title: Ferumoxytol MRA for transcatheter aortic valve replacement planning with renal insufficiency.
abstract: BACKGROUND
  Computed tomography angiography (CTA) is the test of choice for pre-procedure imaging of transcatheter aortic valve replacement (TAVR) candidates. The iodinated contrast required, however, increases the risk of renal dysfunction in patients with pre-existing renal failure. Ferumoxytol is a magnetic resonance imaging (MRI) contrast agent that can be used with renal failure. Its long vascular resonance time allows gated MRA sequences that approach CTA in image quality. We present respiratory and cardiac gated MRA enabled by ferumoxytol that can be post-processed in an analogous fashion to CTA.
  
  
  METHODS
  Seven patients with renal failure presenting for TAVR were imaged with respiratory and cardiac gated MRA at 3T using ferumoxtyol for contrast. Aortic annulus, root and peripheral access dimensions were calculated in a fashion identical to that used for CTA. Of these, 6 patients underwent a TAVR procedure and 5 had intraoperative valve assessment with transesophageal echocardiograph (TEE) using standard clinical protocols that employed both two- and three-dimensional techniques.
  
  
  RESULTS
  Good correlation between MRA aortic annulus measurements and those from TEE were shown in 5 patients with mean annulus area of 392.4mm2(290-470 range) versus 374.1mm2(285-440 range), with a pairwise correlation coefficient of 0.92, p=0.029. All patients received Sapien valve implants (one 20mm, three 23mm, and two 26mm valves). Access decisions were guided by MRA with no complications. Annulus sizing resulted in no greater than trace/mild aortic regurgitation in all patients.
  
  
  CONCLUSIONS
  Ferumoxytol MRA is a safe alternative to CTA in patients with renal failure for pre-TAVR analysis of the aortic root and peripheral access.
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California, San Francisco, United States.
authors.forename: Kimberly
authors.initials: K
authors.lastname: Kallianos
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California, San Francisco, United States.
authors.forename: Travis S
authors.initials: TS
authors.lastname: Henry
authors.affiliation: Department of Cardiology, University of California, San Francisco, United States.
authors.forename: Yerem
authors.initials: Y
authors.lastname: Yeghiazarians
authors.affiliation: Department of Cardiology, San Francisco VA Medical Center, United States.
authors.forename: Jeffrey
authors.initials: J
authors.lastname: Zimmet
authors.affiliation: Department of Cardiology, San Francisco VA Medical Center, United States.
authors.forename: Kendrick A
authors.initials: KA
authors.lastname: Shunk
authors.affiliation: Department of Surgery, San Francisco VA Medical Center, United States.
authors.forename: Elaine E
authors.initials: EE
authors.lastname: Tseng
authors.affiliation: Department of Cardiology, University of California, San Francisco, United States.
authors.forename: Vaikom
authors.initials: V
authors.lastname: Mahadevan
authors.affiliation: Department of Radiology and Biomedical Imaging, University of California, San Francisco, United States. Electronic address: michael.hope@ucsf.edu.
authors.forename: Michael D
authors.initials: MD
authors.lastname: Hope
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001021:Aortic Valve / Q000000981:diagnostic imaging* / Q000601:surgery; D005260:Female; D052203:Ferrosoferric Oxide / Q000494:pharmacology*; D006349:Heart Valve Diseases / Q000150:complications / Q000175:diagnosis* / Q000601:surgery; D006801:Humans; D021621:Imaging, Three-Dimensional; D018810:Magnetic Resonance Angiography / Q000379:methods*; D008297:Male; D008875:Middle Aged; D057234:Preoperative Period; D051437:Renal Insufficiency / Q000150:complications*; D015203:Reproducibility of Results; D065467:Transcatheter Aortic Valve Replacement
chemical_list: D052203:Ferrosoferric Oxide