Acute chest pain--identification of patients at low risk for coronary events. The impact of symptoms, medical history and risk factors.

BACKGROUND: The evaluation of patients with acute chest pain remains challenging, as it implies the risk of fatal misdiagnosis. It is well recognized that typical angina does not specifically identify patients at high risk. We investigated the predictive value of characteristics atypical for myocardial ischemia for exclusion of acute or subacute coronary events, focusing on patients' symptoms, medical history and risk factors. METHODS: We prospectively studied 1288 consecutive patients presenting with acute chest pain at a non-trauma emergency department. Patients' symptoms, history and risk factors were evaluated using seven predefined criteria and assigned as typical or atypical for ischemic coronary chest pain. Positive predictive value (PPV) and 95% confidence intervals (95% CI) were calculated to predict or exclude acute myocardial infarction (AMI) and major adverse cardiac events (MACE: cardiovascular death, percutaneous coronary interventions, bypass surgery, or myocardial infarction) within six months. RESULTS: AMI occurred in 168 patients (13%), and 6-months MACE (including AMI) overall in 240 patients (19%). Presence of four or more criteria typical for myocardial ischemia was associated with a PPV of 0.21 (0.17 to 0.25) for predicting AMI and 0.30 (0.25 to 0.35) for 6-months MACE. Presence of four or more criteria atypical for coronary ischemia was associated with a PPV of 0.94 (0.91 to 0.96) for excluding AMI and 0.93 (0.90 to 0.96) for excluding 6-months MACE. In 165 of 476 patients under 40 years of age (35%), four or more atypical criteria excluded AMI and 6-months MACE with PPVs of 0.98 (0.96 to 1.0). CONCLUSION: Evaluation of criteria atypical for myocardial ischemia with acute chest pain may help to identify candidates for early discharge, whereas typical characteristics have very little diagnostic value.

Acute chest pain-a stepwise approach, the challenge of the correct clinical diagnosis.

STUDY OBJECTIVE: To assess the safety and the accuracy of a 4 h stepwise diagnostic approach relying on clinical judgement in unselected patients with acute chest pain. DESIGN: Prospective cohort study. SETTING: Emergency department (ED) of a tertiary care university hospital. PATIENTS: 1288 unselected patients presenting with acute chest pain. INTERVENTIONS: After history and physical examination, clinical judgement (step I), governed the need for further patient evaluation: baseline 12 lead electrocardiogramm (ECG) and laboratory examinations (step II), serial 12 lead ECG and laboratory examinations after 4 h (step III), and 4 h troponin T measurement (step IV) to exclude or to confirm a coronary origin of chest pain. Patients were followed clinically for 6 months for future occurrence of cardiac events (myocardial infarction, percutaneous transluminal coronary angioplasty (PTCA), CABG, cardiac death), any death and for accuracy of the ED diagnosis in non-coronary chest pain patients. MEASUREMENTS AND RESULTS: Chest pain was diagnosed to be coronary in origin in 381 and non-coronary in 907 patients, respectively. Cardiac events occurred during follow up in 240 (19%) of 1288 patients, in 233 of 381 (61%) with presumed coronary and seven of 907 (1%) with presumed non-coronary chest pain. Sensitivity, specificity, positive predictive value and negative predictive value for correct detection of coronary chest pain were 97, 86, 61 and 99%, respectively. In non-coronary chest pain patients the agreement between the ED diagnosis and the final diagnosis was good (kappa=0.71, 95% confidence interval (CI) 0.67-0.75). CONCLUSIONS: The 4 h stepwise approach guided by clinical judgement was safe for ruling out impending cardiac events in unselected patients with acute chest pain. However, more extensive evaluation is necessary for accurate rule-in of coronary chest pain.