Preinfarction angina: clinical significance and relationship with total ischemic time in patients with ST-elevation myocardial infarction.

OBJECTIVES: Preinfarction angina (PIA) may play a protective role in patients with ST-elevation myocardial infarction. Data on the relationship between PIA and time to reperfusion are scarce. We aimed to assess infarct size by peak troponin-T (TnT) in patients with or without PIA in three different time intervals to a primary percutaneous coronary intervention (PPCI), the relationship between PIA and left ventricular ejection fraction, and its impact on midterm survival. PATIENTS AND METHODS: Single-center, retrospective analyses were carried out of 575 consecutive PPCI-treated patients, divided into three groups from symptom onset to reperfusion: less than 3, 3-6, and greater than 6 h.
RESULTS: Patients with PIA had smaller infarct size [TnT=3.76 (5.07) vs. 5 (6.12) ng/ml, P=0.024]. Infarct size of patients with PIA versus no-PIA was lower for patients presenting within 3-6 h from onset of symptoms [3.73 (5.38) vs. 5.53 (6.9) ng/ml, P=0.028], but not different for those who presented less than 3 h [4.15 (5.53) vs. 4.0 (3.96) ng/ml, P=0.702] nor for those who presented greater than 6 h [3.65 (4.24) vs. 5.0 (5.9) ng/ml, P=0.141]. On multivariate analyses, only PIA protected from moderate to severe left ventricle dysfunction (odds ratio=0.557, 95% confidence interval: 0.352-0.881, P=0.012), but failed to reduce overall mortality [hazard ratio=0.784, 95% confidence interval: 0.356-1.724, P=0.545; median follow-up time=23 (20) months].
CONCLUSION: PPCI-treated patients within 3-6 h from symptom onset had smaller infarcts if they had experienced PIA, with no benefit for those who presented less than 3 h nor for those who presented greater than 6 h from symptom onset. Moderate to severe left ventricle dysfunction was less prevalent in PIA patients. However, PIA failed to have an independent impact on midterm survival.