title: The DENALI Trial: an interim analysis of a prospective, multicenter study of the Denali retrievable inferior vena cava filter.
abstract: OBJECTIVE
  To assess safety and effectiveness of a nitinol retrievable inferior vena cava (IVC) filter in patients who require caval interruption to protect against pulmonary embolism (PE).
  
  
  METHODS
  Two hundred patients with temporary indications for an IVC filter were enrolled in this prospective, multicenter clinical study. Patients undergoing filter implantation were to be followed for 2 years or for 30 days after filter retrieval. At the time of the present interim report, all 200 patients had been enrolled in the study, and 160 had undergone a retrieval attempt or been followed to 6 months with their filter in place. Primary study endpoints included technical and clinical success of filter placement and retrieval. Patients were also evaluated for recurrent PE, new or worsening deep vein thrombosis, and filter migration, fracture, penetration, and tilt.
  
  
  RESULTS
  Clinical success of placement was achieved in 94.5% of patients (172 of 182), with a one-sided lower limit of the 95% confidence interval of 90.1%. Technical success rate of filter placement was 99.5%. Technical success rate of retrieval was 97.3%; 108 filters were retrieved in 111 attempts. In two cases, the filter apex could not be engaged with a snare, and one device was engaged but could not be removed. Filter retrievals occurred at a mean indwell time of 165 days (range, 5-632 d). There were no instances of filter fracture, migration, or tilt greater than 15° at the time of retrieval or 6-month follow-up.
  
  
  CONCLUSIONS
  In this interim report, the nitinol retrievable IVC filter provided protection against pulmonary embolism, and the device could be retrieved with a low rate of complications.
authors: Division of Interventional Radiology, Department of Radiology, Perelman School of Medicine at the University of Pennsylvania, 1 Silverstein, 3400 Spruce St., Philadelphia, PA 19104. Electronic address: william.stavropoulos@uphs.upenn.edu.
authors: S William
authors: SW
authors: Stavropoulos
authors: Division Surgical Critical Care, Carolina's Medical Center, Charlotte, North Carolina.
authors: Ronald F
authors: RF
authors: Sing
authors: Division of Interventional Radiology, Lakeland Regional Medical Center, Lakeland, Florida.
authors: Fakhir
authors: F
authors: Elmasri
authors: Division of Interventional Cardiology and Peripheral Vascular Disease, Ohio Health Heart and Vascular, Riverside Methodist Hospital, Columbus, Ohio.
authors: Mitchell J
authors: MJ
authors: Silver
authors: Department of Radiology, Division of Interventional Radiology, Baptist Cardiac and Vascular Institute, Miami, Florida.
authors: Alex
authors: A
authors: Powell
authors: Division of Interventional Radiology, Penn State Milton S. Hershey Medical Center, Hershey, Pennsylvania.
authors: Frank C
authors: FC
authors: Lynch
authors: Division of Interventional Radiology, Department of Radiology, University of Alabama at Birmingham Medical Center, Birmingham, Alabama.
authors: Ahmed Kamel Abdel
authors: AK
authors: Aal
authors: Division of Cardiovascular Medicine, Yale University School of Medicine, New Haven, Connecticut.
authors: Alexandra J
authors: AJ
authors: Lansky
authors: C. R. Bard, Murray Hill, New Jersey.
authors: Richard A
authors: RA
authors: Settlage
authors: Section of Vascular Surgery, Department of Surgery, Yale University School of Medicine, New Haven, Connecticut.
authors: Bart E
authors: BE
authors: Muhs
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000497:Alloys; D020878:Device Removal / Q000009:adverse effects; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D011474:Prosthesis Design; D011655:Pulmonary Embolism / Q000209:etiology / Q000517:prevention & control*; D012008:Recurrence; D012307:Risk Factors; D013997:Time Factors; D016896:Treatment Outcome; D014481:United States; D016306:Vena Cava Filters / Q000009:adverse effects; D020246:Venous Thrombosis / Q000150:complications / Q000175:diagnosis / Q000628:therapy*; D055815:Young Adult
chemical_list: D000497:Alloys; C013616:nitinol