Abstract 3267: High Prevalence of Myocardial Bridging: Evaluation by MDCT Coronary Angiography
Background: Myocardial bridging (MB) of the left anterior descending coronary artery (LAD), i.e., an intramyocardial coronary course, may cause anginal symptoms in the absence of obstructive coronary artery disease (CAD). Reports on the prevalence of MB in the general population vary; higher rates are reported on autopsy (40–80%) than angiography (0.5 to 16%). Multidetector computed tomography (MDCT) coronary angiography is ideally suited to evaluate MB; it provides direct visualization of the orientation and position of the coronary artery in relation to the myocardium.
Methods: 300 consecutive coronary angiograms obtained by 64 slice MDCT were evaluated retrospectively; 55 patients with bypass surgery, or poor quality studies were excluded. The axial and multiplanar reformatted images were analyzed for the presence of CAD in all vessels and for MB in the LAD. MB was defined as an LAD segment partially or completely surrounded by myocardium (Figure 1⇓).
Results: MB was found in 44% (108/245) of the patients. Deep MB (intra-myocardial LAD segment covered completely by muscle bundle) was noted in 9 patients (8.5%). Mean MB length was 28.7± 16.5 mm. MB was significantly more prevalent in the mid vessel (66%, p<0.001) than in the proximal (8.5 %) and distal vessel (25.5%), and present equally in men and women (45% and 41%, p=NS).
Conclusion: MB is present in >40% of men and women, a finding much more consistent with that reported by autopsy studies than by cardiac catheterization. MDCT provides a unique opportunity to accurately and non-invasively diagnose MB, and to provide an alternative to atherosclerosis as an explanation for anginal symptoms.