Temporal trends in results of 9170 myocardial perfusion imaging studies (2004 to 2013)

BACKGROUND: To assess the frequency of normal and abnormal myocardial perfusion imaging (MPI) in a consecutive cohort of patients from Pakistan over a period of 8.5 years. MATERIAL AND METHODS: We assessed 9170 patients who had undergone stress-rest MPI between January 2004 and June 2013. Patients were assessed for change in demographics, risk factors, and frequency of abnormal and normal MPI. RESULTS: Overall mean age and male predominance of studied cohort was ≈ 55 years and ≈ 55:45 (M:F), respectively, with no appreciable decline or rise. Marked decline in exercise as mode of stress (from 71% to 35%, p value significant) was noted during the study period. Regarding the risk factors for CAD, only hypertension was noted to have a significant rising trend during the study period. Trend of MPI results over study period was found non-significant from 2004 till 2006 but from 2007 onward (except 2008), a marginal but significant decline in abnormal MPIs (from 45% to 42%; significant p value) and rise in normal MPI (from 55% to 58%; significant p value) was noted. CONCLUSIONS: We conclude that over the past 8.5 years, a marginal but significant decline in abnormal and a rise in normal MPIs trend have been observed. An exorbitant rise in use of vasodilator as a method of stress was also observed. We envisaged a follow-up study to ascertain lower negative predictive value of vasodilator as a possible reason and till than results of this and other such studies must be read cautiously.