Risk stratification with exercise N(13)-ammonia PET in adults with anomalous right coronary arteries
Paul C Cremer1, Amgad Mentias1, Srikanth Koneru1
1Department of Cardiovascular Medicine , Cleveland Clinic , Cleveland, Ohio , USA.
Insights
Adults with anomalous right coronary artery from the left sinus (AAORCA) and symptoms like angina may have myocardial ischemia. Exercise N(13)-ammonia PET can identify ischemia, guiding surgical unroofing or conservative management.
Area of Science:
- Cardiology
- Cardiac Imaging
- Congenital Heart Disease
Background:
- Anomalous right coronary artery from the left sinus (AAORCA) with interarterial and intramural course requires management decisions.
- Surgical unroofing is recommended for AAORCA with myocardial ischemia, but data on functional testing and management of asymptomatic patients are limited.
Purpose of the Study:
- To evaluate the utility of exercise N(13)-ammonia positron emission tomography (PET) in adults with AAORCA.
- To determine the likelihood of ischemia in patients with typical angina and exertional dyspnea.
- To assess the feasibility of conservative management for patients without ischemia.
Main Methods:
- Retrospective analysis of 27 adult patients with AAORCA who underwent exercise N(13)-ammonia PET between July 2008 and December 2014.
- Cardiac CT was used for anatomical delineation in most patients.
- Exercise N(13)-ammonia PET was employed to assess for myocardial ischemia.
Main Results:
- Myocardial ischemia was detected in 48% of patients (13 out of 27).
- Ischemia was more prevalent in patients reporting typical angina and exertional dyspnea (p<0.05).
- Surgery was performed in 12 patients, primarily those with identified ischemia; no deaths were reported in either surgical or conservatively managed groups at follow-up.
Conclusions:
- Typical angina and exertional dyspnea are associated with myocardial ischemia in AAORCA patients, identifiable via exercise N(13)-ammonia PET.
- Exercise N(13)-ammonia PET can guide surgical unroofing for symptomatic ischemic patients.
- Conservative management appears appropriate for AAORCA patients without ischemia, warranting further long-term studies.
Objective:
In adults with an interarterial and intramural course of an anomalous right coronary artery from the left sinus (AAORCA), surgical unroofing is recommended in the setting of myocardial ischaemia. However, data regarding functional testing are limited, and the management of adults without ischaemia is unclear. To evaluate these patients, we employed an exercise N(13)-ammonia positron emission tomography (PET) protocol. We hypothesised that patients with typical angina and exertional dyspnoea would be more likely to have ischaemia and that patients without ischaemia could be managed conservatively.
Methods:
Between July 2008 and December 2014, we retrospectively identified 27 consecutive patients >18 years old with an interarterial and intramural course of an AAORCA who had exercise N(13)-ammonia PET.
Results:
The majority of patients had anatomic delineation with cardiac CT (25, 93%), and most patients had chest pain (24, 89%). Myocardial ischaemia with PET was common (13, 48%), and ischaemia was more likely in patients with typical angina and exertional dyspnoea (p<0.05). Surgery was performed in 12 patients including 11 patients with ischaemia. At a median follow-up of 245 days, there were no deaths in patients with surgery or in patients managed conservatively.
Conclusions:
In patients with an interarterial and intramural course of an AAORCA, typical angina and exertional dyspnoea are associated with ischaemia on exercise N(13)-ammonia PET. Referral for surgical unroofing in symptomatic patients with ischaemia on exercise N(13)-ammonia PET and initial conservative management in patients without ischaemia seems appropriate, though larger studies with long-term follow-up are needed.
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