Low-risk chest pain patients younger than 40 years do not benefit from admission and stress testing

A number of studies have suggested clinical decision rules for patients age <40 who are at low risk for acute coronary syndrome (ACS) and may be safe for discharge from the emergency department. Despite this, many such patients continue to be admitted for observation in low-risk observation units. We hypothesized that patients age <40 without coronary artery disease, with a nonischemic electrocardiogram (ECG), and normal initial troponin I (TnI) who are admitted to a CPU are at very low risk (<1%) for ACS or 30-day major adverse cardiac event (MACE) and would not benefit from observation care.

This was a prospective, observational study of consecutive patients admitted to the CPU in a large-volume academic urban emergency department. Eligibility criteria included age >18 but <40, American Heart Association low-to-intermediate risk, nonischemic ECGs, and normal initial TnI. Standard descriptive statistics were used for demographics, cardiac comorbidities, and risk scores. Our primary outcomes were CPU ACS rate and 30-day MACE. MACE was defined as death, nonfatal AMI, revascularization, or out of hospital cardiac arrest. A sample size of at least 400 was chosen to have 1% precision about an expected outcome rate of 0.3% (based on prior CPU data of patients of all ages). Confidence intervals (CIs) were calculated using the refined Wilson simple asymptotic method with continuity correction. All patients were called at 30 days. All charts on index visit and any subsequent visit within 30 days were reviewed using standardized chart abstractions forms by 2 trained abstractors blinded to the hypothesis of the study. A Social Security Death Index search was performed on all patients.

Three hundred eighty-four patients accounting for 403 CPU admissions were enrolled over a 28-month period. Mean age was 34.3 ± 4.5; 42% were women; and 89%, 8%, 2%, and 1% had Thrombolysis in Myocardial Infarction scores of 0, 1, 2, and 3, respectively. No patient had an abnormal TnI. The ACS rate was 0 (95% CI, 0-0.8%). The 30-day MACE rate was 0 (95% CI, 0-0.8%). Forty-two percentage of these patients received stress testing but 0 (95% CI, 0-1.8%) were positive.

Patients age <40 with a normal ECG and normal first biomarker have <1% risk of ACS or 30-day MACE, such that admission and stress testing are of no benefit.