Prevalence and Risk Factors
The true prevalence of IMR is unknown due to a number of factors. The
heterogeneity of MR patients presented in different studies makes the
assessment of the prevalence more challenging. In addition, the impact
of the imaging modality used to identify MR or timing of imaging at the
time of the diagnosis make the accurate assessment of MR less desirable
[11]. As note earlier, IMR occurs in 25% of patients presenting
with AMI without CHF and in 50% of patients with post-infarct CHF
[1–4]. It is estimated that up to 20% of patients undergoing
cardiac catheterization for symptomatic CAD [12] and nearly up to
28% of patients undergoing coronary artery bypass graft (CABG) [13]
may have IMR.
The risk factors for developing IMR are; inferior AMI (38%) versus
anterior AMI (10%) at echocardiographic follow-up after 2 years [14,
15], advanced age, female gender, prior acute MI, large infarct size,
recurrent myocardial ischemia, multi-vessel CAD and CHF on admission
[16].