Dr. Stephan Miller and colleagues at the University of Tübingen in Germany have discovered that silent myocardial infarction raises the likelihood of a future major cardiac event for 14% of patients with symptomatic peripheral vascular disease evaluated with MRA.
They made the finding after developing a new MR protocol that combined delayedenhancement myocardial MRA with a conventional contrast-enhanced peripheral vascular runoff study. The delayed myocardial perfusion images were acquired 10 minutes after MRA using the same 0.18-mmol administration of gadolinium-based contrast media.
Evidence of a previous myocardial infarction appeared for 58 of 182 (32%) patients with confirmed peripheral vascular disease. Twenty-six patients, in consultations after the procedure, admitted that they were not aware of their previous infarction. The clinical relevance of the findings proved themselves out when subjects were interviewed two years later. Major adverse cardiac events, such as unstable angina, revascularization, or cardiac-related death, arose among eight of 26 (31%) patients with an occult progressing infarction. The MACE rate for patients with unknown infarction was 34% and 6% for patients whose delayed-enhancement MRA studies ruled out MI.
Miller concluded that the add-on cardiac sequence is a meaningful supplement to peripheral vascular MRI that provides important information to help physicians stratify patient risk and choose optimal therapy.
