Abstract 16263: Stress Myocardial Perfusion Imaging in Myocardial Bridging

Abstract

Introduction: The physiologic relevance of myocardial bridging (MB) that is found on invasive (ICA) and CT coronary angiography (CTA) is not known. Myocardial perfusion imaging (MPI) may be useful in objectively assessing altered myocardial blood flow associated with MB. We studied the prevalence of ischemia on MPI and mortality among patients with MB. Methods: Patients with MPI studies within 6 months of MB identified on ICAs (2002-2014) or CTAs (2005-2014) at the Mayo Clinic were retrospectively studied. Exclusion criteria included a history of myocardial infarction (MI), coronary artery bypass grafting and hemodynamically significant coronary artery disease (CAD, coronary artery stenosis ≥ 50%) were excluded. Results: 1116 individuals had MB on ICA out of which 300 had MPI studies. 511 individuals had MB on CTA out of which 63 had MPI studies. After excluding patients with CAD, 114 patients with MB identified on ICA and 31 patients with MB identified on CTA remained for analysis. Patients in the ICA and CTA cohort were the same age (60±13 years for ICA vs 60±12 years for CTA cohort, p=0.9). The ICA cohort was likely to include smokers (47 vs 26%, p=0.03) and those with hyperlipidemia (67 vs 45%, p=0.03). The prevalence of ischemia on MPI was similar in the ICA and CTA cohorts (42 vs. 44%, p=0.5). After a median follow-up of 1166 days, the ICA cohort had 12 patient deaths (8%). There was no death in the CTA cohort. The presence of ischemia on MPI was not associated with increased mortality on long-term follow-up (Log Rank p=0.9). Conclusions: Ischemia on MPI is commonly found in patients with MB who do not have significant CAD. While patients with MB identified on ICA are more likely to have traditional CAD risk factors, the prevalence of ischemia on MPI was similar when compared to patients with MB on CTA. In this small retrospective study, ischemia identified on MPI was not associated with increased mortality.