Discussion:
The Schwarz classification is used for guiding therapeutic considerations in patients with an identified myocardial bridge. This classification is broken down into types A, B, and C. Type A patients have an incidental finding of myocardial bridging on angiography without objective signs of ischemia and do not require treatment. Type B patients demonstrate ischemia during stress testing and should receive treatment with beta-blockers or calcium-blockers. Type C patients have significantly altered intracoronary hemodynamics, with objective signs of ischemia, including symptoms. These patients should be managed with medical therapy initially, and if that fails, operative intervention should be pursued.6
Beta-blockers are useful in patients with myocardial bridging due to their negative inotropic and chronotropic effects coupled with reduced sympathetic drive, allowing for increased length of diastolic coronary filling and reduced compression. Calcium-channel blockers can be used as an alternative. Nitrates should be used with caution in these patients, as they increase systolic compression within the bridge while vasodilating the proximal segment. These altered hemodynamics may exacerbate retrograde flow thereby reducing the threshold for myocardial ischemia.
In patient’s refractory to medical therapy, stenting may be considered.  However, significant rates of in stent restenosis have been identified small numbers of patients. Additional concerns surrounding stenting include stent fracture, thrombosis, and increased risk of perforation during deployment, all of which has limited the utility of this treatment.4,5
A surgical gold standard has not been established for patients with an isolated myocardial bridge and refractory symptoms due to the infrequent finding of need for surgical intervention. Coronary artery bypass graft (CABG) with use of the left internal mammary artery (LIMA) to the LAD has been described. Concerns regarding the ability of the CABG graft to remain open due to competitive flow in a patient with non-obstructive CAD limits enthusiasm for this approach. Alternatively, the literature suggests that for patients with isolated myocardial bridge, the surgeon may carefully unroof the intra-myocardial component of the affected vessel. A perceived benefit of unroofing is that it can be done in isolation or in combination with CABG if necessary. The unroofing technique has been shown to be safe and effective in improving symptoms in a small number of patients. Interestingly, very little is in the literature regarding the actual angiographic outcome of patients who undergo surgical unroofing of a myocardial bridge as a result of significant symptoms. This case report demonstrates complete unroofing as confirmed by post-operative angiography in addition to significant symptomatic improvement.