Absence of chest discomfort in type 1 NSTEMI patients: predictors and impact on outcome.

Background: The absence of chest discomfort has been hypothesized to delay treatment and consequently result in worse outcomes in patients with non-ST-elevation myocardial infarction (NSTEMI).

Methods: In 888 consecutive patients with type 1 NSTEMI, symptoms were systematically classified as chest discomfort defined as chest pain or pressure, dyspnea or other symptoms, e.g. epigastric pain. Patient characteristics predictive for the absence of chest discomfort and the impact of the symptom type on adverse in-hospital events (all-cause mortality, cardiogenic shock, and mechanical ventilation) were analyzed.

Results: Chest discomfort was reported in 81.0%, dyspnea without chest discomfort in 12.2%, and only other symptoms in the remaining 6.9% of patients. In a multivariable regression analysis, female sex (p = 0.035), diabetes mellitus (p = 0.003), the absence of any family history of coronary artery disease (CAD) (p = 0.002), anemia (p < 0.001), and atrial fibrillation or flutter at presentation (p = 0.017) were independent predictors for the absence of chest discomfort. The absence of chest discomfort was associated with a higher rate of in-hospital adverse events (10.6% for chest discomfort vs. 29.6% for dyspnea and 27.9% for other symptoms, p < 0.001), which appeared partially mediated (p = 0.044) by longer times from diagnosis to invasive management (p < 0.001).

Conclusions: In type 1 NSTEMI, the absence of chest discomfort is associated with a higher rate of adverse in-hospital events. Women, diabetics, patients without a family history of CAD, patients with anemia, and patients with atrial fibrillation are more likely to present without chest discomfort and special attention may be required to avoid delayed invasive management in these patients.