Yield of Diagnosis and Prediction of Patients Undergoing Both Stress Echocardiography and Stress Myocardial Perfusion Imaging

Background:  Stress echocardiography (SE) and stress myocardial perfusion imaging (MPI) SPECT are both recommended to assess CAD and to predict cardiac outcome. We investigated the yield of referring patients for both stress modalities.

Methods: During 2010 -2013, we sorted out from the cardiology data base, 320 patients who underwent both SE   and MPI within time interval of 6 months. Excluded patients who underwent intervention or cardiac event during this period.  The patients were compared by, image quality, test results:  normal, abnormal (ischemia – scar/wall motion abnormality) non diagnostic/ equivocal test, additional findings. In patients who underwent coronary angiography within 3 months, correlation of stress MPI and SE with coronary catheterization was done. The patients were followed up for prediction of primary outcome (cardiac death and MI), and for secondary outcome (ACS, CABG, PCI).

Results: Of the 309 patients, there were 35% women and 54% had CAD. Time interval between SE and stress MPI was 76 ±52 days. The first test was performed by SE in 201 (65%) patients. Image quality: adequate/inadequate, 99 % and 1% by MPI and 82% and 18% by SE. Additional findings (valve disease, PHT, LVH...) were documented by SE in 31%.  Test results: normal, abnormal (ischemia/scar), equivocal; 60%, 16% and 24% for SE and 66%, 29% and 5% for MPI (x² =17, p<0.002).Forty three (14%) pts underwent coronary angiography; 11 were non obstructive and 32 had ≥ 70% stenosis. Significant correlation was found by stress MPI (x² =19.9, p<0.018) and non significant (x² =15.9, 0.069) by SE. During 4 yrs follow-up, there were: 11pts with primary outcome and 25 pts with secondary outcome which were not predicted by SE and significantly predicted by MPI (p<0.001)

Conclusion: The majority of patients underwent SE prior stress MPI and had  substantial equivocal or non diagnostic tests. About third of the patients had additional cardiac finding diagnosed by SE only. The catheterization results as well as cardiac outcome seems to be better identified by stress MPI.