Study Questions Routine Stress Testing in Chest Pain Units

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Routine stress cardiac testing of patients who present to emergency department (ED) chest pain units may do more harm than good, according to a single-center study published in the June 24, 2013, issue of JAMA Internal Medicine. Only half of such test results turn out to be true positives, while few patients stand to benefit from revascularization.

Luke K. Hermann, MD, and colleagues at Mount Sinai Medical Center (New York, NY) prospectively collected data on 4,181 patients evaluated with provocative cardiac testing over a 6-year period starting in March 2004 at the ED-based chest pain unit of their tertiary care center. All patients had signs or symptoms of possible ACS but lacked an ischemic ECG result or positive biomarker findings.

Chest pain was reported in 93.5% of the cohort, and 73.2% were considered at intermediate risk for CAD. Approximately one-third of patients were male.

Less Than 1% of Patients Stand to Benefit

Provocative tests (12.2% ECG stress tests and 80.8% perfusion imaging studies) were positive for inducible myocardial ischemia in 470 patients (11.2%). Among them, 123 patients (26.2%) subsequently underwent coronary angiography, while the remaining 347 (73.8%) were discharged home with a presumptive diagnosis of CAD and medical management plan. Patient characteristics were similar between the 2 groups, but the mean summed stress score was higher in the angiography group.

Of the patients who underwent diagnostic angiography, only 63 (51.2%) showed obstructive disease (≥ 50% in the left main artery or ≥ 70% in other locations). The researchers then classified patients in this group according to whether their anatomic features suggested revascularization would be beneficial according to American Heart Association (AHA) recommendations; by this metric, revascularization offered potential benefit (AHA class I or IIa) to 44.4% of patients with obstructive disease, uncertain benefit (AHA class IIb) to 14.3%, and harm (AHA class III) to 41.3%.

In all, the proportion of CAD patients who stood to benefit from revascularization represented 0.7% of the entire study cohort.

Of the remaining 59 patients without obstructive disease on angiography, 31 had normal findings and 28 had nonobstructive disease.

‘Zero Percent Miss Rate’ Ill-Advised

“The yield of provocative cardiac testing in the chest pain unit . . . was extremely low,” the researchers conclude. “While AHA guidelines suggest that provocative testing risk stratifies patients to a potentially near-zero short-term adverse event rate, there is increasing recognition that a negative result on serial biomarker evaluation (typically a prerequisite for provocative testing) may also achieve this goal, making further risk stratification attempts redundant or inherently difficult.”

Dr. Hermann told TCTMD in a telephone interview the researchers were “shocked” that so few of the patients who underwent stress testing actually stood to benefit from intervention.

“I was a big believer in this process,” he said, noting that he helped implement the chest pain unit at Mount Sinai. “And I’ve come to believe that we overreached. We’ve gone too far in the direction of testing.”

The current approach to dealing with possible ACS in the chest pain unit is problematic, Dr. Herman commented. “We haven’t explicitly said so, but we’ve adopted an approach that looks for a zero percent miss rate, and that’s not doable in medicine. That’s a recipe for disaster.”

While one study is unlikely to change clinical practice, he acknowledged, the hope is that the current findings will inspire discussion on how best to weigh benefit against risk in this context.

“From my perspective, what needs to happen is more of a consensus approach or endorsement of a test threshold that gives everyone a target to shoot for. It’s not enough to just say, ‘You can’t miss this diagnosis.’ When you say that, people start testing everybody . . . and that has negative implications when it’s applied across the spectrum of medicine,” Dr. Hermann stressed.

Liability Risk Looms Large

The most obvious alternative to stress testing after negative biomarker results is to discharge patients home, he suggested, noting that he and some of his colleagues follow this approach. “It’s sort of an individual choice at this point, because you’re not backed up by the guidelines,” Dr. Hermann commented. “And if you have a bad outcome [which can happen] regardless of what we do, then potentially there’s a liability risk because you’re not following what is presumed to be best practice, which is codified in the guidelines.”

CTA may prove to be a good option in such situations, he added, because the test is faster, involves less radiation than perfusion imaging, and can define the anatomy.

An editorial accompanying the paper, by Allen Kachalia, MD, JD, of Brigham and Women’s Hospital (Boston, MA), and Michelle M. Mello, JD, PhD, of the Harvard School of Public Health (Boston, MA), also advocates for balance between benefit and risk but asks whether physicians are more risk averse to adverse outcomes or to malpractice liability. Moreover, they raise the issue of whether the financial rewards of added testing conflict with the desire to curb health care costs.

“From an ethical perspective, motivations matter. A physician who orders a test that involves risk, cost, burden, or dignitary harm to a patient primarily for the purpose of obtaining a personal benefit—be it increased reimbursement or reduced liability risk—commits an ethical wrong,” they write.

In the case of provocative testing, liability appears to be spurring “precaution-taking behavior in medical practice beyond what is socially optimal and reasonably calculated to benefit patients,” Drs. Kachalia and Mello comment. Possible solutions include restructuring the payment system to avoid rewarding overutilization and making compensation processes for medical injury less onerous, they suggest.

Not Time to Write Off Testing

In another accompanying editorial, Lee Goldman, MD, of Columbia University Medical Center (New York, NY), stresses that he is “not as pessimistic” as the researchers about routine stress testing.

“The goal of provocative testing extends well beyond finding patients whose coronary anatomy alone warrants revascularization,” he writes, adding that hopefully patients with positive results had their medical therapy adjusted and those with negative results received “at least some degree of reassurance, an especially important benefit given their oftentimes recurrent symptoms.”

While this study alone does not merit a change in general recommendations, it does provide a starting point for discussions on the best approach to decision making and the cost-effectiveness of predischarge testing strategies, Dr. Goldman notes.

Ajay S. Kirtane, MD, SM, also of Columbia University Medical Center, said that, in the current study, “the main issue is that we just don’t know who these patients were [in terms of pretest CAD risk]. Who are they testing? Who are they sending home? It’s difficult to know.”

Before chest pain units began routinely conducting stress tests, he said, the “missed MI rate was too high.” Admittedly, biomarkers were not as sensitive then, but even today, the issue remains that “we don’t want to be blowing people off,” Dr. Kirtane continued, adding that “we can always benefit from further refinement of the chest pain algorithm.”

 


Sources:
1. Hermann LK, Newman DH, Pleasant WA, et al. Yield of routine provocative cardiac testing among patients in an emergency department-based chest pain unit. JAMA Intern Med. 2013;173:1128-1133.

2. Goldman L. How provocative is provocative testing [invited commentary]? JAMA Intern Med. 2013;173:1134-1135.

3. Kachalia A, Mello MM. Defensive medicine—legally necessary but ethically wrong? Inpatient stress testing for chest pain in low-risk patients [viewpoint]. JAMA Intern Med. 2013;173:1056-1057.

 

 

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Disclosures
  • Drs. Herman, Goldman, and Kirtane report no relevant conflicts of interest.
  • Drs. Kachalia and Mello report having received honoraria from various hospitals and professional societies for presentations on the topic of malpractice reform. Dr. Kachalia has received such honoraria from Quantia MD and Zurich Insurance.

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