Evaluation of a device combining an IVC filter and a central venous catheter (Angel Catheter) for Pulmonary Embolism Prophylaxis in Poly-trauma Patients in a Level 1 UK Trauma Centre

Dr M R Akhtar, Dr J K Tun, Dr A Zaman, Dr J Y Chun, Dr O Jaffer, Dr N Bunker, Dr T Fotheringham St. Bart’s & The Royal London Hospitals Purpose

 To evaluate outcomes of Angel Catheter use for pulmonary embolism prophylaxis in polytrauma patients in a Level 1 UK Trauma centre

Introduction

 Temporary IVC filter for thromboembolic prophylaxis should be considered for patients with contraindications to anticoagulation

 Timing is key: Majority of patients who suffer from a PE, do so within the first 21 days in ICU

 Less than 50% of IVC filters are removed in Trauma patients who are more susceptible to loss to follow up (usually secondary to repatriation to base hospital for rehabilitation)  High risk patients in whom anticoagulation is a contraindicated and can pose a serious risk  Actively bleeding patients e.g. polytrauma / pelvic lower limb trauma  Traumatic brain injury patients  known/previous PE or DVT  Known hypercoagulable state

Introduction

Angel filter:

 Retrievable Nitinol Inferior Vena Cava (IVC) filter which can be easily resheathed, combined with a triple lumen central venous catheter. Bard IVC Filter Vs Angel Filter

 Can be placed without fluoroscopic guidance, thus in acutely unwell trauma patients, there is no need for an additional transfer to and procedure in the IR suite in the acute phase

 Eliminates non-retrievability or loss to follow up due to the external reminder that the patient has a ‘venous line’ and thus filter in situ.

 Cost Neutral: The Angel catheter costs approx £1400 (compared to £700 for a conventional IVC filter insertion kit, and £700 for conventional IVC filter removal kit : total of £1400)

INSERTION TECHNIQUE

1 2 3

4 5 6 MATERIALS AND METHODS

 Retrospective review of all Angel catheter insertion at the Royal London Hospital from September 2013 to January 2017.

 All ACs were inserted under ultrasound guidance by Intensive Care Consultants.

 Filter position was checked on plain film radiography  Trauma and PACS database evaluated to gather the information required.

OUR EXPERIENCE

Total number of Angel Catheters placed from Sept 57 (40 male, 17 female) 2013- Jan 2017

Mean age of polytrauma patients 42 yrs

Types of traumatic injury Traumatic brain injury: 30 Thoracic injury: 28 Abdominal visceral injury: 17 Vascular injury: 9 Pelvic injury: 34 Spinal injury: 20 Long bone injury: 24 Mean time from admission to Angel Catheter 3 days placement OUR EXPERIENCE

DVT / PE 2 out of 37 had a diagnosed DVT 1 out of 37 had a possible DVT 1 out of 37 had a PE Femoral approach of procedure 37 right / 20 left femoral approach

Final position of the filter on Abdominal X-ray Majority placed over L2/ L3 (n=9)

Suboptimal filter placement 9 (1 at common iliac vein confluence, and 7 over the origin of the renal veins but without complication renal vein thrombus) Average number of days the Angel catheter 7 +/- 4 days remained in situ RESULTS  Of the 57 patients, 4 patients died with catheter in-situ from sequlae of traumatic injury sustained.  All patients had a pre-removal cavograms, 4 of which demonstrated peri-filter clot burden.  Successful clot removal on filter retrieval was seen in all but 1 patient requiring subsequent conventional IVC filter insertion.  1 of the patients had complicated retrieval secondary to filter fracture in situ.  This patient had the angel filter catheter (right CFV approach) in situ for 20 days, and was mobilising/receiving regular physio to his right leg.  The fractured filter was retrieved by partially resheathing it and retrieving it down to the right common femoral vein under fluoroscopic where it was removed by venous cut down by the surgeons.

Examples:

TOO HIGH

Here, using current practice as a potential pitfall, we can see the filter is deployed at/above the renal veins and needs to be withdrawn.

Filters deployed across the level or above the renal vein can in theory have an increased risk of renal vein thrombosis.

The patient subsequently had the filter withdrawn to an appropriate position under fluoroscopic guidance.

TOO LOW

Angel catheter is incorrectly positioned too low.

The body of the unsheathed filter is distorted, bridging the IVC bifurcation.

It is subsequently retrieved under fluoroscopic guidance, and re-sited with a right groin approach. CONCLUSIONS

1. Safe and effective device to use in the acute phase of admission in polytrauma patients

2. No significant risk of AC migration or IVC perforation.

3. The patient should be immoblised and in need of thromboprophylaxis.  We have since seen two further filter fractures – also in patients who were no longer immobile, having either started physio or having uncontrolled movements secondary to confusion on ICU.  The last filter fracture was successfully retrieved via endovascular intervention with a 16 Fr sheath, two snares and by cutting the external catheter..

4. There is a demonstrable risk of malposition with risk of renal vein thrombosis as Angel Catheters are inserted ‘blind’ – 8 out of 37 patients initially had the filter placed across the renal veins.  Therefore, standard anatomy reference values are important in guiding length of catheter insertion. 5. We have expanded our use of the catheter to insertion in the elective peri-operative patient and look forward to publishing the data soon.