Significance of Microalbuminuria in Predicting Silent Myocardial Ischemia in Patients with Type 2 Diabetes Using Myocardial Perfusion Imaging

Fractional Flow Reserve Derived from Computer Tomography in Asymptomatic Patients with Type 2 Diabetes and Albuminuria without Significant Coronary Artery Stenosis—A Surrogate for Coronary Microvascular Dysfunction?

Background: Type 2 diabetes mellitus (T2D) patients with albuminuria have coronary microvascular dysfunction (CMD). Fractional flow reserve assessed by coronary computed tomography angiography (FFRct) is dependent on the structure and function of the microcirculation and is likely influenced by CMD. We aimed to evaluate if asymptomatic patients with T2D who had no significant coronary artery stenosis but had been diagnosed with albuminuria had lower value of nadir FFRct compared to asymptomatic patients with T2D and no albuminuria. Methods and results: This was a cross-sectional study which compared the mean nadir FFRct values in coronary arteries in patients with T2D who had no symptoms of angina. The T2D patients were divided into two groups (albuminuria and no albuminuria) with albuminuria being defined as albumin–creatinine-ratio (ACR) ≥30 milligram per gram. The nadir FFRct values were compared between the two groups for left anterior descendent artery (FFRct-LAD), circumflex artery (FFRct-CX), and right coronary artery (FFRct-RCA) by using a two-sample Wilcoxon rank-sum (Mann–Whitney) test. Ninety-eight patients without albuminuria and 26 patients with albuminuria were included. No significant differences in mean values were detected for FFRct-CX 0.86 ± 0.07 and 0.88 ± 0.0, FFRct-RCA 0.88 ± 0.05 and 0.88 ± 0.07, or for FFRct-LAD 0.82 ± 0.07 and 0.82 ± 0.07 in patients with albuminuria and without albuminuria, respectively. Conclusion: In this observational study, we did not find that FFRct was affected by CMD. Therefore, it is not a surrogate for microvascular dysfunction in asymptomatic T2D patients with albuminuria.

Silent coronary artery disease in type 2 diabetes: a narrative review on epidemiology, risk factors, and clinical studies

Silent coronary artery disease (CAD) is one of the manifestations of heart disease that particularly affects subjects with type 2 diabetes mellitus (T2DM). From a clinical point of view, silent CAD represents a constant challenge for the diabetologist, who has to decide whether a patient could or could not be screened for this disease. In the present narrative review, several aspects of silent CAD are considered: the epidemiology of the disease, the associated risk factors, and main studies conducted, in the last 20 years, especially aimed to demonstrate the usefulness of the screening of silent CAD, to improve cardiovascular outcomes in type 2 diabetes.

Renal Function, Albumin-Creatinine Ratio and Pulse Wave Velocity Predict Silent Coronary Artery Disease and Renal Outcome in Type 2 Diabetic and Prediabetic Subjects

INTRODUCTION

Silent coronary heart disease is frequently undetected in type 2 diabetes mellitus (DM2) and pre-diabetes determined by glucose intolerance (GI). Pulse wave velocity (PWV) and albumin-creatinine ratio (ACR) have been considered markers of cardiovascular mortality, coronary heart disease and chronic renal failure.

AIM

To evaluate the incidence of coronary artery disease (CAD) and the relationship between urinary albumin-creatinine ratio, glomerular filtration rate (GFR) and PWV in type 2 DM with silent CAD.

METHODS

We analyzed 92 individuals (44 male), 49 (60±7y) type 2 DM non-insulin dependents and 43 prediabetics (43±4y), with Grade I-II hypertension and no symptoms of CAD. All type 2 DM patients were under antidiabetic treatment with A1C hemoglobin between 5.5 and 6.5%. Every patient underwent a myocardial perfusion SPECT scan. In those subjects with ischemic patterns, coronary angiography was performed. In addition, PWV, glomerular filtration rate, and ACR were evaluated.

STATISTICS

mean±SEM, and ANOVA among groups.

RESULTS

48.59% of DM2 and 25.58% of GI patients had silent coronary artery had silent coronary artery disease and higher ACR, PWV and reduced GFR. Higher ACR and PWV and reduced GFR. DM2 and GI showed a negative relationship between GFR and ACR. Moreover, this relation was also observed in different levels of GFR (>60 ml/min and <60ml.min (p<0.05) in patients with CAD, suggesting a cardio-renal interaction in DM2.

CONCLUSION

Higher PWV, lower GFR and ACR predict the incidence of CAD in DM2. Dysglycemic individuals also represent a group of higher risk for coronary artery disease with similar predictors as in DM2. Diabetic and prediabetics still develop renal microalbuminuria. Thus, PWV seems to represent a reliable marker of renal impairment and coronary artery disease.