Background : Mortality after a normal stress-rest myocardial SPECT is low. Stress only testing is associated with reduced radiation and a shorter test duration. However there is little information in real life about its safety
Objective : To compare mortality rate of myocardial perfusion SPECT (MPI) performed in the traditional stress-rest or rest-stress sequence with the stress only protocol.
Methods : Patients without previous myocardial infarction, with normal LVEF and LV size who underwent a normal MPI with Tc99M between 01/2010 and 12/2014 (n=2980)were followed up for death of any cause.
Results : The median follow-up was 828 (841-876) days. A normal MPI SPECT was performed with stress only in 1504 patients and with stress-rest in 1476 patients. Patients in the stress only group were significantly (p<0.001) younger (63+13 vs 66+12), more likely to be women (67.9% vs 46.7%) , to be imaged in the prone position (26% vs 16%) and to use Bruce rather than dipyridamole protocol (59 Vs 52%). They were significantly (p<0.001) less likely to suffer from hypertension (60 vs 70%), diabetes (27 vs 32%), and hypercholesterolemia (62 vs 70%), previous percutaneous coronary angioplasty (14 vs 31%) or coronary bypass surgery (4.4% vs 10.0%). Annual mortality rate was 2.1% in the stress only group and 2.0% in the stress-rest group (p=0.9). In the stress only group, 389 patients (26%) were considered to have a normal MPI SPECT after being imaged in the prone position. Their annual mortality was 2% (p=0.91 with supine imaging)
Conclusions : Normal stress only MPI SPECT is usually performed in a younger and healthier population than traditional stress-rest or rest stress MPI SPECT and associated with a similar total mortality.
