Editorial | Current Devices in the Treatment of Acute Iliofemoral Deep Vein Thrombosis | Which Medical Device

 

Disclosures: O’Sullivan GJ is a Paid Medical Advisor to: Covidien, Mansfield, MA, USA; Cook Medical, Bloomington, IN, USA; Marvao Medical, Galway, Ireland; Medrad/Bayer, Netherlands.

 

 

An associated inflammatory response within the vessel with resulting valvular destruction and incompetency leads to the development of the ‘post thrombotic syndrome’ (PTS) in a large proportion of patients)[4]. It has been demonstrated that morbidity may be reduced with removal/lysis of intraluminal thrombus and restoration of vessel patency[5-7]. Potential mortality arising from emboli is also reduced by its early treatment.

 

Treatment includes surgical venous thrombectomy, catheter directed thrombolysis (CDT) in isolation or with mechanical thrombectomy and what has come to be known as Pharmaco-mechanical thrombolysis (PMT). This latter technique combines mechanical thrombectomy and thrombolysis in one single device to remove thrombus.  Current research demonstrates equivalent outcomes for PMT with increased rapidity when compared with CDT. However, there is a need for further research including randomised control trials to further assess- this is the aim of the ATTRACT trial currently nearing end recruitment in the USA (8). 

 

Devices used to perform mechanical thrombectomy include the Aspirex S Catheter (Straub Medical) and also the Arrow-Trerotola percutaneous thrombolytic device(Arrow, Reading, PA).  The Aspirex S Catheter (Straub, Medical AG) offers variable luminal diameters (6F-10F) and a shaft length of 85-110cm. Using an over the wire catheter system, it contains a high-speed rotational coil within the catheter body. This creates a negative pressure through an L-shaped aspiration port that facilitates suction of thrombus into catheter, maceration of thrombus within the catheter and subsequent removal.  Advantages of the Aspirex S catheter include its variable diameters, and also its demonstrated use in both peripheral and central venous thrombectomy. However, treatment of iliofemoral DVT using mechanical thrombectomy often requires combination with catheter directed thrombolysis.

 

Systems currently used in the performance of Pharmaco-mechanical thrombolysis include the Trellis Peripheral Infusion System (Covidien, Santa Clara, CA), the Angiojet System (Medrad) with thrombolytic agent combined and the EKOS EndoWave Infusion Catheter System (EKOS Corporation, Bothell, WA).

 

The EKOS Endowave Infusion Catheter System uses the combination of a 5.2Fr infusion catheter (106cm in length) with incorporated microinfusion pores and an ultrasound core wire to promote thrombus lysis. It allows for the treatment of a segment length ranging between 6cm and 50cm. When placed within the thrombus, high frequency ultrasound waves are dispensed into the thrombus segment in conjunction with the thrombolytic agent. The resulting energy dissipation results in the loosening of fibrin strands within the thrombus increasing the surface area for thrombolysis exposure. Furthermore, enhanced delivery of the thrombolytic agent to the site of thrombus occurs due to acoustic microstreaming formed by the ultrasound waves. Temperature changes associated with ultrasound energy dissipation, potential clot lysis and dissolution are monitored and recorded. This allows automatic adjustment of ultrasound power to optimise treatment. Saline is also infused to aid heat dissipation to prevent damage to vessel walls.

 

Whilst most research and studies pertain to the use of ultrasound-enhanced thrombolysis in the arterial system for acute ischaemic stroke, some studies have reviewed its use in the treatment of deep venous thrombosis. Motarjeme reported faster lysis times and successful achievement of venous patency of 83% in a case series of 12 patients[9]. Grommes et al also demonstrated successful complete lysis in 85% (>90% restored patency)[10].  Whilst complications of bleeding have been reported, these rates appear reduced when compared with catheter directed thrombolysis in isolation[11].However, disadvantages of this system would still appear to include the average lengths of treatment required (21-24hours) and the associated high dependency monitoring required. 

 

In our institution, the use of EKOS is increasing. It should result in shorter ICU stays for CDT patients, and therefore the initial cost will rapidly fade as a factor. A recent trial involving EKOS in sub-massive PE yielded excellent results; on the other hand recent research has not demonstrated any significant overall clinical benefit in comparison with standard catheter directed thrombolysis in the treatment of Iliofemoral DVT (12).

 

The Angiojet System uses a 6F catheter system of variable length of 50–140cm in combination with a pump drive unit and pump set in the treatment of iliofemoral DVT.  Following insertion of the catheter system into the appropriate segment, the thrombolytic agent is dispensed directly into the thrombus under high pressure. Following a period of 20-30 minutes, high velocity saline jets are then pumped retrogradely into the region that allows for loosening of the thrombus from the vessel wall. Due to the high velocity of the saline jets, a localised negative pressure area is created (as described by the Bernoulli effect) and capture of the thrombus within the catheter tip occurs. Further high-pressure jets within the catheter tip allow fragmentation and evacuation of the thrombus. 

 

Currently, prospective observational studies are being undertaken with the use of the Angiojet rheolytic thrombectomy systems (13). Risks associated with this device refer to potential pulmonary emboli, more common in upper limb DVT therapy, potential systemic release of thrombolytic agent, haemolysis with resulting renal failure and fluid overload and bradyarrythmias [14, 15].

 

The Trellis Peripheral Infusion System consists of an 8 Fr multilumen catheter of 80-120 cm shaft length, a proximal and distal balloon cuff and a power unit connected to a dispersion wire contained between the cuffs. The dispersion wire stirs the thrombolytic agent through the thrombus to increase its surface area and therefore increase success of lysis. This allows for the performance of isolated localised combined Pharmaco-mechanical thrombolysis (treatment zone of 15-30cm) with minimisation of the systemic release of the lytic agent. This has allowed its use in those with contraindications secondary to risks of systemic haemorrhage. Furthermore, the lysed thrombus is aspirated with reduction of emboli risk. Other advantages include its use in both extremity and central venous thrombus obstruction and reduced incidence of haemolysis. Limitations refer to the 8F sheath, which may reduce its capability to treat below knee thrombi, and also to the maximum balloon expansion of <16mm. This limits its ability to fully occlude the IVC and therefore the potential isolated benefits described above. However, methods to overcome this have been described using a ‘pull-back’ technique (16).

 

In our institution Trellis and Possis AngioJet are used interchangeably, both yield excellent results for acute DVT; typically cases take less than 2 hours skin to skin for acute Iliofemoral-DVT- provided the popliteal vein is clear. These are truly single session devices, and again, if the popliteal vein is clear, only 1/5 patients needs to go on CDT (in ICU) overnight following treatment. So there is a significant cost saving by avoiding ICU. On the other hand they are time intensive in operation, and take fully 2 hours; whereas EKOS takes five to ten minutes (literally) and the thrombolytic agent and the ultrasound vibration do the work. EKOS, in our experience, typically shortens DVT treatment by one to two days, and so the initial cost is rapidly absorbed if ICU stays are shorter.

 

Current extraction catheters include the Pronto 0.035’ Extraction Catheter (Vascular Solutions) and is suitable for the removal of thrombus within vessels greater than 4mm in diameter. The major advantage with this catheter is its compatibility with a standard 0.035’ guidewire and a 10F sheath but most importantly that it offers the ability to aspirate using an over-the–wire technique without removal of the wire.  An alternative is a simple detachable hub sheath (e.g. Terumo Destination 8F 90cm) but this has the disadvantage of needing wire removal with each aspiration- but it is cheaper than the Pronto.

 

Active, catheter based treatment of DVT will increase. In our institution, currently we treat only symptomatic Iliofemoral DVT patients. As randomised trials are performed (e.g. the ATTRACT trial [8]) in the coming years, further light will be shone on this area with potential increased use of thrombectomy and Pharmaco-mechanical devices in the management of acute DVT.

 

User comments: Current Devices in the Treatment of Acute Iliofemoral Deep Vein Thrombosis

 

1. Kahn, S.R., The post-thrombotic syndrome: the forgotten morbidity of deep venous thrombosis. J Thromb Thrombolysis, 2006. 21(1): p. 41-8.

2. Prandoni, P., Healthcare burden associated with the post-thrombotic syndrome and potential impact of the new oral anticoagulants. Eur J Haematol, 2012. 88(3): p. 185-94.

3. Prandoni, P. and S.R. Kahn, Post-thrombotic syndrome: prevalence, prognostication and need for progress. Br J Haematol, 2009. 145(3): p. 286-95.

4. Kahn, S.R., et al., Determinants and time course of the postthrombotic syndrome after acute deep venous thrombosis. Ann Intern Med, 2008. 149(10): p. 698-707.

5. Enden, T., et al., Long-term outcome after additional catheter-directed thrombolysis versus standard treatment for acute iliofemoral deep vein thrombosis (the CaVenT study): a randomised controlled trial. Lancet, 2012. 379(9810): p. 31-8.

6. Sharifi, M., et al., Endovenous therapy for deep venous thrombosis: the TORPEDO trial. Catheter Cardiovasc Interv, 2010. 76(3): p. 316-25.

7. Comerota, A.J., et al., Catheter-directed thrombolysis for iliofemoral deep venous thrombosis improves health-related quality of life. J Vasc Surg, 2000. 32(1): p. 130-7.

8 Comerota, A.J. The ATTRACT trial:rationale for early intervention for iliofemoral DVT. Perspect Vasc Surg Endovasc Ther, 2009. 21(4): p 221-4.

9. Motarjeme, A., Ultrasound-enhanced Thrombolysis. J Endovasc Ther, 2007. 14(2): p. 251-6.

10. Grommes, J., et al., Safety and feasibility of ultrasound-accelerated catheter-directed thrombolysis in deep vein thrombosis. Eur J Vasc Endovasc Surg, 2011. 41(4): p. 526-32.

11. Owens, C.A., Ultrasound-Enhanced Thrombolysis: EKOS EndoWave Infusion Catheter System. Semin Intervent Radiol, 2008. 25(1): p. 37-41.

12 Baker, R et al., Ultrasound-accelerated vs Standard Catheter-directed Thrombolysis-A comparative Study in Patients with Iliofemoral Deep vein Thrombosis. JVIR, 2012. 23(11): p1460-1466 

13 PEARL II Peripheral Use of AngioJet Rheolytic Thrombectomy. www.clinicaltrials.gov; Identifier No. NCT01086215

14 Lee MS et al., Angiojet Thrombectomy. J Invasive Cardiol. 2004; 16(10): 587-91.

15 Jeyabalan G et al., Bradyarrhythmias During Rheolytic Pharmacomechanical Thrombectomy for Deep Vein Thrombosis. J Endovasc ther 2010;17:416-422

16 O’Sullivan GJ  The role of interventional radiology in the management of deep venous thrombosis: advanced therapy. 2011 CVIR 34:445–461