Long-term clinical course of patients with isolated myocardial bridge.

BACKGROUND Myocardial bridge (MB) is regarded as a common benign lesion on coronary angiography (CAG). It is known to be harmless but may cause several cardiac events and recurrent hospitalization, so in the present study the long-term clinical course of patients with isolated MB and predictors of readmission were investigated. METHODS AND RESULTS Total 684 patients (343 males, 60.5+/-11.2 years) with persistent chest pain without critical stenosis on CAG were enrolled. The patients were divided into 2 groups according to the presence of MB. Clinical follow-up was performed with respect to readmission after baseline CAG. At a mean follow-up of 37 months, 92 patients (13.3%) were re-admitted because of 79 recurrent chest pain refractory to medication (11.5%), 8 myocardial infarctions (1.2%), 1 life-threatening arrhythmia (0.1%) and 4 deaths (0.6%). There was a significant higher incidence of readmission in the MB group (P=0.038). In multivariate analysis, long MB (hazard ratio (HR) 2.780; 95% confidence interval (CI) 1.070-7.218, P=0.036) and spontaneous vasospasm in CAG (HR 2.335; 95%CI 1.055-5.171, P=0.037) were the predictors of readmission. Moreover, additional use of aspirin or statin decreased the readmission rate. CONCLUSIONS This study suggests that MB on non-occlusive CAG is not benign and may cause recurrent chest pain, myocardial infarction or life-threatening arrhythmia. Especially, patients with a long MB and vasospasm on CAG need intensive medical therapy, including antiplatelet treatment.