Impact of Myocardial Bridge-mural Coronary Artery on Myocardial Blood Supply.

Objective To explore the impact of myocardial bridge-mural coronary artery (MB-MCA) on myocardial blood supply. Methods The imaging data of 74 patients with the isolate MB in the left anterior descending artery undergoing 256-slice CT coronary angiography and myocardial perfusion imaging (MPI) were retrospectively analyzed. The subjects were divided into incomplete and complete MB types. The length of MB and the systolic stenosis degree of MCA were measured.The type and length of MB and the systolic stenosis degree of MCA (according to Noble grade) were compared between the normal and abnormal MPI groups. The clinical characteristics including age, gender, body mass index, hypertension, dyslipidemia, diabetes mellitus, and smoking history were also reviewed. Results There were 38 incomplete MB cases and 13 complete MB cases in the normal MPI group,and 5 and 18 in the abnormal MPI group (χ=18.134,P=0.000). The MB length in the normal and abnormal MPI group were (14.7±3.7) mm and (15.5±4.5) mm (t=0.804,P=0.424). However, the systolic stenosis degree of MCA showed significant difference (χ=17.839,P=0.000). The clinical characteristics were not significantly differentt between the normal and abnormal MPI groups (P>0.05). Conclusions The MB type and the systolic stenosis degree of MCA can affect myocardial perfusion.Patients with complete MB and the moderate-to-severe systolic stenosis degree of MCA are more susceptible to myocardial ischemia. However, the MB length is not correlated with myocardial ischemia.