Stentless bioprostheses improve postoperative coronary flow more than stented prostheses after valve replacement for aortic stenosis.

OBJECTIVE In some randomized studies, stentless aortic valves have demonstrated hemodynamic advantages in comparison with stented prostheses. The effect of more physiologic flow dynamics on coronary artery flow has not been investigated yet. This study compares coronary perfusion after aortic valve replacement with stented or stentless porcine bioprostheses in a prospective randomized study. METHODS A total of 24 patients (73 +/- 6 years) referred for treatment of aortic stenosis were randomized to aortic valve replacement with stented (Medtronic Mosaic; (Medtronic Inc, Minneapolis, Minn) or stentless (Medtronic Freestyle; Medtronic Inc) prostheses. Coronary flow was measured by means of magnetic resonance imaging preoperatively, 5 days after the operation, and 6 months postoperatively, then with evaluation of coronary flow reserve. Echocardiography was performed to quantify transvalvular gradients and left ventricular mass regression. RESULTS Coronary flow increased in both groups significantly (P < .001) after aortic valve replacement. This increase was higher in the stentless group compared with that seen in the stented group (343 +/- 137 vs 221 +/- 66 mL/min). Also, coronary flow reserve was higher for stentless valves (3.4 +/- 0.3 for stentless valves and 2.3 +/- 0.1 for stented valves). Mean pressure gradients for Freestyle valves were lower (10 +/- 4 and 8 +/- 3 mm Hg, respectively, vs 19 +/- 6 postoperatively and 15 +/- 4 mm Hg at follow-up for Mosaic valves, P < .05). Left ventricular mass regression was similar in both groups. CONCLUSIONS Normalization of coronary artery flow after aortic valve replacement for aortic stenosis was more pronounced for stentless valves compared with stented valves. The fact that the stentless design also demonstrated a superior hemodynamic performance with lower pressure gradients might be explained by the design being closer to physiologic anatomy and thus the presence of lower turbulence levels in the sinuses of Valsalva.

[1]  S. Armstrong,et al.  Late results of heart valve replacement with the Hancock II bioprosthesis. , 2001, The Journal of thoracic and cardiovascular surgery.

[2]  Prosthetic aortic valve replacement. , 2005, The Journal of thoracic and cardiovascular surgery.

[3]  L. Shapiro,et al.  Profiles of coronary blood flow velocity in patients with aortic stenosis and the effect of valve replacement: a transthoracic echocardiographic study. , 1994, British heart journal.

[4]  M. Eriksson,et al.  Eleven years' experience with the Biocor stentless aortic bioprosthesis: clinical and hemodynamic follow-up with long-term relative survival rate. , 2002, European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery.

[5]  M. Ruel,et al.  Long-term outcomes of valve replacement with modern prostheses in young adults. , 2005, European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery.

[6]  G. Grunkemeier,et al.  Twenty years' experience with the Medtronic Hall valve. , 2001, The Journal of thoracic and cardiovascular surgery.

[7]  C. Higgins,et al.  Assessment of coronary flow velocity reserve using fast velocity-encoded cine MRI for noninvasive detection of restenosis after coronary stent implantation. , 2001, Journal of cardiovascular magnetic resonance : official journal of the Society for Cardiovascular Magnetic Resonance.

[8]  R. Emery,et al.  Replacement of the aortic valve in patients under 50 years of age: long-term follow-up of the St. Jude Medical prosthesis. , 2003, The Annals of thoracic surgery.

[9]  P. Camici,et al.  Role of positron emission tomography in the investigation of human coronary circulatory function. , 1994, Cardiovascular research.

[10]  D. Hildick-Smith,et al.  Coronary flow reserve improves after aortic valve replacement for aortic stenosis: an adenosine transthoracic echocardiography study. , 2000, Journal of the American College of Cardiology.

[11]  P K Paulsen,et al.  Quantitation of the turbulent stress distribution downstream of normal, diseased and artificial aortic valves in humans. , 1992, European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery.

[12]  T. David,et al.  Aortic valve replacement with the Toronto SPV: long-term clinical and hemodynamic results. , 2002, European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery.

[13]  A. Moritz,et al.  Effect of mechanical aortic valve orientation on coronary artery flow: comparison of tilting disc versus bileaflet prostheses in pigs. , 2002, The Journal of thoracic and cardiovascular surgery.

[14]  E. Lansac,et al.  A four-dimensional study of the aortic root dynamics. , 2002, European journal of cardio-thoracic surgery : official journal of the European Association for Cardio-thoracic Surgery.

[15]  D. Neglia,et al.  Prognostic Role of Myocardial Blood Flow Impairment in Idiopathic Left Ventricular Dysfunction , 2002, Circulation.

[16]  J. Pepper,et al.  The relationship of myocardial stroke work to coronary flow velocity immediately after aortic valve replacement. , 1999, The Annals of thoracic surgery.

[17]  R. Sakata,et al.  Long-term follow up in patients receiving a small aortic valve prosthesis. , 2002, Journal of Heart Valve Disease.

[18]  Michael Markl,et al.  Time-resolved three-dimensional magnetic resonance velocity mapping of aortic flow in healthy volunteers and patients after valve-sparing aortic root replacement. , 2005, The Journal of thoracic and cardiovascular surgery.

[19]  A. Moritz,et al.  Initial in vivo results of the new Medtronic Advantage(TM) bileaflet valve in aortic position and comparison to the SJM. , 2002, Cardiovascular surgery.

[20]  O. Lund,et al.  Standard aortic St. Jude valve at 18 years: performance profile and determinants of outcome. , 2000, The Annals of thoracic surgery.

[21]  Susan Armstrong,et al.  Late hemodynamic and clinical outcomes of aortic valve replacement with the Carpentier-Edwards Perimount pericardial bioprosthesis. , 2002, The Journal of thoracic and cardiovascular surgery.