Coronary Flow in Patients With Myocardial Bridges, Coronary Fistulae in the Setting of Unstable Non-Obstructive Coronary Disease

Оbjective Our aim was to describe the difference in epicardial coronary flow at baseline on background anti-ischaemic therapy and following intracoronary glyceryl trinitrate in patients with acute coronary syndrome and non-obstructive coronary disease with and without myocardial bridges and coronary artery fistulae. Materials and methods Coronary flow was characterized in a group of 88 patients with coronary stenoses <50% diagnosed with acute coronary syndrome using the corrected Thrombolysis in Myocardial Infarction frame count (cTFC) method at coronary angiography at baseline and after the application of 200 µg glyceryl trinitrate. Results Тhe patients with myocardial bridges and coronary artery fistulae accounted for 4.4% (n=4) and 2.2% (n=2), respectively, of the patients with acute coronary syndrome. Sixty-two (70%) of all patients demonstrated slow progression of the contrast media (cTFC>25 frames) in at least one coronary artery. Coronary flow was similarly impaired in the patients with myocardial bridges, coronary artery fistulae, and those without coronary anomalies and variants. After the intracoronary infusion of glyceryl trinitrate, the epicardial flow improved in the patients with myocardial bridges and to a lesser degree in the cases with coronary fistulae. Most of the patients who responded to glyceryl trinitrate were on background therapy with calcium channel blockers. Conclusion The epicardial coronary flow of patients with non-obstructive coronary disease with myocardial bridges and acute coronary syndrome showed less impairment compared to baseline in response to intracoronary glyceryl trinitrate applied at background anti-ischaemic therapy that included calcium channel blockers.