Pre-infarction angina (PIA) has been suggested to have a protective role in ST elevation myocardial infarction (STEMI), limiting necrosis extent and guaranteeing greater myocardial functional recovery.
Objectives: To study the differences in angiographic and echocardiographic findings, between STEMI patients with and without PIA undergoing primary percutaneous coronary intervention (PPCI) and to assess the in-hospital and mid-term (6-months) clinical outcomes between both patients groups.
Material and Methods: We prospectively enrolled 238 consecutive patients with first acute myocardial infarction. Patients were divided into 2 groups; those with or without PIA. Left ventricular ejection fraction (LVEF), LV systolic and diastolic volumes, Wall motion score index and degree of mitral regurgitation (MR) were measured by echocardiography on admission and after 90 days. Coronary angiography was assessed regarding; number of diseased vessels, the culprit artery, TIMI flow pre and post procedure, TIMI frame count, collateral circulation and thrombus grading. Major adverse cardiac events (MACE) were reported in-hospital and up to 6 months follow-up.
Results: Of the 238 patients included, 42 (17%) had PIA and 196 (83%) had no PIA. No significant difference was encountered regarding baseline LV volumes, LVEF and WMSI assessed be echocardiography in both groups (PIA Vs non PIA groups: EDV 85.5±17 Vs 90.8±27 ml/m 2, p = 0.2, ESV 44.3±13 Vs 45.6±16 ml/m 2, p = 0.6, EF 48.6±9% Vs 46.4±8 , P = 0.1, WMSI 1.35±0.22 Vs 1.35±0.18, p = 0.9, respectively). However, at 90 days echocardiographic follow-up, significant increase in LV volumes and further impairment of LV systolic function was noticed in non PIA group (PIA Vs non PIA groups: EDV 81.8±27 Vs 103±49 ml/m 2, p = 0.008, ESV 42.1±16 Vs 49.7±22 ml/m 2, p = 0.04, EF 50±15% Vs 43.6±17% , P = 0.02 respectively) ) with significant improvement of WMSI among patients with PIA (1.13±0.35 in PIA group Vs 1.31±0.5 in non PIA group, p = 0.03). Angiographically, baseline TIMI flow was significantly better among PIA group (p < 0.0001), while final TIMI flow and TIMI frame count were not significantly different (p = 0.2 for both), Nevertheless, TIMI frame count tended to be significantly better in PIA among patients presenting by anterior STEMI (p = 0.09). PIA group was associated with lower grades of thrombus burden than non PIA group (p = 0.002) and better collateral circulation (p = 0.001). During follow up, mortality, TLR,TVR were more but not significantly different in non PIA( p = 0.5, 0.5 and 0.9 respectively), but there was a significant increase in develepment of heart failure in non PIA group ( 2 (4%) patients in PIA Vs 43 (22%) patients in non PIA group, p = 0.02)
Conclusion: PIA seems to be associated with smaller infarct size, better regional and global left ventricular function recovery, better angiographic findings and less incidence of heart failure.