How Safe Is the Outpatient Management of Patients With Acute Chest Pain and Mildly Increased Cardiac Troponin Concentrations?

Study Questions:

How should patients with increased high-sensitivity cardiac troponin T (hs-cTnT), but normal or borderline-high conventional cTn concentrations presenting to the emergency department (ED) be managed?

Methods:

The authors evaluated 643 consecutive ED patients with chest pain who had been discharged for outpatient management after exclusion of acute myocardial infarction (AMI) using serial measurements of conventional cTn. The frequency of patients who had hs-cTnT with elevated values (>14 ng/L), but <30 ng/L, and the rates of all-cause mortality and subsequent AMI at 30, 90, and 360 days in these patients were determined.

Results:

Of the 114 patients who had increased hs-cTnT concentrations, 96 (84%) had an adjudicated noncoronary cause of chest pain. Thirty-, 90-, and 360-day mortality was 0.9%, 2.7%, and 5.2%. The 30-, 90-, and 360-day rate of AMI was 0.0%, 1.9%, and 7.6%. Increased hs-cTnT was associated with increased mortality and AMI at 90 days (p = 0.006 and p = 0.081, respectively) and 360 days (p = 0.001 for both).

Conclusions:

The authors concluded that hs-cTnT is a strong predictor of intermediate- and long-term mortality and AMI in low-risk patients discharged from the ED after AMI was excluded using the conventional cTnT assay. Given the relatively low rate of 30-day events, the authors suggest that patients without acute coronary syndrome and small increases in hs-cTnT require further investigations and treatments, but not necessarily immediate hospitalization.

Perspective:

The result is not surprising, but is one of importance. This group, using the hs-cTnT assay, has shown that even if AMI is excluded, there is an increased frequency of events over both the intermediate- and long-term. The frequency of short-term events was small, suggesting that follow-up of those with elevated cTn values does not need to be done in the hospital. However, similar to the situation observed in patients with elevated cTn values who are critically ill and postoperative, these elevations do define those with cardiac disease. Perhaps evaluations of these patients will lead to preventive approaches that will improve their prognosis.

Clinical Topics: Acute Coronary Syndromes, ACS and Cardiac Biomarkers

Keywords: Prognosis, Myocardial Infarction, Acute Coronary Syndrome, Follow-Up Studies, Biological Markers, Chest Pain, Troponin T, Critical Illness, Emergency Service, Hospital, Patient Discharge


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