Management of the Elderly Aortic Stenosis Patient
Management of the Elderly Aortic Stenosis Patient
The incidence of aortic stenosis increases with age and thus it occurs frequently in elderly patients. Once severe obstruction has developed, death occurs within 3 years unless the aortic valve is replaced. The results of aortic valve surgery, even in octogenarians, are usually excellent in the absence of comorbidity. The exception to this rule is for the aortic stenosis patient who has low ejection fraction, a low cardiac output and a transvalvular gradient of <30 mm Hg. Such patients have far advanced left ventricular dysfunction and increased operative mortality. However, even these patients may benefit from surgery if they have truly severe aortic stenosis. Because valve area is unreliable at low cardiac outputs, output should be increased pharmacologically in such patients and the valve area recalculated. If the transvalvular gradient increases with output, severe aortic stenosis is present and valve replacement may be beneficial. However, if output increases but gradient does not, only mild stenosis is present and surgery is unlikely to prolong life.
Management of most patients with aortic stenosis, including the elderly, is straightforward. Asymptomatic patients, even those with severe valvular narrowing, have an excellent prognosis. The risk of sudden death in such patients is less than 2% per year and it seems promising that exercise testing may help to identify many of those asymptomatic patients who are at especially high risk. Once symptoms develop, prompt aortic valve replacement (AVR) can return age-corrected prognosis to that of a normal population. As shown in Figure 1, this is especially true of patients in whom a prosthetic valve is placed after age 65, presumably because such patients have a relatively shorter experience with the dangers of a prosthetic valve and with the potential need for reoperation. Further, these data emphasize that AVR should not be denied to patients simply because of advanced age. Indeed, there are many reports of octogenarians and even nonagenarians that demonstrate an excellent result following AVR.
(Enlarge Image)
Age-corrected survival 10 years following aortic valve replacement for aortic stenosis is demonstrated for patients aged >65 years (solid line) and <65 years (dotted line). As can be seen, survival in elderly patients following aortic valve replacement is not different from the age-corrected survival of the normal population. Reprinted with permission from J Am Coll Cardiol. 1990;15:566-573.[5]
At the other end of the spectrum are those patients with far advanced congestive heart failure and decreased systolic ejection performance. Even in this group, prognosis is excellent if such patients have a mean systolic gradient of greater than 40 mm Hg. In such patients, afterload mismatch contributes substantially to the reduced ejection fraction. Following AVR, the aortic orifice is increased several fold, the gradient falls, afterload is reduced, and ejection fraction rises.
The most difficult group of patients with aortic stenosis to care for is patients with reduced ejection fraction, heart failure, and low transvalvular gradient. While there are no specific studies of elderly patients with this condition, it seems unlikely that advanced age would improve prognosis. In an early study of this group of patients, my colleagues and I examined a group of 14 patients who had experienced pulmonary edema and who had an average ejection fraction of 28%. As shown in Figure 2, patients with a high transvalvular gradient had a good outcome while patients with a mean transvalvular gradient of less than 30 mm Hg had a poor outcome. These findings have been borne out in subsequent studies. Lund found that postoperative prognosis was inversely related to preoperative transvalvular gradient. Thus, those patients with the highest preoperative gradient had the best postoperative outcome while those patients with the lowest gradient had the worst outcome. In a recent study published by Connolly et al. from the Mayo Clinic, operative risk for the low gradient low ejection fraction group was 21%, and within 4 years, 50% of the patients had succumbed. While prognosis in this group is generally poor, most series have shown that many such patients do improve following surgery. A recent study from the Cleveland Clinic demonstrated a definite survival advantage to AVR in this group. The obvious clinical issue is to determine preoperatively which of these high-risk patients might benefit from AVR vs. which patients are likely to have a poor prognosis.
(Enlarge Image)
Outcome of 14 patients with aortic stenosis and severely impaired left ventricular function (average ejection fraction, 0.28) is shown. Patients with a mean gradient of more than 30 mm Hg had a good outcome (solid circles) while patients with a gradient lower than 30 mm Hg (X's) had a poor outcome. Reprinted with permission from Circulation. 1980;62:42-88.[7]
The incidence of aortic stenosis increases with age and thus it occurs frequently in elderly patients. Once severe obstruction has developed, death occurs within 3 years unless the aortic valve is replaced. The results of aortic valve surgery, even in octogenarians, are usually excellent in the absence of comorbidity. The exception to this rule is for the aortic stenosis patient who has low ejection fraction, a low cardiac output and a transvalvular gradient of <30 mm Hg. Such patients have far advanced left ventricular dysfunction and increased operative mortality. However, even these patients may benefit from surgery if they have truly severe aortic stenosis. Because valve area is unreliable at low cardiac outputs, output should be increased pharmacologically in such patients and the valve area recalculated. If the transvalvular gradient increases with output, severe aortic stenosis is present and valve replacement may be beneficial. However, if output increases but gradient does not, only mild stenosis is present and surgery is unlikely to prolong life.
Management of most patients with aortic stenosis, including the elderly, is straightforward. Asymptomatic patients, even those with severe valvular narrowing, have an excellent prognosis. The risk of sudden death in such patients is less than 2% per year and it seems promising that exercise testing may help to identify many of those asymptomatic patients who are at especially high risk. Once symptoms develop, prompt aortic valve replacement (AVR) can return age-corrected prognosis to that of a normal population. As shown in Figure 1, this is especially true of patients in whom a prosthetic valve is placed after age 65, presumably because such patients have a relatively shorter experience with the dangers of a prosthetic valve and with the potential need for reoperation. Further, these data emphasize that AVR should not be denied to patients simply because of advanced age. Indeed, there are many reports of octogenarians and even nonagenarians that demonstrate an excellent result following AVR.
(Enlarge Image)
Age-corrected survival 10 years following aortic valve replacement for aortic stenosis is demonstrated for patients aged >65 years (solid line) and <65 years (dotted line). As can be seen, survival in elderly patients following aortic valve replacement is not different from the age-corrected survival of the normal population. Reprinted with permission from J Am Coll Cardiol. 1990;15:566-573.[5]
At the other end of the spectrum are those patients with far advanced congestive heart failure and decreased systolic ejection performance. Even in this group, prognosis is excellent if such patients have a mean systolic gradient of greater than 40 mm Hg. In such patients, afterload mismatch contributes substantially to the reduced ejection fraction. Following AVR, the aortic orifice is increased several fold, the gradient falls, afterload is reduced, and ejection fraction rises.
The most difficult group of patients with aortic stenosis to care for is patients with reduced ejection fraction, heart failure, and low transvalvular gradient. While there are no specific studies of elderly patients with this condition, it seems unlikely that advanced age would improve prognosis. In an early study of this group of patients, my colleagues and I examined a group of 14 patients who had experienced pulmonary edema and who had an average ejection fraction of 28%. As shown in Figure 2, patients with a high transvalvular gradient had a good outcome while patients with a mean transvalvular gradient of less than 30 mm Hg had a poor outcome. These findings have been borne out in subsequent studies. Lund found that postoperative prognosis was inversely related to preoperative transvalvular gradient. Thus, those patients with the highest preoperative gradient had the best postoperative outcome while those patients with the lowest gradient had the worst outcome. In a recent study published by Connolly et al. from the Mayo Clinic, operative risk for the low gradient low ejection fraction group was 21%, and within 4 years, 50% of the patients had succumbed. While prognosis in this group is generally poor, most series have shown that many such patients do improve following surgery. A recent study from the Cleveland Clinic demonstrated a definite survival advantage to AVR in this group. The obvious clinical issue is to determine preoperatively which of these high-risk patients might benefit from AVR vs. which patients are likely to have a poor prognosis.
(Enlarge Image)
Outcome of 14 patients with aortic stenosis and severely impaired left ventricular function (average ejection fraction, 0.28) is shown. Patients with a mean gradient of more than 30 mm Hg had a good outcome (solid circles) while patients with a gradient lower than 30 mm Hg (X's) had a poor outcome. Reprinted with permission from Circulation. 1980;62:42-88.[7]
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