THE INDEPENDENCY OF ST ELEVATION IN LEAD AVR AND ST DEPRESSION AS A PREDICTOR FOR MULTI-VESSEL DISEASE IN PATIENTS WITH NON-ST ELEVATION MYOCARDIAL INFARCTION

Abstract

Both ST elevation in lead aVR and ST depression have a predictive value for multi-vessel disease in patients with non-ST elevation myocardial Infarction (NSTEMI). However, the mutual relation between the two findings is not elucidated. Therefore, we aimed to assess the independency of the two findings as a predictor for multi-vessel disease in patients with NSTEMI. We retrospectively reviewed 340 consecutive NSTEMI patients who underwent coronary angiography within five days of presentation from January 2013 to December 2013. Electrocardiograms were interpreted in a blinded fashion; aVR(+) was defined as ST elevation ≧0.05 mV and STd(+) was defined as ST depression ≧0.05 mV in two contiguous leads in 12-lead electrocardiogram. Patients were divided into four groups; STd(+)aVR(+), STd(+)aVR(-), STd(-)aVR(+), and STd(-)aVR(-). Angiographic characteristics, in-hospital percutaneous or surgical revascularization procedure as well as in-hospital major adverse cardiac event (MACE) including death, recurrent myocardial infarction, target vessel revascularization, lethal ventricular arrhythmias were compared between those groups. Among 340 patients, 56 patients (16.5%) had STd(+)aVR(+), 41 (12.1%) had STd(+)aVR(-), 13 (3.8%) had STd(-)aVR(+), and 230 (67.6%) had STd(-)aVR(-). In 97 patients with ST depression, there was no statistical difference between STd(+)aVR(+) and STd(+)aVR(-) groups in the rate of multi-vessel disease, Thrombolysis in Myocardial Infarction (TIMI) flow grade of 0-2, in-hospital revascularization procedure and in-hospital MACE. In contrast, in 243 patients without ST depression, patients with STd(-)aVR(+) had a higher rate of multi-vessel disease (77% vs. 43%, p= 0.018) and in-hospital coronary artery bypass graft (CABG) (31% vs. 5%, p< 0.001) compared to STd(-)aVR(-)group. There was no statistical difference between STd(-)aVR(+) and STd(-)aVR(-) groups in the rate of TIMI flow grade of 0-2, in-hospital percutaneous coronary intervention and in-hospital MACE. With the use of multivariate analysis in all studied population, ST depression was strongly associated with multi-vessel disease (odds ratio [OR] 1.90; 95% confidence interval [CI] 1.05 to 3.48; p=0.034). However, ST elevation in lead aVR lost its statistical significance (OR 1.84; 95% CI 0.93 to 3.70; p=0.082). In NSTEMI patients without ST depression, ST elevation in lead aVR has a predictive value for multi-vessel disease and in-hospital CABG. However, ST depression carries a stronger predictive value for multi-vessel disease and ST elevation in lead aVR lost its statistical significance in the presence of coexisting ST depression.