost to follow-up. After the procedure, 45/108 (41.6%) of the patients underwent pulmonary CT angiography to rule out pulmonary thromboembolism. Nineteen patients had a pulmonary thromboembolism post aspiration thrombectomy and 26 patients did not demonstrate any pulmonary thromboembolism on pulmonary CT angiography. All of the pulmonary thromboembolisms detected were asymptomatic and resolved spontaneously with conservative treatment. During the mid-term follow-up, one of the patients who initially demonstrated PTE post procedure had recurrence of DVT, whereas in the long-term follow-up group 4/ 11 (36%) patients with DVT recurrence had PTE post aspiration thrombectomy.

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Fig. 3. May Thurner syndrome with DVT. This 31 year old male patient presented with pain and swelling of his left lower extremity of 15 days duration. CT venography revealed MTS and left sided DVT extending from the external iliac vein up to the popliteal vein. Figure A shows the features of the May Thurner syndrome. The white arrow denotes the right common iliac artery that is compressing the left common iliac vein against the lumbar vertebra. Figure B shows DVT in the left external iliac vein and figure C shows the DVT extending up to the left popliteal vein.

Fig. 4. Treatment and recurrence. Post aspiration thrombectomy venography (figure A) revealed venous stenosis at the left common iliac vein which was treated with stent placement and balloon dilatation. Three years later in 2010, the patient presented with stent collapse between the right common iliac artery and the lumbar vertebra (figure C), along with recurrence of DVT as seen in figure D.

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IV. DISCUSSION

Deep vein thrombosis causes considerable morbidity due to its recurrent nature and long term sequelae such as the post-thrombotic syndrome (PTS). Post-thrombotic syndrome often leads to severe clinical disability, quality of life (QOL) impairment and high socioeconomic costs (Vedantham et al, 2006). Estimates of the 2-year cumulative incidence of PTS vary enormously, ranging between 23% and 60% (Ashrani and Heit, 2009). In most cases, PTS develops within 1 to 2 years after DVT and severe PTS occurs in 5% to 10% of patients after DVT (Kahn and Ginsberg, 2004). Patients with iliofemoral DVT are at particularly high risk for PTS and late disability (Vedantham et al, 2006). The primary goals in the treatment of acute DVT of the lower extremity are elimination of the embolic potential of existing thrombus, restoration of unobstructed flow, prevention of further thrombosis, and preservation of venous valve function.

The standard treatment recommended for acute DVT of the leg according to the latest ACCP guidelines is initial treatment with low-molecular-weight heparin (LMWH), unfractioned heparin (UFH), or fondaparinux for at least 5 days and until the INR is > 2.0 for 24 h, along with concurrent initiation of vitamin K antagonist (VKA) on the first treatment day. However, anticoagulation does not have significant fibrinolytic activity and patients with severe, extensive, proximal DVTs remain at high risk of developing post thrombotic morbidity, with up to 75% having chronic painful edema and 40% having venous claudication when treated with anticoagulant therapy alone (Kearon et al, 2008).

A study in Germany found that systemic thrombolytic treatment for acute DVT achieved significantly better short-term and 12 month follow-up clinical outcomes than

24

conventional heparin/anticoagulation therapy, but at the expense of a serious increase in major bleeding (6%) and pulmonary embolism (4.5%), compared with no occurrences in those receiving conventional regimens. Thrombus reduction >50% or complete recanalization was observed in 6%, 36% and 54% of patients on heparin therapy, patients on local treatment and systemic lysis, respectively (Schweizer et al, 2000). Recently, Comerota analyzed twelve studies published between 1968 and 1990 that randomized patients with acute DVT to anticoagulation alone versus systemic thrombolytic therapy. On comparison of the patients managed with anticoagulation alone versus those treated with systemic thrombolysis, summary analysis of the lytic outcomes in the 12 trials demonstrated that 5 % vs. 45% had significant or complete lysis, 14% vs. 18% had partial lysis and 81% vs. 37% had either no objective phlebographic clearing or had extension of their thrombus. Major bleeding complications in the anticoagulation group were between 27% compared to 2-33% in the thrombolysis group, whereas minor bleeding complications in the anticoagulation group were between 0.4-12% and 5-25% in the thrombolysis group (Comerota, 2010). At present the ACCP recommends systemic thrombolytic therapy if CDT is not available only in selected patients with extensive proximal DVT (e.g., symptoms for < 14 days, good functional status, life expectancy of > 1 year) who have a low risk of bleeding (Kearon et al, 2008).

Delivering the thrombolytic agent directly into the thrombus by means of catheter-directed thrombolysis (CDT) techniques offers significant advantages over systemic therapy, such as better efficacy, lower drug dosages and infusion time, less complications and it is more cost effective. A single-center, retrospective study of 32 patients treated either with systemic thrombolysis (16) or catheter-directed local thrombolysis (16) for massive iliofemoral thrombosis was undertaken to assess preservation of venous valve function 2-3

25

years after treatment. Initial technical success rates were not available for comparison. Major bleeding complications were encountered in 13% of CDT patients versus 6% in systemic-treated patients, whereas minor bleeding events were 25% (CDT) versus 38% (systemic thrombolysis). The mid-term results suggest that CDT achieves better lysis (50% vs. 31%) and preservation of valve function (44% vs 13%) than systemic thrombolysis (Laiho et al, 2004). So far, the largest published experience with catheter-directed thrombolysis (CDT) approach in lower-extremity DVT has been from the National Venous Thrombolysis Registry, which reported a collective multicenter experience with 287 patients (303 limbs) in whom one-year follow-up was available (Mewissen et al, 1999). Of the 287 patients treated, 66% had acute DVT and the location of DVT was in the iliofemoral segment in 71% of patients with involvement of the inferior vena cava (ICV) in 21%. Complete thrombolysis was achieved in 31% of cases, whereas partial (>50%) thrombolysis with restoration of forward flow was achieved in 52% of patients. One third of patients received adjunctive stenting for residual narrowing. Overall, thrombosis-free survival was observed in 60% of patients at 1 year. Seventy-eight percent of patients with complete lysis had patent veins at 1 year, compared to only 37% who had insignificant lysis (<50%). For a patient with acute IFDVT and no history of previous DVT, when CDT was performed via the popliteal vein accessed with ultrasound guidance, complete lysis occurred in 65% and the 1-year patency was 96%. Complications included an 11% incidence of major bleeding that required transfusion of blood products and a 16% incidence of minor bleeding. The risks of intracranial hemorrhage and death were 0.2 and 0.4% respectively (Mewissen et al, 1999). The catheter-directed venous thrombolysis in acute iliofemoral vein thrombosis trial (the CaVenT Study), is an ongoing open, multicenter, randomized, controlled trial with 103 patients comparing catheter-directed thrombolysis versus anticoagulation therapy alone.

26

Fifty patients were allocated adjunctive CDT along with anticoagulation and 53 patients underwent standard anticoagulation therapy alone. After CDT, grade III (complete) lysis was achieved in 48% and grade II (50%–90%) lysis in 40% patients. One patient suffered major bleeding and two had clinically relevant bleeding related to the CDT procedure. After 6 months, iliofemoral patency was found in 32 (64.0%) in the CDT group vs. 19 (35.8%) controls. The long-term results of the CaVenT study are awaited (Enden et al, 2009). The current ACCP guidelines suggest that CDT may be used to reduce acute symptoms and postthrombotic morbidity if appropriate expertise and resources are available in selected patients with extensive acute proximal DVT (e.g., iliofemoral DVT, symptoms for < 14 days, good functional status, life expectancy > 1 year) who have a low risk of bleeding. They further recommend correction of underlying venous lesions using balloon angioplasty and stents after successful CDT in patients with acute DVT and the same intensity and duration of anticoagulant therapy as for comparable patients who do not undergo CDT (Kearon et al, 2008). The Society of Interventional Radiology (SIR) considers the use of CDT as an adjunct to anticoagulant therapy as an acceptable initial treatment strategy for acute iliofemoral DVT in carefully selected ambulatory patients with long life expectancy who are considered to be at low risk for bleeding (Vedantham et al, 2006)

Pharmacomechanical thrombolysis (PMT) devices such as the Arrow Trerotola, AngioJet, and Trellis system may attenuate the morbidity of CDT by permitting a dose reduction in thrombolytic drug administration. Recently a systemic review of PMT in the treatment of DVT analyzed 16 retrospective case series that reported the use of rheolytic, rotational, or ultrasound-assisted PMT in a total of 481 patients. Technical success of 82-100% was reported with Grade II or III lysis in 83-82-100% of patients. Significant improvement in thrombus removal was noted using CDT in combination with PMT

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compared to the use of PMT alone (62.4% + 24.9 vs. 26% + 24.1). The different devices all appeared to be safe, with no reported procedure-related deaths or strokes and <1% incidence of symptomatic PE. Bleeding complications were reported in 6/16 studies, in which 4-14% of patients required transfusion (global incidence 11/146 patients, 7.5%). Seventy five percent to 98% of patients demonstrated significant mid-term improvement in symptoms with similar radiological findings (Karthikesalingam et al, 2011). The ACCP suggests pharmacomechanical thrombolysis (e.g., with inclusion of thrombus fragmentation and/or aspiration) in preference to CDT alone in patients with acute DVT to shorten treatment time if appropriate expertise and resources are available and does not recommend treatment with percutaneous mechanical thrombectomy alone (Kearon et al, 2008).

A previous study on the treatment of acute lower extremity DVT with combined aspiration thrombectomy and CDT reported an initial technical success rate of 91%, and 50% patients underwent stenting and balloon angioplasy in the left common iliac vein. There was a 1% incidence of major bleeding, 4% incidence of minor bleeding and 61% patients were detected to have PE pre-operatively. On follow-up multi-detector computerized tomography (MDCT) venography at 5.7 ± 5.6 months, 72% showed no thrombus, 22% partial thrombus, and 6% showed obstruction. On short term follow-up (<1 y), 38% developed PTS and 8% were admitted due to DVT recurrence. A telephone interview of 81% patients at 22.8 ± 10.7 months postoperatively revealed that 46% were asymptomatic, 46% had moderate improvement, and 6% were mildly improved (Jeon et al, 2010). In another study that employed aspiration thrombectomy treatment for acute lower extremity DVT without CDT, the initial technical success was 88.9% and 81.4% underwent stenting in the common iliac vein or external iliac vein due to residual stenosis. The clinical and imaging follow-up periods were 3-40 months (mean 15 months). On follow-up sonography

28

or CT, the patency of all lower deep veins was well preserved, including the stents, except in two patients who showed a recurrent DVT after 2 weeks and 2 months respectively (Kwon et al, 2009). The initial technical success result of 85% and 73% rate of post procedural stenting in the current study using the aspiration thrombectomy as the sole approach to the treatment of acute lower extremity proximal DVT compares favorably with the previous studies. Unfortunately, mid-term and long-term follow-up results were not available in these studies to compare their findings with the present study.

Mid-term and long-term prospective data on the treatment of acute DVT of the lower extremity is scant in literature. Four ongoing studies were identified, which have not published their results to date: the PEARL registry (NCT00778336), the ATTRACT trial (NCT00790335), the CAVA trial (NCT00970619) and the SONIC I Safety and Efficacy study (NCT00640731). One study comparing the 1, 3 and 5 years results after conventional anticoagulation versus lysis/stenting showed that the primary iliofemoral venous patency rates at 1, 3, and 5 years were 24%, 18%, and 18% in the anticoagulation group versus 83%, 69%, and 69% in the lysis/stenting group (AbuRahma et al, 2001). The results of the present aspiration thrombectomy study of 85%, 64% and 59.6% primary venous patency rates at immediate post procedure, mid-term follow-up and long-term follow-up respectively are comparable to the patency rates reported for the lysis/stenting group. In comparing the long-term symptom resolution between the two groups, 30% of patients reported resolution of symptoms in the anticoagulation group in contrast to 78% in the lysis/stenting group (AbuRahma et al, 2001). The patients treated with aspiration thrombectomy in the current study had 73.3% and 71.1% resolution of symptoms at mid-term and long-term follow-up, similar to the results of the lysis/stenting group in the study by AbuRahma et al.

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In both the mid-term and long-term follow-ups of the present study the most common risk factors identified in DVT recurrence were the presence of MTS, IVC filter and post-operative status. There was also a relatively higher incidence of DVT recurrence in the patients who had originally presented with sub-acute DVT in comparison to acute DVT on both mid-term and long-term follow-up, 5 versus 7 and 5 versus 5, especially considering the low percentage of initial patients in the sub-acute group (13.9%) versus the acute group (86/1%). These results suggest that this treatment module should exclude those patients with sub-acute DVT of the lower extremity, due to the hard organized nature of the thrombi.

Out of the 55.5% of patients with May Thurner syndrome (MTS) who underwent aspiration thrombectomy in this study, 70% were female. Ninety five percent (57/60) of the patients with MTS required stent placement post aspiration thrombectomy. Forty six patients with MTS remained during mid-term follow up, and 6 patients had recurrence of DVT in the same side as the treated venous segment, whereas 86.96% had no evidence of DVT recurrence. Thirty two MTS patients remained during long-term follow up, and 5 patients had recurrence of DVT, whereas 84.37% were asymptomatic.

The limitations of this study are that the limb circumference of the patients were not measured pre and post procedure, valvular reflex was not assessed at the onset of the study and late valvular dysfunction status could not be clinically evaluated using duplex ultrasonographic data.

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V. CONCLUSION

Aspiration thrombectomy is a safe and effective treatment for acute proximal DVT. Clinical mid and long-term results are encouraging. In the background of recent internal bleeding, recent surgery, patients with bleeding disorders, severe hypertension, or recent cardiovascular accident, thrombolysis of suprapopliteal DVT is contraindicated and aspiration thrombectomy could be the alternative treatment choice. The advocacy of aspiration thrombectomy as the sole treatment for acute DVT could also be justified on the basis of cost effectiveness and less potential for vein wall damage.

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36 -국문요약 -

급성/아 급성 하지 심부 정맥 혈전증의 치료에 있어서 단독 흡인

혈전 제거술의 중 장기 임상적 결과

아주대학교대학원의학과 안젤리 (지도교수: 원제환) 목적: 급성/아 급성 하지 심부 정맥 혈전증의 치료에 있어서 단독 흡인 혈전 제거술의 중 장기 임상적 결과를 통해 그 유용성을 알아보고자 한다. 대상과 방법: 2005 년부터 2010 년 까지 5 년 간의 기간동안 급성/아급성 하지 심부 정맥 혈전증으로 하대정맥 필터 설치 후 9-10 Fr 가이딩 카테터 유도하에 흡인 혈전 제거술을 시행 받은 108 명을 대상으로 하였다. 시술의 포함 기준은 하대정맥 포함과 관계 없이 4 주 이내에 발생한 급성/아급성 장골대퇴정맥 또는 대퇴슬와정맥 혈전증을 보인 경우다. 시술 후 정맥 조영술을 시행하여 남아있는 혈전이 있거나 협착이 확인된 경우 추가적으로 풍선 혈관 성형술 및 스텐트 삽입치료를 시행하였다. 흡인된 혈전을 걸러서 그 양을 측정하여 400ml 이상인 경우 또는 혈전제거가 불완전한 경우에는 추가적으로 유로키나아제 혈전 용해제를 주입하였다. 결과: 흡인 혈전 제거술 이후 해부학적 성공률은 85% (92/108 명)였다. 혈전 제거술 이후에 등급 1 또는 등급 2 에 해당하는 잔여 혈전이 확인된 16 명의 환자에서는 추가적으로 유로키나아제를 이용한 혈전용해술을 시행하였다. 73% (79/108 명)의 환자들은 시술 후 잔여 정맥 협착이 확인되어 추가적으로 혈관 성형술 및 스텐트 삽입치료를 시행받았다. 시술과 관련된 사망은 없었다. 중간 기간 추적 관찰에서 81.3% (61/75 명)의 환자들은 심부 정맥 혈전증의 재발소견 없었고 18.7% (14/75 명)의 환자군은 재발소견을 보였다. 73.3% (55/75 명)은 무증상이었고 26.6% (20/75 명)은

37 심부 정맥 혈전증과 관련된 증상을 보였다. 장기 추적 관찰 기간 동안 남아있던 52 명의 환자들에서 78.8% (41/52 명)의 환자들은 재발 소견 없었고 21.1% (11/52 명)은 재발 소견을 보였다. 71.1% (37/52 명)의 환자들은 장기추적관찰에서 무증상이었으며 28.8% (15/52 명)의 환자들은 심부 정맥 혈전증과 관련된 증상을 보였다. 결론: 흡인 혈전 제거술은 급성 근위부 심부 정맥 혈전증의 치료에 있어서 주요합병증 없이 안전하고 경제적이며 효과적인 치료 방법이다. 중 장기 추적 결과에서도 다른 치료방법과 유사한 임상결과를 보였다. 핵심어: 심부정맥혈전증, 혈전용해술, 혈전제거술, 카테터, 메이-써널 증후군.