10 May

The Natural History and Rate of Progression of Aortic Stenosis: Outcome

Although it is generally accepted that patients presenting for coronary artery bypass grafting with moderate or severe aortic stenosis (regardless of symptom status) undergo concomitant aortic valve replacement, the treatment of patients presenting for myocardial revascularization with coexisting asymptomatic mild aortic stenosis remains challenging. Given the bimodal rate of progression, it is no wonder that there is no consensus on how to deal with such patients.
Proponents of prophylactic aortic valve replacement at the time of myocardial revascularization argue that repeated surgery is technically more challenging and carries a higher operative mortality. Fiore and colleagues reviewed 28 patients who had aortic valve replacement surgery subsequent to coronary bypass surgery and found an operative mortality rate of 18%, compared with 9.1% in those undergoing combined valve and coronary surgery. This is very similar to the 18.2% perioperative mortality in a review of 44 patients requiring aortic valve replacement who had previously undergone coronary bypass surgery.
If one elects to be conservative and initially perform coronary bypass surgery alone, retrospective studies suggest that the average time to subsequent aortic valve replacement is between 5 and 7.6 years. Otto and her colleagues suggest that when patients are prospectively followed up, those patients with a baseline Doppler jet velocity of <3.0 m/s (peak instantaneous gradient of <36 mm Hg) are “unlikely to develop symptoms due to aortic stenosis over the next 5 years.” Assuming an annual risk of serious prosthetic valve-related complication to be 2%, then the 5-year risk would be approximately 10%. Others have estimated the 5-year risk for serious valve-related complications to be higher at approximately 15 to 20%.

In the review of 28 patients mentioned above, the actuarial survival at 1 and 5 years was no different in patients who had combined coronary and valve surgery vs those who had valve surgery subsequent to coronary bypass. At 10 years, there was a trend toward a greater survival advantage in those patients in whom valve surgery had been delayed. These data along with the increased operative risk of combined surgery and the subsequent risk of valve-related complications make it hard to justify routine prophylactic aortic valve replacement surgery.

Categories: Aortic Stenosis
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