Objective: To evaluate myocardial necrosis extent after myocardial infarction (MI) and reperfusion with primary coronary angioplasty in nondiabetic patients and the relationship with unstable preinfarction angina (PA).
Design: Prospective cohort study.
Setting: Studies suggest PA limits infarct size. This effect is questioned in patients treated with primary coronary angioplasty.
Patients: Seventy-eight, nondiabetic, consecutive MI patients.
Interventions: Primary coronary angioplasty and scintigraphic study to assess the myocardial infarct size.
Main outcome measures: Scintigraphic myocardial infarct size.
Results: There were 32 patients with PA (PA +) and 46 without PA (PA −) in the 24-h period prior to MI onset. There were no significant differences in the baseline characteristics between the two groups. The scintigraphy indicated myocardial infarct size significantly smaller in PA + patients: mean, 18.0% (SD, 14.7) vs 27.0% (SD, 20.1) [p = 0.033]. This occurs even though Thrombolysis in Myocardial Infarction grade 3 flow achieved in both groups was similar (84.8% vs 84.4%, p = 1.000). We found a higher percentage of ST-segment resolution (≥ 70%) in PA + patients (65.6% vs 45.7%, p = 0.082) together with a lower incidence of left ventricular systolic dysfunction (3.2% vs 18.6%, p = 0.071).
Conclusions: PA exerts a beneficial effect in nondiabetic patients with ST-segment elevation acute MI even when treated with primary PCI. The infarct size is limited, and left ventricular systolic function is preserved. The effects may be related to a better preservation of tissue reperfusion in patients with PA.