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Influence of type of aortic valve prosthesis on coronary blood flow velocity
Matija Jelenc1, Katja Ažman Juvan, Nadja Tatjana Ružič Medvešček
1Department of Cardiovascular Surgery, University Medical Centre Ljubljana, Ljubljana, Slovenia. jelenc@gmail.com
Insights
Aortic valve replacement (AVR) type impacts coronary blood flow. Mechanical prostheses improved left anterior descending coronary artery flow velocity more than bioprosthetic ones, influencing coronary circulation post-surgery.
Area of Science:
- Cardiovascular Surgery
- Interventional Cardiology
- Biomedical Engineering
Background:
- Severe aortic valve stenosis affects coronary blood flow.
- Aortic valve replacement (AVR) improves flow, but prosthesis type matters.
- This study examines how AVR prosthesis type influences coronary blood flow velocity.
Purpose of the Study:
- To investigate the impact of different aortic valve prostheses on coronary blood flow velocity.
- To compare coronary blood flow dynamics after AVR with mechanical versus bioprosthetic valves.
Main Methods:
- Measured left anterior descending (LAD) and right coronary artery (RCA) blood flow velocity intraoperatively before and after AVR.
- Used Doppler probe and adenosine infusion for hyperemia.
- Compared stentless bioprosthesis (Sorin Freedom Solo) with bileaflet mechanical prosthesis (St. Jude Medical Regent).
Main Results:
- Mechanical prosthesis (St. Jude) increased LAD systolic proportion (SF) and normalized systolic velocity (NSF) significantly more than the bioprosthesis (Sorin).
- No significant change in LAD velocity profile with Sorin prosthesis, despite improved valve function.
- No effect on RCA flow velocity profile observed with either prosthesis.
Conclusions:
- Aortic valve prosthesis type significantly influences LAD coronary flow velocity profile.
- Differences likely stem from valve design and systolic transvalvular flow patterns.
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.
Conclusion:
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.
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