Stress tests: How to make a calculated choice

,

Applied Evidence

Stress tests: How to make a calculated choice

J Fam Pract. 2007 April;56(4):287-E1

By

Dennis P. Breen, MD

Spare your patients unnecessary stress testing by determining their pretest probability for CAD.

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References

1. Snow V, Barry P, Fihn SD, et al. Evaluation of primary care patients with chronic stable angina: guidelines from the American College of Physicians. Ann Intern Med 2004;141:57-64.

2. Diamond GA. A clinically relevant classification of chest discomfort. J Am Coll Cardiol 1983;1:574-575.

3. Morise AP. Are the American College of Cardiology/American Heart Association guidelines for exercise testing for suspected coronary artery disease correct? Chest 2000;118:535-541.

4. Shaw LJ, Peterson ED, Shaw LK, et al. Use of a prognostic treadmill score in identifying diagnostic coronary disease subgroups. Circulation 1998;98:1622-1630.

5. Gibbons RJ, Balady GJ, Bricker JT, et al. ACC/AHA 2002 guideline update for exercise testing: A report of the American College of Cardiology/American Heart Association Task Force on practice guidelines (Committee on Exercise Testing). 2002. Available at: www.acc.org/qualityandscience/clinical/guidelines/exercise/exercise_clean.pdf. Accessed on March 6, 2007.

6. Gibbons RJ, Chatterjee K, Daley J, et al. ACC/AHA/ACP-ASIM guidelines for the management of patients with chronic stable angina: A report of the American College of Cardiology/American Heart Association task force on practice guidelines (Committee on Management of Patients with Chronic Stable Angina). J Am Coll Cardiol 1999;33:2092-2197.

7. Pellikka PA, Sarano ME, Nishimura RA, et al. Outcome of 622 adults with asymptomatic, hemodynamically significant aortic stenosis during prolonged follow-up. Circulation 2005;111:3290-3295.

8. Lewis JF, McGorray S, Lin L, et al. Exercise treadmill testing using a modified exercise protocol in women with suspected myocardial ischemia: Findings from the national heart, lung and blood institute-sponsored women’s ischemia syndrome evaluation (WISE). Am Heart J 2005;149:527-533.

9. Klocke FJ, Baird MG, Lorell BH, et al. ACC/AHA/ASNC guidelines for the clinical use of cardiac radionuclide imaging—executive summary: A report of the American College of Cardiology/American Heart Association task force on practice guidelines (ACC/AHA/ASNC committee to revise the 1995 guidelines for the clinical use of cardiac radionuclide imaging). J Am Coll Cardiol 2003;42:1318-1333.

10. Lee TH, Boucher CA. Clinical practice. noninvasive tests in patients with stable coronary artery disease. N Engl J Med 2001;344:1840-1845.

11. Myers J, Voodi L, Umann T, Froelicher VF. A survey of exercise testing: Methods, utilization, interpretation, and safety in the VAHCS. J Cardiopulm Rehabil 2000;20:251-258.

12. Ashley EA, Myers J, Froelicher V. Exercise testing in clinical medicine. Lancet 2000;356:1592-1597.

13. Cosmai EM, Heller GV. The clinical importance of electrocardiographic changes during pharmacologic stress testing with radionuclide myocardial perfusion imaging. J Nucl Cardiol 2005;12:466-472.

14. Kwok JM, Miller TD, Hodge DO, Gibbons RJ. Prognostic value of the duke treadmill score in the elderly. J Am Coll Cardiol 2002;39:1475-1481.

15. Morise AP, Olson MB, Merz NB, et al. Validation of the accuracy of pretest and exercise test scores in women with a low prevalence of coronary disease. The NHLBI-sponsored Women’s Ischemia Syndrome Evaluation (WISE) Study. Am Heart J 2004;147:1085-1092.

16. InfoRetriever [web site] Clinical Rules and Calculators (2007). InfoRetriever Search Results, Exercise Testing, Diagnostic Tests, Chest Pain. Available at: www.infopoems.com/irsearch/display_article.cfm?resource=D&article=34. Accessed on January 26, 2007.

17. Morrow K, Morris CK, Froelicher VF, et al. Prediction of cardiovascular death in men undergoing noninvasive evaluation for coronary artery disease. Ann Intern Med 1993;118:689-695.

18. Kwok JF, Christian TE. Effective use of the exercise stress test to detect and predict coronary artery disease. Emerg Med 2001;33:12-22.Available at: www.emedmag.com/html/pre/fea/features/051501.asp. Accessed on March 7, 2007.

Practice recommendation

Estimate pretest probability of CAD in patients with chest pain on the basis of age, sex, pain characteristics, and cardiovascular risk factors (B).
Low pretest probability patients should undergo an exercise treadmill test alone (C).
Intermediate pretest probability patients, including those with complete right bundle branch block or less than 1 mm ST depression at rest should have an exercise treadmill test without imaging (B). Patients with an electronically paced ventricular rhythm (C) or left bundle-branch block (B) require myocardial perfusion imaging.
In high pretest probability patients, coronary angiography is an appropriate initial strategy for CAD diagnosis (C).
In women, the data are insufficient to justify routine stress imaging tests as the initial test for CAD (C).

Strength of recommendation (SOR)

Good quality patient-oriented evidence
Inconsistent or limited-quality patient-oriented evidence
Consensus, usual practice, opinion, disease-oriented evidence, case series

Are you a wise “consumer” of stress tests? That is: Do you consider your patient’s CAD probability score before ordering an exercise treadmill test or pharmacologic stress myocardial imaging (PSMI)? Are you as well-versed as you’d like to be on the predictive value of things like the Duke Treadmill Score?

If your answer is No to either question, this review may help guide your use of stress tests, based on evidence.

What is the pretest probability of CAD?

The decision to order an exercise stress test or a PSMI should be based on history, physical examination, and pretest probability for CAD. You can estimate the pretest probability for CAD in a chest pain patient based on the patient’s age, sex, and pain characteristics.¹

Determine whether symptoms are typical, atypical, or nonanginal, based on whether the chest pain is substernal, brought on by exertion, or relieved by rest or nitroglycerin.²

To recap:

Typical angina requires all 3 pain characteristics
Atypical angina, only 2
Nonanginal chest pain, 1.²

Use this information (along with the patient’s age) to determine whether he has a high, intermediate, low, or very low likelihood of CAD (TABLE 1). From the low, to the intermediate, to the high pretest probability levels, the positive predictive value increases progressively (21%, 62%, and 92%) and the negative predictive value decreases progressively (94%, 72%, and 28%).³ (These values are based on a review of symptomatic patients who had angiography following stress testing.)

TABLE 1
How to determine pretest probability of coronary artery disease

STEP 1			STEP 2		STEP 3
Ask 3 questions:			Total the number of “yes” answers to identify symptom pattern:		Find the cell in the matrix (below) where age, gender, and symptom pattern converge:
Is chest pain substernal? Is chest pain brought on by exertion? Is chest pain relieved within 10 minutes by rest or nitrolycerin?			0 of 3=Asymptomatic		High probability		>90%
			1 of 3=Nonanginal chest pain		Intermediate		10%–90%
			2 of 3=Atypical angina		Low		<10%
			3 of 3=Typical angina		Very low		<5%
AGE (YRS)	SYMPTOMS
	ASYMPTOMATIC		NONANGINAL CHEST PAIN		ATYPICAL ANGINA		TYPICAL ANGINA
	MEN	WOMEN	MEN	WOMEN	MEN	WOMEN	MEN	WOMEN
35–45	Very low	Very low	Intermediate	Very low	Intermediate	Intermediate	Intermediate	Intermediate
45–55	Low	Very low	Intermediate	Low	Intermediate	Intermediate	High	Intermediate
55–65	Intermediate	Low	Intermediate	Intermediate	Intermediate	Intermediate	High	Intermediate
65–75	Intermediate	Intermediate	Intermediate	Intermediate	Intermediate	Intermediate	High	High
Adapted from Diamond GA.²

Your patients’ score dictates whether testing is required, and if so what kind.

Very low pretest probability patients should not have an exercise test, since they have a high risk of false-positive results. Evaluate and treat them for noncardiac causes of chest pain and begin primary prevention of CAD.

Low pretest probability patients should undergo exercise treadmill testing alone since negative results carry a high negative predictive value in both men and women, but positive test results may be false and can be evaluated by more studies.³

Intermediate pretest probability patients, including those with complete right bundle branch block or less than 1 mm ST depression at rest should have an exercise treadmill test without imaging modality.^3-5 However, intermediate pretest probability patients with baseline ECG abnormalities such as electronically paced ventricular rhythm or left bundle-branch block will require myocardial perfusion imaging.⁵

High pretest probability patients should have coronary angiography as an initial strategy for diagnosis of CAD.³

History, exam, and ECG determine test suitability

Can your patient take an exercise stress test, or will he need a pharmacologic stress test instead? (See “A guide to sensitivity, specificity, and likelihood ratios for stress tests.”) Can he pedal a bicycle, walk, or exercise for 6 minutes? On physical examination, take note of his gait, mobility, and limb strength.

FAST TRACK

Intermediate pretest probability patients with left bundle branch block require myocardial perfusion imaging

What medications is the patient taking? Digoxin may cause false ST changes, beta-blockers may prevent attaining maximum heart rate, and antihypertensive agents and vasodilators may alter the blood pressure response, producing a false negative result. Nitrates attenuate angina and the associated ST depression of ischemia.⁶ In addition, metabolic abnormalities and cocaine or alcohol use may affect heart rate, metabolic oxygen demand and the ability to perform the exercise treadmill testing.