Patients with non-ST-elevation myocardial infarction and without chest pain are treated less aggressively and experience higher in-hospital mortality.

BACKGROUND Lack of chest pain or atypical pain does not exclude acute coronary syndrome (ACS). AIM To assess demographic and clinical characteristic as well as treatment strategies in patients with atypical chest pain on admission in hospitals without on-site invasive facility (IF). METHODS Twenty-nine community hospitals participated in the Registry of Acute Coronary Syndromes. A total of 2382 patients with ACS were enrolled. Patients admitted to hospitals with suspected ACS were stratified according to their pain symptoms as either typical (TS) or atypical which also included lack of pain (ATS). RESULTS Of all patients with initial ACS diagnosis 152 (6.4%) presented without chest pain on admission. Patients from group ATS in comparison to group TS were more often women (49 vs. 39%; p=0.01), and less frequently had past medical history of coronary artery disease (54.3 vs. 72.5%; p <0.0001), myocardial infarction (15.2 vs. 32.1%; p <0.0001), arterial hypertension (65.6 vs. 74.5; p <0.0001) or renal insufficiency (1.3 vs. 5%; p=0.04). Invasive treatment was undertaken in 9.2% of patients from group ATS and in 14.6% from group TS (p=0.049). In-hospital mortality among all patients remaining in community hospitals for conservative treatment was similar in both groups (ATS vs. TS: 8.7 vs. 5.9%; p=NS). Among patients with typical and atypical symptoms the occurrence of ST-segment elevation myocardial infarction (STEMI), non-ST-segment elevation myocardial infarction (NSTEMI) and unstable angina (UA) was similar. Patients with NSTEMI and UA with atypical symptoms were less likely transferred for invasive diagnostic, for NSTEMI 9.4 vs. 18.1% (p=0.03) and for UA 6.1 vs. 12.9% (p=0.04). In-hospital mortality was similar among typical and atypical groups in STEMI and UA patients. However, it was significantly higher among NSTEMI patients with atypical chest pain treated conservatively (3.6 vs. 0%; p=0.05). CONCLUSIONS There is a significant group of ACS patients without chest pain on admission who are usually women with less severe past medical history. This subset of patients is treated less aggressively in terms of antiplatelet therapy and invasive approach. It is patients with diagnosis of NSTEMI who due to being misdiagnosed due to their atypical chest pain have poorer outcome.