title: Effectiveness of a low contrast load CT angiography protocol in octogenarians and nonagenarians being evaluated for transcatheter aortic valve replacement.
abstract: BACKGROUND
  Transcatheter aortic valve replacement (TAVR) typically requires computed tomographic angiography (CTA) for aortoiliofemoral assessment to determine feasibility of a transfemoral approach, although many candidates being considered for TAVR are at increased risk of contrast-induced nephropathy (CIN).
  
  
  OBJECTIVE
  To determine the feasibility and safety of a load contrast load CTA protocol in octogenarians and nonagenarians at risk of CIN.
  
  
  METHODS
  We evaluated 54 consecutive octogenarians and nonagenarians considered for TAVR who underwent CTA using a standard contrast protocol (n=21) versus a protocol incorporating low-dose contrast in patients at risk of CIN (n=33). We compared clinical characteristics, CTA image quality (score 1-4) and interpretability, and clinical outcomes, including CIN and vascular complications.
  
  
  RESULTS
  The mean age was 88.5±4.0 years, 37% were male, and chronic renal insufficiency was common in both the standard and low-dose contrast cohorts (57% vs. 70%, P=.39). The low-dose contrast protocol was associated with a significantly less contrast volume compared to standard contrast protocol (127±18 ml vs 76±55 ml, P<.001). Individuals imaged using low-dose (n=16) versus standard (n=17) contrast protocols received 80% less contrast volume (23±10 vs. 125±23 ml, P<.001). There was similar graded image quality (3.8±0.4 vs. 3.9±0.3, P=.76) and interpretability (100% for each, P=1.0) between standard and low-dose contrast protocol groups. There was no significant difference in rates of CIN after CTA between standard and low-dose contrast protocol groups (10% vs. 3%, P=.55), with no CIN events in those imaged by low-dose CTA. There were no major vascular injuries associated with TAVR or pigtail insertion, no major bleeding for CTA, and no noninterpretable studies in all patients.
  
  
  CONCLUSIONS
  In this proof-of-principle study, a low-dose contrast protocol appears feasible and safe in octogenarians and nonagenarians undergoing screening for TAVR, and results in significant reduction in contrast load as compared to a standard contrast protocol without observed differences in image quality or safety.
authors.affiliation: Department of Medicine, NewYork-Presbyterian Hospital and the Weill Cornell Medical College, New York, NY, USA.
authors.forename: Micheas
authors.initials: M
authors.lastname: Zemedkun
authors.affiliation: Departments of Imaging, Medicine, and Biomedical Sciences, Cedars-Sinai Heart Institute, Cedars-Sinai Medical Center, Los Angeles, CA, USA.
authors.forename: Troy M
authors.initials: TM
authors.lastname: LaBounty
authors.affiliation: Department of Medicine, NewYork-Presbyterian Hospital and the Weill Cornell Medical College, New York, NY, USA.
authors.forename: Geoffrey
authors.initials: G
authors.lastname: Bergman
authors.affiliation: Department of Medicine, NewYork-Presbyterian Hospital and the Weill Cornell Medical College, New York, NY, USA.
authors.forename: Shing-Chiu
authors.initials: SC
authors.lastname: Wong
authors.affiliation: Department of Medicine, NewYork-Presbyterian Hospital and the Weill Cornell Medical College, New York, NY, USA.
authors.forename: Fay Y
authors.initials: FY
authors.lastname: Lin
authors.affiliation: Department of Medicine, NewYork-Presbyterian Hospital and the Weill Cornell Medical College, New York, NY, USA.
authors.forename: Dolores
authors.initials: D
authors.lastname: Reynolds
authors.affiliation: Department of Radiology, NewYork-Presbyterian Hospital and the Weill Cornell Medical College, New York, NY, USA.
authors.forename: Millie
authors.initials: M
authors.lastname: Gomez
authors.affiliation: Department of Medicine, NewYork-Presbyterian Hospital and the Weill Cornell Medical College, New York, NY, USA.
authors.forename: Allison M
authors.initials: AM
authors.lastname: Dunning
authors.affiliation: Department of Medical Imaging and Division of Cardiology, St. Paul's Hospital, University of British Columbia, Vancouver, BC, Canada.
authors.forename: Jonathon
authors.initials: J
authors.lastname: Leipsic
authors.affiliation: Department of Radiology, NewYork-Presbyterian Hospital and the Weill Cornell Medical College, New York, NY, USA. Electronic address: jkm2001@med.cornell.edu.
authors.forename: James K
authors.initials: JK
authors.lastname: Min
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000792:Angiography / Q000009:adverse effects / Q000379:methods*; D001024:Aortic Valve Stenosis / Q000601:surgery*; D003287:Contrast Media / Q000008:administration & dosage* / Q000009:adverse effects; D005240:Feasibility Studies; D005260:Female; D006801:Humans; D008297:Male; D012189:Retrospective Studies; D014057:Tomography, X-Ray Computed / Q000009:adverse effects / Q000379:methods*; D065467:Transcatheter Aortic Valve Replacement / Q000379:methods*
chemical_list: D003287:Contrast Media
keywords: Computed tomography angiography; Contrast-induced nephropathy; Transcatheter aortic valve replacement; Transfemoral approach