Patch plasty of the left anterior descending artery as a practical option for a myocardial bridge: a case report

A myocardial bridge causes a specific intraluminal flow pattern and can affect endothelial function, response to vasoactive agents, development of atherosclerosis and a patient's prognosis. Additionally, the reliability of preoperative functional assessment, including fractional flow reserve (FFR) and reasonable patient's selection for myotomy or coronary artery bypass grafting (CABG) may be controversial.

A 63-year-old man presented with shortness of breath. Echocardiography revealed severe aortic regurgitation and left ventricular dilatation. Coronary angiography revealed a myocardial bridge in the anterior descending artery (LAD) without atherosclerosis. The myocardial bridge caused 75% stenosis in systole due to compression and kinking, and 25% stenosis in diastole by visual assessment, with a FFR of 0.80 and instantaneous wave-free ratio of 0.88. Quantitative assessment showed a minimal luminal diameter of 0.79 mm in systole, corresponding to 72.7% stenosis. A median sternotomy was performed. Following aortic cross-clamping and aortic valve replacement, the myocardial bridge was completely divided. However, the unroofed segment appeared thin and diffusely spastic. The unroofed segment of the LAD was longitudinally incised and enlarged using a free right internal thoracic artery (ITA) patch, which was ∼25 × 12 mm. There were no post-operative complications. Post-operative coronary angiography confirmed the enlargement of the unroofed segment. Vascular remodelling caused normalization of the diameter 6 months later.

Myotomy concomitant with patch plasty using the ITA can be effective and durable option for myocardial bridges, particularly when expected CABG patency may be suboptimal because of moderate diastolic stenosis or a distal myocardial bridge location.