Ammar Ahmed Chaudhry MD, Presenter: Nothing to Disclose

Maryam Gul, Abstract Co-Author: Nothing to Disclose

Luke Gerges DO, Abstract Co-Author: Nothing to Disclose

Eric J. Feldmann MD, Abstract Co-Author: Nothing to Disclose

In low-intermediate coronary artery disease (CAD) risk patients with a negative EKG and normal troponin levels, CCTA demonstrates a 95-99% negative predictive value allowing it to safely exclude CAD-related cardiogenic chest pain. However, the suboptimal positive predictive value (50-90%) typically results in recommending noninvasive stress testing for “borderline obstructive” 50-69% diameter stenoses. We aim to evaluate the incremental clinical utility of stress nuclear myocardial perfusion imaging (MPI) in patients with 50-69% and 70-99% stenoses by CCTA criteria.  

In this retrospective study, 1000 patients who presented to the ED with symptoms of ACS were evaluated using 64- or 320-detector row ECG-gated CCTA. Patients with obstructive 50-70% diameter stenoses on CCTA were recommended to obtain a follow-up stress test (typically nuclear MPI) to exclude stress-induced ischemia. Patients receiving MPI within one month of their CCTA were included in the study. We identified 100 such patients and performed a chart review of the MPI results. Note, none of the patients had significant pre-procedure ECG findings at rest or troponin elevation at the time of either CCTA or pre-nuclear stress test.

In 100 patients, (ages 32-89; males 59, females 41), 95% of the patients with intermediate risk of ACS on CCTA were identified to have a completely normal nuclear stress test (i.e. asymptomatic and no ECG changes). All these patients were noted to have less than 70% stenosis as measured on CCTA. 5% of patients had positive stress test (defined as ST-depression +/- symptoms) and all of these patients were noted to have greater than 70% stenosis. 4/5 of these patients had LAD involvement, 3/5 had LCx and 2/5 had RCA involvement.

Patients with intermediate coronary artery stenosis without complete occlusion have been a conundrum for physicians; the dilemma being whether to observe or proceed with further work up. Our study shows that patients with intermediate risk of ACS should be recommended to have follow-up nuclear stress test if CCTA reveals coronary vessel occlusion of 70% or greater. Patients with coronary vessel occlusion of less than 70-percent can be observed with continued clinical management of modifiable risk factors.

Patients with coronary vessel occlusion of less than 70-percent on CCTA can be observed with continued clinical management of modifiable risk factors.

Chaudhry, A, Gul, M, Gerges, L, Feldmann, E, Incremental Clinical Utility of Stress Nuclear Myocardial Perfusion Imaging (MPI) in Patients with Stenotic but Non-occlusive Disease as Diagnosed by CCTA Criteria.  Radiological Society of North America 2014 Scientific Assembly and Annual Meeting, - ,Chicago IL. http://archive.rsna.org/2014/14008967.html