The mystery poor prognosticator! Pharmacologic stress MPI prevalence and predictors: Insights from the Middle East

Abstract

In this issue of The Journal, Dakik et al. compared the referral patterns of pharmacologic and physical stress myocardial perfusion imaging (MPI) at the American University of Beirut Medical Center (AUMC), a large tertiary hospital serving Lebanon and the Middle East region.The message from this study would seem to be of significant importance to the daily practice of nuclear cardiology in many developing countries worldwide. The authors concluded that patients referred for pharmacologic stress were older and predominantly female compared to patients undergoing exercise stress. The pharmacologic stress patients also had a higher prevalence of diabetes mellitus and hypertension. The study also showed interesting differences between MPI data from the pharmacologic and physical stress groups. In the pharmacologic stress group, there was a higher prevalence of abnormal scans as well as a higher prevalence of ischemia on MPI and more frequent impaired left ventricular function with an ejection fraction \ 50%. The significant predictors for referral to pharmacologic stress were older age and diabetes mellitus. The authors showed similar results on a separate analysis including only patients with no history of prior CAD. They also showed similar results for both genders.The message coming from this article provokes several important questions and thoughts.What are the reasons behind differences in utilization of pharmacologic MPI between developed and developing countries?The cost and lack of availability of the new pharmacologic stressors represent a challenge to world regions where CAD mortality is continuously on the rise. How does this affect the availability and utilization of MPI in these regions?Metabolic syndrome is one of the great health problems in the world right now, particularly in developing countries, and is tightly linked to physical inactivity and sedentary life styles. It represents a link between higher referral to pharmacologic rather than physical exercise, and at the same time is an important direct cause of high-risk myocardial perfusion studies. How can optimal utilization of MPI help in addressing this global critical health problem?Among the limitations of this study, as stated by the authors, is the relatively small number of patients, and that the study is a single-center investigation that may not necessarily represent the whole country or the region. Also, there was no follow-up data in this study. However, to our knowledge this is the first prospective study comparing referral patterns and predictors of pharmacologic versus physical MPI coming out of the Middle East region.The robust data over many decades from multiple scientific reports and meta-analysis have proved the clear effectiveness of both physical and pharmacologic MPI studies as diagnostic and prognostic tools in the evaluation of patients with known or suspected CAD. 1 Moreover, in terms of safety, all pharmacologic stressors used in conjunction with MPI have proved safety margin comparable to treadmill exercise, and to each...