title: The porcine valve type predicts obstructive thrombosis beyond the first three postoperative months in bioprostheses in the aortic position.
abstract: BACKGROUND
  Obstructive thrombosis of bioprosthetic valves is considered rare but may have dramatic consequences for the individual patient including repeat valve replacement, thrombolysis, or long-term anticoagulation. Whether the risk of obstructive thrombosis is dependent on the type of bioprosthesis (porcine versus bovine pericardial) is uncertain.
  
  
  RESULTS
  Between 2007 and 2012 a total of 1751 patients received a single stented bioprosthesis in the aortic valve position, 749 (43%) were porcine and 1002 (57%) bovine. During a mean follow-up of 3.4±1.9years, obstructive thrombosis (identified by an increase in mean pressure gradient≥20mm Hg or a decrease in velocity ratio≥0.05 and confirmed by either ECG-gated computer tomography, a return to baseline of stenosis parameters under treatment with a vitamin K antagonist, or histology in case of reoperation) was diagnosed in 17 patients with a porcine (2.3%) and none with a bovine valve (p<0.001). The cumulative probability of developing an obstructive thrombosis was significantly higher in patients with a porcine valve (p<0.001 log-rank test). Adjusting for differences in baseline variables and stratification by the estimated propensity score showed that strata with a high probability of receiving a bovine valve had the highest number of obstructive thrombosis in porcine valves. These findings were further confirmed in a Poisson model and a competing risk model including all-cause mortality. Treatment of obstructive thrombosis with a vitamin K antagonist was safe and effective in 15/17 patients.
  
  
  CONCLUSIONS
  The porcine valve type is an independent predictor of obstructive thrombosis in bioprostheses in the aortic position.
authors.affiliation: Division of Cardiology and Angiology II, University Heart Center Freiburg, Bad Krozingen, Germany.
authors.forename: Nikolaus
authors.initials: N
authors.lastname: Jander
authors.affiliation: Center for Medical Biometry and Medical Informatics, Medical Center, University of Freiburg, Freiburg, Germany.
authors.forename: Harriet
authors.initials: H
authors.lastname: Sommer
authors.affiliation: Division of Cardiovascular Surgery, University Heart Center Freiburg, Bad Krozingen, Germany.
authors.forename: Clarence
authors.initials: C
authors.lastname: Pingpoh
authors.affiliation: Division of Cardiology and Angiology II, University Heart Center Freiburg, Bad Krozingen, Germany.
authors.forename: Rolf-Peter
authors.initials: RP
authors.lastname: Kienzle
authors.affiliation: Division of Cardiology and Angiology II, University Heart Center Freiburg, Bad Krozingen, Germany.
authors.forename: Gabriele
authors.initials: G
authors.lastname: Martin
authors.affiliation: Division of Cardiology and Angiology II, University Heart Center Freiburg, Bad Krozingen, Germany.
authors.forename: Wolfgang
authors.initials: W
authors.lastname: Zeh
authors.affiliation: Section of Cardiovascular Radiology, Department of Radiology, University Hospital Freiburg, Germany.
authors.forename: Gregor
authors.initials: G
authors.lastname: Pache
authors.affiliation: Division of Cardiovascular Surgery, University Heart Center Freiburg, Bad Krozingen, Germany.
authors.forename: Matthias
authors.initials: M
authors.lastname: Siepe
authors.affiliation: Division of Cardiovascular Surgery, University Heart Center Freiburg, Bad Krozingen, Germany.
authors.forename: Friedhelm
authors.initials: F
authors.lastname: Beyersdorf
authors.affiliation: Center for Medical Biometry and Medical Informatics, Medical Center, University of Freiburg, Freiburg, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: Schumacher
authors.affiliation: Division of Cardiology and Angiology II, University Heart Center Freiburg, Bad Krozingen, Germany.
authors.forename: Franz-Josef
authors.initials: FJ
authors.lastname: Neumann
authors.affiliation: Division of Cardiology and Angiology II, University Heart Center Freiburg, Bad Krozingen, Germany. Electronic address: jan.minners@universitaets-herzzentrum.de.
authors.forename: Jan
authors.initials: J
authors.lastname: Minners
mesh_terms: D000368:Aged; D000818:Animals; D001021:Aortic Valve / Q000601:surgery*; D001705:Bioprosthesis / Q000009:adverse effects*; D002417:Cattle; D004452:Echocardiography; D005260:Female; D005500:Follow-Up Studies; D005858:Germany / Q000453:epidemiology; D006331:Heart Diseases / Q000175:diagnosis / Q000209:etiology*; D006349:Heart Valve Diseases / Q000601:surgery; D006350:Heart Valve Prosthesis / Q000009:adverse effects*; D006801:Humans; D008297:Male; D011183:Postoperative Complications / Q000175:diagnosis / Q000453:epidemiology / Q000209:etiology*; D011184:Postoperative Period; D011379:Prognosis; D011474:Prosthesis Design; D012189:Retrospective Studies; D015996:Survival Rate / Q000639:trends; D013552:Swine; D013927:Thrombosis / Q000175:diagnosis* / Q000453:epidemiology / Q000209:etiology*; D013997:Time Factors
keywords: Bioprosthesis; Obstructive thrombosis; Valvular heart disease