title: Influence of type of aortic valve prosthesis on coronary blood flow velocity.
abstract: BACKGROUND
  Severe aortic valve stenosis is associated with high resting and reduced hyperemic coronary blood flow. Coronary blood flow increases after aortic valve replacement (AVR); however, the increase depends on the type of prosthesis used. The present study investigates the influence of type of aortic valve prosthesis on coronary blood flow velocity.
  
  
  METHODS
  The blood flow velocity in the left anterior descending coronary artery (LAD) and the right coronary artery (RCA) was measured intraoperatively before and after AVR with a stentless bioprosthesis (Sorin Freedom Solo; n = 11) or a bileaflet mechanical prosthesis (St. Jude Medical Regent; n = 11). Measurements were made with an X-Plore epicardial Doppler probe (Medistim, Oslo, Norway) following induction of hyperemia with an adenosine infusion. Preoperative and postoperative echocardiography evaluations were used to assess valvular and ventricular function. Velocity time integrals (VTI) were measured from the Doppler signals and used to calculate the proportion of systolic VTI (SF), diastolic VTI (DF), and normalized systolic coronary blood flow velocities (NSF) and normalized diastolic coronary blood flow velocities (NDF).
  
  
  RESULTS
  The systolic proportion of the LAD VTI increased after AVR with the St. Jude Medical Regent prosthesis, which produced higher LAD SF and NSF values than the Sorin Freedom Solo prosthesis (SF, 0.41 ± 0.09 versus 0.29 ± 0.13 [P = .04]; NSF, 0.88 ± 0.24 versus 0.55 ± 0.17 [P = .01]). No significant changes in the LAD velocity profile were noted after valve replacement with the Sorin Freedom Solo, despite a significant reduction in transvalvular gradient and an increase in the effective orifice area. AVR had no effect on the RCA flow velocity profile.
  
  
  CONCLUSIONS
  The coronary flow velocity profile in the LAD was significantly influenced by the type of aortic valve prosthesis used. The differences in the LAD velocity profile probably reflect differences in valve design and the systolic transvalvular flow pattern.
authors: Department of Cardiovascular Surgery, University Medical Centre Ljubljana, Ljubljana, Slovenia. jelenc@gmail.com
authors: Matija
authors: M
authors: Jelenc
authors: Katja Ažman
authors: KA
authors: Juvan
authors: Nadja Tatjana Ružič
authors: NT
authors: Medvešček
authors: Borut
authors: B
authors: Geršak
mesh_terms: D000368:Aged; D001021:Aortic Valve / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D001024:Aortic Valve Stenosis / Q000000981:diagnostic imaging / Q000503:physiopathology* / Q000601:surgery*; D001783:Blood Flow Velocity; D003326:Coronary Circulation; D003331:Coronary Vessels / Q000503:physiopathology*; D019544:Equipment Failure Analysis; D005260:Female; D006350:Heart Valve Prosthesis; D006801:Humans; D008297:Male; D011474:Prosthesis Design; D016896:Treatment Outcome; D014463:Ultrasonography