A 70-year-old male is seen in the office for chest pain. He reports that he is getting substernal chest pain, without radiation, when he mows his lawn. The pain resolves with 1015 minutes of rest. He has never had pain at rest. He has no other cardiac complaints and his review of systems is otherwise negative. He has an unremarkable medical history and takes only a baby aspirin a day. On examination, his blood pressure is 160/70, pulse 85, and respiratory rate 16. His cardiac examination is notable for a harsh, 3/6 systolic ejection murmur along the sternal border that radiates to the carotid arteries. His carotid pulsation is noted to rise slowly and is small and sustained. His lungs are clear. The remainder of his examination is normal.
Subsequent workup confirms the diagnosis of critical aortic stenosis. Which of the following treatments would be most appropriate at this time?
- a beta-blocker
- an ACE inhibitor
- a long-acting nitrate with as-needed sublingual nitroglycerin
- balloon valvuloplasty
- aortic valve replacement
Answer(s): E
Explanation:
Aortic stenosis is one of the most common valvular abnormalities found in adults. It can be congenital -- such as a unicuspid or bicuspid valve--or acquired. In young adults, acquired aortic stenosis is often seen as a consequence of rheumatic fever. This is becoming less common in developed nations. In adults over the age of 65, the most common cause of aortic stenosis is age-related degenerative, calcific aortic stenosis. The valvular cusps are immobilized and the stenosis caused by calcium deposits along the flexion lines of the valves. Acquired aortic stenosis typically has a prolonged asymptomatic period. During this time the stenosis may be found incidentally by auscultation of the characteristic harsh, holosystolic murmur in the aortic valve area that radiates to the carotid arteries. There may also be a slow, small, and sustained arterial pulsation (pulsus parvus and tardus) due to the relative outflow obstruction. The cardinal symptoms of aortic stenosis that signal advancing disease, and increased risk of mortality, are angina, heart failure, and syncope. An ECG will show left ventricular hypertrophy in approximately 85% of symptomatic cases of aortic stenosis.
A normal ECG is possible but would be more likely in early, asymptomatic stages. S-T segment elevation would be more consistent with acute cardiac ischemia and Q waves would be more consistent with a completed MI. Low-voltage QRS complexes can be seen in several conditions, including pericardial effusion, COPD, or obesity. When considering the diagnosis of aortic stenosis, the initial diagnostic test of choice would be echocardiography. It would provide information on both the structure (bicuspid, tricuspid, and the like) and the function (valve area, pressures) of the valve. The size and function of the left ventricle can also be determined. If aortic stenosis is found on echocardiogram and the patient is symptomatic, the next test would be cardiac catheterization.
This would allow for direct measurement of the pressure gradient across the valve. It would also allow for evaluation of the status of the coronary arteries in order to determine whether CABG would need to be performed along with valve replacement. Exercise stress testing is relatively contraindicated in the setting of symptomatic aortic stenosis. Holter monitoring would only be useful if there were a concomitant arrhythmia. Electrophysiologic studies would not play a role in the typical evaluation of aortic stenosis.