Abstract 18551: The Detection of Diastolic Stunning by Two-Dimensional Speckle Tracking Imaging Improves Initial Diagnosis in Emergency Department Patients with Suspected Acute Coronary Syndromes

Abstract

Background: Differential diagnosis of chest pain (CP) in emergency department (ED) is important for the management of acute coronary syndrome (ACS). Regional left ventricular (LV) diastolic dysfunction or diastolic stunning (DS), detected by strain image (SI) derived from two-dimensional speckle tracking technology, may persist after an episode of transient severe myocardial ischemia. We studied the incremental value of the detection of diastolic stunning by SI over the initial diagnosis (InDx) of CP in the ED for identifying patients with ACS. Methods: Consecutive 128 patients (75 men, 61 ±13 years) with CP consistent with ACS were enrolled. SI (ARTIDA, Toshiba) was acquired in the apical long-axis, two- and four-chamber views within 6 hrs in ED. Transverse strain curves were obtained and peak values of strain at the closure of aortic valve (A) and at the one third of diastolic duration (B) were measured. The SI-diastolic index (SI-DI) was determined as (A-B)/A×100% and used to identify regional LV DS. In the 40 normal subjects the SI-DIs were 76.5±10.6, 80.7±8.4, 79.4±11.6 % in the territories of the left anterior descending branch (LAD), the left circumflex branch (LCX) and the right coronary artery (RCA), respectively.Clinical evaluation, serial ECGs, and troponin (Tn) were performed in all patients, with coronary angiography (CAG) performed as clinically indicated. The InDx or “definite ACS” (D-ACS) was based on presenting CP, ECG and Tn. Final diagnosis of D-ACS was defined as elevated Tn and significant disease on CAG (>50% stenosis). Results: 57 patients were diagnosed as having D-ACS. Regional LV DS (SI-DI<40%) had been detected in the perfusion territories of the coronary arteries with culprit lesions in 52 (91%) of D-ACS, whereas it had been noted in 9 (13%) of chest pain syndrome (CPS). SI-DIs were 25.8±15 (n=75), 17.5±14 (n=36), 21.1±11 % (n=14) in the culprit lesions of LAD, LCX and RCA, respectively, and 70±13% (n=217) in the segments corresponding to the non-culprit lesions. For D-ACS, quantitative SI plus InDx increased sensitivity by 28% to 95% (P<0.01), and non-significantly increased NPV by 21% to 97%. Conclusion: Adding the detection of regional LV DS by SI to InDx in ED increased sensitivity and NPV for detecting D-ACS.