Lessons learned from the detection of ischemia in asymptomatic diabetics (DIAD) study

Gender differences in outcome in patients with diabetes mellitus

BACKGROUND

Diabetes mellitus is an independent risk factor in the development of coronary artery disease (CAD), myocardial infarction (MI), and cardiac death (CD). The major adverse cardiac events (MACEs) between men and women in diabetic patients stratified by CAD (previous MI and/or coronary revascularization, CR) were analyzed.

METHODS AND RESULTS

A cohort of 1327 consecutive diabetic patients (age 66.5 ± 9 years) underwent gated SPECT (single-photon emission computed tomography). During a mean follow-up of 4.7 ± 2.2 years post gated SPECT, MACEs (non-fatal MI, CD, and late CR) were evaluated according to gender stratified by CAD. Among diabetic patients without known CAD (N = 731), men had more MACEs (sHR 1.9;95%CI 1.2-3.2) than women. Among diabetic patients with known CAD (N = 596), there was no difference in MACEs in diabetic men and women (sHR 1.15;95%CI 0.73-1.8). Diabetic women with known CAD (n = 143) were the group with the highest risk (sHR 1.7; P = .041) for MACEs (4.5% MACEs/year, [95%CI 3.1%-6.4%]), compared to the remaining diabetic patients (N = 1184) (3% MACEs/year, [95%CI 2.6%-3.5%]).

CONCLUSIONS

The prognosis of diabetic patients for MACEs is different in men and women stratified by CAD. The worst prognosis for MACEs occurs in women with known CAD.

Cardiac outcomes 3 years after screening for asymptomatic coronary artery disease in patients with type 2 diabetes: value of myocardial perfusion imaging and coronary calcium score

OBJECTIVE

The aim of the study was to identify the possible association among myocardial perfusion imaging (MPI) variables, coronary calcium score (CCS), and adverse events at medium term in type 2 asymptomatic diabetes mellitus patients.

MATERIALS AND METHODS

Patients who participated in a first study that included a stress-rest MPI and a CCS assessment were asked to take part in this study. The present study protocol required a control single-photon emission computerized tomography after 3 years. Forty-one patients gave their informed consent.

RESULTS

Of the 41 patients, 13 (32%) showed perfusion defects at the initial MPI. Of them, at 3 years, five continued showing perfusion defects, whereas another two had new defects (incidence of ischemia of 17%). Thus, 61% of the initial positive MPIs were normal at 3 years (P=0.04). In these cases the therapy was modified between the two studies. Left ventricular ejection fraction at stress showed a slight increase at 3 years (P=NS). Ventricular volumes significantly decreased at 3 years (P<0.01). Three patients (7.3%) developed an event during the follow-up (FU): two noncardiac deaths and one non-ST elevation myocardial infarction. The only variables that showed a possible association with the occurrence of events at FU were a CCS higher than 100 and less than 5 metabolic equivalents (METS) reached during the stress test (P=0.01).

CONCLUSION

A CCS higher than 100 and a low functional capacity (<5 METS), but not an abnormal MPI, can be associated with cardiac events at 3-year FU in asymptomatic type 2 diabetic patients.

Progression to overt or silent CAD in asymptomatic patients with diabetes mellitus at high coronary risk: main findings of the prospective multicenter BARDOT trial with a pilot randomized treatment substudy

OBJECTIVES

The purpose of this study was to evaluate prevalence, progression, treatment, and outcome of silent coronary artery disease (CAD) in asymptomatic patients with diabetes (DM) at high coronary risk.

BACKGROUND

Despite the close association of diabetes and CAD, general CAD screening in asymptomatic patients with DM is discouraged even though outcome data in patients at high coronary risk are lacking.

METHODS

Prospective multicenter outcome study-with a pilot randomized treatment substudy. The study comprised 400 asymptomatic patients with DM (type 2) without history or symptoms of CAD at high CAD risk. They underwent clinical evaluation and myocardial perfusion single-photon emission computed tomography (MPS) at baseline and after 2 years. Patients with normal MPS received usual care; those with abnormal MPS received medical or combined invasive and medical management.

RESULTS

An abnormal MPS was found in 87 of 400 patients (22%). In patients with normal MPS, MACE occurred in 2.9% and ischemia or new scar in 3.2%. Patients with abnormal MPS had more MACE (9.8%; hazard ratio: 3.44; 95% confidence interval [CI]: 1.32 to 8.95; p = 0.011) and ischemia or new scar (34.2%; odds ratio: 15.91; 95% CI: 7.24 to 38.03; p < 0.001) despite therapy, resulting in "overt or silent CAD progression" of 35.6% versus 4.6% (odds ratio: 11.53; 95% CI: 5.63 to 24.70; p < 0.001). Patients with abnormal MPS randomized to medical versus invasive-medical strategies had similar event rates (p = 0.215), but more ischemic or new scar findings (54.3% vs. 15.8%; p < 0.001).

CONCLUSIONS

High-risk asymptomatic patients with DM and normal MPS (78%) have a low rate of first manifestations of CAD. Patients with abnormal MPS at baseline (22%) have a 7-fold higher rate of progression to "overt or silent CAD," despite therapy. Randomized patients' outcomes suggest that a combined invasive and medical strategy for silent CAD may reduce scintigraphic but not symptomatic CAD progression versus medical therapy alone. (Trial of Invasive versus Medical therapy of Early coronary artery disease in Diabetes Mellitus ISRCTN87953632).

[Incidence and prognostic value of ischemic heart disease in high risk cardiovascular asymptomatic diabetic patients detected by gated myocardial perfusion SPECT study]

AIM

To determine the clinical utility of the gated myocardial perfusion SPECT to detect silent ischemia in asymptomatic diabetic patients without previous coronary events and to evaluate the prognosis of this population.

MATERIAL AND METHODS

A retrospective study of 56 asymptomatic diabetics referred for a gated myocardial perfusion SPECT for diagnosis of ischemic disease was performed. The criteria for ischemia were: mild SDS<4, moderate SDS 4-8, severe SDS>8. A multivariable statistical analysis was carried out to identify possible predictive variables of an abnormal SPECT. The cardiovascular events were recorded up to December-2010.

RESULTS

A high proportion of the 56 patients had an abnormal perfusion study (46.4%), there being moderate-severe ischemia in 10.7%, necrosis with ischemia in 5.4% and necrosis in 7.1%. We found no statistical differences in the type of stress used (treadmill or dipyridamole). The patients had a high combination of cardiovascular risk factors. In the multivariate analysis, diabetic nephropathy was the only factor related to an abnormal SPECT (p=0.043). The events recorded in the follow-up were: 2 early revascularizations, 5 cardiology admissions, 10 non-cardiac related deaths. The existence of ischemia in the SPECT was significantly related to the appearance of cardiovascular events (p<0.05).

CONCLUSION

A gated myocardial perfusion SPECT in asymptomatic diabetics with high combination of cardiovascular risk factors detects silent ischemia in a significant proportion and this seems to be related to future coronary events. Diabetic nephropathy implies a greater likelihood of abnormal studies. However, the screening criteria in this population still need to be established for better performance and lower cost.