title: A cross-sectional imaging study to identify organs at risk of thermal injury during renal artery sympathetic denervation.
abstract: BACKGROUND
  The technology used to perform catheter-based renal artery sympathetic denervation has evolved: catheters can now access arteries as small as 3mm in diameter and create ablation zones of up to 10mm in depth. Recent evidence suggests that the procedure may be more effective if a more thorough ablation strategy is employed. Limited data are available regarding inadvertent soft tissue thermal injury during such procedures.  We used computed tomography (CT) to identify structures lying within the expected thermal ablation field or the 'at risk zone' (ARZ).
  
  
  METHODS
  63 consecutive CT aortograms were reviewed, yielding 100 renal arteries anatomically eligible for treatment. Structures lying within a predefined ARZ (within 10mm of the renal artery wall) were recorded.
  
  
  RESULTS
  The 63 subjects had a mean age of 74.6years, 48% were males and 88% had hypertension.  The inferior vena cava and renal veins were in the ARZ in all cases.  Psoas muscles and small bowel were within the ARZ in at least a fifth of the kidneys. Other structures found in the ARZ included the liver, pancreas, adrenal glands and diaphragm.
  
  
  CONCLUSIONS
  This study describes the variable anatomical relationship between renal arteries and important abdominal structures that may be exposed to thermal energy during modern denervation procedures.  The consequence of delivering such thermal energy to these structures is unknown but clinicians should be alert to the presenting symptoms if these structures are damaged. CT may have a pre-procedure role in assessing this risk.
authors.affiliation: NIHR Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, London, UK; National Heart and Lung Institute, Imperial College, London, UK. Electronic address: h.patel3@rbht.nhs.uk.
authors.forename: Hitesh C
authors.initials: HC
authors.lastname: Patel
authors.affiliation: Department of Radiology, Royal Brompton Hospital, London, UK.
authors.forename: Sofia
authors.initials: S
authors.lastname: Otero
authors.affiliation: Department of Radiology, Royal Brompton Hospital, London, UK.
authors.forename: Joanna B
authors.initials: JB
authors.lastname: Moser
authors.affiliation: NIHR Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, London, UK; National Heart and Lung Institute, Imperial College, London, UK.
authors.forename: Carl
authors.initials: C
authors.lastname: Hayward
authors.affiliation: NIHR Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, London, UK; National Heart and Lung Institute, Imperial College, London, UK.
authors.forename: Stuart D
authors.initials: SD
authors.lastname: Rosen
authors.affiliation: NIHR Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, London, UK; National Heart and Lung Institute, Imperial College, London, UK.
authors.forename: Alexander R
authors.initials: AR
authors.lastname: Lyon
authors.affiliation: NIHR Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, London, UK; National Heart and Lung Institute, Imperial College, London, UK.
authors.forename: Raad
authors.initials: R
authors.lastname: Mohiaddin
authors.affiliation: NIHR Cardiovascular Biomedical Research Unit, Royal Brompton Hospital, London, UK; National Heart and Lung Institute, Imperial College, London, UK.
authors.forename: Carlo
authors.initials: C
authors.lastname: di Mario
authors.affiliation: Department of Radiology, Royal Brompton Hospital, London, UK; National Heart and Lung Institute, Imperial College, London, UK.
authors.forename: Simon
authors.initials: S
authors.lastname: Padley
mesh_terms: D000368:Aged; D015331:Cohort Studies; D003430:Cross-Sectional Studies; D005260:Female; D006358:Hot Temperature / Q000009:adverse effects*; D006801:Humans; D008297:Male; D008875:Middle Aged; D058958:Organs at Risk / Q000000981:diagnostic imaging*; D012077:Renal Artery / Q000000981:diagnostic imaging* / Q000601:surgery*; D012189:Retrospective Studies; D013562:Sympathectomy / Q000009:adverse effects*; D014057:Tomography, X-Ray Computed / Q000379:methods; D016896:Treatment Outcome
keywords: Ablation; Anatomy; Cross-sectional imaging; Renal denervation; Safety