The use of a web-based tool that estimated the probability of both acute coronary syndrome (ACS) and pulmonary embolism (PE) in patients who presented to the emergency department (ED) with chest pain and shortness of breath significantly reduced exposure to medical radiation and treatment costs in a study published online Nov. 25 in Circulation: Cardiovascular Imaging.

The researchers, led by Jeffrey A. Kline, MD, of Indiana University School of Medicine in Indianapolis, hypothesized that when clinicians became aware of a low probability of ACS and PE, they would opt for measures that would lower radiation exposure and the cost of care without an increased risk for delayed diagnosis, adverse events and readmissions.

In this two-phase study, investigators evaluated the accuracy of the probability tool and what effect a low probability of ACS and PE would have on clinical decision-making. All enrolled participants came to the ED with chest pain and new or worsened dyspnea or trouble breathing. They all had a nondiagnostic electrocardiogram that showed no ischemia or infarction.

They used an internet-based program with 17 predictor variables for each patient to calculate a pretest probability. Clinicians were randomized to either receive the probability estimates for ACS and PE and subsequently suggested interventions that were lower in cost and reduced radiation exposure or no probability estimates. Investigators followed the patients for 90 days.  

The proportion of the randomized patients exposed to more than 5 mSv of radiation to the chest with no major cardiac-related diagnosis went from 33 percent to 25 percent. Participants in the intervention group were exposed to significantly less radiation compared with controls (an average of 0.06 mSv vs. 0.34 mSv) as well as lower average treatment costs ($934 vs. $1,275). Adverse events were less frequent in the intervention group (11 percent vs. 16 percent in the control group).

Fewer diagnostic tests did not lead to greater patient satisfaction, which the authors noted as a study limitation and attributed to the lack of shared decision-making during the trial.

Although the findings suggest this type of tool could lead to significant benefits to patients and to the healthcare system, the authors hinted that current practice may not lend itself to more widespread use.

“For patients with chest pain and dyspnea, the remote possibility of failing to diagnose acute coronary syndrome or pulmonary embolism, and the specter of the patient’s death, and concern for possible allegation of negligence, compels many emergency clinicians in the U.S. to order diagnostic tests at exceedingly low pretest probabilities," they wrote.