Prognostic value of transthoracic echocardiography in the evaluation of suspected myocardial infarction

Abstract

Abstract Introduction Transthoracic bedside echocardiography (TTE) in the emergency department is recommended in patients with suspected myocardial infarction (MI), who do not qualify for early discharge using accelerated protocols. The prognostic value of routine echocardiographic parameters like wall motion abnormalities in patients with suspected MI, has not been evaluated so far. Therefore, our aim was to analyze whether TTE is a suitable risk stratification tool in patients presenting with suspected MI. Methods In a prospective cohort study, 2,719 patients presenting to the emergency department with symptoms indicate of MI were recruited. Patients with ST-segment elevation myocardial infarction (STEMI) and without available TTE were excluded. In the final dataset of 2,086 patients, pathological TTE-findings were defined as the composite of reduced systolic left ventricular(LV) function <50%, regional wall motion abnormalities (WMA) and severe valvular defects. Patients were followed up for up to 5 years to assess all-cause mortality and major adverse cardiac events (MACE), composited of cardiac rehospitalization, revascularization, MI excluding the index events, and death. Kaplan-Meier survival curves were created and compared using the log rank test. Cox-proportional hazard ratios with adjustment for age, sex, cardiovascular risk factors and high-sensitivity troponin were calculated for individual echocardiographic pathological findings. Results Among 2,086 patients 63.7% were male and the mean age was 64 years. Acute myocardial infarction was present in 308 (14.7%). 32.5% showed any pathological TTE-findings: A reduced systolic LV-function was detected in 18.6%, 18.4% had wall motion abnormalities, composed of 7.5% with akinesia and 10.9% with hypokinesia. Severe valvular defects were present in 7.8%. In patients with any pathological TTE-finding the rate of MACE was significantly higher than in patients without pathological findings (p<0.001, Figure 1A): After 5 years, MACE occurred in 320 (29.99%) of patients with a normal TTE, whereas 319 (59.65%) patients with at least one pathology developed MACE after 5 years. Overall mortality as a single component of the combined endpoint occurred in 86 (8.71%) patients with a normal TTE, while in patients with pathologies 152 (30.46%) had died (p<0.001, Figure 1B). Following cox-regression, valvular defects (HR 2,23 (95% CI 1,66-2,78)), highly reduced systolic LV-function <30% (HR 2,51 (95% CI 1,68-3,76)), and akinesia (HR 1,94 (95% CI 1,30-2,91)), were independent predictors of all-cause mortality at five years (Figure 2). Conclusion We describe the value of TTE as prognostic tool in patients with suspected MI and found that patients with pathologies in TTE were at substantially higher cardiovascular risk compared to patients without pathologies. Especially regional akinesia, highly reduced LV-function and severe valvular defects were strong predictors of mortality within 5 years.Kaplan-Meier survival curvesAdjusted cox-proportional hazard ratios