VALIDATION OF PROGNOSTIC AND NEGATIVE PREDICTIVE VALUES OF NORMAL CARDIAC PERFUSION STUDY IN THE LOCAL POPULATION

Abstract

The aim of this study was to evaluate theprognostic value of a normal MPI in our population. PATIENTS AND METHOD: This study included 413 patients with normal MPI (with adequate stress) performed with sestaMIBI. Out of 413 patients, 217 were male and 196 were female with mean age 52.4 ± 9.8 years (median 52 years). The study was indicated for chest pain diagnosis in 330 (80%) and for the assessment of functional capacity in remaining 83 (20%) patients. The cardiac risk factors were prevalent including hypertension in 92 (22.3%), diabetes in 52 (12.6%) and dyslipidemia in 52 (12.6%). Furthermore, 21.5% patients had >2 risk factors. 248 (60%) individuals underwent dynamic stress following Bruce or Modified Bruce Protocol and end points were achievement of >85% target heart rate, chest pain or appearance of significant ECG changes. Remaining 165 (40%) individuals had dipyridamole intervention (standard protocol). A stress-rest (one day protocol) SPECT study was acquired using single head ECAM (Siemens) or double head Toshiba GCA-7200A gamma cameras. These patients were followed up for 18 months ± 5 months and occurrences of hard cardiac events (MI or cardiac death) were asked on telephone. RESULTS: The observed cardiac deaths were 3/413 (0.73%) and non-fatal MIs were seen in 4/413 (0.97%) on 18 months follow up. The observed cardiac mortality rate for patients with normal MPI was 0.73%. Risk adjusted (controlling for age, sex and type of stress) overall cardiac survival exceeded 99.27%. For women and men, the average cardiac survival was 99% and 99.5% respectively (p=0.001). Additionally for patients undergone exercise, the annualized survival rate was 99.6% and 98.8% for those who had dipyridamole intervention. CONCLUSION: A normal sestaMIBI SPECT study with adequate stress is associated with annualized cardiac death rate of 0.5% and a negative predictive value of 98.33%. Furthermore, these statistics of our population are comparable with most of the published studies.