Exertional dyspnea in patients with diabetes mellitus: evaluation by myocardial perfusion scintigraphy

ABSTRACT

Coronary Artery disease is a major cause of morbidity and mortality in patients with diabetes mellitus. They have high incidence of silent ischemia as pain perception is blunt in such patients. As a result many of them present with atypical symptoms like exertional dyspnea, instead of classical chest pain as their chief presenting complaint. We evaluated incidence of myocardial perfusion scintigraphic [MPS] evidence of coronary artery disease [CAD] in patients with type II diabetes mellitus without known CAD presenting with exertional dyspnea as chief presenting complaint. We conducted stress-redistribution SPECT MPS with intravenous injection of 93-130 MBq [2.5-3.5 mCi] 201T1-thallous chloride in 290 subjects with type II diabetes mellitus having exertional dyspnea [SOB] as study group [151 male and 139 female, age range 20 to 76 years]. 138 asymptomatic subjects with type II diabetes mellitus also underwent same procedure as control group [56 male and 82 female, age range 29 to 65 years]. Upon the bases of clinical history, study groups were further divided into three categories, Esob=exertional SOB [n=54], AcpD= atypical chest pain with dyspnea [n=114] and TcpD=typical chest pain with dyspnea [n=122]. We conducted visual analysis on reconstructed tomographic slices. CAD was present in 34.78% control [ischemia 23.91%, myocardial infarction 10.87%] and in 66.9% study group subjects [ischemia 49.31%, myocardial infarction 17.87%]. Incidence of CAD was high in Esob group than control [48.15% vs. 34.78%], AcpD group than Esob [64.91% vs. 48.15%] and TcpD group than AcpD [77.05% vs. 64.91%]. Stress induced ischemia [SII] was more frequent in Esob group than control [37.04% vs. 23.91%] and AcpD group than Esob [50% vs. 37.04%]. However, its occurrence was almost similar in TcpD and AcpD groups [54.1% vs. 50%]. Observed frequency of myocardial infarction was almost same in control [10.87%] and Esob [11.11%] group. Incidence of myocardial infarction was higher in AcpD group than control [14.91% vs. 10.87%] and TcpD group than AcpD [22.95% vs. 14.91%]. Our study concludes that incidence of myocardial ischemia and infarction is quite high in patients with type-II diabetes mellitus presenting with exertional dyspnea. Presence of chest pain further increases the likelihood of CAD in these patients. We should perform MPS in all patients with type II diabetes mellitus who present with exertional dyspnea, even if they have no chest pain