title: The stentless quadrileaflet bovine pericardial mitral valve: echocardiographic assessment.
abstract: OBJECTIVE
  Recently, a stentless chordally supported quadrileaflet mitral valve (QMV) bioprosthesis made of selected tanned bovine pericardium treated to minimize calcification, has become available for clinical trial. The aim of this study was to report both the echocardiographic appearance and hemodynamic performance of this valve by means of echocardiography.
  
  
  METHODS
  The QMV was implanted in 22 patients (mean age 38 +/- 12 years) requiring isolated mitral valve replacement for valve lesions not deemed suitable for repair. Echocardiography was performed pre-operatively, and at one and three months postoperatively. Transthoracic echocardiography (TTE) was used to monitor mean instantaneous pressure gradient as calculated from the long modified Bernoulli equation, cardiac index (CI), pressure half-time and effective orifice area (EOA) using the Hatle and continuity equations. Regurgitation patterns were sought by color Doppler transesophageal echocardiography in all valves intraoperatively following valve implantation, and by TTE in the outpatient clinic at follow up.
  
  
  RESULTS
  After a mean follow up of 8.3 months (range: 1 to 18 months), all patients were well and symptomatically improved. At three months postoperatively, the mean pressure gradient ranged from 1.7 to 2.2 mmHg. The EOA was larger using the Hatle as compared with the continuity equation (2.4 +/- 0.7 cm2 versus 1.8 +/- 0.5 cm2, respectively; p < 0.005). Mitral regurgitation was trivial in 77% and mild in 14% of patients at 3 months after surgery; moderate mitral stenosis was noted in one patient. The CI improved significantly postoperatively (p < 0.005), and left ventricular function was maintained.
  
  
  CONCLUSIONS
  The hemodynamic performance of this novel prosthesis is favorable. Although follow up is too short to assess durability, it is hoped that the unique design and improved valve preservation technique of this device will enhance long-term durability.
authors.affiliation: Division of Cardiology, Johannesburg Hospital, University of the Witwatersrand, South Africa.
authors.forename: S J
authors.initials: SJ
authors.lastname: Middlemost
authors.forename: P
authors.initials: P
authors.lastname: Manga
mesh_terms: D000328:Adult; D000818:Animals; D001705:Bioprosthesis; D001783:Blood Flow Velocity; D002417:Cattle; D003326:Coronary Circulation; D018618:Echocardiography, Doppler, Color; D017548:Echocardiography, Transesophageal; D005500:Follow-Up Studies; D006349:Heart Valve Diseases / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery; D006350:Heart Valve Prosthesis; D019918:Heart Valve Prosthesis Implantation; D006801:Humans; D008943:Mitral Valve / Q000000981:diagnostic imaging* / Q000503:physiopathology / Q000601:surgery; D012189:Retrospective Studies; D015607:Stents; D016896:Treatment Outcome; D017725:Ventricular Pressure