Left anterior descending coronary artery myocardial bridging by multislice computed tomography: Correlation with clinical findings

Objective: To assess the relationship between left anterior descending (LAD) coronary artery myocardial bridging detected by 64-slice computed tomography (CT) and clinical findings. Methods: 221 consecutive patients were examined with coronary 64-slice CT angiography. 21 patients with coronary stenosis > 50% were excluded. The length, depth, and luminal narrowing of LAD myocardial bridges during systole and diastole were measured. CT findings were compared with the treadmill ECG-stress test, and clinical symptoms. Results: Myocardial bridges of the LAD were found in 23% of patients (51/221) (length, 14.9 +/- 6.5 mm; depth, 2.6 +/- 1.6 mm). A significant difference was noted between the LAD luminal diameter before the intramyocardial Course and intramyocardially, for both diastole and systole (p < 0.001): with a higher diameter reduction of 27% for end-systole compared to end-diastole with 15% (p = 0.006). Systolic LAD intramyocardial luminal narrowing > 50% was found in 3/25 (8%). 30/51 (59%) of bridges were "deep" (> 2 mm myocardial depth), 21/51 (41%) were "superficial". The prevalence of a positive ECG-stress tests for the anterior myocardial region was significantly higher in patients with LAD myocardial bridges(34/50: 68%) compared to those without (28/144; 19.4%) (p < 0.001). There was no difference between "superficial" and "deep" LAD myocardial bridges in regard to a positive treadmill ECG-stress test. Typical angina was rare with 6%. Conclusion: LAD myocardial bridges are common findings and can possibly explain a positive exercise ECG-stress test for anterior myocardial ischemia. Intramyocardial LAD segments show mild-to-moderate luminal narrowing at rest, which is higher during end-systolic phase. (C) 2008 Elsevier Ireland Ltd. All rights reserved.