Long-term additive prognostic value of heterogeneity myocardial perfusion imaging of SPECT over clinical and ischemia in high-risk diabetic patients

Currently, type II diabetes mellitus (DM), has reached epidemic levels in the world. Risk stratification is paramount in patients with DM due to not all patients with DM have a similar cardiovascular (CV) risk. Imaging has thus taken a central role in the assessment of CV health and in the diagnosis, evaluation, and management of CV diseases in DM. The prognostic value of relative myocardial perfusion imaging (MPI) using single-photon emission tomography (SPECT) is well established. Consistent with this data, DM patients with abnormal relative MPI results also have higher rates of death and non-fatal MI than those with normal results. However, DM patients with normal stress tests also have higher rates of cardiac events than non-DM counterparts with normal tests and despite that most guidelines recommend a systematic screening of asymptomatic high risk patients with diabetes for silent ischemia, real benefit of this strategy has not been demonstrated compared with optimal medical treatment without ischemia detection. New more sensitive noninvasive imaging to assess MPI abnormalities is needed.

Coronary microvascular dysfunction (CMVD) is closely associated with coronary artery disease; it is an independent risk factor and predicts future coronary events or clinically manifest disease up to 10 years later. To date, non-invasive measurement of CMVD myocardial perfusion heterogeneity imaging (MPHI) by SPECT is not available into clinical practice. We developed a new method to study the CMVD by SPECT. In this study, we use a mathematic technique from entropy analysis to provide precise, objective, automated quantification of MPHI at stress and at rest with SPECT. We sought to assess the prognostic value of MPHI in high-risk diabetic patients being investigated for ischemia. Therefore, we prospectively evaluated the incremental prognostic value of MPHI in patients with type 2 DM during long-term follow-up. Coronary microvascular dysfunction is closely associated with coronary artery disease; it is an independent risk factor and predicts future coronary events or clinically manifest disease up to 10 years later.

In this study, we use a new mathematic technique from entropy analysis to provide precise, objective, automated quantification of perfusion heterogeneity at stress with camera SPECT. This method may be a non-invasive imaging to assess coronary microvascular dysfunction.

The main hypothesis is that the presence of myocardial perfusion heterogeneity is predictive of 5-year cardiovascular events in patients referred to the Nuclear Cardiology Department for routine evaluation of known or suspected CAD in diabetes patients with very high risk cardiovascular.

Inclusion Criteria:

• Type 2 diabetes mellitus
• Clinical indication for myocardial perfusion imaging
• Diabetics with very high risk of cardiovascular events defined by the SCORE risk

Exclusion Criteria:

• Pregnant woman
• Breast feeding women
• Severe comorbidity with life expectancy 6 months

high-risk cardiovascular type 2 diabetic patients