Prognosis of patients with previous myocardial infarction, coronary slow flow, and normal coronary angiogram

Background There is a common assumption that patients with coronary slow flow (CSF) have an excellent prognosis in the absence of coronary artery stenoses. Little is known about whether a history of previous coronary events affects the long-term survival in this population. In this retrospective, observational study, we assessed the possible association of a previous coronary event and long-term prognosis in patients with CSF but without significant coronary artery stenoses. Methods A total of 141 patients (70 male; median age: 59 years, range: 33-78 years) with CSF and normal coronary angiograms were included in the study. Patients were followed up for all-cause mortality during a period of 47 +/- 22 months. Results Previous myocardial infarction (MI) was reported by 16 (11%) patients who had similar left ventricular ejection fraction (LVEF) as those without previous MI (51 +/- 16 vs. 53 +/- 16%, p = 0.595). Patients with previous MI more often had an abnormal resting electrocardiogram (69 vs. 40%, p = 0.03), while there were no significant differences in other baseline clinical characteristics (p > 0.05 for age, gender, risk factors, pharmacological treatment). In univariate Cox analysis, only previous MI was associated with unfavorable long-term survival (log-rank p = 0.012), while an abnormal electrocardiogram, LVEF, and other clinical variables were not (log-rank p > 0.05, for all). Kaplan-Meier analysis revealed unfavorable long-term survival in patients with CSF and a history of previous MI. Conclusion In patients with CSF and an otherwise normal coronary angiogram, a history of a previous MI is associated with unfavorable long-term outcomes.