Exercise Testing in Patients with Aortic Stenosis: Conclusion
The most complete description of exercise testing in adults is by Nylander et al who paid particular attention to exercise capacity, symptoms and blood pressure response. They tested 76 adults ranging from 52 to 78 years of age; 77 percent had a history of chest pain, 74 percent had congestive heart failure, and 46 percent had symptoms of dizziness, vertigo or syncope on effort. No patient without angina had evidence of coronary artery disease, and 24 percent of those with angina had evidence of coronary artery disease (>75 percent stenosis of a major vessel). They noted a 10 mm Hg or more drop in systolic blood pressure in 29 patients, and 33 patients had a subnormal increase in blood pressure defined as less than a 10 mm Hg increase in SBP per 30 watt workload. Thirteen of these patients had no symptom of effort vertigo or syncope. This study demonstrated the frequency of an abnormal blood pressure response, the disparity between the history and actual work capacity, the lack of coronary artery disease in patients without angina, and the safety of exercise testing in this population.
Although this case presentation demonstrates the potentially dangerous consequences of exercise testing in patients with AS, much of the literature suggests it is a relatively safe procedure in both the pediatric and adult patient, when appropriately performed. Attention should be focused on the minute-by-minute response of blood pressure, the patients symptoms, and the heart rate for slowing and premature ventricular and atrial arrhythmias. In the presence of an abnormal blood pressure response, a patient with AS should undergo at least a two-minute cool-down walk at a lower stage of exertion to avoid the acute left ventricular volume overload which may occur when placed supine. As in the elderly, detrained, or CAD patient, when testing patients with AS, protocols with high (>2 METs) and unequal work increments should be avoided. generic yaz birth control
Prospective studies of exercise testing in adult patients with aortic stenosis are needed to further evaluate its role in therapeutic decision-making. Exercise plays an important role in the objective assessment of symptoms, hemodynamic response, and functional capacity. Whether ST segment depression indicates significant CAD or not remains unclear. By performing exercise testing pre- and postoperatively, the benefits of surgery and baseline impairment can be quantified. Exercise testing offers the opportunity to evaluate disparities between history and clinical findings; for example, in the elderly “asymptomatic subject” with physical and/or Doppler findings of severe aortic stenosis. Often echocardiographic studies are inadequate in such patients, particularly when they are smokers. When Doppler echocardiography reveals a significant gradient in the asymptomatic patient with normal exercise capacity, he could be followed closely until symptoms develop. In patients with an inadequate systolic blood pressure response, ie, less than 10 mm Hg increase per stage or a fall in systolic BP from the resting value when symptoms occur, surgery appears to be indicated.