President Bush’s Stress Test-and Stent: Guideline-Directed Care?

Former President George W. Bush, who recently completed a 100-km bike ride in support of wounded US soldiers, was sent by his physician for a screening stress test on a routine physical examination. The indication for this test remains unclear because he was completely asymptomatic and he reported no modifiable risk factors (such as hypertension or hyperlipidemia) during his 2006 physical examination. This stress test resulted in an abnormal ECG finding and prompted a coronary CT, which found minimal/mild calcification of the coronary arteries but reflected a coronary stenosis. He was therefore electively admitted and underwent coronary artery stenting for a seemingly asymptomatic, incidentally discovered stenosis. The medical management of this public figure has raised concerns about the appropriateness of noninvasive cardiac screening as well as the indications to treat asymptomatic coronary artery disease in patients who are highly functional and report no exercise-related symptoms.

Screening asymptomatic patients for coronary disease
According to the 2010 update to the ACC/AHA guidelines for screening asymptomatic individuals,¹ risk scoring and assessment remains a class I indication for all patients. Getting a screening ECG in asymptomatic patients without a history of diabetes or hypertension is a class IIb recommendation and can be indicated in certain circumstances. However, getting an exercise ECG test on low-risk individuals is usually not recommended.
 
When it comes to stress testing, it may be reasonable to get exercise stress testing on intermediate-risk individuals (including sedentary adults who are considering starting a vigorous exercise program [class IIb]), partially to gauge functional capacity. Furthermore, asymptomatic male patients older than 45 years who have one or more atherosclerotic risk factors (ie, smoking, diabetes, family history of premature coronary disease, hypertension, hyperlipidemia) may also be reasonable candidates for exercise testing for prognostication purposes. In these patients, the ST/HR index (the quotient of the difference between ST depression at peak exercise and the exercise-induced increase in heart rate) can provide prognostic information about coronary risk.^2,3
 
The greater the number of risk factors, the more likely the individual will be to benefit from exercise stress testing. For this reason, it is not recommended as a screening modality for individuals with no risk factors, since these patients are more likely to have false-positive results because of their low pre-test probabilities.

Revascularize asymptomatic disease?
With respect to management, there are only 2 goals that should be considered when the decision is made to intervene upon a coronary stenosis with either percutaneous coronary intervention (PCI) or bypass graft. These are (1) to make the patient feel better or (2) to extend the patient’s life. There is little evidence that revascularizing asymptomatic disease in an active patient who has not been receiving maximal medical therapy will improve survival. As with everything, there are exceptions to this rule, such as a severe left main stenosis. Without knowing the details of President Bush’s lesion, however, it is impossible to conclude whether his PCI was indicated.

The very public airing of this controversy, however, heightens awareness for physicians and patients alike to carefully consider the need for a stress test or revascularization for a coronary lesion. The question must always be asked: Does the therapeutic benefit of an intervention or result of a screening test improve patient outcomes?

References:
1. Greenland P, Alpert JS, Beller GA, et al. 2010 ACCF/AHA guidelines for assessment of cardiovascular risk in asymptomatic adults: a report of the American College of Cardiology Foundation/American Heart Association task force on practice guidelines. Circulation. 2010;122:e584-e636. (Full text)
2. Okin PM, Anderson KM, Levy D, et al. Heart rate adjustment of exercise-induced ST segment depression: improved risk stratification in the Framingham Offspring Study. Circulation. 1991;83:866-874. 
3. Okin PM, Grandits G, Rautaharju PM, et al. Prognostic value of heart rate adjustment of exercise-induced ST segment depression in the Multiple Risk Factor Intervention Trial. J Am Coll Cardiol. 1996;27:1437-1443.
 

Resources ACC/AHA Pocket Reference for Screening Asymptomatic Individuals ACC/AHA/SCAI Practice Guideline for Percutaneous Coronary Intervention