Authors:

G Daquarti¹ , H Sanabria¹ , D Rosa¹ , M Cornelli¹ , M Gobbo¹ , C Rapallo¹ , M Vera¹ , E Aguirre¹ , D Coronel¹ , N Blanco¹ , N Perez Balino¹ , O Masoli¹ , A Meretta¹ , ¹Cardiovascular Institute of Buenos Aires (ICBA) - Buenos Aires - Argentina ,

Background: Diabetes mellitus is associated with high risk of coronary artery disease. Coronary microvascular dysfunction (CMD) leads an increased risk of cardiovascular events in diabetic patients even in absence of epicardial coronary artery disease or normal perfusion rest-stress studies. With the new Cadmium Zinc Telluride (CZT) Gamma Cameras, high resolution gated spect images are obtained and coronary flow reserve (CFR) assessment can be done using Technetium-99m based perfusion tracers. 

Purpose: The aim of this study was to investigate the prevalence of CMD in type 2 diabetic patients
with normal rest-stress myocardial perfusion imaging using CZT-Spect.

Methods: 40 type 2 diabetic patients without history of cardiovascular disease were referred for gated spect perfusion dipyridamole rest-stress test and CFR assessment with DSpect® using Tc-99m MIBI. Normal perfusion images were defined visually by consensus of two experimented nuclear cardiologists and compared with normal database.  CFR was obtained by stress / rest flow ratio with 4DM® software. CMD was defined as CFR < 2.  Relationships between CFR and glycated haemoglobin, LDL-cholesterol and systolic blood pressure were determined. 

Results: Median CFR in diabetic patients was lower than healthy controls (1.86 vs 2.58; p<0,001). The prevalence of CMD in diabetics was 53% with gender differences between groups (table). No significant correlations between CFR,  glycated haemoglobin, LDL-cholesterol or systolic blood pressure were found.

Conclusion: We found a high prevalence of CMD in type 2 diabetic patients with normal rest-stress perfusion study. Females are more affected than men.