Aortic Stenosis — When to Operate

Abstract & Commentary

By Harold L. Karpman, MD, FACC, FACP, Clinical Professor of Medicine, UCLA School of Medicine. Dr. Karpman reports no financial relationship to this field of study.

Synopsis: Even if asymptomatic, early elective aortic valve replacement should be considered for increasingly symptomatic patients with severe aortic valve stenosis because they have a poor prognosis with a high event rate and a risk of rapid functional deterioration, especially if the peak aortic jet velocity is above 5.5 m/sec.

Source: Rosenhek R, et al. Natural history of very severe aortic stenosis. Circulation 2010;121:151-156.

The prognosis for asymptomatic patients with severe aortic stenosis is usually quite favorable and a watchful waiting approach, which has been demonstrated to be quite safe, is usually the clinical approach utilized by most physicians.1-4 However, it must be clearly recognized that when symptoms start to develop in patients with severe aortic stenosis, a very poor prognosis can be expected unless an aortic valve replacement procedure is urgently performed.5-7 Asymptomatic patients usually are not recommended for aortic valve replacement for many reasons, including the immediate operative risk, the long-term morbidity and mortality, and the potential need for reoperation.8 However, many clinicians have argued in favor of an earlier intervention because of the higher operative risk that occurs as patients become increasingly symptomatic,9 the risks of late symptom reporting by stoical patients, and the risk of sudden death even though this risk is generally quite low in asymptomatic patients.1,2

Rosenhek and his colleagues prospectively followed 116 consecutive, asymptomatic patients with very severe isolated aortic stenosis in an attempt to define its natural history and to determine which patients should be selected for valve replacement before they became symptomatic. They concluded that in asymptomatic patients with severe aortic stenosis, the presence of a calcified aortic valve combined with rapid hemodynamic progression identified a high-risk population in whom early elective valve replacement should be considered.2

Commentary

Despite being asymptomatic, patients with very severe aortic stenosis quite often have a poor prognosis with a high event rate and a significant risk of rapid functional deterioration. This study by Rosenhek et al demonstrated that event-free survival rate for patients with severe aortic stenosis (defined by a peak aortic jet velocity of 4.0-5.0 m/sec) diminished from 82% at year 1 to 39% at year 4. The survival rates were significantly worse for patients with a very severe stenosis (defined by a peak jet velocity of 5.0-5.5 m/sec): These patients had a survival rate of only 76% at year 1 and 17% a year 4. Patients with aortic stenosis and associated coronary artery disease had a worse chance of event-free survival because a more rapid hemodynamic deterioration usually occurs.2,8 However, the presence of coronary artery disease was not found to be of statistically significant additional prognostic importance and neither was treatment with statin drugs, renin-angiotensin-aldosterone system inhibitors, or beta blockers.

Clinicians should recognize that patients with very severe aortic stenosis (i.e., defined as those patients with a peak aortic jet velocity 3 5.5 m/sec) tend to have more severe and rapid onset of symptoms than do those patients with a lower jet velocity. Therefore, even asymptomatic patients with very severe aortic stenosis should be considered for early elective valve replacement surgery because of the risk of rapid functional deterioration often associated with an increased event rate. All patients with aortic stenosis should be closely followed, evaluated carefully with respect to early symptom development. Additionally, they should be frequently monitored echocardiographically to determine any aortic jet velocity changes of significance.

References

1. Otto CM, et al. Prospective study of asymptomatic valvular aortic stenosis. Circulation 1997;95:2262-2270.

2. Rosenhek R, et al. Predictors of outcome in severe, asymptomatic aortic stenosis. N Engl J Med 2000;343:611-617.

3. Bonow RO, et al. ACC/AHA 2006 guidelines for the management of patience with valvular heart disease. J Am Coll Cardiol 2006;48:e1-e148.

4. Vahanian A, et al. Guidelines on the management of valvular heart disease. Eur Heart J 2007;28:230-268.

5. Horstcotte D, Loogen F. The natural history of aortic valve stenosis. Eur Heart J 1988;9(suppl E):57-64.

6. Ross J Jr, Braunwald E. Aortic stenosis. Circulation 1968;38(1 Suppl):61-67.

7. Frank S, et al. Natural history of valvular aortic stenosis. Br Heart J 1973;35:41-46.

8. Hammermeister K, et al. Outcomes 15 years after valve replacement with a mechanical versus a bioprosthetic valve. J Am Coll Cardiol 2000;36:1152-1158.

9. STS National Database. STS US Cardiac surgery database: 1997 aortic valve replacement patients. Available at: www.ctsnet.org/doc/3031.