title: Off-pump tricuspid valved stent implantation: the next step.
abstract: OBJECTIVE
  Off-pump transcatheter valved stent implantation could be a treatment option for patients suffering from symptomatic tricuspid regurgitation (TR) who are classified as inoperable. In this study, we present our recent short-term results of transventricular tricuspid valved stent implantation and compare different stent types for atrial anchorage.
  
  
  METHODS
  Fifteen pigs received a self-expandable valved stent implantation off-pump via a transventricular access. Successfully implanted pigs were observed over a period of 6 h (n = 9), 48 h (n = 1) and 4 weeks (n = 1). Haemodynamic and full transoesophageal echocardiographic (TOE) evaluations were done before, 1 h, 3 h (n = 11; all successfully implanted pigs), and 6 h (n = 9; acute group) after implantation. Nine days postimplantation, one pig received additional angiography, computed tomography (CT) and transthoracic echocardiography (TTE). Post-mortem, gross examination was conducted to analyse the stent position and deformation. In two pigs (48 h and 4 weeks survival) histological staining and immunohistochemistry of surrounding myocardium was performed.
  
  
  RESULTS
  The heart rate significantly increased in all pigs postimplantation from 66.8 ± 13.6 to 101.8 ± 24.6 bpm, whereas cardiac output and pressure levels remained unchanged. Orthotopic positioning was reproducibly achieved. TOE showed an efficient reduction of paravalvular leakages from a mean grade of 1.4 1 h postimplantation to a mean of 0.9 at 6 h postimplantation due to a special sealing pouch. The ratio early and late ventricular filling velocities remained constant and the valvular gradient across the valved stent stayed low during the observation period. Angiography, CT and TTE confirmed orthotopic positioning and mild grade of paravalvular leakage after 9 days (n = 1). Only mild TR was observed here. The ventricular part of the stent was deformed to an oval shape in 7 of 14 animals as shown via post-mortem examination. The surrounding tissue after 1 month (n = 1) showed normal morphology, without inflammation or calcification.
  
  
  CONCLUSIONS
  This study shows the feasibility of catheter-based replacement of the tricuspid valve by a valved stent in an off-pump procedure. The successive enhancements in this tricuspid valved stent design lead to a prototype being ready for mid- to long-term evaluations.
authors.affiliation: Department of Cardiovascular Surgery, University Hospital Schleswig-Holstein, Kiel, Germany.
authors.forename: Jan-Paul
authors.initials: JP
authors.lastname: Gundlach
authors.forename: Jawid
authors.initials: J
authors.lastname: Madjidyar
authors.forename: Martin
authors.initials: M
authors.lastname: Marczynski-Bühlow
authors.forename: Saskia
authors.initials: S
authors.lastname: Pokorny
authors.forename: Telse Maike
authors.initials: TM
authors.lastname: Bähr
authors.forename: Jochen
authors.initials: J
authors.lastname: Cremer
authors.forename: Georg
authors.initials: G
authors.lastname: Lutter
mesh_terms: D000818:Animals; D002114:Calcinosis; D047549:Coronary Artery Bypass, Off-Pump / Q000379:methods*; D017548:Echocardiography, Transesophageal; D005260:Female; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation / Q000009:adverse effects / Q000295:instrumentation / Q000379:methods; D015607:Stents; D013552:Swine; D014261:Tricuspid Valve / Q000601:surgery*
keywords: Off-pump; Transthoracic echocardiography; Transventricular; Tricuspid valve; Valved stent