Advantages and Shortcomings ofAdvantages and Shortcomings ofCurrent Mechanical Thrombectomy Current Mechanical Thrombectomy

Devices in DVTDevices in DVT

Mahmood K. Razavi, MDMahmood K. Razavi, MD

Director, Clinical Trials & ResearchDirector, Clinical Trials & Research

Vascular & Interventional Specialists Vascular & Interventional Specialists

of Orange Countyof Orange County

Disclosures Disclosures

Scientific Advisory Board– 480 Biomedical, Abbott Vascular, Bard, Boston

Scientific, Covidien, EmboMedix, Javlin, Mercator, Neuravi, Reflow Medical, Trivascular, Veneti, Walk Vascular

Consultant– Cordis

Grants– NIH, WL Gore

Mechanical Thrombectomy DevicesMechanical Thrombectomy Devices

29 different devices have been used (& growing)

Eleven are FDA cleared for use in the U.S. (general thrombectomy indication)

Only few actively marketed

Mechanisms of ActionMechanisms of Action

Pure mechanical mechanism– Aspiration– Disruption/maceration– Re-circulation– Energy assisted (RF, laser, US)

Lytic assisted– Pharmaco-mechanical

Partial List of PMT DevicesPartial List of PMT Devices

Angiojet DVX/ AVX Xpeedior

Hydrolyzer Helix/X-Sizer/Brush Oasis Trerotola Device

Resolution 360 wire Akonya Eliminator Aspirex/Rotarex Thrombex PMT ProLumen Rinspirator Cleaner

Lytic Assisted DevicesLytic Assisted Devices

Trellis-8 and Trellis-6– Pharmacomechanical lysis

Ekos Lysus system– Ultrasound accelerated lysis

Angiojet + lytics– Power pulse

AdvantagesAdvantages

Speed up lysis Potential for single session treatment Reduced dose of lytics May be used in pts with contraindication to

thrombolytic drugs

67 yo F with 5 day hx of LLE edema and pain who is 7 days s/p spinal fusion. US revealed extensive ilio-femoral DVT. IVC filter was requested.

Retrievable IVC filter placed Symptoms worsened over the next 2 days

3 months later pt returned3 months later pt returnedfor IVC filter removal.for IVC filter removal.Sx had improved substantiallySx had improved substantiallybut some residual ankle edemabut some residual ankle edemapersistedpersisted..

Limitations Limitations

Paucity of data– Prove efficacy– Comparative analysis– Long term safety

Largely ineffective as stand alone techniques– Best results when used in combination with

lytics Device-dependent increased risk of PE

Courtesy:Nick Yee MDCourtesy:Nick Yee MD

Efficacy of CDT in Acute DVTEfficacy of CDT in Acute DVT

80% of clot removed in 80% of patients

Stand Alone PMT in DVTStand Alone PMT in DVT

Results of stand alone therapy in proximal DVT disappointing– 4/17 pts had >90% & 6/17 had 50%-90% clot

removal (10/17 >50% clot clearance)*– 9 pt received additional CDT

Most studies report results of combination tx– Drug during PMT– Debulk prior to CDT or clean up after

* Kasirajan K. et al. JVIR 2001;12

54 yo female with breast cancer and swollen Rt. arm54 yo female with breast cancer and swollen Rt. arm

Complete occlusion of right Complete occlusion of right axillary and subclavian veinaxillary and subclavian vein

Following 24 hours Urokinase treatmentFollowing 24 hours Urokinase treatment

15 minutes angiojet thrombolysis15 minutes angiojet thrombolysis

PMT in DVTPMT in DVT

Aspiration thrombectomy in acute IF DVT N= 27 Success= restoration of flow without residual

obstruction Aspiration only 24

– UK infusion 3 Successful recanalization 24/27

– Adjunctive stents 22

Kwon SH, et al Clin Radiol 2009Kwon SH, et al Clin Radiol 2009

40 year old male, 10 days post heart-lung transplant40 year old male, 10 days post heart-lung transplant

Swollen Swollen face,face,

distended distended neck neck veinsveins

Complete occlusion of Superior Vena Cava Complete occlusion of Superior Vena Cava

800 cc angiojet exchange and Palmaz 308 stent800 cc angiojet exchange and Palmaz 308 stent

Relief of venous distensionRelief of venous distension

PMT + CDT versus CDTPMT + CDT versus CDT

Retrospective analysis of 40 consecutive limbs (36 pts) with UE or LE DVT

CDT+ rheolytic PMT CDT alone P-valueLimbs (patients) 27 (21) 40 (36)

Tx duration (hrs) 26.3 ± 16.6 48 ± 27 0.0004

Mean UK dose (U) 2.7 ± 1.8 M 5.6 ± 5.3 M 0.008

Complete lysis 73% 82%

Kim HS et al Cardiovasc Interv Radiol 2006;29:1003-7Kim HS et al Cardiovasc Interv Radiol 2006;29:1003-7

Pharmacomechanical vs. CDTPharmacomechanical vs. CDT Retrospective review of pts with LE DVT over 8

yrs

Lin PH et al Am J Surg 2006;192:782-788Lin PH et al Am J Surg 2006;192:782-788

Rheolytic + lytics CDT P-valueLimbs (patients) 52 (49) 46 (44)

Complete success 75% 70% ns

Sx improved 24 hr 81% 72% ns

Adjuvant stents 82% 78% ns

Mean ICU stay 0.6 ± 0.3 d 2.4 ± 1.2 d < 0.04

Bleed 4% 6% ns

Transfusion 0.2 ± 0.3 1.2 ± 0.7 < 0.05

Total costs $47,742 ± $19,247 $85,301 ± 24,832 < 0.01

EKOS Study Results: EfficacyEKOS Study Results: Efficacy

Parikh S. et al JVIR 2008; 19

Registry DemographicsRegistry Demographics Number of Patients 147

Age 51 ± 18 years

Gender– Men 68 (46%)– Women 70 (48%)– Not Reported 9 (6%)

Clinical Presentation Average DaysOnset of DVT

– Acute (<14 days) 33 (22%) 8– Acute on Chronic (<14 days; prior Hx DVT) 63 (43%) 19*– SubAcute (14 to 28 days) 19 (13%) 21– SubAcute on Chronic (14 – 28 days; prior Hx DVT) 14 (10%) 19– Chronic (> 28 days) 18 (12%) 67

* Average > 14 days due to occasional reporting of days since onset of original DVT episode that resulted in chronic part of acute-on-chronic

Reported Degree of Clot Clearance with Trellis

Hilleman DE JVIR 2008; 19

ConclusionConclusion

Role of mechanical thrombectomy devices as the “stand alone” mode of therapy in treatment of DVT is limited at this time

Combination of thrombolysis and mechanical thrombectomy can reduce the treatment time & possibly the bleeding complications of thrombolysis