Noninvasive assessment of the diabetic patient for coronary artery disease

MDCT assessment of CAD in type-2 diabetic subjects with diabetic neuropathy: the role of Charcot neuro-arthropathy

OBJECTIVES

To compare the CACS and CAD severity assessed by MDCT in neuropathic type-2 diabetic patients with and without Charcot-neuroarthropathy (CN).

METHODS

Thirty-four CN asymptomatic-patients and 36 asymptomatic-patients with diabetic-neuropathy (DN) without CN underwent MDCT to assess CACS and severity of CAD. Patients were classified as positive for significant CAD in presence of at least one stenosis >50 % on MDCT-coronary-angiography (MDCT-CA). Groups were matched for age, sex and traditional CAD risk-factors. The coronary-angiography (CA) was performed in all patients with at least a significant stenosis detected by MDCT-CA, both as reference and eventually as treatment.

RESULTS

CN patients showed higher rates of significant CAD in comparison with DN subjects [p < 0.001], while non-significant differences were observed in CACS (p = 0.980). No significant differences were also observed in CACS distribution in all subjects for stenosis ≥/<50 % (p = 0.814), as well as in both groups (p = 0.661 and 0.559, respectively). The MDCT-CA showed an overall diagnostic-accuracy for significant CAD of 87%.

CONCLUSIONS

These preliminary data suggest that CN-patients have a higher prevalence of severe CAD in comparison with DN-patients, while coronary plaques do not exhibit an increased amount of calcium. MDCT may be helpful to assess the CV risk in such asymptomatic type-2-diabetic patients with autonomic-neuropathy.

KEY POINTS

Type 2-diabetic-patients with CN result having more severe coronary artery plaque-burden. MDCT-CA may stratify the CV risk in type 2-diabetic-patients with CN. Adequate diagnostic is mandatory for optimal management of type 2-diabetic-patients with CN.

Strategies to enhance cardiovascular disease prevention in patients with diabetes

PURPOSE OF REVIEW

To describe current strategies to enhance cardiovascular disease (CVD) prevention in patients with abnormal glucose regulation.

RECENT FINDINGS

Early detection of glucose abnormalities and a multifactorial approach to all modifiable risk factors are effective strategies to reduce the burden of CVD in patients with diabetes mellitus. Available evidence suggests that an overly aggressive approach to lowering of glucose may contribute to complications; different hypoglycaemic agents may vary in the likelihood with which their use may give rise to complications. Thus, a decrease of glucose levels below that recommended in available guidelines is not recommended.

SUMMARY

Given its increasing prevalence and its substantial concomitant risk for CVD, diabetes mellitus can no longer be perceived as an endocrine disorder only bearing high risk of microvascular complications. Further research involving prospective clinical trials will be necessary to clarify the benefits of early detection and treatment of diabetes in preventing the subsequent development or exacerbation of CVD.

Noninvasive diagnosis of coronary artery disease in patients with diabetes by dobutamine stress real-time myocardial contrast perfusion imaging

OBJECTIVE

The aim of this study was to assess the accuracy of real-time myocardial contrast perfusion imaging (MCPI) during dobutamine stress in the diagnosis and localization of coronary artery disease (CAD) in patients with diabetes. Myocardial contrast echocardiography is a new technique that allows evaluation of myocardial perfusion. Its utility in diabetic patients has not been defined.

RESEARCH DESIGN AND METHODS

Dobutamine-atropine stress test was performed in conjunction with MCPI using Optison or Definity at rest and at peak stress in 128 patients with diabetes and suspected CAD who underwent coronary angiography within 1 month. CAD was defined as > or =50% stenosis in one or more coronary artery. MCPI was considered diagnostic of CAD in the presence of reversible perfusion abnormalities. The normalcy rate of MCPI was additionally determined in 18 asymptomatic nondiabetic patients with low probability.

RESULTS

CAD was detected in 101 (79%) patients by angiography. Reversible perfusion abnormalities were detected in 90 patients with and 13 patients without CAD. The overall sensitivity of MCPI was 89% (95% CI 83-95), specificity 52% (33-71), and accuracy 81% (75-88). Reversible abnormalities were detected in two or more vascular distributions in 44 of 56 patients with multivessel CAD and in 8 of 63 patients without (sensitivity 68%, specificity 87%, positive predictive value 84%, and accuracy 79%). Regional sensitivity was 75% (65-85) for left anterior descending CAD, 71% (60-83) for left circumflex, and 67% (55-78) for right CAD. MCPI was normal in 16 of the 18 patients with low clinical probability of CAD (normalcy rate 89%).

CONCLUSIONS

MCPI is a useful noninvasive technique for the diagnosis and localization of CAD in diabetic patients. The extent of perfusion abnormalities can identify patients with multivessel CAD with a moderate sensitivity and high specificity.

Risk reduction of cardiac events by screening of unknown asymptomatic coronary artery disease in subjects with type 2 diabetes mellitus at high cardiovascular risk: an open-label randomized pilot study

BACKGROUND

Evaluated the efficacy of reducing the risk of cardiac events by a preclinical diagnosis of CAD in subjects with type 2 diabetes mellitus with 2 or more cardiovascular risk factors.

METHODS

One hundred forty-one subjects with type 2 diabetes mellitus without known cardiac disease and asymptomatic, aged >45 to <76 years, were randomized into the screening arm for CAD (71 patients) or to the control arm (70 patients). The screening consisted in performing an exercise electrocardiogram test and dipyridamole stress echocardiography; if 1 test was abnormal, coronary angiography is done. Screening was positive in 15 subjects (21.4%). At coronary angiography, which was performed in 14 of 15 patients, stenoses > or =50% of vessel diameter were present in 9 patients, of these 4 underwent coronary artery bypass grafting and 4 underwent percutaneous transluminal coronary angioplasty. Stenoses <50% of vessel diameter were present in 5 patients.

RESULTS

Mean follow-up was 53.5 months (range, 42-54 months). During this period, 1 major (myocardial infarction) and 3 minor events (angina) occurred in the screening arm. Eleven major and 4 minor events occurred in the control arm. In the screened arm, the proportion of all events was significantly less (P = .018) (RR .226, 95% CI 0.707-0.719, P = .012); the proportion of major to minor events was significantly less (P = .006) (RR .07, 95% CI 0.0087-0.565, P = .013).

CONCLUSIONS

The preclinical diagnosis of CAD is effective in reducing the risk of cardiac events, especially major events, in subjects with type 2 diabetes mellitus at high cardiovascular risk.

Diabetes mellitus in pregnancy

This article reviews normal and abnormal carbohydrate metabolism in pregnancy, with an emphasis on the challenges that are faced by those who care for the pregnant woman who has hyperglycemia. The growing problem of type 2 diabetes in pregnancy, the controversial use of oral antihyperglycemic agents for the treatment of gestational diabetes, and the long-term issue of diabetes prevention in those whose hyperglycemia resolves postpartum are also addressed.

Diagnosis of CAD in patients with diabetes: who to evaluate

Effective diagnosis and treatment of coronary artery disease (CAD) are key to the management of patients with diabetes. Although the use of specialized cardiac testing for CAD screening in asymptomatic patients varies widely and is the source of current controversy, evidence is emerging on the prevalence and predictors of asymptomatic ischemia in diabetic patients. Accurate diagnosis and risk stratification are essential in symptomatic patients with known or suspected CAD. Noninvasive cardiac testing has an important role in these patients, although evaluation for revascularization with cardiac catheterization is warranted in high-risk circumstances. This article reviews recent information that may help guide the clinician in the appropriate use of cardiac testing in diabetic patients.

Cardiac events in 735 type 2 diabetic patients who underwent screening for unknown asymptomatic coronary heart disease: 5-year follow-up report from the Milan Study on Atherosclerosis and Diabetes (MiSAD)

OBJECTIVE

To report the cardiac events in type 2 diabetic outpatients screened for unknown asymptomatic coronary heart disease (CHD) and followed for 5 years.

RESEARCH DESIGN AND METHODS

During 1993, 925 subjects aged 40-65 years underwent an exercise treadmill test (ETT). If it was abnormal, the subjects then underwent an exercise scintigraphy. Of the 925 subjects, 735 were followed for 5 years and cardiac events were recorded.

RESULTS

At the entry of the study, 638 of the 735 followed subjects had normal ETT, 45 had abnormal ETT with normal scintigraphy, and 52 had abnormal ETT and abnormal scintigraphy. The 52 subjects with abnormal scintigraphy and ETT underwent a cardiological and diabetological follow-up; the subjects with just abnormal ETT had a diabetological follow-up only. During the follow-ups, 42 cardiac events occurred: 1 fatal myocardial infarction (MI), 20 nonfatal MIs, and 10 cases of angina in the 638 subjects with normal ETT; 1 fatal MI in the 45 subjects with normal scintigraphy; and 1 fatal MI and 9 cases of angina in the 52 subjects with abnormal scintigraphy. In these 52 subjects all cardiac events were significantly more frequent (chi(2) = 21.40, P < 0.0001) but the ratio of major (cardiac death and MI) to minor (angina) cardiac events was significantly lower (P = 0.002). Scintigraphy abnormality (hazard ratio 5.47; P < 0.001; 95% CI 2.43-12.29), diabetes duration (1.06; P = 0.021; 1.008-1.106), and diabetic retinopathy (2.371; P = 0.036; 1.059-5.307) were independent predictors of cardiac events on multivariate analysis.

CONCLUSIONS

The low ratio of major to minor cardiac events in the positive scintigraphy group may suggest, although it does not prove, that the screening program followed by appropriate management was effective for the reduction of risk of major cardiac events.