Intervention With Cerebral Embolic Protection in TEVAR: Gaseous Protection

Overview

Vascular brain infarction (VBI) occurs in 67% of patients undergoing TEVAR. Overt stroke occurs in 13% of these patients and 88% of patients suffer from neurocognitive impairment. Cerebral air embolisation during the stent-graft deployment phase of TEVAR may be a cause of VBI. Standard treatment to de-air stent-grafts is through the use of a saline flush. This study aims to investigate whether carbon-dioxide or saline is the better fluid to de-air TEVAR stent-grafts prior to insertion in to the patient and compare VBI rate in the carbon-dioxide group and saline group.

Full Title of Study: “Carbon-Dioxide Flushing Versus Saline Flushing in Thoracic Endovascular Aortic Repair to Reduce Neurological Injury: A Pilot Randomised Controlled Trial”

Study Type

  • Study Type: Interventional
  • Study Design
    • Allocation: Randomized
    • Intervention Model: Parallel Assignment
    • Primary Purpose: Prevention
    • Masking: Double (Participant, Outcomes Assessor)
  • Study Primary Completion Date: June 6, 2024

Detailed Description

Thoracic endovascular aortic repair (TEVAR) is the re-lining of the thoracic aorta to prevent life threatening haemorrhage and death from rupture. This involves a small cut in the femoral artery in the groin and under imaging guidance, the insertion of wires and a stent into the thoracic aorta. Prior to insertion into the patient, stents are flushed with saline to remove air and prevent air reaching the brain that can cause a form of brain injury known as vascular brain infarction (VBI). However, our preliminary clinical data suggests that saline flushing is not effective at de-airing stent-grafts used in TEVAR. Carbon-dioxide has been used extensively in cardiac surgery to displace air from the chest cavity to prevent peri-procedural cerebral air embolisation. We hypothesise that flushing the stent-grafts with carbon-dioxide may be better at removing air from the stent-grafts than saline flush. Patients undergoing TEVAR will be approached to participate in this study. After written consent is obtained, participants will be randomised to undergo (TEVAR) with carbon dioxide or saline flushing of stent-grafts. Pre-operatively, participants will undergo extensive neurocognitive testing, and a baseline blood test. Intra-operatively, participants will undergo continuous transcranial doppler monitoring (TCD) of the middle cerebral artery (MCA) to look for cerebral air embolisation at stent-graft deployment phase of TEVAR. Blood testing pre-op, immediately post op, and 24 hours post op will be taken to measure for biomarkers of brain injury. Post-operatively, participants will undergo another diffusion-weighted brain MRI within 72 hours post-procedure, stroke and delirium assessment at day 1, 3 and day 7 +/- day of discharge, and at 6-weeks and 6-month follow-up.

Interventions

  • Other: CO2 flushing
    • As above
  • Other: Saline flushing
    • As above

Arms, Groups and Cohorts

  • Experimental: carbon-dioxide
    • Flushing of stent-grafts in TEVAR with carbon-dioxide
  • Active Comparator: Saline
    • Flushing of stent-grafts with saline

Clinical Trial Outcome Measures

Primary Measures

  • Recruitment
    • Time Frame: 36 months
    • The number of patients recruited into the trial will be collected
  • Retention
    • Time Frame: 36 months
    • The proportion of patients undergoing follow-up assessments will be collected
  • Study design for full randomised controlled trial
    • Time Frame: 36 months
    • The proportion of patients who are eligible for the trial will be collected

Secondary Measures

  • Number, size and location of new ischaemic lesions on post-operative diffusion-weighted MRI scans
    • Time Frame: 36 months
    • Using DW-MRI at <72 hours post operatively (day 1-7), and also 6 months post operatively, we will assess for new ischaemic lesions
  • Number of gaseous and solid intra-operative transcranial doppler microembolic signals by phase of TEVAR
    • Time Frame: Duration of surgery, 36 months collection
    • At all London units, transcranial doppler insonation of the middle cerebral artery will be carried out during the procedure, and analysed offline at a later date to evaluate gaseous or solid emboli during TEVAR
  • Number of participants with stroke or delirium as an inpatient
    • Time Frame: These will be carried out within 48 hours of patients’ return to level 1 care. 36 months collection
    • Patients will undergo stroke and delirium assessment.
  • Serial biomarker blood tests
    • Time Frame: 36 months
    • Blood samples will be taken preoperatively, at the end of the procedure and 24 hours late. These will be analysed for a biomarker of neuroglial injury, S100B
  • Risk factor assessment
    • Time Frame: 36 months
    • Data such as stent type will be collected.
  • Neurological assessment, delirium assessment and quality of life testing
    • Time Frame: Pre-op, first outpatient assessment (approximately 6 weeks), 6 months. 36 months collection
    • Patients will undergo a baseline neurocognitive, delirium and quality of life testing. These will be repeated as an outpatient to measure change post operatively.

Participating in This Clinical Trial

Inclusion Criteria

  • All participants suitable for TEVAR with capacity to consent Exclusion Criteria:

  • Participants who lack capacity to consent – Contraindications to MRI such as pacemaker – Pregnant participants – Participants who do not wish to participate – Participants <18yrs

Gender Eligibility: All

Minimum Age: 18 Years

Maximum Age: N/A

Are Healthy Volunteers Accepted: Accepts Healthy Volunteers

Investigator Details

  • Lead Sponsor
    • Imperial College London
  • Collaborator
    • Imperial College Healthcare NHS Trust
  • Provider of Information About this Clinical Study
    • Sponsor
  • Overall Official(s)
    • Richard Gibbs, Principal Investigator, Imperial College London
  • Overall Contact(s)
    • Lydia Hanna, 07747002704, l.hanna@imperial.ac.uk

References

Perera AH, Rudarakanchana N, Monzon L, Bicknell CD, Modarai B, Kirmi O, Athanasiou T, Hamady M, Gibbs RG. Cerebral embolization, silent cerebral infarction and neurocognitive decline after thoracic endovascular aortic repair. Br J Surg. 2018 Mar;105(4):366-378. doi: 10.1002/bjs.10718. Epub 2018 Feb 12.

Kahlert P, Eggebrecht H, Janosi RA, Hildebrandt HA, Plicht B, Tsagakis K, Moenninghoff C, Nensa F, Mummel P, Heusch G, Jakob HG, Forsting M, Erbel R, Schlamann M. Silent cerebral ischemia after thoracic endovascular aortic repair: a neuroimaging study. Ann Thorac Surg. 2014 Jul;98(1):53-8. doi: 10.1016/j.athoracsur.2014.03.037. Epub 2014 May 17.

Masada K, Kuratani T, Shimamura K, Kin K, Shijo T, Goto T, Sawa Y. Silent cerebral infarction after thoracic endovascular aortic repair: a magnetic resonance imaging study. Eur J Cardiothorac Surg. 2019 Jun 1;55(6):1071-1078. doi: 10.1093/ejcts/ezy449.

Inci K, Koutouzi G, Chernoray V, Jeppsson A, Nilsson H, Falkenberg M. Air bubbles are released by thoracic endograft deployment: An in vitro experimental study. SAGE Open Med. 2016 Dec 7;4:2050312116682130. doi: 10.1177/2050312116682130. eCollection 2016.

Rohlffs F, Tsilimparis N, Saleptsis V, Diener H, Debus ES, Kolbel T. Air Embolism During TEVAR: Carbon Dioxide Flushing Decreases the Amount of Gas Released from Thoracic Stent-Grafts During Deployment. J Endovasc Ther. 2017 Feb;24(1):84-88. doi: 10.1177/1526602816675621. Epub 2016 Oct 26.

Martens S, Neumann K, Sodemann C, Deschka H, Wimmer-Greinecker G, Moritz A. Carbon dioxide field flooding reduces neurologic impairment after open heart surgery. Ann Thorac Surg. 2008 Feb;85(2):543-7. doi: 10.1016/j.athoracsur.2007.08.047.

Ganguly G, Dixit V, Patrikar S, Venkatraman R, Gorthi SP, Tiwari N. Carbon dioxide insufflation and neurocognitive outcome of open heart surgery. Asian Cardiovasc Thorac Ann. 2015 Sep;23(7):774-80. doi: 10.1177/0218492315583562. Epub 2015 May 4.

Bismuth J, Garami Z, Anaya-Ayala JE, Naoum JJ, El Sayed HF, Peden EK, Lumsden AB, Davies MG. Transcranial Doppler findings during thoracic endovascular aortic repair. J Vasc Surg. 2011 Aug;54(2):364-9. doi: 10.1016/j.jvs.2010.12.063. Epub 2011 Mar 3.

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