A Previously Healthy 42 Year old Man Presents To The Emergency With Syncope

A previously healthy but inactive 42-year-old man is seen in the ER after a first episode of syncope, which occurred while he was playing basketball.
On questioning, he describes a 2-month history of exertional chest pain. He has not seen a physician during his adult life.
Physical examination reveals the following findings. His supine blood pressure is 116/80 mm Hg without any significant orthostatic change. There is no jugular venous distention, but there are slowly rising, small-amplitude, and somewhat sustained carotid pulses. His lungs are clear. A sustained and slightly laterally displaced apex impulse is noted, as well as a soft first heart sound and a single second heart sound, a prominent fourth heart sound, and a grade 3/6 harsh, late-peaking, crescendo–decrescendo systolic murmur heard best at  the cardiac base and radiating to the carotids with a high-frequency component at the cardiac apex. No clubbing, cyanosis, or edema is noted.

1. What is the most likely valvular lesion in this patient?
2. What is the most likely cause of aortic stenosis in this age-group?
3. What is the average survival of patients w ith uncorrected aortic stenosis
after the onset of syncope?
4. How is the severity of aortic stenosis most accurately determined?
5. What is the best therapy for symptomatic aortic stenosis?

Answers:

1. What is the most likely valvular lesion in this patient?
The history of angina and syncope and the classic physical examination findings make aortic stenosis an almost certain diagnosis in this patient.
The characteristic arterial pulses described have been referred to as pulsus parvus et tardus. The single second heart sound indicates the absence of the aortic component, suggesting severe immobility of the aortic valve. The murmur is also characteristic of aortic stenosis with its crescendo– decrescendo quality and the late peaking. Do not be fooled by the high frequency
component at the cardiac apex. Although the murmur of aortic stenosis is most often heard at the upper cardiac border with radiation to the carotid arteries, the murmur may also radiate to the apex, where it may be mistaken for the murmur of mitral regurgitation.


2. What is the most likely cause of aortic stenosis in this age-group?
Between 35 and 65 years of age, degenerative change in a congenitally bicuspid aortic valve is the predominant cause of aortic stenosis. Beyond 65 years of age, aortic stenosis usually results from calcification of a previously normal tricuspid aortic valve (senile calcific aortic stenosis). Although the exact cause of senile aortic stenosis is unknown, it is associated with hypertension and hyperlipidemia. Isolated aortic stenosis in the United States rarely results from rheumatic disease.

3. What is the average survival of patients with uncorrected aortic stenosis after the onset of syncope?
Patients with aortic stenosis may remain asymptomatic for years, but once symptoms develop the course of the disease may be quite fulminant.
According to studies conducted before valve surgery w as available, such patients with syncope due to aortic stenosis could expect to survive an average of 3 years after the onset of syncope. The average survival after the onset of angina pectoris or HF is 5 and 2 years, respectively. Therefore,
the onset of angina, syncope, or HF due to aortic stenosis signals the need for valve replacement. Patients should also be questioned about more subtle symptoms such as exertional dyspnea or a decrease in exercise capacity, as these symptoms may also indicate the need for surgery.

4. How is the severity of aortic stenosis most accurately determined?
The severity of aortic stenosis can be precisely determined by either cardiac catheterization or Doppler/echocardiography. Both techniques can provide accurate estimations of the pressure gradient and the aortic valve area.
Doppler echocardiography is generally used for evaluation and follow -up because it is noninvasive and easily repeated. The normal aortic valve area is 3 cm2. Mild, moderate, and severe aortic stenosis are present w hen the valve area is >1.5 cm2, betw een 1.5 and 1 cm2, and <1 cm2, respectively.
Aortic stenosis is said to be critical w hen the valve area is 0.7 cm2 or less.
Pressure gradient measurements alone are not adequate to determine the severity of aortic stenosis because, as already discussed, pressure gradients are determined by both the area of the stenotic valve and the blood flow across the valve.
Physical examination findings such as the late peaking murmur and the absent aortic component of the second heart sound may be suggestive of severe aortic stenosis but are poorly sensitive and
specific compared w ith the information yielded by the aortic valve area.
Echocardiography can also evaluate ventricular function and hypertrophy as well as provide information about the etiology of the aortic stenosis.

5. What is the best therapy for symptomatic aortic stenosis?
Aortic valve replacement is the best therapy for symptomatic aortic stenosis.
In symptomatic patients with severe aortic stenosis, aortic valve replacement results in a postoperative survival that is close to that of the general population. Older patients also generally have a good survival following aortic valve replacement for aortic stenosis.
Long-term results of balloon aortic valvuloplasty (a catheter-based procedure) have been disappointing. Therefore, it is used primarily for palliation in patients who are not candidates for aortic valve replacement because of other medical problems or as a bridge to aortic valve replacement in patients deemed too ill for surgery. How ever, serious complications and mortality are high in these patients and restenosis generally recurs within 6 to 12 months.