Occurrence of typical perfusion defects attributed to jailed or occluded side branch after ramus descendens anterior stenting in a patient cohort referred for 13NH3 myocardial PET/CT.

Coronary stenting is frequently accompanied by occlusion or jailing of side branches. This can cause small reversible or persistent perfusion defects on myocardial perfusion single photon emission computed tomography studies, but data from NH3 myocardial perfusion PET/computed tomography (CT) are lacking. This study aimed to describe the occurrence of perfusion defects in patients with ramus descendes anterior (RDA) stents on myocardial perfusion imaging as measured by NH3 PET/CT.From 10 September 2013 till 29 August 2014, 53 consecutive RDA-stented patients, who were referred for NH3 PET/CT, were entered into a database. All scans were evaluated for the occurrence of reversible or persisting perfusion defects within the RDA flow territory, which was categorized as normal, infarction, ischemia, or as a small persisting defect after stent placement or small area of ischemia after stent placement, attributable to side-branch occlusion (SBO).Of the 53 patients [65±10 years, male : female 33 (62%) : 20 (38%)] with an RDA stent, 29 had received a stent in the proximal RDA, 18 in the mid-RDA, and six in both the proximal and the mid-RDA.NH3-measured myocardial perfusion was scored as normal in 26 (49%), as infarction in 5 (9%), and as ischemia in 2 patients (4%). Six patients (11%) showed a small persisting defect within the RDA flow territory, whereas 14 patients (26%) showed a small area of ischemia in the RDA territory.myocardial perfusion abnormalities attributed to SBO are frequently observed on NH3 PET/CTs of patients with RDA stents. In the present cohort, 38% of patients showed such small defects in the RDA territory, which proved to be reversible in 70% of the cases. Recognizing and reporting SBO-related perfusion abnormalities will help clinicians to interpret NH3 myocardial PET/CT properly.