Papillary muscle ischemia on high-resolution cine imaging of nitrogen-13 ammonia positron emission tomography: Association with myocardial flow reserve and prognosis in coronary artery disease

Background The evaluation of papillary muscle (PM) perfusion through existing perfusion imaging, including single-photon emission computed tomography and magnetic resonance imaging, is not possible. Therefore, this study sought to investigate the detection of PM ischemia in coronary artery disease (CAD) using nitrogen-13 (N-13) ammonia positron emission tomography (NH3PET) and its association with global myocardial flow reserve (MFR) and major adverse cardiac events (MACE). Methods Data of adenosine-stress NH3PET for 263 consecutive patients with known or suspected CAD were retrospectively analyzed. PM ischemia was defined as the absence of PM accumulation under stress conditions and PM presence at rest on high-resolution cine imaging derived from PET-computed tomography scanner with time-of-flight technology. The primary outcome was MACE. Results Of 263 patients, 30 experienced mean follow-up period of 910 days (MACE), while 31 (11.8%) presented PM ischemia. Compared to patients without PM ischemia, those with PM ischemia reported a significantly lower global MFR and a significantly higher rate of MACE (P< .0001). Conclusion NH3PET enables the detection of PM ischemia in approximately 10% of patients with known or suspected CAD. PM ischemia is associated with reduced global MFR and is an important sign in predicting prognosis.

Automated summary

This study found that NH3PET can be used to detect papillary muscle ischemia, which is present in approximately 10% of patients with known or suspected CAD. Papillary muscle ischemia is associated with reduced global MFR and increased rate of major adverse cardiac events. Papillary muscle ischemia is an important predictor of prognosis.