title: Very low intravenous contrast volume protocol for computed tomography angiography providing comprehensive cardiac and vascular assessment prior to transcatheter aortic valve replacement in patients with chronic kidney disease.
abstract: BACKGROUND
  Transcatheter aortic valve replacement (TAVR) is a lifesaving procedure for many patients high risk for surgical aortic valve replacement. The prevalence of chronic kidney disease (CKD) is high in this population, and thus a very low contrast volume (VLCV) computed tomography angiography (CTA) protocol providing comprehensive cardiac and vascular imaging would be valuable.
  
  
  METHODS
  52 patients with severe, symptomatic aortic valve disease, undergoing pre-TAVR CTA assessment from 2013-4 at Columbia University Medical Center were studied, including all 26 patients with CKD (eGFR<30 mL/min) who underwent a novel VLCV protocol (20 mL of iohexol at 2.5 mL/s), and 26 standard-contrast-volume (SCV) protocol patients. Using a 320-slice volumetric scanner, the protocol included ECG-gated volume scanning of the aortic root followed by medium-pitch helical vascular scanning through the femoral arteries. Two experienced cardiologists performed aortic annulus and root measurements. Vascular image quality was assessed by two radiologists using a 4-point scale.
  
  
  RESULTS
  VLCV patients had mean (±SD) age 86 ± 6.5, BMI 23.9 ± 3.4 kg/m(2) with 54% men; SCV patients age 83 ± 8.8, BMI 28.7 ± 5.3 kg/m(2), 65% men. There was excellent intra- and inter-observer agreement for annular and root measurements, and excellent agreement with 3D-transesophageal echocardiographic measurements. Both radiologists found diagnostic-quality vascular imaging in 96% of VLCV and 100% of SCV cases, with excellent inter-observer agreement.
  
  
  CONCLUSIONS
  This study is the first of its kind to report the feasibility and reproducibility of measurements for a VLCV protocol for comprehensive pre-TAVR CTA. There was excellent agreement of cardiac measurements and almost all studies were diagnostic quality for vascular access assessment.
authors.affiliation: Department of Medicine, Division of Cardiology, Columbia University Medical Center and New York-Presbyterian Hospital, New York, NY, USA.
authors.forename: Todd C
authors.initials: TC
authors.lastname: Pulerwitz
authors.affiliation: Department of Medicine, Division of Cardiology, Columbia University Medical Center and New York-Presbyterian Hospital, New York, NY, USA.
authors.forename: Omar K
authors.initials: OK
authors.lastname: Khalique
authors.affiliation: Department of Medicine, Division of Cardiology, Columbia University Medical Center and New York-Presbyterian Hospital, New York, NY, USA.
authors.forename: Tamim N
authors.initials: TN
authors.lastname: Nazif
authors.affiliation: Department of Radiology, Columbia University Medical Center and New York-Presbyterian Hospital, New York, NY, USA.
authors.forename: Anna
authors.initials: A
authors.lastname: Rozenshtein
authors.affiliation: Department of Radiology, Columbia University Medical Center and New York-Presbyterian Hospital, New York, NY, USA.
authors.forename: Gregory D N
authors.initials: GD
authors.lastname: Pearson
authors.affiliation: Department of Medicine, Division of Cardiology, Columbia University Medical Center and New York-Presbyterian Hospital, New York, NY, USA.
authors.forename: Rebecca T
authors.initials: RT
authors.lastname: Hahn
authors.affiliation: Department of Medicine, Division of Cardiology, Columbia University Medical Center and New York-Presbyterian Hospital, New York, NY, USA.
authors.forename: Torsten P
authors.initials: TP
authors.lastname: Vahl
authors.affiliation: Department of Medicine, Division of Cardiology, Columbia University Medical Center and New York-Presbyterian Hospital, New York, NY, USA.
authors.forename: Susheel K
authors.initials: SK
authors.lastname: Kodali
authors.affiliation: Department of Surgery, Columbia University Medical Center and New York-Presbyterian Hospital, New York, NY, USA.
authors.forename: Isaac
authors.initials: I
authors.lastname: George
authors.affiliation: Department of Medicine, Division of Cardiology, Columbia University Medical Center and New York-Presbyterian Hospital, New York, NY, USA.
authors.forename: Martin B
authors.initials: MB
authors.lastname: Leon
authors.affiliation: Department of Radiology, Columbia University Medical Center and New York-Presbyterian Hospital, New York, NY, USA.
authors.forename: Belinda
authors.initials: B
authors.lastname: D'Souza
authors.affiliation: Department of Biomedical Engineering, Columbia University Medical Center and New York-Presbyterian Hospital, New York, NY, USA.
authors.forename: Ming Jack
authors.initials: MJ
authors.lastname: Po
authors.affiliation: Department of Medicine, Division of Cardiology, Columbia University Medical Center and New York-Presbyterian Hospital, New York, NY, USA; Department of Radiology, Columbia University Medical Center and New York-Presbyterian Hospital, New York, NY, USA. Electronic address: ae2214@cumc.columbia.edu.
authors.forename: Andrew J
authors.initials: AJ
authors.lastname: Einstein
mesh_terms: D000046:Academic Medical Centers; D061605:Administration, Intravenous; D000368:Aged; D000369:Aged, 80 and over; D006328:Cardiac Catheterization / Q000009:adverse effects / Q000379:methods*; D000072226:Computed Tomography Angiography / Q000009:adverse effects / Q000379:methods*; D003287:Contrast Media / Q000008:administration & dosage* / Q000009:adverse effects; D017023:Coronary Angiography / Q000009:adverse effects / Q000379:methods*; D003324:Coronary Artery Disease / Q000150:complications / Q000000981:diagnostic imaging*; D003331:Coronary Vessels / Q000000981:diagnostic imaging*; D005240:Feasibility Studies; D005260:Female; D005919:Glomerular Filtration Rate; D006349:Heart Valve Diseases / Q000150:complications / Q000000981:diagnostic imaging* / Q000628:therapy; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects / Q000379:methods*; D006801:Humans; D007472:Iohexol / Q000008:administration & dosage* / Q000009:adverse effects; D007668:Kidney / Q000503:physiopathology; D008297:Male; D061330:Multidetector Computed Tomography / Q000009:adverse effects / Q000379:methods*; D009519:New York City; D015588:Observer Variation; D011237:Predictive Value of Tests; D051436:Renal Insufficiency, Chronic / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D015203:Reproducibility of Results; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D016896:Treatment Outcome
chemical_list: D003287:Contrast Media; D007472:Iohexol
keywords: Chronic kidney disease; Computed tomography angiography; Transcatheter aortic valve replacement; Very low contrast volume