Changes of Myocardial Function in Patients with Non-ST-Elevation Acute Coronary Syndrome Awaiting Coronary Angiography

The optimal timing of coronary angiography in patients with non–ST elevation (NSTE) acute coronary syndromes (ACS) is debated. American Heart Association and American College of Cardiology guidelines recommend an early invasive strategy <12 to 48 hours after the onset of symptoms. The objective of the present study was to determine possible changes in myocardial function in patients with NSTE ACS awaiting coronary angiography. One hundred two patients with suspected NSTE ACS were enrolled, including 56 with NSTE myocardial infarctions (NSTEMIs), 23 with unstable angina pectoris, and 23 with noncoronary chest pain. Global and regional myocardial function was measured as longitudinal and circumferential strain using speckle-tracking echocardiography. Measurements were performed at admission and immediately before coronary angiography (30 ± 16 hours after admission). In patients with NSTEMIs, there was deterioration in longitudinal global strain from −16.1 ± 2.6% at admission to −15.0 ± 2.6% before coronary angiography (p <0.001). This was due to deterioration in longitudinal strain in the territory supplied by the infarct-related artery from −14.2 ± 4.2% to −12.0 ± 4.1% (p <0.001). Patients with NSTEMIs due to acute coronary occlusion underwent prominent worsening in longitudinal and circumferential strains (−15.7 ± 2.9% to −13.9 ± 3.0%, p = 0.001, and −16.7 ± 4.0% to −15.0 ± 3.9%, p = 0.01, respectively) compared to patients with NSTEMIs without occlusions. There were no changes in strain in patients with unstable angina pectoris or noncoronary chest pain. In patients with NSTEMIs without acute coronary occlusions, myocardial function improved after revascularization, whereas patients with acute occlusions demonstrated no improvement. In conclusion, myocardial function deteriorates in patients with NSTEMIs awaiting coronary angiography. Patients with acute coronary occlusions have the most prominent deterioration, and this subgroup shows no recovery of function after revascularization.