MR with Moyukh + Dr. Chitale: Stress Tests and Coronary Fistulas

A middle aged female with a vague history of “extra coronaries” who presents with worsening dyspnea on exertion. Her initial stress echo was negative, but when here symptoms progressed 2 years later she had an MRI which confirmed 2 extra coronary fistulas. Although she did not meet strict criteria for repair, the repair was ultimately done due to her persistent symptoms, and she is now symptom-free!
*When should we order a stress echo instead of the usual treadmill EKG stress test? 
The bottom line – for the most part, we should start with treadmill EKG tests, not exercise echoes!
-Hard indications: an uninterpretable EKG (LBBB, TWI, paced), evaluation of exercise-related LVOT, AS, and pulmonary hypertension
-Soft indications: as in this case, we sometimes order it when our pre-test probability for ACS so high that we aren’t going to believe a negative EKG treadmill
-Contraindications: baseline wall motion abnormalities, severe CHF (hard to see wall motion abnormalities) or poor images with prior echoes (as in morbid obesity), other contraindications to exercise (will need a nuclear test)
*Coronary Fistulas
What? Extra coronary arteries that connect with a) the RA/RV chamber or b) the PA, creating a L-> R shunt
Inline image 2
Why are these a problem, and how can they present?
a) they can cause ischemia by coronary steal -> angina or angina equivalent (in this patient, SOB)
b) overtime lead to pulmonary hypertension
How do you decide when to repair these?
There are certain criteria, including angina, evidence of pulmonary hypertension, and a high shunt fraction. This patient did not meet any of these strict criteria, but was still repaired because of refractory symptoms. As Nishant aptly pointed out, it is possible that shunt fractions worsen with exercise, so people with exercise-related symptoms may not meet the criteria even though they could benefit from the repair.

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