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Aortic valve replacement for patients with mild to moderate aortic stenosis undergoing coronary artery bypass surgery
1Jacksonville Heart Center, Florida 32250, USA.
Insights
For patients needing coronary artery bypass grafting (CABG), prophylactic aortic valve replacement (AVR) is considered when aortic stenosis shows a gradient >20-25 mmHg. This approach balances risks of worsening stenosis against surgical complications.
Area of Science:
- Cardiovascular Surgery
- Cardiac Surgery
- Valvular Heart Disease
Background:
- Aortic valve replacement (AVR) is typically reserved for symptomatic patients.
- An aging population increases the incidence of mild-to-moderate aortic stenosis in patients requiring coronary artery bypass grafting (CABG).
- Progression of untreated aortic stenosis can lead to severe symptoms and increased mortality.
Purpose of the Study:
- To evaluate the risks and benefits of prophylactic AVR in asymptomatic patients with mild-to-moderate aortic stenosis undergoing CABG.
- To determine the optimal management strategy for aortic stenosis in patients requiring concurrent CABG.
Main Methods:
- Analysis of data on aortic stenosis progression rates and associated mortality.
- Comparison of operative risks and late outcomes for isolated CABG versus combined CABG and AVR.
- Assessment of hemodynamic benefits of AVR in patients with varying degrees of aortic stenosis.
Main Results:
- Untreated aortic stenosis progresses, with approximately 25% of patients requiring late AVR at high risk (14-24% mortality).
- Performing AVR during CABG slightly increases operative risk (2-6%) but offers significant long-term benefits.
- Patients with an aortic valve gradient >20-25 mmHg are at considerable risk of developing symptomatic stenosis before the CABG benefits wane.
Conclusions:
- Concurrent AVR during CABG is a reasonable consideration for patients with a measurable aortic valve gradient (>20-25 mmHg).
- Deferring AVR may be acceptable for very mild gradients (<25 mmHg), but stenosis progression can be rapid.
- Prophylactic AVR in this context balances the risk of future symptomatic disease against the perioperative risks of combined procedures.
Abstract:
Aortic valve replacement (AVR) is not normally recommended in asymptomatic patients, even if aortic stenosis is severe. However, as the population ages, an increasing number of patients with mild or moderate aortic stenosis will require coronary artery bypass grafting (CABG). In these cases, risk of "prophylactic" AVR needs to be weighed against risks of subsequent worsening of the mildly or moderately diseased aortic valve. If unoperated, aortic stenosis will worsen at an average of 6-8 mmHg per year (-0.1 cm2/year valve area), and one-quarter of such patients will require late AVR with a high operative mortality (14-24%). If AVR is performed at the time of CABG, operative risk is increased only slightly (from 1-3% to 2-6%), as are late mortality (1-2% per year) and morbidity (1-2% per year), mainly from hemorrhagic complications. Intrinsic gradients of most prosthetic valves are sufficiently low that even patients with low aortic valve gradients are likely to derive hemodynamic benefit from AVR. Thus, if there is a measurable (>20-25 mmHg) gradient across the aortic valve in a patient who requires CABG, the patient is at considerable risk for developing symptomatic aortic stenosis prior to reaching the end of expected benefit from CABG; in this case AVR should be considered. It may be reasonable in patients with very mild gradients (<25 mmHg) to defer aortic valve surgery; however, it should be noted that aortic stenosis progression is generally more rapid when the initial gradient is small.