Extensive unroofing of myocardial bridge: A case report and literature review.

Background: Myocardial bridge is defined as a segment of a coronary artery that takes an intramyocardial course. The presence of myocardial bridge has been observed in as many as 40%-80% of cases on autopsy, angiographically from 0.5% to 16.0%, and often asymptomatic. However, it has been associated with angina, coronary spasm, myocardial infarction, arrhythmias, syncope, sudden cardiac arrest, and death. Conflicting opinions exist on the timing of surgical intervention for myocardial bridge.

Methods: We present an unusual case of a young female, with prior aortic surgery, who had refractory chest pain despite optimal medical therapy. Stress testing revealed anterior ischemia. Cardiac catherization showed myocardial bridge of the left anterior descending artery with significant compromise of blood flow (fractional flow reserve = 0.75 with adenosine). We proceeded with surgery. Intraoperatively, we found an unusually long (10-cm) intramyocardial segment of the left anterior descending artery which was managed by surgically unroofing. Our patient felt better post procedure. Repeat cardiac catheterization showed no further narrowing of the left anterior descending artery with a fractional flow reserve of 0.87 in its distal segment.

Results/discussion: Myocardial bridge is present mostly in female patients (74.5%), with median age at 56.2 years and mostly involving the left anterior descending artery (77.2%). The average length of myocardial bridge is 21.85 ± 16.10 mm (range: 5-70 mm). Our case is unique as the involved myocardial bridge was 10 cm in length, the longest ever reported. Multiple imaging modality revealed significant coronary insufficiency, with a subsequent clinical and angiographic improvement upon unroofing of the culprit coronary vessel.

Conclusion: Management decision on myocardial bridge remains controversial. This is a case of the longest symptomatic myocardial bridge, with a subsequent improvement post unroofing.