title: The use of the AVERT system to limit contrast volume administration during peripheral angiography and intervention.
abstract: BACKGROUND
  The AVERT(TM) Contrast Modulation System (AVERT) (Osprey Medical, MN) is designed to reduce contrast volume administration during angiography. The AVERT provides an adjustable resistance circuit which decreases the pressure head delivering contrast towards the patient. The AVERT has not been previously studied in patients undergoing peripheral digital subtraction angiography (DSA). The purpose of this study was (1) to evaluate contrast savings with the AVERT and (2) to evaluate the ability to generate clinically acceptable DSA images in the process. To better define the mechanism of action in the peripheral circulation, we also developed a bench model to study the effects of the AVERT on the hydrodynamics of contrast delivery.
  
  
  METHODS
  Patients undergoing lower extremity DSA (diagnostic or intervention, sheath or catheter) were studied. The following variables were recorded for each injection: starting control syringe contrast volume, contrast volume injected towards patient, contrast volume returned to AVERT reservoir, net contrast administered to the patient and % savings. The AVERT resistance was adjusted manually based on operator's discretion--balancing image quality and contrast savings.
  
  
  RESULTS
  About 408 DSA angiographic sequences were obtained in 22 patients undergoing 29 procedures. Almost 68% of the patients had chronic kidney disease. An 82% presented with critical limb ischemia, 18% had claudication. There was an overall 37% ± 14% savings of contrast (31% for diagnostic DSA, 40% for interventional procedures). Overall 91% of all images were acceptable for clinical decision making. Specifically, 94% of diagnostic and 87% of interventional images were acceptable. Injection through a 4 Fr catheter (77% acceptable) resulted in poorer image quality as compared to a 5 Fr catheter (96% acceptable). Image quality for 5, 6, and 7 Fr sheath injections was 86%, 91%, 98%, respectively. The bench model of peripheral angiography demonstrated a significant reduction in reflux of contrast proximal to the end of the catheter without loss of antegrade image quality - confirming the in vivo findings.
  
  
  CONCLUSIONS
  We demonstrate that the use of the AVERT device during peripheral angiography results in significant contrast savings without compromising image quality.
authors.affiliation: Department of Medicine, Division of Cardiology, University of Texas Health Science Center San Antonio, San Antonio, Texas.
authors.forename: Anand
authors.initials: A
authors.lastname: Prasad
authors.affiliation: Department of Medicine, Division of Cardiology, University of Texas Health Science Center San Antonio, San Antonio, Texas.
authors.forename: Carolina
authors.initials: C
authors.lastname: Ortiz-Lopez
authors.affiliation: Baker IDI Heart and Diabetes Institute, Department of Cardiovascular Medicine, Alfred Hospital, Melbourne, Australia.
authors.forename: David M
authors.initials: DM
authors.lastname: Kaye
authors.affiliation: Baker IDI Heart and Diabetes Institute, Department of Cardiovascular Medicine, Alfred Hospital, Melbourne, Australia.
authors.forename: Melissa
authors.initials: M
authors.lastname: Byrne
authors.affiliation: Baker IDI Heart and Diabetes Institute, Department of Cardiovascular Medicine, Alfred Hospital, Melbourne, Australia.
authors.forename: Shane
authors.initials: S
authors.lastname: Nanayakkara
authors.affiliation: Department of Medicine, Division of Cardiology, University of Texas Health Science Center San Antonio, San Antonio, Texas.
authors.forename: S Hinan
authors.initials: SH
authors.lastname: Ahmed
authors.affiliation: Department of Medicine, Division of Cardiology, University of Texas Health Science Center San Antonio, San Antonio, Texas.
authors.forename: Steven R
authors.initials: SR
authors.lastname: Bailey
authors.affiliation: The Zena and Michael A. Wiener Cardiovascular Institute, the Icahn School of Medicine at Mount Sinai, New York, New York.
authors.forename: Roxana
authors.initials: R
authors.lastname: Mehran
authors.affiliation: Department of Medicine, Division of Cardiology, University of Texas Health Science Center San Antonio, San Antonio, Texas.
authors.forename: Salil
authors.initials: S
authors.lastname: Sethi
authors.affiliation: Department of Medicine, Division of Cardiology, University of Texas Health Science Center San Antonio, San Antonio, Texas.
authors.forename: Avantika
authors.initials: A
authors.lastname: Banerjee
authors.affiliation: Department of Medicine, Division of Cardiology, University of Texas Health Science Center San Antonio, San Antonio, Texas.
authors.forename: Marvin
authors.initials: M
authors.lastname: Eng
mesh_terms: D000368:Aged; D015901:Angiography, Digital Subtraction / Q000009:adverse effects / Q000295:instrumentation*; D002406:Catheterization, Peripheral / Q000009:adverse effects / Q000295:instrumentation*; D003287:Contrast Media / Q000008:administration & dosage* / Q000009:adverse effects; D057510:Endovascular Procedures / Q000009:adverse effects / Q000295:instrumentation*; D004867:Equipment Design; D005260:Female; D005263:Femoral Artery / Q000000981:diagnostic imaging; D006801:Humans; D035002:Lower Extremity / Q000098:blood supply*; D008297:Male; D008875:Middle Aged; D008953:Models, Anatomic; D008955:Models, Cardiovascular; D058729:Peripheral Arterial Disease / Q000150:complications / Q000000981:diagnostic imaging* / Q000628:therapy*; D011237:Predictive Value of Tests; D011677:Punctures; D051436:Renal Insufficiency, Chronic / Q000150:complications / Q000175:diagnosis; D012307:Risk Factors; D062666:Vascular Access Devices
chemical_list: D003287:Contrast Media
keywords: Imaging; angiographic/fluoroscopic; angiography; contrast agents; critical; endovascular intervention; limb ischemia; peripheral intervention; peripheral/renal