To Stress or Not to Stress? That is the Question

Approximately one million percutaneous coronary interventions are performed annually in the United States.¹ There are conflicting opinions and no good consensus as to whether or not patients should undergo routine stress testing post PCI.² The charge for a treadmill stress test with myocardial perfusion imaging (MPI) is approximately $1000 (technical and professional fee). This equates to one billion dollars per year for stress testing alone in this group of patients, assuming each patient were to have only one stress test in follow-up. Whether or not to perform routine stress tests with MPI post coronary intervention is, therefore, not only an important clinical question but a major health-care economic issue as well. Eisenberg and his colleagues, in this issue of the Journal of Invasive Cardiology, report on the “Utility of Routine Functional Testing After Percutaneous Transluminal Coronary Angioplasty: Results From the ROSETTA Registry,”³ and they are to be congratulated for their attempt to shed some light in this area with the first prospective study trying to address this question. See Eisenberg, et al. on pages 318–322 Although this is a good first attempt at trying to answer the question, it falls short of the mark. This is a prospective observational study and, as the authors point out, there are considerable, but not necessarily unexpected, differences between the group of patients who underwent routine stress testing versus those who had selective administration of stress tests based on symptoms. Despite the difference in initial strategy regarding post PCI stress testing, there was little difference in the rate of follow-up procedures, i.e. repeat angiography, PCI or CABG. Nonetheless, routine functional stress testing post PCI was associated with a decreased frequency of follow-up clinical events. The difference would have to be due, therefore, to more intensive medical therapy. It is noted that “although clinical status was similar between the two groups, patients in the routine functional testing group, were more likely to receive two or more anti-anginal medications (p4 Although there is an attempt to correct for these disparities in the multivariate analysis, the failure to consider multivessel disease and medical therapy are important crucial omissions. Finally, the primary composite endpoint of death, MI and unstable angina is primarily driven by unstable angina that is never defined. Unstable angina is a “soft” endpoint with subjective interpretation particularly if it is not rigorously defined a priori. Unstable angina itself is of no consequence unless it leads to an increased incidence of death and MI. There is a presumption in the paper that unstable angina may have lead to increased hospitalizations, but this is not documented. Finally, the majority of functional tests that were performed with treadmill stress tests without associated MPI or wall motion analysis with concomitant echocardiography. It has been well documented that both MPI and echochardiography increase the sensitivity and specificity of post PCI stress testing.⁵ It is curious, therefore, that the routine use of stress electrocardiography alone, a test with low sensitivity and specificity in the post PCI setting, would improve outcomes. Dr. Eisenberg has just published the ADORE Trial⁶, a randomized, prospective trial that was underpowed to detect differences in clinical events but nonetheless concluded that routine functional test post PCI is not indicated. In summary, whether or not routine functional testing post PCI improves long-term outcomes is an important clinical question with major economic implications that remains to be resolved. In the asymptomatic patient, particulary the diabetic, there is no debate regarding the value of post PCI non-invasive evaluation. In the patient who was symptomatic pre PCI and who is asymptomatic post PCI — “To stress or not to stress?” That is the question, and that remains the question, still unanswered.