Circumflex artery-related acute myocardial infarction: limited ECG abnormalities but poor outcome

Background: Circumflex (CX) artery-related myocardial infarction (MI) is less well represented in trials on ST-elevation acute myocardial infarction (STEMI), most often due to the absence of significant ST-segment elevation, and therefore the outcome of these patients is less well known. We aimed to compare the outcome of patients with CX versus right coronary artery (RCA) related STEMI in a large cohort of patients treated with primary angioplasty.

Methods: A total of 1683 consecutive patients with STEMI were studied. Patients who lacked STsegment elevation were also included if they had persistent chest pain with signs of ischaemia or regional wall motion abnormalities on echocardiography. Coronary angioplasty was performed according to standard procedures. After the intervention, all patients received aspirin and clopidogrel or ticlopidine.

Results: The infarct-related vessel was the CX in 229 patients (14%) and the RCA in 600 patients (36%). No differences in baseline characteristics were present. Mean extent of ST-segment elevation or deviation was significantly higher in patients with the RCA as infarct-related vessel. Enzymatic infarct size was significantly higher in the CXrelated MI (1338+/-1117 IU/l vs. 1806+/-1498 IU/l, p<0.001). Left ventricular ejection fraction <45% was more often present in patients with CXrelated MI (37 vs. 26%, p<0.01). Both short- and long-term mortality were significantly higher in the CX-related MI.

Conclusion: This study emphasises the fact that CX-related infarction has a worse prognosis compared with RCA-related infarction. (Neth Heart J 2007;15:286-90.).