Myocardial bridging: retrospective analysis and scintigraphic testing of patients with no angiographically significant atherosclerotic coronary disease.

Introduction And Objective: The clinical relevance of myocardial bridging (MB) is a matter of debate. The objective of this work was to examine its prevalence, clinical presentation, prognosis, and functional features on scintigraphy in a group of patients with no significant atherosclerotic coronary disease.

Methods: We retrospectively examined 7039 consecutive cardiac angiograms performed between January 1994 and December 2004, selecting cases in which MB was not accompanied by significant coronary disease (defined as luminal stenosis > 50%), valvular heart disease or cardiomyopathy. Patient characteristics such as age, gender, vascular risk factors and clinical presentation were recorded. We then contacted these patients by telephone to determine cardiovascular events since diagnosis (hospitalization, infarction, death) or symptoms of angina, and to invite them for myocardial perfusion scintigraphy (MPS) with stress testing.

Results: The prevalence of MB was 0.97% (68 patients). The study population without significant coronary disease, valvular heart disease or cardiomyopathy was composed of 31 subjects, mean age 51.45 +/- 13.77 years, 94% (29 patients) male. Clinical presentations were: non-ST elevation acute coronary syndromes with or without biomarkers of necrosis 34% (14 patients), stable angina 23% (7 patients), atypical chest pain 16% (5 patients), ST-elevation myocardial infarction 13% (4 patients), other 3% (1 patient). Left ventricular function was normal in all patients, and angiography showed MB of the left anterior descending artery, 63% (19 patients) in the mid portion, and 33% (12 patients) in the distal portion. All subjects were treated medically. We were able to contact 24 (77%) of the 31 patients, all of whom underwent MPS; mean time since angiography was 61.25 months, with no cardiovascular events (hospitalization, infarction, death) or symptomatic angina. MPS only identified three patients with findings consistent with anterior wall ischemia.

Conclusions: In this series, 58% of the patients with MB and no significant atherosclerotic coronary disease presented with acute coronary syndromes. In all the subjects contacted, the prognosis had been good during the time since diagnosis. In the majority of them, no signs of ischemia were detected on MPS.