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Exercise stress testing performed within a week following primary percutaneous coronary intervention (PCI) appears to be safe and may provide a simple and economical method to assess prognosis and function, according to a new prospective study conducted in Australia. The results were published online May 1, 2012, ahead of print in the European Heart Journal: Acute Cardiovascular Care.

Anecdotal reports and case studies have indicated there could be a risk of stent thrombosis with exercise stress testing soon after PCI, but strong data are lacking.

To further examine this issue, a group led by Ajita Kanthan, MBBS, of Westmead Hospital (Westmead, Australia), enrolled 689 patients who underwent primary PCI and were subsequently included in a cardiac rehabilitation program. Of these, 230 underwent symptom- and sign-limited nurse-supervised treadmill stress testing within 7 days following PCI, while the remaining 443 deferred stress testing until a later date; 16 did not undergo exercise testing due to mobility limitations.

Absence of Adverse Events

All patients were taking aspirin and clopidogrel at the time of testing. The early testing group had lower rates of abciximab therapy, fewer patients with more than 1 vessel stented, lower total stent length, and fewer patients who received drug-eluting stents.

There were more positive stress tests in the early testing group than in the deferred group. However, the primary endpoint, a composite of death, MI, and MACE during or within 24 hours of the test, did not occur in any patient in either group (table 1).

Table 1. Early Exercise Stress Testing after PCI

^a Death, MI, and MACE.

The most common reason for discontinuation of the stress test was dyspnea (58%), followed by fatigue (24%), angina (9%), and drop in systolic blood pressure of at least 20 mm Hg (1.3%).

According to the study authors, there are a number of advantages to early exercise testing.

“Firstly, it may be incorporated into a risk stratification protocol to determine appropriateness for early return to work,” they write. “Secondly, it allows identification of patients with a poorer prognostic outlook.” In addition, it could allow an early assessment of the functional importance of residual CAD, Dr. Kanthan said in an e-mail communication with TCTMD.

Potential Risk, Little Advantage

Even in the face of only anecdotal evidence, though, some experts might balk at potential risks to such testing so soon after PCI.

Ajay J. Kirtane, MD, SM, of Columbia University Medical Center (New York, NY), said in a telephone interview with TCTMD that while the study is interesting academically, it is unlikely to have much effect on practice.

“While they showed that it was safe in their hands, I think that people are going to be reluctant, because you don’t want to have that 1 event occur, whether it’s 1 in 500 or 1 in 1,000,” he said. “You don’t want that risk, [especially] when I don’t think there is that much advantage to be gained by doing a stress test within 7 days.”

Dr. Kirtane acknowledged that there could be an advantage to being able to quickly determine the significance of residual disease in untreated vessels, and to setting up cardiac rehabilitation earlier. Bu, the increasing use of fractional flow reserve (FFR) could make exercise testing for this purpose less relevant. “If you do FFR in the cath lab you don’t have to do the stress test at all,” he said.

Dr. Kirtane added that clinicians typically will wait at least 6 weeks following PCI before conducting a stress test, but there has been increasing concern over the overuse of these tests. Some professional societies, he noted, are working on guidelines that could suggest no stress testing at all, even within a full year following PCI.

“That’s going to limit the applicability of a study like this in the United States,” he said. “But if you had to do [an early stress test], you might now be a bit more reassured that it’s safe.”

Related Stories:

• Post-Revascularization Stress Testing Appears Overused
• Coronary CTA Bests Exercise Testing as Diagnostic Tool for Suspected CAD
• Stress Testing More Likely Among Physicians Who Bill for Such Services

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