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CHICAGO -- As many as 10% of clinicians will send their patients with chest pain directly to the cath lab, but a new study showed that this usual-care strategy is less effective in reducing bad outcomes and wastes resources compared with a precision strategy.

Overall, patients following precision medicine protocols had a 71% reduced risk of experiencing a composite primary endpoint of death, myocardial infarction, or catheterization with or without obstructive coronary artery disease versus patients whose doctors used best judgment in ordering care (adjusted HR 0.29, 95% CI 0.20-0.41, P<0.001), reported Pamela Douglas, MD, of the Duke Clinical Research institute in Durham, North Carolina, during the American Heart Association annual meeting.

"The PRECISE study provides the first randomized evidence for a risk-based testing strategy to reduce extra testing and improve efficiency of care, while maintaining excellent patient outcomes, such as using guideline-directed medications, reducing chest pain, and minimizing the number of heart attacks or heart disease-related deaths," she said during a press conference.

Four percent of the precision strategy group (n=44) experienced the primary composite endpoint compared with 11.3% of usual-care patients (n=118), mostly driven by the number of patients who were sent for catheterization (2.6% and 10.2%, respectively).

In the precision group, obstructive coronary artery disease was identified in 108 patients compared with 70 in the usual-care group.

"There were no deaths or myocardial infarction events in the precision strategy participants who were assigned to deferral testing," Douglas noted, adding that in almost every subgroup, the results favored the precision strategy.

"We were pleasantly surprised by the reduced use of testing in the precision care group, more efficient use of heart catheterization, and enhanced preventive medication use, all of which point to long-term benefits for patients' health," she added. "Our findings may help with evaluating the millions of people globally every year who see their doctors with stable chest pain by accurately identifying those at low risk for clinical events who can safely delay diagnostic testing."

Patients experiencing chest discomfort in the precision testing arm of the trial were classified by their doctors according to the PROMISE Minimal Risk Tool, which calculates a score based on age; sex; race and ethnicity; history of hypertension, diabetes, or dyslipidemia; family history of premature coronary artery disease; smoking status; symptoms unrelated to physical or mental stress; and high-density lipoprotein cholesterol level.

If patients in the precision strategy group were deemed to be high risk, they were sent for a coronary CT angiogram with or without CT-derived fractional flow reserve (FFR) testing, while those who were deemed low risk had testing deferred.

Commenting on the study, designated discussant Julia Indik, MD, PhD, of the University of Arizona College of Medicine in Tucson, said that one of the reasons the study is important is that it may prevent a cascade of unnecessary testing.

"It is complicated knowing what to do with a patient who comes to the office with chest pain," she noted. "When you perform a test on the patient, there is the possibility of having a false positive, and then we subject patients to more tests, riskier tests, angiographic tests, and that can incur further risk and costs."

Indik said the goal of PRECISE was to focus on which patients really need further testing. "And it did show that following the PRECISE algorithm, unnecessary tests could be avoided."

She added that the potential of PRECISE and other studies presented at the meeting are being muted by the need for more staff, especially after losses incurred during the COVID-19 pandemic. "We also have to educate our cardiologists on how to reduce testing," she said.

In PRECISE, 1,047 patients were treated according to the precision protocol -- 21% were thought to be low risk and 89% of that group were not tested, while 11% were given further tests. In the usual-care cohort of 1,046 patients, 21% were also deemed to be at low risk, but 89% of them were tested.

Of the patients at high risk in the precision group, 48% went on to receive a coronary CT angiogram, and another 31% received a coronary CT angiogram plus FFR testing, while 1% had a treadmill ECG ordered, and 2% each were tested with stress echocardiography or SPECT/PET. In 16% of the cases, no tests were ordered.

In contrast, 32% of the usual-care patients underwent SPECT/PET, 30% were tested with stress echocardiography, 11% had a treadmill ECG ordered, 10% underwent cardiac MRI stress testing, 10% were sent directly for cardiac catheterization, and 7% were not given any tests.

Across both groups, mean age was 58-59, 48% to 52% were women, 16% were in a racial or ethnic minority group, and 94% had at least one major cardiovascular risk factor.

Limitations to the study included the inability to know outcomes that occurred outside the 12-month study period, Douglas said, adding that costs and benefits are still being studied.

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