Author + information
- Burcak Kilickiran Avci,
- Ece Yurtseven,
- Sevgi Ozcan,
- Barıs Ikitimur,
- Bilgehan Karadag,
- Vural Ali Vural and
- Zeki Ongen
Acute occlusion of the circumflex artery (Cx) frequently presents a diagnostic challenge. In this study, patients hospitalized with acute myocardial infarction (MI) and angiographically determined Cx occlusions as culprit lesions were investigated in terms of their clinical presentation (ST segment elevation [STEMI] vs. non-ST segment elevation MI [NSTEMI]) and electrocardiographic findings.
A total of 362 consecutive patients hospitalized with acute MI during years 2009-2012 were retrospectively screened. Patients without history of previous coronary artery disease and in whom a single culprit lesion (causing total occlusion or ≥90% stenosis associated with less than TIMI III distal flow) was detected in coronary angiography (n=131) were enrolled. Patients were divided into three groups according to the site of the culprit lesion as follows: Cx group (n=33), right coronary artery (RCA) group (n=43) and left anterior descending artery (LAD) group (n=55). The electrocardiographic findings at initial presentation of the Cx group were investigated and compared with the other patients, along with echocardiographically determined left ventricular ejection fractions (EF) and peak creatinine kinase MB (CK-MB) levels.
There were 82 cases (63%) with STEMI and 49 cases (37%) with NSTEMI. In patients presenting with STEMI, only 13% had Cx as the culprit lesion, whereas Cx was determined as culprit in 45% of the cases with NSTEMI (p<0.001). Significantly more patients in the Cx group presented with NSTEMI compared with the other groups (67 % in Cx group vs. 21% in RCA group vs. 33% in LAD group, p<0.001). As would be expected, patients in the Cx group had higher EF (p<0.001) and lower peak CK-MB (p<0.001) values compared to the LAD group. ST segment elevation was most frequently observed in leads DIII (63.6%) and aVF (63.6%) and ST segment depression was most frequently seen in leads V5 (50%) and V4 (45.5%) in the Cx group. Out of 33 patients with Cx as the culprit artery, 10 (30%) had no specific ST segment (elevation and/or depression) changes. There were six distinct ST segment changes: (1) inferior (DII, DIII, aVF) ST elevation (21.2%), (2) lateral (V5,V6) ST elevation (9.1%), (3) posterior (V7-V9) ST elevation (12.1%), (4) septal (V1-V4) ST depression (30.3%), (5) anterolateral (V4-V6) ST depression (39.4%), and (6) high lateral (DI,aVL) ST depression (21.2%). ECG changes were not significantly different in cases with distally located Cx culprit lesions compared to ones with proximally located culprit Cx lesions.
Acute MI associated with the Cx artery frequently present as NSTEMI. The detection of site of culprit lesion in these patients by using initial ECG findings seem to be difficult. The findings of this study once again underlines the need for improvement in the diagnostic approach of acute Cx occlusions.