Abstract 9941: Prior Myocardial Infarction is Associated with Endothelial Dysfunction in Women with Microvascular Coronary Dysfunction

Background: Patients with signs and symptoms of ischemia but no obstructive coronary artery disease (CAD) often have microvascular coronary dysfunction (MCD). MCD is associated with an elevated risk of myocardial infarction (MI), yet the pathophysiological mechanism(s) are not well understood. We compared endothelial-dependent and endothelial-independent pathways in women with MCD with and without a prior history of MI. Methods: 67 women with persistent chest pain, clinical evidence of myocardial ischemia, and no obstructive CAD by angiography, underwent clinically-ordered coronary reactivity testing, which included infusion of intracoronary acetylcholine (ACH), adenosine and nitroglycerin to determine percent change in coronary artery diameter and flow. History of prior MI was obtained through supervised, self-reported questionnaire and confirmed with medical record evidence of elevated troponin when available. Data were analyzed using a Wilcoxon signed-rank test. Results: Overall 10 (15%) women (51±12 years) had a history of MI (4 confirmed by available medical records) and 57 (55±9 years) had no prior MI (No-MI). There were no group differences in rates of age, hypertension, dyslipidemia, body mass index, smoking history, family history of heart disease, or diabetes (data not shown). Intracoronary ACH response (endothelial-dependent pathway) was significantly lower in the group with prior MI compared to no-prior MI group (figure). Measurements of coronary flow reserve with adenosine infusion and coronary vasodilation with nitroglycerin infusion (both endothelial-independent pathways) were not different between groups. Conclusions: Prior MI in women with MCD is associated with endothelial dysfunction. Future study should consider coronary endothelial dysfunction as a MCD treatment target in women with a history of MI and no obstructive CAD.