Cardiac imaging for risk stratification in diabetes

Incremental effect of coronary obstruction on myocardial microvascular dysfunction in type 2 diabetes mellitus patients evaluated by first-pass perfusion CMR study

BACKGROUND

Type 2 diabetes mellitus (T2DM) frequently coexists with obstructive coronary artery disease (OCAD), which are at increased risk for cardiovascular morbidity and mortality. This study aimed to investigate the impact of coronary obstruction on myocardial microcirculation function in T2DM patients, and explore independent predictors of reduced coronary microvascular perfusion.

METHODS

Cardiac magnetic resonance (CMR) scanning was performed on 297 T2DM patients {188 patients without OCAD [T2DM(OCAD -)] and 109 with [T2DM(OCAD +)]} and 89 control subjects. CMR-derived perfusion parameters, including upslope, max signal intensity (MaxSI), and time to maximum signal intensity (TTM) in global and segmental (basal, mid-ventricular, and apical slices) were measured and compared among observed groups. According to the median of Gensini score (64), T2DM(OCAD +) patients were subdivided into two groups. Univariable and multivariable linear regression analyses were performed to identify independent predictors of microcirculation dysfunction.

RESULTS

T2DM(OCAD -) patients, when compared to control subjects, had reduced upslope and prolonged TTM in global and all of three slices (all P < 0.05). T2DM(OCAD +) patients showed a significantly more severe impairment of microvascular perfusion than T2DM(OCAD -) patients and control subjects with a more marked decline upslope and prolongation TTM in global and three slices (all P < 0.05). From control subjects, through T2DM(OCAD +) patients with Gensini score ≤ 64, to those patients with Gensini score > 64 group, the upslope declined and TTM prolonged progressively in global and mid-ventricular slice (all P < 0.05). The presence of OCAD was independently correlated with reduced global upslope (β =  - 0.104, P < 0.05) and global TTM (β = 0.105, P < 0.05) in patients with T2DM. Among T2DM(OCAD +) patients, Gensini score was associated with prolonged global TTM (r = 0.34, P < 0.001).

CONCLUSIONS

Coronary artery obstruction in the context of T2DM exacerbated myocardial microcirculation damage. The presence of OCAD and Gensini score were independent predictors of decreased microvascular function.

TRIAL REGISTRATION

Retrospectively registered.

Plaque assessment by coronary CT angiography may predict cardiac events in high risk and very high risk diabetic patients: A long-term follow-up study

BACKGROUND AND AIMS

The aim of the present study is to evaluate whether advanced coronary atherosclerosis analysis by CCTA may improve prognostic stratification among diabetic patients at high cardiovascular risk (CV risk).

METHODS AND RESULTS

The study population consisted of 265 consecutive diabetic patients at high CV risk who underwent CCTA for suspected CAD between January 2011 and December 2016. For every patients both traditional and advanced, qualitative and quantitative coronary plaque analysis were performed. The occurrence of cardiac death, ACS, and non-urgent revascularization were recorded at follow-up. Among the 265 patients enrolled, 21 were lost to follow-up, whereas 244 (92%) had a complete follow-up (mean 45 ± 22 months) and were classified at high (n = 67) or very high cardiovascular risk (n = 177), according to ESC Guidelines. A total of 63 events were recorded (3 Cardiac Death, 3 NSTEMI, 8 unstable angina, 36 late non-urgent revascularization and 13 non-cardiac death) in 57 different patients. Elevated fibro-fatty plaque volume was the only predictor of events over age, gender and traditional risk factor when ACS and MACE were considered as end-points [HR (95% CI) 6.01 (1.65-21.87), p = 0.006 and 3.46 (2.00-5.97); p < 0.001].

CONCLUSION

The present study confirms the prognostic role of advance coronary atherosclerosis evaluation beyond risk factors and stenosis severity, even in diabetics. Despite the very high cardiovascular risk of study population, a not negligible portion (23%) of patients exhibited totally normal coronaries.

Type 1 Diabetes in Pregnancy: A Review of Complications and Management

BACKGROUND

Pre-gestational diabetes can pose significant risk to the mother and infant, thus requiring careful counselling and management. Since Saint Vincent's declaration in 1989, adverse maternal and fetal outcomes, such as preeclampsia, perinatal mortality, congenital anomalies, and macrosomia, continue to be associated with type 1 diabetes. Although pregnancy is not considered an independent risk factor for the development of new onset microvascular complications, it is known to exacerbate pre-existing microvascular disease. Strict glycaemic control is the optimal management for pre-existing type 1 diabetes in pregnancy, as raised HbA1C is associated with increased risk of maternal and fetal complications. More recently, time in range on Continuous Glucose Monitoring glucose profiles has emerged as another useful evidence-based marker of fetal outcomes.

OBJECTIVES

This review summarises the complications associated with pre-gestational type 1 diabetes, appropriate evidence-based management, including preparing for pregnancy, intrapartum and postpartum care.

METHODS

A structured search of the PubMed and Cochrane databases was conducted. Peer-reviewed articles about complications and management guidelines on pre-gestational type 1 diabetes were selected and critically appraised.

RESULTS

One hundred and twenty-three manuscripts were referenced and appraised in this review, and international guidelines were summarised.

CONCLUSION

This review provides a comprehensive overview of the recurring themes in the literature pertaining to type 1 diabetes in pregnancy: maternal and fetal complications, microvascular disease progression, and an overview of current guideline-specific management.

Role of microvascular dysfunction in left ventricular dysfunction in type 2 diabetes mellitus

BACKGROUND

Although microvascular disease (mVD) has been linked to poor cardiovascular outcomes in diabetes mellitus, the contribution of mVD to diabetic cardiomyopathy (DC) is unexplored. We investigated whether LV systolic and diastolic dysfunction is associated with mVD in T2DM.

METHODS

We recruited 32 asymptomatic patients with T2DM (age 71 ± 4 years, 31% females) from a community-based population. All underwent a comprehensive echocardiogram at baseline including assessment of global longitudinal strain (GLS) and diastolic function. Adenosine stress perfusion on cardiac magnetic resonance imaging (CMR) was performed in all patients. Coronary sinus flow (CSF) was measured offline at rest and peak stress with coronary flow reserve (CFR) calculated as the ratio of global stress and rest CSF.

RESULTS

Resting CSF was reduced in 15 (47%) compared to 4 (13%) with adenosine-stress (p = 0.023). Overall, CFR was observed to be reduced in the cohort (2.38 [IQR 2.20]). Abnormal CFR was not associated with diabetes duration of ≥10 years or poor glycaemic control. CFR was not associated with abnormal GLS (OR 1.04 [95% CI 0.49, 2.20], p = 0.93). However, a modest negative correlation was observed with e' and CFR (r = -0.49, p = 0.004).

CONCLUSION

This pilot study did not show correlation between subclinical systolic dysfunction and a novel MRI biomarker of microvascular disease. However, there was a weak correlation with myocardial relaxation. Confirmation of these findings in larger studies is indicated.

Understanding the multifaceted mechanisms of diabetic wound healing and therapeutic application of stem cells conditioned medium in the healing process

Mesenchymal stem cells (MSCs) transplantation seems to be a promising new therapy for diabetic wound healing (DWH), and currently, arrays of MSCs from various sources ranging from umbilical, adipose to dental sources are available as a treatment modality for this disease. However, it now appears that only a fraction of transplanted cells actually assimilate and survive in host tissues suggesting that the major mechanism by which stem cells participate in tissue repair are most likely related to their secretome level. These include a wide range of growth factors, cytokines, and chemokines, which can be found from the conditioned medium (CM) used to culture the cells. Basic studies and preclinical work confirm that the therapeutic effect of CMs are comparable with the application of stem cells. This review describes in detail the wound healing process in diabetes and the cellular and biological factors that influence the process. Subsequently, through a comprehensive literature search of studies related to wound healing in diabetics, we aim to provide an overview of scientific merits of using MSCs-CM in the treatment of diabetic wound as well as the significant caveats, which restricts its potential use in clinical set-ups. To our best knowledge, this is one of the first review papers that collect the importance of stem cells as an alternative treatment to the DWH. We anticipate that the success of this treatment will have a significant clinical impact on diabetic wounds.

Asymptomatic coronary artery disease in a Norwegian cohort with type 2 diabetes: a prospective angiographic study with intravascular ultrasound evaluation

Aims

The prevalence of asymptomatic coronary artery disease (CAD) in type 2 diabetes (T2D) is unclear. We investigated the extent and prevalence of asymptomatic CAD in T2D patients by utilizing invasive coronary angiography (ICA) and intravascular ultrasound (IVUS), and whether CAD progression, evaluated by ICA, could be modulated with a multi-intervention to reduce cardiovascular (CV) risk.

Methods

Fifty-six T2D patients with ≥ 1 additional CV risk factor participated in a 2 year randomized controlled study comparing hospital-based multi-intervention (multi, n = 30) versus standard care (stand, n = 26), with a pre-planned follow-up at year seven. They underwent ICA at baseline and both ICA and IVUS at year seven. ICA was described by conventional CAD severity and extent scores. IVUS was described by maximal intimal thickness (MIT), percent and total atheroma volume and compared with individuals without T2D and CAD (heart transplant donors who had IVUS performed 7–11 weeks post-transplant, n = 147).

Results

Despite CV risk reduction in multi after 2 years intervention, there was no between-group difference in the progression of CAD at year seven. Overall, the prevalence of CAD defined by MIT ≥ 0.5 mm in the T2DM subjects was 84%, and as compared to the non-T2DM controls there was a significantly higher atheroma burden (mean MIT, PAV and TAV in the T2D population were 0.75 ± 0.27 mm, 33.8 ± 9.8% and 277.0 ± 137.3 mm³ as compared to 0.41 ± 0.19 mm, 17.8 ± 7.3% and 134.9 ± 100.6 mm³ in the reference population).

Conclusion

We demonstrated that a 2 year multi-intervention, despite improvement in CV risk factors, did not influence angiographic progression of CAD. Further, IVUS revealed that the prevalence of asymptomatic CAD in T2D patients is high, suggesting a need for a broader residual CV risk management using alternative approaches.

Trial registration Clinical trials.gov id: NCT00133718 (https://clinicaltrials.gov/ct2/show/NCT00133718)

Electronic supplementary material

The online version of this article (10.1186/s12933-019-0832-2) contains supplementary material, which is available to authorized users.

Prognostic Value and Therapeutic Perspectives of Coronary CT Angiography: A Literature Review

Coronary stenosis severity is both a powerful and a still debated predictor of prognosis in coronary artery disease. Coronary computed tomographic angiography (CCTA) has emerged as a noninvasive technique that enables anatomic visualization of coronary artery disease (CAD). CCTA with newer applications, plaque characterization and physiologic/functional evaluation, allows a comprehensive diagnostic and prognostic assessment of otherwise low-intermediate subjects for primary prevention. CCTA measures the overall plaque burden, differentiates plaque subtypes, and identifies high-risk plaque with good reproducibility. Research in this field may also advance towards an era of personalized risk prediction and individualized medical therapy. It has been demonstrated that statins may delay plaque progression and change some plaque features. The potential effects on plaque modifications induced by other medical therapies have also been investigated. Although it is not currently possible to recommend routinely serial scans to monitor the therapeutic efficacy of medical interventions, the plaque modulation, as a part of risk modification, appears a feasible strategy. In this review we summarize the current evidence regarding vulnerable plaque and effects of lipid lowering therapy on morphological features of CAD. We also discuss the potential ability of CCTA to characterize coronary atherosclerosis, stratify prognosis of asymptomatic subjects, and guide medical therapy.

Diabetes and Subclinical Coronary Atherosclerosis

It is well known that diabetic patients have a high risk of cardiovascular events, and although there has been a tremendous effort to reduce these cardiovascular risks, the incidence of cardiovascular morbidity and mortality in diabetic patients remains high. Therefore, the early detection of coronary artery disease (CAD) is necessary in those diabetic patients who are at risk of cardiovascular events. Significant medical and radiological advancements, including coronary computed tomography angiography (CCTA), mean that it is now possible to investigate the characteristics of plaques, instead of solely evaluating the calcium level of the coronary artery. Recently, several studies reported that the prevalence of subclinical coronary atherosclerosis (SCA) is higher than expected, and this could impact on CAD progression in asymptomatic diabetic patients. In addition, several reports suggest the potential benefit of using CCTA for screening for SCA in asymptomatic diabetic patients, which might dramatically decrease the incidence of cardiovascular events. For these reasons, the medical interest in SCA in diabetic patients is increasing. In this article, we sought to review the results of studies on CAD in asymptomatic diabetic patients and discuss the clinical significance and possibility of using CCTA to screen for SCA.

Coronary Atherosclerosis Assessment by Coronary CT Angiography in Asymptomatic Diabetic Population: A Critical Systematic Review of the Literature and Future Perspectives

The prognostic impact of diabetes mellitus (DM) on cardiovascular outcomes is well known. As a consequence of previous studies showing the high incidence of coronary artery disease (CAD) in diabetic patients and the relatively poor outcome compared to nondiabetic populations, DM is considered as CAD equivalent which means that diabetic patients are labeled as asymptomatic individuals at high cardiovascular risk. Lessons learned from the analysis of prognostic studies over the past decade have challenged this dogma and now support the idea that diabetic population is not uniformly distributed in the highest risk box. Detecting CAD in asymptomatic high risk individuals is controversial and, what is more, in patients with diabetes is challenging, and that is why the reliability of traditional cardiac stress tests for detecting myocardial ischemia is limited. Cardiac computed tomography angiography (CCTA) represents an emerging noninvasive technique able to explore the atherosclerotic involvement of the coronary arteries and, thus, to distinguish different risk categories tailoring this evaluation on each patient. The aim of the review is to provide a wide overview on the clinical meaning of CCTA in this field and to integrate the anatomical information with a reliable therapeutic approach.

Prognostic Value of Coronary Computed Tomography Angiography in Patients With Diabetes: A Meta-analysis

OBJECTIVE

The usefulness of coronary computed tomography angiography (CTA) for the evaluation of coronary artery disease (CAD) in patients with diabetes is ambiguous. We therefore performed a meta-analysis of studies reporting event rates and hazard ratios (HR) to determine the prognostic value of CTA in this patient population.

RESEARCH DESIGN AND METHODS

We searched PubMed and Embase up to November 2015. Study subjects' characteristics, events (all-cause mortality or cardiac death, nonfatal myocardial infarction, unstable angina pectoris, stroke, revascularization), and events excluding revascularization were collected. We calculated the prevalence of obstructive and nonobstructive CAD on CTA, annualized event rates, and pooled unadjusted and adjusted HR using a generic inverse random model.

RESULTS

Eight studies were eligible for inclusion into this meta-analysis, with 6,225 participants (56% male; weighted age, 61 years) with a follow-up period ranging from 20 to 66 months. The prevalence of obstructive CAD, nonobstructive CAD, and no CAD was 38%, 36%, and 25%, respectively. The annualized event rate was 17.1% for obstructive CAD, 4.5% for nonobstructive CAD, and 0.1% for no CAD. Obstructive and nonobstructive CAD were associated with an increased HR of 5.4 and 4.2, respectively. A higher HR for obstructive CAD was observed in studies including revascularization compared with those that did not (7.3 vs. 3.7, P = 0.124).

CONCLUSIONS

CTA in patients with diabetes allows for safely ruling out future events, and the detection of CAD could allow for the identification of high-risk patients in whom aggressive risk factor modification, medical surveillance, or elective revascularization could potentially improve survival.

Predictors of coronary heart disease in Japanese patients with type 2 diabetes: Screening for coronary artery stenosis using multidetector computed tomography

Aims/Introduction:  Multidetector computed tomography (MDCT) coronary angiography has been applied as a tool for non‐invasive evaluation of the coronary arteries. The purpose of the present study was to evaluate the effectiveness of MDCT in screening for coronary artery disease (CAD), and to identify the indications for screening in diabetes patients with CAD.

Materials and Methods:  The study population consisted of 52 Japanese type 2 diabetes patients who underwent examination with a 64‐slice MDCT scanner, electrocardiogram (ECG), echocardiography and ultrasonographic scanning of the carotid arteries. Regression analysis was carried out to assess the correlation between MDCT results and CAD risk factors.

Results:  Stenosis of the coronary artery was detected in 19/52 patients. Of the 19 patients, 7 patients had no symptoms, including chest pain, and no ischemic changes in ECG. Significant differences between patients with stenosis and those without stenosis were detected by mean IMT (1.21 vs 0.95 mm), and duration of diabetes (20 vs 13 years). Two‐tailed χ²‐test showed that a duration of diabetes of more than 20 years (odds ratio 6.222) and more than 1.1 mm of mean‐IMT (odds ratio 4.600) significantly correlated with the stenosis.

Conclusions:  It was shown that MDCT is useful in detecting coronary artery stenosis in diabetic patients without symptoms of CAD or ECG abnormality, and the predictors of CAD are mean IMT and duration of diabetes. It is recommended that patients with more than 1.1 mm mean IMT at the carotid artery and/or more than 20 years duration of diabetes should be screened for CAD by carrying out MDCT.

Myocardial perfusion imaging for evaluation of suspected ischemia and its relationship with glycemic control in South African subjects with diabetes mellitus

BACKGROUND

The relationship between myocardial perfusion imaging (MPI) abnormalities, diabetes mellitus, and glucose control in South African populations is unknown. It was hypothesized that in subjects undergoing MPI for suspected coronary artery disease (CAD), those with diabetes would have more extensive perfusion defects and that diabetes control would influence MPI abnormalities. The aim of this study was to examine the relationship between the severity of CAD diagnosed with MPI in subjects with and without diabetes and to determine the relationship between diabetes control and extent of CAD.

METHODS

This study was a retrospective chart review of 340 subjects in whom MPI scans were performed over a 12-month period.

RESULTS

Subjects with diabetes had a higher prevalence of abnormal MPI, with more extensive ischemia, compared with subjects without diabetes (85.6% versus 68%; odds ratio 2.81, P<0.01). Glycated hemoglobin ≥7.0% was associated with a higher risk of abnormal MPI, with more extensive ischemia, compared with subjects having diabetes and glycated hemoglobin <7.0% (odds ratio 2.46, P=0.03) and those without diabetes (odds ratio 4.55, P=0.0001).

CONCLUSION

Subjects with diabetes have more extensive myocardial ischemia when compared with subjects without diabetes. Furthermore, poorer diabetes control is associated with more abnormalities on MPI scanning.

Prognostic value of multidetector computed tomography coronary angiography in diabetes: excellent long-term prognosis in patients with normal coronary arteries

OBJECTIVE

To assess the prognostic role of multidetector computed tomography coronary angiography (MDCT-CA) in patients with diabetes with suspected coronary artery disease (CAD). Use of MDCT-CA is increasing in patients with suspected CAD. However, data supporting its prognostic value in patients with diabetes are limited.

RESEARCH DESIGN AND METHODS

Between January 2006 and September 2007, 429 consecutive diabetic patients were prospectively studied with MDCT-CA for detecting the presence and assessing the extent of CAD (disease extension and coronary plaque scores). Patients were classified according to the presence of normal coronary arteries and nonobstructive (<50%) and obstructive (≥50%) coronary lesions. The composite rates of hard cardiac events (cardiac death, nonfatal myocardial infarction, unstable angina) and all cardiac events (including revascularization) were the end points of the study.

RESULTS

Twenty-four patients were excluded because MDCT-CA data were not able to be interpreted. Of the remaining 405 patients, clinical follow-up (mean 62 ± 9 months) was obtained in 390 (98%). Multivariate analysis showed that predictors of hard and all events were obstructive CAD, three-vessel CAD, and left main coronary artery (LMCA) disease. Cumulative event-free survival was 100% for hard and all events in patients with normal coronary arteries, 78% for hard events and 56% for all events in patients with nonobstructive CAD, and 60% for hard events and 16% for all events in patients with obstructive CAD. Three-vessel CAD and LMCA disease were associated with a higher rate of hard cardiac events.

CONCLUSIONS

MDCT-CA provides long-term prognostic information for patients with diabetes with suspected CAD, showing excellent prognosis when there is no evidence of atherosclerosis and allowing risk stratification when CAD is present.

Diagnostic Accuracy of 64-Slice MDCT Coronary Angiography for the Assessment of Coronary Artery Disease in Korean Patients with Type 2 Diabetes

BACKGROUND

A 64-slice multidetector computed tomography (MDCT) is well known to be a useful noninvasive form of angiography for the general population, but not for certain patients with diabetes. The aim of this study was to investigate the diagnostic accuracy and usefulness of 64-slice MDCT coronary angiography for detecting coronary artery disease in Korean patients with type 2 diabetes mellitus (T2DM).

METHODS

A total of 240 patients were included, 74 of whom had type 2 diabetes (M:F=40:33; 41.8±9.5 years). We compared significant coronary stenosis (>50% luminal narrowing) in MDCT with invasive coronary angiography (ICA) by segment, artery, and patient. We also evaluated the influence of obesity and coronary calcium score on MDCT accuracy.

RESULTS

Of the 4,064 coronary segments studied, 4,062 segments (T2DM=1,109) were assessed quantitatively by both MDCT and ICA, and 706 segments (T2DM=226) were detected as a significant lesion by ICA in all patients. Sensitivity, specificity, as well as positive and negative predictive values for the presence of significant stenosis in T2DM were: by segment, 89.4%, 96.4%, 85.8%, and 97.4%, respectively; by artery (n=222), 95.1%, 92.9%, 94.4%, and 93.8%, respectively; by patients (n=74), 98.4%, 100.0%, 98.4%, and 90.0%, respectively. Regardless of presence of diabetes, there was no significant difference in diagnostic accuracy. Obesity (≥25 kg/m(2)) and coronary calcium score did not also affect the diagnostic accuracy of MDCT.

CONCLUSION

The 64-slice MDCT coronary angiography was found to have similar diagnostic accuracy with ICA, regardless of diabetes. These results suggest MDCT may be helpful to reduce unnecessary invasive studies for patients with diabetes.

Microalbuminuria predicts silent myocardial ischaemia in type 2 diabetes patients

PURPOSE

Myocardial ischaemia is frequently silent in patients with type 2 diabetes. Although it has been proposed as a potential screening tool, the role of myocardial perfusion single photon emission computed tomography (MPS) has recently been questioned, due to the low prevalence of positive scans and the low rate of cardiac events. The aim of this study was to assess if pretest clinical variables can identify a subgroup of asymptomatic patients with type 2 diabetes at risk of silent myocardial ischaemia and a subsequent poor outcome

METHODS

This prospective study included 77 patients (50 men, mean age 63 ± 9 years) with type 2 diabetes and no known coronary artery disease (CAD) or angina pectoris who underwent gated MPS to screen for CAD between March 2006 and October 2008. MPS images were interpreted using a semiquantitative visual 20-segment model to define summed stress, rest and difference scores. Ischaemia was defined as a sum difference score (SDS) ≥2. Patients were followed-up (median 4.1 years, range 0.8 - 6.1 years) and cardiac hard events (cardiac death or nonfatal myocardial infarction) were recorded.

RESULTS

Silent ischaemia was detected in 25 of the 77 patients (32 %). Specifically, 10 patients (13 %) had mild ischaemia (SDS 2 to ≤4) and 15 patients (19 %) had severe ischaemia (SDS >4). In univariate binary logistic analysis, microalbuminuria was the only significant predictor of silent ischaemia on MPS (odds ratio 4.42, 95 % CI 1.27 - 15.40; P = 0.019). The overall accuracy of microalbuminuria for predicting silent ischaemia was 71.4 % and was 89.6 % for predicting severe ischaemia. Kaplan-Meier curves showed no significant group differences in 5-year cardiac event-free survival between patients with and those without microalbuminuria, or between patients with SDS ≥2 and those with SDS <2. In contrast, 5-year event-free survival was significantly lower in patients with SDS >4 than in patients with SDS ≤4: 55.6 % (95 % CI 39.0 - 72.2 %) vs. 94.5 % (95 % CI: 91.4 - 97.6 %), respectively (Breslow test, chi-square 20.9, P < 0.001). Median cardiac event-free survival was not observed in the whole group, while the 25th percentile of cardiac event-free survival was reached only in patients with SDS >4 (2.3 years). In univariate Cox regression analysis, SDS >4 predicted cardiac event-free survival (hazard ratio 12.87, 95 % CI 2.86 - 27.98; P = 0.001), while SDS ≥2 did not (hazard ratio 2.78, 95 % CI 0.62 - 12.46, P = 0.16).

CONCLUSION

In this group of patients with type 2 diabetes, microalbuminuria was the only predictor of silent ischaemia on MPS. Assessment of microalbuminuria should be routinely considered among the first risk stratification steps for CAD in patients with type 2 diabetes, even though severe ischaemia on MPS is a major predictor of cardiac event-free survival.

The relationship between glycosylated hemoglobin and myocardial perfusion imaging

BACKGROUND

The relationship between long-term glucose control (measured by glycosylated hemoglobin [HgbA1C]) and myocardial perfusion imaging (MPI) abnormalities in symptomatic diabetic patients has not been studied.

HYPOTHESIS

We hypothesized that diabetic patients with poorly controlled HgbA1C would have more abnormal MPI compared to both patients without diabetes and diabetic patients with tighter glycemic control.

METHODS

This was a retrospective evaluation of 1037 consecutive patients referred for MPI. All patients completed a 1-day MPI protocol. The electronic medical records were accessed for demographics and relevant medical history.

RESULTS

Diabetic patients had a higher risk of abnormal MPI (including ischemia, infarction, and mixed ischemia/infarction) compared to nondiabetic patients (relative risk [RR] = 1.77). The populations with suboptimal (HgbA1C ≥ 7%) and poor (HgbA1C ≥ 8%) glycemic control had significantly higher risk of abnormal MPI (RR = 1.78 and 2.17, respectively) compared to nondiabetic patients. Coronary angiography supported the MPI results; 66% of diabetic patients had coronary artery disease (CAD), which was higher than the 53% of patients without diabetes found to have CAD.

CONCLUSIONS

The importance of strict glycemic control to reduce cardiovascular complications in diabetic patients is well known. Our study shows a significantly higher risk of abnormal MPI and CAD in diabetic patients with suboptimal and poor long-term glycemic control, further emphasizing the need for aggressive risk factor modification to minimize vascular complications from DM.

Cryoplasty versus conventional balloon angioplasty of the femoropopliteal artery in diabetic patients: long-term results from a prospective randomized single-center controlled trial

The purpose of this study was to investigate the immediate and long-term results of cryoplasty versus conventional balloon angioplasty in the femoropopliteal artery of diabetic patients. Fifty diabetic patients (41 men, mean age 68 years) were randomized to cryoplasty (group CRYO; 24 patients with 31 lesions) or conventional balloon angioplasty (group COBA; 26 patients with 34 lesions) of the femoropopliteal artery. Technical success was defined as <30% residual stenosis without any adjunctive stenting. Primary end points included technical success, primary patency, binary in-lesion restenosis (>50%), and freedom from target lesion recanalization. Cox proportional hazards regression analysis was performed to adjust for confounding factors of heterogeneity. In total, 61.3% (19 of 31) in group CRYO and 52.9% (18 of 34) in group COBA were de novo lesions. More than 70% of the lesions were Transatlantic Inter-Society Consensus (TASC) B and C in both groups, and 41.4% of the patients in group CRYO and 38.7% in group COBA suffered from critical limb ischemia. Immediate technical success rate was 58.0% in group CRYO versus 64.0% in group COBA (p = 0.29). According to 3-year Kaplan-Meier estimates, there were no significant differences with regard to patient survival (86.8% in group CRYO vs. 87.0% in group COBA, p = 0.54) and limb salvage (95.8 vs. 92.1% in groups CRYO and COBA, respectively, p = 0.60). There was a nonsignificant trend of increased binary restenosis in group CRYO (hazard ratio [HR] 1.3; 95% CI 0.6-2.6, p = 0.45). Primary patency was significantly lower in group CRYO compared with group COBA (HR 2.2; 95% CI 1.1-4.3, p = 0.02). Significantly more repeat intervention events because of recurrent symptoms were required in group CRYO (HR 2.5; 95% CI 1.2-5.3, p = 0.01). Cryoplasty was associated with lower primary patency and more clinically driven repeat procedures after long-term follow-up compared with conventional balloon angioplasty.

[Macrovascular diabetic complications: clinical characteristics, diagnosis and management]

Diabetes mellitus (DM) is an independent risk factor for coronary heart disease, stroke, peripheral arterial disease and heart failure, which are the main causes of death in these patients. Moreover, patients with DM and cardiovascular disease have a worse prognosis than nondiabetics, present lower short-term survival, higher risk of recurrence of the disease and a worse response to the treatments proposed. In the last decades, diagnostic and therapeutic progress had already shown benefits concerning cardiovascular risk reduction in these patients, but their absolute mortality risk is still twice that of non-diabetic patients. Because of this, the adoption of intensive treatment, with strict cardiovascular risk factor control, is a priority. The present study presents the main clinical characteristics and also the practical approach for screening, diagnosis and treatment of patients with diabetic macrovascular disease.

Myocardial perfusion scintigraphy in asymptomatic diabetic patients: a critical review

The increasing prevalence of diabetes mellitus and the associated high cardiovascular risk has made the non-invasive identification of silent coronary heart disease in diabetic individuals an important issue. This strategy could identify higher risk asymptomatic patients with diabetes mellitus in whom coronary revascularization may improve the outcome beyond that achieved by currently recommended medical management. Stress myocardial perfusion imaging has been shown to be effective in detecting coronary heart disease and predicting adverse cardiac events in asymptomatic diabetic patients. However, the clinical utility of myocardial perfusion scintigraphy is debated intensively due to the paucity of prospective and outcome based evidence. The controversy stems from several observational studies, epidemiologic data and cost-effectiveness analyses. Thus, although several authors and professional organizations advocate the use of stress imaging for screening higher risk asymptomatic diabetic patients, others are cautious in recommending any kind of stress testing in that population. This review is based on a broad survey of the literature and discusses the potential role of stress myocardial perfusion scintigraphy in screening asymptomatic diabetic subjects for coronary heart disease in the current era and in relation with other non-invasive screening tools.

Screening asymptomatic patients with diabetes for unknown coronary artery disease: does it reduce risk? An open-label randomized trial comparing a strategy based on exercise testing aimed at revascularization with management based on pharmacological/behavioural treatment of traditional risk factors. DADDY-D Trial (Does coronary Atherosclerosis Deserve to be Diagnosed and treated early in Diabetics?)

BACKGROUND

Coronary artery disease is the leading cause of morbidity and mortality in patients with type 2 diabetes. Screening for asymptomatic coronary artery disease with treatment by means of revascularization seems to be an appealing option for prevention. The utility of such a strategy has never been challenged in a randomized trial.

METHODS/DESIGN

In the present study a cohort of diabetic patients without any symptoms and without known coronary artery disease will be screened at two diabetes outpatients services. Those with intermediate or high risk (equal or greater than 10% according to the Italian risk chart) will be asked to participate and enrolled. They will be seen and followed in order to provide the best adherence to medical therapy. Half of the patients will be randomized to undergo an exercise tolerance testing while the other group will continue to be regularly seen at diabetes outpatients services. Best medical/behavioral therapy will be offered to both groups. Those patients with a positive exercise tolerance testing will be studied by coronary angiography and treated according to the severity of coronary lesions by percutaneous stenting or surgery.The objective of the study is to evaluate the efficacy of the screening strategy aimed at revascularization. A cost-effectiveness analysis will be performed at the end of the follow up.

DISCUSSION

The study will provide useful information about prevention and treatment of diabetic patients at high risk of coronary events. It will be made clearer if detection of silent coronary artery disease has to be recommended and followed by treatment. Given the simplicity of the study protocol, it will be easily transferable to the real world.

TRIAL REGISTRATION

(ClinicalTrials.gov): NCT00547872.

Clinical insights from the Fenofibrate Intervention and Event Lowering in Diabetes study: a community practice perspective

Achieving adequate control of cardiovascular risk in type 2 diabetes mellitus (DM) is crucially important; however, the atherogenic dyslipidaemia (including low high-density lipoprotein cholesterol and hypertriglyceridaemia) typically encountered in type 2 DM is often managed inadequately. Evidence from the Fenofibrate Intervention and Event Lowering in Diabetes study suggests that fenofibrate reduces the risk of long-term macrovascular and microvascular type 2 diabetic complications, especially in patients demonstrating features of the metabolic syndrome. Fenofibrate represents a useful treatment option for controlling cardiovascular risk in type 2 diabetes patients in the community setting.

Glycemia and cardiovascular disease in type 1 diabetes mellitus

OBJECTIVE

To evaluate the role of glycemic control in the development of cardiovascular disease (CVD) in type 1 diabetes mellitus (DM).

METHODS

We review the literature regarding coronary atherosclerosis, coronary artery calcification, and the epidemiologic studies related to the role of glycemia and the classic risk factors for coronary artery disease (CAD) in type 1 DM.

RESULTS

Four prospective studies (Wisconsin Epidemiologic Study of Diabetic Retinopathy, EURODIAB, Steno Diabetes Center Study of Adults With Type 1 DM, and Pittsburgh Epidemiology of Diabetes Complications study) do not show that glycemic control predicts CAD occurrence. Findings from the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications study show that compared with conventional insulin therapy, intensive insulin therapy reduces CVD among patients with type 1 DM and is associated with lower prevalence of coronary artery calcification. The discrepancies between the findings from the Diabetes Control and Complications Trial/Epidemiology of Diabetes Interventions and Complications study and the Pittsburgh Epidemiology of Diabetes Complication study are likely due to differences between the study populations and the lower prevalence of renal disease in the former study. Besides duration of DM and albuminuria/overt nephropathy, insulin resistance is a major determinant of CAD associated with type 1 DM.

CONCLUSIONS

Discrepant study results regarding the relationship between glycemia and CAD/coronary artery calcification may be related to the prevalence of renal disease and the presence of the metabolic syndrome. Published data suggest that addressing traditional risk factors including albuminuria, the metabolic syndrome, and inflammatory markers is better for preventing and treating CAD than focusing exclusively on glycemic control, which is still necessary for preventing microvascular complications. Furthermore, there is a synergistic effect of glycemic control and albuminuria on the development of CVD.

Differences in heart rate response to adenosine and regadenoson in patients with and without diabetes mellitus

BACKGROUND

Adenosine and regadenoson increase heart rate (HR) when used as stress agents to produce coronary hyperemia due to direct sympathetic stimulation. We hypothesized that the HR response will be lower in patients with than in those without diabetes mellitus (DM).

METHODS

We studied the HR response (percentage maximal increase) in 2,000 patients in The ADenoscan Versus regAdenosoN Comparative Evaluation for Myocardial Perfusion Imaging (ADVANCE MPI 1 and 2) Trials with known DM status.

RESULTS

There were 643 patients with a history of DM (65.4 +/- 0.4 years, 32% women) and 1,357 patients with no DM (65.5 +/- 0.3 years, 29% women). Compared with non-DM, the DM group had higher HR at baseline (68.4 +/- 0.48 vs 65.2 +/- 0.31 beat/min, P < .001) and smaller HR response after adenosine or regadenoson administration (29.4% +/- 0.64% vs 36.1% +/- 0.54%, P < .001). Insulin therapy was associated with further blunting in the HR response (25.9% +/- 1.0% vs 31.2% +/- 0.8%, P < .001). After adjusting for beta-blocker intake, baseline HR, age, gender, renal function, systolic blood pressure, and left ventricular systolic function, DM independently accounted for a decrease in the HR response.

CONCLUSIONS

The HR response to adenosine and regadenoson in patients with DM is blunted. If additional studies confer an agreement between traditional tests for determination of autonomic neuropathy and this measure, then examination of HR response to these agents during myocardial perfusion imaging might add prognostic power.

[Cardiovascular disease in type 1 diabetes mellitus]

The association between type 1 diabetes and coronary heart disease has become very clear since the late 1970. It has been demonstrated that there is an important increased risk in morbidity and mortality caused by coronary artery disease in young adults with type 1 diabetes compared with the non diabetic population. The underlying pathogeneses is still poorly understood. While the role of glycemic control in the development of microvascular disease complication is well established its role in CVD in patients with DM1 remains unclear with epidemiologic studies reporting conflicting data. Recent findings from the DCCT/EDIC showed that prior intensive diabetes treatment during the DCCT was associated with less atherosclerosis, largely because of reduced level of HbA1c during the DCCT. The improvement of glycemic control itself appeared to be particularly effective in younger patients with shorter duration of the disease. Other analyses suggested the glycemia may have a stronger effect on CAD in patients without than in those with albuminúria. Other major determinants of coronary artery disease are the components of metabolic syndrome and the surrogate measure of insulin resistence: eGDR. It is proposed that patients with DM1 should have aggressive medical therapy, risk factor modification and careful monitoring not only of his blood sugar but also of the other processes involved in the atherosclerotic process, mostly the ones with family history of type 2 diabetes.

Why to screen heart disease in diabetes

The expanding diabetic epidemic and the high risk of cardiovascular events in diabetic patients suggest that screening heart disease in this population is an important issue. Nonetheless, the advisability of large-scale screening in asymptomatic individuals with diabetes is debated, because available techniques are expensive and have suboptimal diagnostic accuracy. Moreover, all diabetic patients should be treated aggressively as if they all had a positive screening test, because diabetes could be considered a coronary risk equivalent. In this article, we underline the importance of an early diagnosis of coronary artery disease and heart failure in diabetic patients, suggesting that positive screening tests have significant implications in clinical management.

Noninvasive measures of cardiovascular changes in diabetes mellitus

PURPOSE OF REVIEW

Advances in noninvasive medical technology have led to more aggressive pursuit of cardiovascular disease detection in patients with diabetes mellitus. Studies measuring carotid intima-media thickness, arterial stiffness and coronary artery calcification have documented early markers of cardiovascular disease. Such markers have gained popularity for research and clinical use. This paper reviews recent studies using noninvasive technology for detection and monitoring of cardiovascular disease as it pertains to diabetes patients.

RECENT FINDINGS

Studies published in the review period have utilized noninvasive techniques to monitor subclinical cardiovascular disease in diabetes patients, including carotid intima-media thickness to evaluate carotid atherosclerosis, pulse wave velocity and pulse wave analysis to measure arterial stiffness, electron beam computed tomography to evaluate coronary artery calcification, and magnetic resonance imaging to study cardiovascular plaque. These techniques have shown promising results and will have useful application for diabetes patients in the future.

SUMMARY

Noninvasive testing is being redefined to include new techniques for detection and monitoring of cardiovascular changes. In the appropriate clinical setting, these tests offer novel approaches to monitoring - each with its own benefits and caveats. Further refinement of techniques will lead to increased applicability and improved ability for early detection of subclinical cardiovascular disease.