Exercise stress testing in the primary care office

Only 13 percent of family physicians currently perform EST. Barriers cited include lack of physician training and the high cost of EST equipment.¹ The first barrier can be overcome by adding EST training during primary care residencies with a standardized curriculum. High-quality courses are available through the National Procedures Institute and the American Academy of Family Physicians Annual Scientific Assembly. Cost should not be a concern because the cost of the equipment is reasonable and, when combined with a Holter-monitoring system, can quickly pay for itself.

INDICATIONS

Establishing the pretest probability of CAD is crucial before performing EST. Patient age, sex, and description of the chest pain are the best determinants, and patients can be stratified into low, intermediate, and high-risk pretest probability.^2,5 Each cardiac risk factor increases the pretest probability of CAD. Since the sensitivity of EST in determining CAD is only 67 percent, patients with high pretest probability may need EST testing with Sestamibi (nuclear scan) imaging with its higher sensitivity of 83 percent. In patients with low-to-intermediate pretest probability, the predictive value of a negative test can be as high as 99.3 percent.¹ This is the population that is usually studied in the primary care office in contrast to cardiology practices, where the pretest probability is much higher.

CONTRAINDICATIONS

Contraindications to EST include acute myocardial infarction, unstable angina, pulmonary embolism, severe aortic stenosis, decompensated congestive heart failure, acute medical illness, hypertrophic obstructive cardiomyopathy, uncontrolled hypertension, dissecting aneurysm, and acute myocarditis or pericarditis.⁶ Careful selection of patients is critical. Those with left bundle-branch block, patients taking digoxin, patients with pacemakers, and those with significant ST segment abnormalities at baseline should be considered for Sestamibi nuclear imaging EST or stress echocardiography. Those unable to walk two blocks or two flights of stairs should have an adenosine or dobutamine Sestamibi study done instead of EST without imaging.