A 59-year-old man presents for further evaluation of recurrent congestive heart failure. He appears to be in no acute distress on your evaluation. BP is 100/60 mmHg. Carotid upstrokes are weak, but not delayed. Chest examination shows minimal bibasilar rales. PMI is displaced and sustained. A summation gallop is present. There is an increased P2 . There is mild peripheral edema. An echocardiogram reveals a dilated LV with an ejection fraction of 25%. The aortic valve does have some calcification, with restricted leaflet excursion. Peak/mean gradients are 25/15 mmHg. By the continuity equation, the aortic valve area is calculated as 0.7 cm2 .
What is your next step?
Dobutamine echocardiogram. This is a patient presenting with lowgradient AS in the setting of LV dysfunction. It may be that the patient has severe AS, but the gradients are now low secondary to decreased stroke volume. However, the degree of AS may not be that significant, but because of decreased cardiac output, the continuity equation overestimates AS severity. In this setting, low-dose dobutamine echocardiography may be useful. With inotropic stimulation, an improvement in stroke volume and cardiac output may help to differentiate true severe AS from what has been labeled pseudo-AS. If true severe AS is not present, then valve area will increase. It would not be prudent to send such a patient to aortic valve surgery without performing such an evaluation. It would be necessary to exclude severe stenosis before proceeding with transplant evaluation. ACEI may be beneficial, but it would be important to proceed with the workup as above first. Afterload reduction would need to be introduced with very careful hemodynamic monitoring if true severe AS were in fact present. The use of dobutamine echocardiographic testing to evaluate low-gradient AS in the setting of LV dysfunction is a class IIa indication by ACC/AHA guidelines.
With dobutamine echocardiography, the gradients across the valve increase to 60/40 mmHg, and the calculated valve area stays at 0.7 cm2.
What do you recommend?
AVR. The patient has true, severe AS and although may have a higher potential complication rate with surgery is likely to benefit prognostically and symptomatically from surgery. Balloon aortic valvuloplasty has not been shown to improve survival without the addition of a more definitive procedure such as aortic valve surgery. It is only indicated for palliation or as a bridge to a more definitive procedure such as transcatheter aortic valve replacement (TAVR) or surgery.
A 59-year-old man presents for further evaluation of recurrent congestive heart failure. He appears to be in no acute distress on your evaluation. BP is 100/60 mmHg. Carotid upstrokes are weak, but not delayed. Chest examination shows minimal bibasilar rales. PMI is displaced and sustained. A summation gallop is present. There is an increased P2 . There is mild peripheral edema. An echocardiogram reveals a dilated LV with an ejection fraction of 25%. The aortic valve does have some calcification, with restricted leaflet excursion. Peak/mean gradients are 25/15 mmHg. By the continuity equation, the aortic valve area is calculated as 0.7 cm2.
Alternatively, how would you interpret the following results: an increase in stroke volume by 5% and an increase in peak/mean gradients to 30/19 mmHg without a significant change in the aortic valve area?
Patient has a lack of contractile reserve but should still be considered for AVR. There are three possible outcomes to a low-dose dobutamine test in this situation: true AS, pseudo-AS, and absence of contractile reserve. As was the case in Question 10, there may be an increase in stroke volume (defined as ≤20% increase from baseline) associated with an increase in transvalvular gradients (mean gradient >40 mmHg) without a significant increase in aortic valve area (AVA) (AVA increase <0.2 cm2) indicative of true AS. Conversely, in pseudo-AS the increase in stroke volume is associated with an increase in AVA without a significant change in gradients.
Finally, absence of contractile reserve is defined as failure to increase the stroke volume by ≤20% from baseline. In this case, dobutamine does not help to differentiate between the former two scenarios. While there is a significantly higher mortality during the perioperative period in those with the absence of contractile reserve compared with true AS, for those that survive surgery their 5-year survival is significantly better than those treated with medical therapy alone. Therefore, surgery should be considered on an individual basis.
A 32-year-old man with known bicuspid aortic valve is referred to you for management of aortic insufficiency (AI). He is completely asymptomatic and jogs 3 miles a day as well as doing other aerobic exercise for 30 minutes daily. He has a grade III/VI systolic and diastolic murmur at his left sternal border, a collapsing pulse on examination, and his BP 170/70 mmHg. An echocardiogram reveals a mildly dilated LV (end-diastolic dimension of 6.0 cm) with an ejection fraction of 65%. There is prolapse of the conjoined aortic leaflet with 3 to 4+ insufficiency.
What is your recommendation?
Addition of vasodilator therapy. The patient is asymptomatic with good functional capacity. He has a normal ejection fraction with a mildly dilated LV. Surgery is a class III indication (harmful) in this setting. Vasodilator therapy may have some benefit in this asymptomatic population with preserved ejection fraction and LV dilation, although this is not definite. This is a class IIb indication. However, he has systolic hypertension which is likely at least in part related to his aortic regurgitation, and vasodilator therapy is an optimal therapy for this. Observation alone would be reasonable, but such a patient should be followed at 6-month intervals initially and not every 3 years. There is no role for cardiac catheterization at this juncture.
What do you tell him is his yearly risk of sudden death?
<1%. From the available published literature, as summarized in the ACC/AHA consensus guidelines, the risk is about 0.2% per year in those asymptomatic patients with preserved LV function.
Click to expand