title: Clinical value and severity of myocardial perfusion defects in asymptomatic diabetic patients with negative or weakly positive exercise treadmill test.
abstract: OBJECTIVE
  Although coronary artery disease (CAD) is the leading cause of death in type 2 diabetic patients, it is frequently asymptomatic. Myocardial perfusion imaging (MPI) is reported to show ischemia in a significant number of asymptomatic diabetic patients. We studied the prevalence and severity of myocardial perfusion defects in asymptomatic diabetic patients and its clinical impact.
  
  
  METHODS
  One hundred thirty consecutive asymptomatic patients, aged 35-65 years with type 2 diabetes mellitus and with no history of CAD and no cardiac symptoms were recruited in the study. Echocardiography, electrocardiography (ECG), routine laboratory tests and exercise treadmill test (ETT) were performed and patients with weakly positive or negative ETT underwent Dipyridamole MPI. Patients with positive ETT were referred to coronary angiography. Patients were followed for at least 17 months (mean 21.7 months) and any cardiac event was recorded.
  
  
  RESULTS
  We studied 81 female and 49 male patients with mean age of 51.8 years. Negative, weakly positive and positive ETT result was noted in 74.3%, 15% and 10.7% respectively. 75% of patients with positive ETT had coronary artery disease in angiography. Gated myocardial perfusion SPECT was done in 106 patients. MPI showed reversible defect in 26.9% of the patients with a mean summed stress score of 3.3±1.8. Follow up completed in 112 patients and only one patient with abnormal MPI underwent coronary angiography followed by PTCA. No cardiac death, MI, UA or hospital admission occurred among our patients during follow up (17-26 months). Mean stress end diastolic volume (EDV) was significantly higher in patients with reversible defect compared to patients without reversible defect based on MPI findings (62.0±31.6 Vs 48.5±18.4 ml, P=0.04). Blood glucose and HbA1c were significantly higher in patients with ischemia compared to patients without ischemia (P<0.05). Meanwhile the ratio of TG to HDL was 6.06±3.2 in ischemic patients compared to 4.8±2.3 in normal subjects (P=0.03).
  
  
  CONCLUSIONS
  Reversible defects are commonly seen in myocardial perfusion SPECT in asymptomatic diabetic patients and are mild in severity and not associated with adverse cardiac events. Routine approach for detection of CAD beginning with ETT seems to be appropriate in these patients.
authors.affiliation: Nuclear Medicine Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Seyed Rasoul
authors.initials: SR
authors.lastname: Zakavi
authors.affiliation: Cardiology Department, Razavi Hospital, Mashhad, Iran.
authors.forename: Mehdi
authors.initials: M
authors.lastname: Taherpour
authors.affiliation: Endocrinology and Metabolism Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Zohreh
authors.initials: Z
authors.lastname: Moossavi
authors.affiliation: Nuclear Medicine Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Ramin
authors.initials: R
authors.lastname: Sadeghi
authors.affiliation: Nuclear Medicine Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Vahidreza Dabbagh
authors.initials: VD
authors.lastname: Kakhki
authors.affiliation: Endocrinology and Metabolism Research Center, Mashhad University of Medical Sciences, Mashhad, Iran.
authors.forename: Haleh
authors.initials: H
authors.lastname: Rokni
keywords: Coronary artery disease; Diabetes mellitus; Gated myocardial perfusion SPECT; Silent Ischemia