The inter-relationship of diabetes and left ventricular systolic function on outcome after high-risk myocardial infarction

QRS-T angle: is it a specific parameter associated with sudden cardiac death in type 2 diabetes? Results from the SURDIAGENE and the Mini-Finland prospective cohorts

AIMS/HYPOTHESIS

Type 2 diabetes is associated with a high risk of sudden cardiac death (SCD), but the risk of dying from another cause (non-SCD) is proportionally even higher. The aim of the study was to identify easily available ECG-derived features associated with SCD, while considering the competing risk of dying from non-SCD causes.

METHODS

In the SURDIAGENE (Survie, Diabete de type 2 et Genetique) French prospective cohort of individuals with type 2 diabetes, 15 baseline ECG parameters were interpreted among 1362 participants (mean age 65 years; HbA1c 62±17 mmol/mol [7.8±1.5%]; 58% male). Competing risk models assessed the prognostic value of clinical and ECG parameters for SCD after adjusting for age, sex, history of myocardial infarction, N-terminal pro b-type natriuretic peptide (NT-proBNP), HbA1c and eGFR. The prospective Mini-Finland cohort study was used to externally validate our findings.

RESULTS

During median follow-up of 7.4 years, 494 deaths occurred including 94 SCDs. After adjustment, frontal QRS-T angle ≥90° (sub-distribution HR [sHR] 1.68 [95% CI 1.04, 2.69], p=0.032) and NT-proBNP level (sHR 1.26 [95% CI 1.06, 1.50] per 1 log, p=0.009) were significantly associated with a higher risk of SCD. Nevertheless, frontal QRS-T angle was the only marker not to be associated with causes of death other than SCD (sHR 1.08 [95% CI 0.84, 1.39], p=0.553 ). These findings were replicated in the Mini-Finland study subset of participants with diabetes (sHR 2.22 [95% CI 1.05, 4.71], p=0.04 for SCD and no association for other causes of death).

CONCLUSIONS/INTERPRETATION

QRS-T angle was specifically associated with SCD risk and not with other causes of death, opening an avenue for refining SCD risk stratification in individuals with type 2 diabetes.

Low Quantitative Blush Evaluator score predicts larger infarct size and reduced left ventricular systolic function in patients with STEMI regardless of diabetes status

Type 2 diabetes mellitus (T2DM) and diminished myocardial perfusion increase the risk of heart failure (HF) and/or all-cause mortality during 6-year follow up following primary percutaneous coronary intervention (pPCI) for ST elevation myocardial infarction (STEMI). The aim of the present study was to evaluate the impact of myocardial perfusion on infarct size and left ventricular ejection fraction (LVEF) in patients with T2DM and STEMI treated with pPCI. This is an ancillary analysis of an observational cohort study of T2DM patients with STEMI. We enrolled 406 patients with STEMI, including 104 with T2DM. Myocardial perfusion was assessed with the Quantitative Myocardial Blush Evaluator (QUBE) and infarct size with the creatine kinase myocardial band (CK-MB) maximal activity and troponin area under the curve. LVEF was measured with biplane echocardiography using Simpson's method at admission and hospital discharge. Analysis of covariance was used for modeling the association between myocardial perfusion, infarct size and left ventricular systolic function. Patients with T2DM and diminished perfusion (QUBE below median) had the highest CK-MB maximal activity (252.7 ± 307.2 IU/L, P < 0.01) along with the lowest LVEF (40.6 ± 10.0, P < 0.001). Older age (p = 0.001), QuBE below median (p = 0.026), and maximal CK-MB activity (p < 0.001) were independent predictors of LVEF. Diminished myocardial perfusion assessed by QuBE predicts significantly larger enzymatic infarct size and lower LVEF among patients with STEMI treated with pPCI, regardless of diabetes status.

Cardiac Structure and Function and Diabetes-Related Risk of Death or Heart Failure in Older Adults

Background Whether cardiac structure and function abnormalities associated with dysglycemia are sufficient to explain the increased risk of death or heart failure (HF) remains unclear. Methods and Results We analyzed 6059 participants (mean age, 75±5 years; 58% women; and 22% Black individuals) who attended the ARIC (Atherosclerosis Risk in Communities) study visit 5 examination (2011-2013). Participants were categorized as no diabetes, pre-diabetes, and diabetes (on the basis of medical history and glycated hemoglobin values). We assessed whether diabetes modified the association between echocardiographic measures of cardiac structure and function and the composite of all-cause death or HF hospitalization and then estimated the extent to which the increased risk of the composite outcome associated with diabetes was explained by cardiac structure and function. Diabetes was prevalent in 33.5% of the subjects. Death or HF occurred in 1111 (18%) at a rate of 3.6 per 100 person-years. Both measures of cardiac structure and function and diabetes status were significantly associated with worse prognosis after accounting for clinical confounders. While diabetes was consistently associated with a higher risk of events, it did not significantly modify the association between cardiac abnormalities and the risk of death or HF, except for subjects with higher left atrial volume who showed higher relative risk of events (P for interaction <0.001). Measures of cardiac structure and function accounted for ≈16% of the increased risk of death or HF associated with diabetes. Similar results were observed analyzing subjects without prevalent heart disease. Conclusions In a biracial cohort of older adults, the increased risk of events associated with diabetes was partially explained by cardiac structure and function abnormalities.

Influence of diabetes mellitus interactions with cardiovascular risk factors on post-myocardial infarction heart failure hospitalizations

OBJECTIVE

There is a paucity of information regarding how cardiovascular risk factors (RF) modulate the impact of diabetes mellitus (DM) on the heart failure hospitalization (HFH) risk following an acute myocardial infarction (AMI).

METHODS

Adult survivors of an AMI were retrospectively identified from the 2014 US Nationwide Readmissions Database. The impact of DM on the risk for a 6-month HFH was studied in subgroups of RFs using multivariable logistic regression to adjust for baseline risk differences. Individual interactions of DM with RFs were tested.

RESULTS

Of 237,549 AMI survivors, 37.2% patients had DM. Primary outcome occurred in 12,934 patients (5.4%), at a 106% higher rate in DM patients (7.9% vs 4.0%, p < 0.001), which was attenuated to a 45% higher adjusted risk. Higher HFH risk in DM patients was consistent across subgroups and significant interactions were present between DM and other RFs. The increased HFH risk with DM was more pronounced in patients without certain HF RFs compared with those with these RFs [age < 65: OR for DM 1.84 (1.58-2.13) vs age ≥ 65: OR 1.34 (1.24-1.45); HF absent during index AMI: OR for DM 1.87 (1.66-2.10) vs HF present: OR 1.24 (1.14-1.34); atrial fibrillation absent: OR for DM 1.57 (1.46-1.68) vs present: OR 1.19 (1.06-1.33); P_interaction < 0.001 for all]. Similar results were noted for hypertension and chronic kidney disease.

CONCLUSIONS

AMI survivors with DM had a higher risk of 6-month HFHs. The impact of DM on the increased HFH risk was more pronounced in patients without certain RFs suggesting that more aggressive preventive strategies related to DM and HF are needed in these subgroups to prevent or delay the onset of HFHs.

Diabetes and heart failure notions from epidemiology including patterns in low-, middle- and high-income countries

About 463 million people are currently living with diabetes and 64 million with heart failure and in addition, substantial proportions of both diseases are undiagnosed. At ages above 65 years prevalence of diabetes is estimated to be around 19% and heart failure at least 10%. In the western world, incidence of both diabetes and heart failure are slightly decreasing while prevalent cases are increasing in high as well as middle and low-income countries due to a general increased longevity and successful prevention and treatment of cardiac disease and of diabetes complications. Therefore, we will see an increase of epidemic proportions of both diabetes and heart failure if novel preventive strategies are not appropriately introduced. Type 1 and type 2 diabetes are both major contributors to the development of heart failure and the combination of diabetes and heart failure severely affects prognosis. In addition, the changing faces of diabetes complications have resulted in heart failure more often being the first manifestation of cardiac complications. An updated scenario on diabetes and heart failure epidemiology to health care providers is important in order to direct resources towards effective preventive strategies.

Early left ventricular systolic dysfunction in asymptomatic patients with type 1 diabetes: a single-center, pilot study

AIMS

Prevalence and risk factors of pre-symptomatic left ventricular systolic dysfunction (LVSD) in individuals with type 1 diabetes (T1D) have not been adequately studied. The present cross-sectional study assessed the prevalence of early LVSD in asymptomatic patients with type 1 diabetes and investigated potential risk factors.

METHODS

Consecutive patients with T1D, free of cardiovascular disease and significant evident microvascular complications were examined. LVSD was assessed by speckle-tracking echocardiography and calculation of global longitudinal strain (GLS). Abnormal GLS was defined as a value>-18.7%. We looked for possible associations between the presence of LVSD and patient demographic, clinical and laboratory characteristics, as well as with autonomic nervous system (ANS) function and arterial stiffness.

RESULTS

We enrolled 155 T1D patients (29.7% men, age 36.7 ± 13.1 years, diabetes duration 19.1 ± 10.0 years, HbA1c 7.5 ± 1.4% [58 ± 15 mmol/mol]). Early LVSD was prevalent in 53 (34.2%) patients. Multivariable analysis identified male gender (OR:4.14; 95% CI:1.39-12.31, p = 0.011), HbA1c (OR:1.59 per 1% increase; 95% CI:1.11-2.28, p = 0.011), glomerular filtration rate (GFR, OR:0.97; 95% CI:0.95-0.99, p = 0.010) and BMI (OR:1.19; 95% CI:1.06-1.34, p = 0.003) as independent predictors of LVSD presence.

CONCLUSIONS

Early subclinical LVSD is a common finding in asymptomatic patients with T1D, free of macrovascular and significant microvascular complications. Apart from chronic hyperglycemia, increased adiposity may be implicated in its etiology. Further investigation is warranted to identify patients at high risk for whom early screening is required and to determine possible associations between risk markers identified in the present analysis and long-term outcomes.

Unique role of admission hyperglycemia on myocardial infarction size and area at risk following an acute ST-elevation myocardial infarction

Background

Hyperglycemia can adversely affect patients with acute ST-elevation myocardial infarction (STEMI) in both diabetic and non-diabetic patients. The majority of the studies had investigated the impact of admission hyperglycemia (AH) on cardiovascular morbidity and mortality while, in ours, we entailed its impact on final infarction size (FIS) and more interestingly, on the area at risk (AAR), both were estimated by cardiac magnetic resonance (CMR) imaging.

Results

AH showed significant positive correlations to FIS and AAR. Moreover, AH group had higher summation of ST segment elevation (sum STE), more maximum ST segment elevation (max STE), higher echocardiographic wall motion score index (WMSI), higher CMR estimated WMSI, and lower segmental ejection fraction (EF). Multivariate analysis showed that AH was independently associated with increased FIS.

Conclusion

Current study showed an association between AH and large FIS in STEMI patients.

Pharmacological interventions for heart failure in people with chronic kidney disease

BACKGROUND

Approximately half of people with heart failure have chronic kidney disease (CKD). Pharmacological interventions for heart failure in people with CKD have the potential to reduce death (any cause) or hospitalisations for decompensated heart failure. However, these interventions are of uncertain benefit and may increase the risk of harm, such as hypotension and electrolyte abnormalities, in those with CKD.

OBJECTIVES

This review aims to look at the benefits and harms of pharmacological interventions for HF (i.e., antihypertensive agents, inotropes, and agents that may improve the heart performance indirectly) in people with HF and CKD.

SEARCH METHODS

We searched the Cochrane Kidney and Transplant Register of Studies through 12 September 2019 in consultation with an Information Specialist and using search terms relevant to this review. Studies in the Register are identified through searches of CENTRAL, MEDLINE, and EMBASE, conference proceedings, the International Clinical Trials Register (ICTRP) Search Portal and ClinicalTrials.gov.

SELECTION CRITERIA

We included randomised controlled trials of any pharmacological intervention for acute or chronic heart failure, among people of any age with chronic kidney disease of at least three months duration.

DATA COLLECTION AND ANALYSIS

Two authors independently screened the records to identify eligible studies and extracted data on the following dichotomous outcomes: death, hospitalisations, worsening heart failure, worsening kidney function, hyperkalaemia, and hypotension. We used random effects meta-analysis to estimate treatment effects, which we expressed as a risk ratio (RR) with 95% confidence intervals (CI). We assessed the risk of bias using the Cochrane tool. We applied the GRADE methodology to rate the certainty of evidence.

MAIN RESULTS

One hundred and twelve studies met our selection criteria: 15 were studies of adults with CKD; 16 studies were conducted in the general population but provided subgroup data for people with CKD; and 81 studies included individuals with CKD, however, data for this subgroup were not provided. The risk of bias in all 112 studies was frequently high or unclear. Of the 31 studies (23,762 participants) with data on CKD patients, follow-up ranged from three months to five years, and study size ranged from 16 to 2916 participants. In total, 26 studies (19,612 participants) reported disaggregated and extractable data on at least one outcome of interest for our review and were included in our meta-analyses. In acute heart failure, the effects of adenosine A1-receptor antagonists, dopamine, nesiritide, or serelaxin on death, hospitalisations, worsening heart failure or kidney function, hyperkalaemia, hypotension or quality of life were uncertain due to sparse data or were not reported. In chronic heart failure, the effects of angiotensin-converting enzyme inhibitors (ACEi) or angiotensin receptor blockers (ARB) (4 studies, 5003 participants: RR 0.85, 95% CI 0.70 to 1.02; I² = 78%; low certainty evidence), aldosterone antagonists (2 studies, 34 participants: RR 0.61 95% CI 0.06 to 6.59; very low certainty evidence), and vasopressin receptor antagonists (RR 1.26, 95% CI 0.55 to 2.89; 2 studies, 1840 participants; low certainty evidence) on death (any cause) were uncertain. Treatment with beta-blockers may reduce the risk of death (any cause) (4 studies, 3136 participants: RR 0.69, 95% CI 0.60 to 0.79; I² = 0%; moderate certainty evidence). Treatment with ACEi or ARB (2 studies, 1368 participants: RR 0.90, 95% CI 0.43 to 1.90; I² = 97%; very low certainty evidence) had uncertain effects on hospitalisation for heart failure, as treatment estimates were consistent with either benefit or harm. Treatment with beta-blockers may decrease hospitalisation for heart failure (3 studies, 2287 participants: RR 0.67, 95% CI 0.43 to 1.05; I² = 87%; low certainty evidence). Aldosterone antagonists may increase the risk of hyperkalaemia compared to placebo or no treatment (3 studies, 826 participants: RR 2.91, 95% CI 2.03 to 4.17; I² = 0%; low certainty evidence). Renin inhibitors had uncertain risks of hyperkalaemia (2 studies, 142 participants: RR 0.86, 95% CI 0.49 to 1.49; I² = 0%; very low certainty). We were unable to estimate whether treatment with sinus node inhibitors affects the risk of hyperkalaemia, as there were few studies and meta-analysis was not possible. Hyperkalaemia was not reported for the CKD subgroup in studies investigating other therapies. The effects of ACEi or ARB, or aldosterone antagonists on worsening heart failure or kidney function, hypotension, or quality of life were uncertain due to sparse data or were not reported. Effects of anti-arrhythmic agents, digoxin, phosphodiesterase inhibitors, renin inhibitors, sinus node inhibitors, vasodilators, and vasopressin receptor antagonists were very uncertain due to the paucity of studies.

AUTHORS' CONCLUSIONS

The effects of pharmacological interventions for heart failure in people with CKD are uncertain and there is insufficient evidence to inform clinical practice. Study data for treatment outcomes in patients with heart failure and CKD are sparse despite the potential impact of kidney impairment on the benefits and harms of treatment. Future research aimed at analysing existing data in general population HF studies to explore the effect in subgroups of patients with CKD, considering stage of disease, may yield valuable insights for the management of people with HF and CKD.

Need for pacing in patients who qualify for an implantable cardioverter-defibrillator: Clinical implications for the subcutaneous ICD

BACKGROUND

Implantation of the subcutaneous implantable cardioverter-defibrillator (S-ICD) is spreading and has been shown to be safe and effective; however, it does not provide brady-pacing. Currently, data on the need for brady-pacing and cardiac resynchronization therapy (CRT) implantation in patients with ICD indication are limited.

METHODS

The Multicenter Automatic Defibrillator Implantation Trial (MADIT)-II enrolled post-MI patients with reduced ejection fraction (EF ≤ 35%), randomized to either an implantable cardioverter-defibrillator (ICD) or conventional medical therapy. Kaplan-Meier analyses and multivariate Cox models were performed to assess the incidence and predictors of pacemaker (PM), or CRT implantation in the conventional arm of MADIT-II, after excluding 32 patients (6.5%) with a previously implanted PM.

RESULTS

During the median follow-up of 20 months, 24 of 458 patients (5.2%) were implanted with a PM or a CRT (19 PM, 5 CRT). Symptomatic sinus bradycardia was the primary indication for PM implantation (n = 9, 37%), followed by AV block (n = 5, 21%), tachy-brady syndrome (n = 4, 17%), and carotid sinus hypersensitivity (n = 1, 4%). Baseline PR interval >200 ms (HR = 3.07, 95% CI: 1.24-7.57, p = .02), and CABG before enrollment (HR = 6.88, 95% CI: 1.58-29.84, p = .01) predicted subsequent PM/CRT implantation. Patients with PM/CRT implantation had a significantly higher risk for heart failure (HR = 2.67, 95% CI = 1.38-5.14, p = .003), but no increased mortality risk (HR = 1.06, 95% CI = 0.46-2.46, p = .89).

CONCLUSION

The short-term need for ventricular pacing or CRT implantation in patients with MADIT-II ICD indication was low, especially in those with a normal baseline PR interval, and such patients are appropriate candidates for the subcutaneous ICD.

Type 2 diabetes increases the long-term risk of heart failure and mortality in patients with atrial fibrillation

AIMS

Impact of type 2 diabetes mellitus (T2DM) on non-thromboembolic outcomes in atrial fibrillation (AF) is insufficiently explored. This prospective cohort study of AF patients aimed (i) to analyse the association between T2DM and heart failure (HF) events (including new-onset HF), and all-cause and cardiovascular mortality, (ii) to assess the impact of baseline T2DM treatment on outcomes, and (iii) to explore characteristics of new-onset HF phenotypes in relation to T2DM status.

METHODS AND RESULTS

Of 1803 AF patients (515/1288, with/without prior HF), 389 (22%) had T2DM at baseline. After 5 years of median follow-up, T2DM patients had an 85% greater risk of HF events [adjusted hazard ratio (aHR) 1.85; 95% confidence interval (CI) 1.51-2.28; P < 0.001], including a 45% increased risk for new-onset HF (1.45; 1.17-2.28; P = 0.015). T2DM conferred a 56% higher all-cause (1.56, 1.22-2.01; P = 0.003) and a 48% higher cardiovascular mortality (1.48; 1.34-1.93; P = 0.007). Fine-Gray analysis, with mortality as a competing risk, confirmed greater HF risk among T2DM patients. All risks were highest among insulin-treated patients. The prevalence of new-onset HF phenotypes was as follows: 67% preserved ejection fraction (HFpEF), 20% mid-range ejection fraction (HFmrEF) and 13% reduced ejection fraction (HFrEF). On time-dependent Cox regression, adjusted for baseline characteristics and an interim acute coronary event, T2DM increased aHRs for new-onset HFpEF (2.38; 1.30-4.58; P <0.001) and the combined HFmrEF/HFrEF (1.77; 1.11-3.62; P = 0.017).

CONCLUSIONS

Atrial fibrillation patients with T2DM have independently increased risk of new-onset/recurrent HF events, cardiovascular and all-cause mortality, particularly when insulin-treated. The prevailing phenotype of new-onset HF was HFpEF; T2DM conferred higher risk of both HFpEF and HFmrEF/HFrEF.

Type 2 diabetes and heart failure: Characteristics and prognosis in preserved, mid-range and reduced ventricular function

OBJECTIVE

To study the characteristics and prognostic implications of type 2 diabetes in different heart failure entities from a nationwide perspective.

METHODS

This observational study comprised 30,696 heart failure patients prospectively included in the Swedish Heart Failure Registry (SwedeHF) 2003-2011 from specialist care, with mortality information available until December 2014. Patients were categorized into three heart failure entities by their left ventricular ejection fraction (heart failure with preserved ejection fraction: ⩾50%, heart failure with mid-range ejection fraction: 40%-49% and heart failure with reduced ejection fraction: <40%). All-cause mortality stratified by type 2 diabetes and heart failure entity was studied by Cox regression.

RESULTS

Among the patients, 22% had heart failure with preserved ejection fraction, 21% had heart failure with mid-range ejection fraction and 57% had heart failure with reduced ejection fraction. The proportion of type 2 diabetes was similar, ≈25% in each heart failure entity. Patients with type 2 diabetes and heart failure with preserved ejection fraction were older, more often female and burdened with hypertension and renal impairment compared with heart failure with mid-range ejection fraction and heart failure with reduced ejection fraction patients among whom ischaemic heart disease was more common. Type 2 diabetes remained an independent mortality predictor across all heart failure entities after multivariable adjustment, somewhat stronger in heart failure with left ventricular ejection fraction below 50% (hazard ratio, 95% confidence interval; heart failure with preserved ejection fraction: 1.32 [1.22-1.43], heart failure with mid-range ejection fraction: 1.51 [1.39-1.65], heart failure with reduced ejection fraction: 1.46 [1.39-1.54]; p-value for interaction, p = 0.0049).

CONCLUSION

Type 2 diabetes is an independent mortality predictor across all heart failure entities increasing mortality risk by 30%-50%. In type 2 diabetes, the heart failure with mid-range ejection fraction entity resembles heart failure with reduced ejection fraction in clinical characteristics, risk factor pattern and prognosis.

One-year follow-up of the prospective registry of patients using the wearable defibrillator (WEARIT-II Registry)

BACKGROUND

The WEARIT-II Registry demonstrated efficacy and safety of the wearable cardioverter defibrillator (WCD) for at-risk cardiac patients. However, 1-year outcomes in this population have not been reported.

METHODS

The WEARIT-II Registry enrolled 2,000 U.S. patients prescribed the WCD. One-year mortality data from start of WCD use were prospectively collected for 1,846 patients (93%). Outcome data were analyzed by disease etiology and implantable cardioverter defibrillator (ICD) implantation following WCD use.

RESULTS

During 12 months of follow-up, 73 patients died (4%). Kaplan-Meier survival analysis showed differences in all-cause mortality from WCD prescription between patients with ischemic versus nonischemic cardiomyopathy versus congenital/inherited heart disease (4% vs 3% vs 7%, P = 0.013). Patients with ventricular arrhythmia events during WCD use had a higher 1-year mortality (10% vs 3%, P = 0.042). Renal disease, increasing age, prior syncope, and nonbeta-blocker use predicted mortality. One-year mortality was similar in patients who did versus did not receive an ICD following WCD use in ischemic (3% vs 4%, P = 0.470) and nonischemic cardiomyopathy (3% vs 3%, P = 0.892). Patients with congenital/inherited heart disease with no implanted ICD had a trend toward a higher rate of mortality than those who received an ICD (8% vs 3%, P = 0.082). Multivariate models confirmed these findings.

CONCLUSION

One-year follow-up from the WEARIT-II Registry shows an overall good survival in patients prescribed the WCD. Short-term use of WCD allows appropriate risk stratification for decision on an ICD implantation in at-risk ischemic and nonischemic cardiomyopathy patients. Congenital/inherited heart disease patients had a higher risk of 1-year mortality even without an implanted ICD post-WCD.

A history of diabetes predicts outcomes following myocardial infarction: an analysis of the 28 771 patients in the High-Risk MI Database

AIMS

To examine the impact of diabetes mellitus on long-term clinical outcomes in patients with myocardial infarction (MI) complicated by clinical signs of heart failure (HF) or left ventricular dysfunction (LVD).

METHODS AND RESULTS

The High-Risk MI Database consists of individual data from 28 771 patients and was created by merging four large recent randomized clinical trials (VALIANT, EPHESUS, OPTIMAAL, and CAPRICORN) that each examined the impact of pharmacological interventions following MI in patients with evidence of HF or LVD. The mean age of patients was 65 years, 70% were male, and almost 94% Caucasian. Overall, 7368 (26%) had a history of diabetes. All the major outcomes were adjudicated by independent end-point committees. Strong and highly significant associations were found with all major clinical outcomes. Diabetes was associated with an increased risk for all-cause death [adjusted hazard ratio (HR) 1.37; confidence interval (CI) 1.28-1.46; P < 0.001]. The higher risk for all-cause death was largely mediated by higher risk for cardiovascular death (adjusted HR 1.38; CI 1.27-1.48; P < 0.001) predominantly due to a substantially increased risk for fatal re-infarction (adjusted HR 1.78; CI 1.42-2.23; P < 0.001). Additionally, diabetes was associated with an increased risk for hospitalizations, particularly HF hospitalization (adjusted HR 1.50; CI 1.39-1.63; P < 0.001). There were also elevated risks for composite outcomes, particularly death or hospitalization due to HF (adjusted HR 1.48; CI 1.38-1.59; P < 0.001).

CONCLUSION

The risk for adverse outcomes associated with diabetes remains elevated even after debut of coronary artery disease in patients with MI complicated by clinical signs of HF or LVD. This association is particularly strong for HF-related outcomes.

Multicenter Automatic Defibrillator Implantation Trial-Subcutaneous Implantable Cardioverter Defibrillator (MADIT S-ICD): Design and clinical protocol

Patients with diabetes mellitus, prior myocardial infarction, older age, and a relatively preserved left ventricular ejection fraction remain at risk for sudden cardiac death that is potentially amenable by the subcutaneous implantable cardioverter defibrillator with a good risk-benefit profile. The launched MADIT S-ICD study is designed to test the hypothesis that post-myocardial infarction diabetes patients with relatively preserved ejection fraction of 36%-50% will have a survival benefit from a subcutaneous implantable cardioverter defibrillator.

Hyperglycemia-Induced Hypovolemia Is Involved in Early Cardiac Magnetic Resonance Alterations in Streptozotocin-Induced Diabetic Mice: A Comparison with Furosemide-Induced Hypovolemia

Aims

The aim of the study was to assess the early features of diabetic cardiomyopathy using cardiac magnetic resonance within the first week after streptozotocin injection in mice. We focused on the relationship between left ventricular function and hypovolemia markers in diabetic animals compared to a hypovolemic rodent model.

Methods and Results

Swiss mice were randomized into control (group C), streptozotocin-induced diabetes (group D) and furosemide-induced hypovolemia (group F) groups. Cardiac magnetic resonance, non-invasive blood pressure, urine volume, plasma markers of dehydration and cardiac histology were assessed in all groups. Mean blood glucose was higher in diabetic animals than in groups C and F (30.5±5.8 compared to 10.4±2.1 and 11.1±2.8 mmol/L, respectively; p<0.01). Diuresis was increased in animals from group D and F compared to C (14650±11499 and 1533±540 compared to 192±111 μL/24 h; p<0.05). End diastolic and end systolic volumes were lower in group D than in group C at week 1 (1.52±0.36 vs. 1.93±0.35 and 0.54±0.22 vs. 0.75±0.18 mL/kg, p<0.05). These left ventricular volume values in group D were comparable to those observed in the acute hypovolemia model (group F). Increased dehydration plasma markers and an absence of obvious intrinsic myocardial damage (evaluated by cardiac magnetic resonance and histology) suggest that a hemodynamic mechanism underlies the very early drop in left ventricular volumes in group D and provides a potential link to hyperglycemic osmotic diuresis.

Conclusions

Researchers using cardiac magnetic resonance in hyperglycemic rodent models should be aware of this hemodynamic mechanism, which may partially explain modifications in cardiac parameters in addition to diabetic myocardial damage.

Subclinical Detection of Diabetic Cardiomyopathy with MicroRNAs: Challenges and Perspectives

The prevalence of cardiac diabetic diseases has been increased around the world, being the most common cause of death and disability among diabetic patients. In particular, diabetic cardiomyopathy is characterized with a diastolic dysfunction and cardiac remodelling without signs of hypertension and coronary artery diseases. In an early stage, it is an asymptomatic disease; however, clinical studies demonstrate that diabetic myocardia are more vulnerable to injury derived by acute myocardial infarct and are the worst prognosis for rehabilitation. Currently, biochemical and imaging diagnostic methods are unable to detect subclinical manifestation of the disease (prior to diastolic dysfunction). In this review, we elaborately discuss the current scientific evidences to propose circulating microRNAs as promising biomarkers for early detection of diabetic cardiomyopathy and, then, to identify patients at high risk of diabetic cardiomyopathy development. Moreover, here we summarise the research strategies to identify miRNAs as potential biomarkers, present limitations, challenges, and future perspectives.

Dipeptidyl peptidase-4 inhibition improves cardiac function in experimental myocardial infarction: Role of stromal cell-derived factor-1α

BACKGROUND

In addition to degrading glucagon-like peptide-1 (GLP-1), dipeptidyl peptidase-4 (DPP-4) inactivates several chemokines, including stromal cell-derived factor-1α (SDF-1α), a pro-angiogenic and cardiomyocyte protective protein. We hypothesized that DPP-4 inhibition may confer benefit following myocardial infarction (MI) in the diabetic setting as a consequence of enhanced SDF-1α availability rather than potentiating GLP-1. To test this we compared the effects of saxagliptin with those of liraglutide and used the SDF-1α receptor (CXCR4) antagonist plerixafor.

METHODS

Studies were conducted in streptozotocin-diabetic rats. Rats were randomized to receive saxagliptin (10 mg/kg per day), liraglutide (0.2 mg/kg, s.c., b.i.d.), plerixafor (1 mg/kg per day, s.c.), saxagliptin plus plerixafor or vehicle (1% phosphate-buffered saline). Two weeks later, rats underwent experimental MI, with cardiac function examined 4 weeks after MI.

RESULTS

Glycemic control and MI size were similar in all groups. Four weeks after MI, mortality was reduced in saxagliptin-treated rats compared with vehicle treatment (P < 0.05). Furthermore, rats receiving saxagliptin had improved cardiac function compared with vehicle-treated rats (P < 0.05). Antagonism of CXCR4 prevented the improvement in cardiac function in saxagliptin-treated rats and was associated with increased mortality (P < 0.05).

CONCLUSION

Saxagliptin-mediated DPP-4 inhibition, but not liraglutide-mediated GLP-1R agonism, improved cardiac function after MI independent of glucose lowering. These findings suggest that non-GLP-1 actions of DPP-4 inhibition, such as SDF-1α potentiation, mediate biological effects.

Beyond ejection fraction: an integrative approach for assessment of cardiac structure and function in heart failure

Left ventricular ejection fraction (LVEF) has been the central parameter used for diagnosis and management in patients with heart failure. A good predictor of adverse outcomes in heart failure when below ∼45%, LVEF is less useful as a marker of risk as it approaches normal. As a measure of cardiac function, ejection fraction has several important limitations. Calculated as the stroke volume divided by end-diastolic volume, the estimation of ejection fraction is generally based on geometric assumptions that allow for assessment of volumes based on linear or two-dimensional measurements. Left ventricular ejection fraction is both preload- and afterload-dependent, can change substantially based on loading conditions, is only moderately reproducible, and represents only a single measure of risk in patients with heart failure. Moreover, the relationship between ejection fraction and risk in patients with heart failure is modified by factors such as hypertension, diabetes, and renal function. A more complete evaluation and understanding of left ventricular function in patients with heart failure requires a more comprehensive assessment: we conceptualize an integrative approach that incorporates measures of left and right ventricular function, left ventricular geometry, left atrial size, and valvular function, as well as non-imaging factors (such as clinical parameters and biomarkers), providing a comprehensive and accurate prediction of risk in heart failure.

C1q-TNF-related protein-9, a novel cardioprotetcive cardiokine, requires proteolytic cleavage to generate a biologically active globular domain isoform

Prevalence and severity of postmyocardial infarction heart failure continually escalate in type 2 diabetes via incompletely understood mechanisms. The discovery of the cardiac secretomes, collectively known as "cardiokines", has significantly enhanced appreciation of the local microenvironment's influence on disease development. Recent studies demonstrated that C1q-TNF-related protein-9 (CTRP9), a newly discovered adiponectin (APN) paralog, is highly expressed in the heart. However, its relationship with APN (concerning diabetic cardiovascular injury in particular) remains unknown. Plasma CTRP9 levels are elevated in APN knockout and reduced in diabetic mice. In contrast to APN, which circulates as full-length multimers, CTRP9 circulates in the plasma primarily in the globular domain isoform (gCTRP9). Recombinant full-length CTRP9 (fCTRP9) was cleaved when incubated with cardiac tissue extracts, generating gCTRP9, a process inhibited by protease inhibitor cocktail. gCTRP9 rapidly activates cardiac survival kinases, including AMPK, Akt, and endothelial NOS. However, fCTRP9-mediated kinase activation is much less potent and significantly delayed. Kinase activation by fCTRP9, but not gCTRP9, is inhibited by protease inhibitor cocktail. These results demonstrate for the first time that the novel cardiokine CTRP9 undergoes proteolytic cleavage to generate gCTRP9, the dominant circulatory and actively cardioprotective isoform. Enhancing cardiac CTRP9 production and/or its proteolytic posttranslational modification are of therapeutic potential, attenuating diabetic cardiac injury.

Co-morbidities in heart failure

Heart failure is a clinical syndrome characterized by poor quality of life and high morbidity and mortality. Co-morbidities frequently accompany heart failure and further decrease in both quality of life and clinical outcome. We describe that the prevalence of co-morbidities in patients with heart failure is much higher compared to age-matched controls. We will specifically address the most studied organ-related co-morbidities, that is, renal dysfunction, cerebral dysfunction, anaemia, liver dysfunction, chronic obstructive pulmonary disease, diabetes mellitus and sleep apnoea. The pathophysiologic processes underlying the interaction between heart failure and co-morbid conditions are complex and remain largely unresolved. Although common risk factors are likely to contribute, it is reasonable to believe that factors associated with heart failure might cause other co-morbid conditions. Inflammation, neurohumoral pathway activation and hemodynamic changes are potential factors. We try to provide explanations for the observed association between co-morbidities and heart failure, as well as its impact on survival.

Diabetes increases stiffness of live cardiomyocytes measured by atomic force microscopy nanoindentation

Stiffness of live cardiomyocytes isolated from control and diabetic mice was measured using the atomic force microscopy nanoindentation method. Type 1 diabetes was induced in mice by streptozotocin administration. Histological images of myocardium from mice that were diabetic for 3 mo showed disorderly lineup of myocardial cells, irregularly sized cell nuclei, and fragmented and disordered myocardial fibers with interstitial collagen accumulation. Phalloidin-stained cardiomyocytes isolated from diabetic mice showed altered (i.e., more irregular and diffuse) actin filament organization compared with cardiomyocytes from control mice. Sarco/endoplasmic reticulum Ca(2+)-ATPase (SERCA2a) pump expression was reduced in homogenates obtained from the left ventricle of diabetic animals compared with age-matched controls. The apparent elastic modulus (AEM) for live control or diabetic isolated cardiomyocytes was measured using the atomic force microscopy nanoindentation method in Tyrode buffer solution containing 1.8 mM Ca(2+) and 5.4 mM KCl (physiological condition), 100 nM Ca(2+) and 5.4 mM KCl (low extracellular Ca(2+) condition), or 1.8 mM Ca(2+) and 140 mM KCl (contraction condition). In the physiological condition, the mean AEM was 112% higher for live diabetic than control isolated cardiomyocytes (91 ± 14 vs. 43 ± 7 kPa). The AEM was also significantly higher in diabetic than control cardiomyocytes in the low extracellular Ca(2+) and contraction conditions. These findings suggest that the material properties of live cardiomyocytes were affected by diabetes, resulting in stiffer cells, which very likely contribute to high diastolic LV stiffness, which has been observed in vivo in some diabetes mellitus patients.

Diabetic cardiomyopathy: pathophysiology and clinical features

Since diabetic cardiomyopathy was first reported four decades ago, substantial information on its pathogenesis and clinical features has accumulated. In the heart, diabetes enhances fatty acid metabolism, suppresses glucose oxidation, and modifies intracellular signaling, leading to impairments in multiple steps of excitation–contraction coupling, inefficient energy production, and increased susceptibility to ischemia/reperfusion injury. Loss of normal microvessels and remodeling of the extracellular matrix are also involved in contractile dysfunction of diabetic hearts. Use of sensitive echocardiographic techniques (tissue Doppler imaging and strain rate imaging) and magnetic resonance spectroscopy enables detection of diabetic cardiomyopathy at an early stage, and a combination of the modalities allows differentiation of this type of cardiomyopathy from other organic heart diseases. Circumstantial evidence to date indicates that diabetic cardiomyopathy is a common but frequently unrecognized pathological process in asymptomatic diabetic patients. However, a strategy for prevention or treatment of diabetic cardiomyopathy to improve its prognosis has not yet been established. Here, we review both basic and clinical studies on diabetic cardiomyopathy and summarize problems remaining to be solved for improving management of this type of cardiomyopathy.

Diabetes and cardiovascular disease: changing the focus from glycemic control to improving long-term survival

Diabetes mellitus (DM) is the fifth-leading cause of death worldwide and contributes to leading causes of death, cancer and cardiovascular disease, including CAD, stroke, peripheral vascular disease, and other vascular disease. While glycemic management remains a cornerstone of DM care, the co-management of hypertension, atherosclerosis, cardiovascular risk reduction, and prevention of long-term consequences associated with DM are now well recognized as essential to improve long-term survival. Clinical trial evidence substantiates the importance of glycemic control, low-density cholesterol-lowering therapy, blood pressure lowering, control of albuminuria, and comprehensive approaches targeting multiple risk factors to reduce cardiovascular risk. This article presents a review of the role of DM in the pathogenesis of atherosclerosis and cardiac dysfunction, recent evidence on the degree of glycemic control and mortality, and available evidence for a multifaceted approach to improve long-term outcomes for patients.

Congestive heart failure and diabetes mellitus: balancing glycemic control with heart failure improvement

Diabetes mellitus (DM) and congestive heart failure (HF) commonly coexist in the same patient, and the presence of DM in HF patients is associated with increased adverse events compared with patients without DM. Recent guidelines regarding glycemic control stress individualization of glycemic therapy based on patient comorbid conditions and potential adverse effects of medical therapy. This balance in glycemic control may be particularly relevant in patients with DM and HF. In this review, we address data regarding the influence that certain HF medications may have on glycemic control. Despite potential modest changes in glycemic control, clinical benefits of proven pharmacologic HF therapies extend to patients with DM and HF. In addition, we review potential benefits and challenges associated with commonly used glycemic medications in HF patients. Finally, recent data and controversies on optimal glycemic targets in HF patients are discussed. Given the large number of patients with DM and HF and the health burden of these conditions, much needed future work is necessary to define the optimal glycemic treatment in HF patients with DM.

Glycemic variability and glycemic control in the acutely ill cardiac patient

The mechanisms for hyperglycemia-mediated harm in the hospitalized cardiac patient are poorly understood. Potential obstacles in the inpatient management of hyperglycemia in cardiac patients include rapidly changing clinical status, frequent procedures and interruptions in carbohydrate exposure, and short hospital length of stay. A patient's preadmission regimen is rarely suitable for inpatient glycemic control. Instead, an approach to a flexible, physiologic insulin regimen is described, which is intended to minimize glycemic excursions. When diabetes or hyperglycemia is addressed early and consistently, the hospital stay can serve as a potential window of opportunity for reinforcing self-care behaviors that reduce long-term complications.

Role of ER stress in ventricular contractile dysfunction in type 2 diabetes

Background

Diabetes mellitus (DM) is associated with an increased risk of ischemic heart disease and of adverse outcomes following myocardial infarction (MI). Here we assessed the role of endoplasmic reticulum (ER) stress in ventricular dysfunction and outcomes after MI in type 2 DM (T2DM).

Methodology and Principal Findings

In hearts of OLETF, a rat model of T2DM, at 25∼30 weeks of age, GRP78 and GRP94, markers of ER stress, were increased and sarcoplasmic reticulum calcium ATPase (SERCA)2a protein was reduced by 35% compared with those in LETO, a non-diabetic control. SERCA2a mRNA levels were similar, but SERCA2a protein was more ubiquitinated in OLETF than in LETO. Left ventricular (LV) end-diastolic elastance (Eed) was higher in OLETF than in LETO (53.9±5.2 vs. 20.2±5.6 mmHg/µl), whereas LV end-systolic elastance and positive inotropic responses to β-adrenergic stimulation were similar in OLETF and LETO. 4-Phenylbutyric acid (4-PBA), an ER stress modulator, suppressed both GRP up-regulation and SERCA2a ubiquitination and normalized SERCA2a protein level and Eed in OLETF. Sodium tauroursodeoxycholic acid, a structurally different ER stress modulator, also restored SERCA2a protein level in OLETF. Though LV dysfunction was modest, mortality within 48 h after coronary occlusion was markedly higher in OLETF than in LETO (61.3% vs. 7.7%). Telemetric recording showed that rapid progression of heart failure was responsible for the high mortality rate in OLETF. ER stress modulators failed to reduce the mortality rate after MI in OLETF.

Conclusions

ER stress reduces SERCA2a protein via its augmented ubiquitination and degradation, leading to LV diastolic dysfunction in T2DM. Even at a stage without systolic LV dysfunction, susceptibility to lethal heart failure after infarction is markedly increased, which cannot be explained by ER stress or change in myocardial response to sympathetic nerve activation.

Effects of diabetes on myocardial infarct size and cardioprotection by preconditioning and postconditioning

In spite of the current optimal therapy, the mortality of patients with ischemic heart disease (IHD) remains high, particularly in cases with diabetes mellitus (DM) as a co-morbidity. Myocardial infarct size is a major determinant of prognosis in IHD patients, and development of a novel strategy to limit infarction is of great clinical importance. Ischemic preconditioning (PC), postconditioning (PostC) and their mimetic agents have been shown to reduce infarct size in experiments using healthy animals. However, a variety of pharmacological agents have failed to demonstrate infarct size limitation in clinical trials. One of the possible reasons for the discrepancy between the results of animal experiments and clinical trials is that co-morbidities, including DM, modified myocardial responses to ischemia/reperfusion and to cardioprotective agents. Here we summarize observations of the effects of DM on myocardial infarct size and ischemic PC and PostC and discuss perspectives for protection of DM hearts.

Cardiac structure and function, remodeling, and clinical outcomes among patients with diabetes after myocardial infarction complicated by left ventricular systolic dysfunction, heart failure, or both

AIMS

The mechanisms responsible for the increased risk of heart failure (HF) post-myocardial infarction (MI) may differ between patients with versus without diabetes. We hypothesized that after high-risk MI, patients with diabetes would demonstrate patterns of remodeling that are suggestive of reduced ventricular compliance and that are associated with an increased risk of death or HF.

METHODS AND RESULTS

We performed quantitative echocardiographic analysis in 153 patients with diabetes and 451 patients without diabetes enrolled in the VALIANT Echo study. Diabetes was associated with a higher risk of death or HF in age-adjusted models (hazard ratio 1.44, 95% CI 1.04-2.00, P = .028). Diabetic patients were similar to nondiabetic patients with respect to left ventricular (LV) volume and ejection fraction but had higher LV mass index (104.1 ± 27.5 vs 97.1 ± 28.6 g/m(2), P = .009), relative wall thickness (0.41 ± 0.08 vs 0.38 ± 0.07, P < .0001), and left atrial volume index (LAVi) (26.2 ± 8.1 vs 24.0 ± 8.2 mL/m(2), P = .008)-all parameters that were significantly related to the risk of death or HF hospitalization. Changes in LV volume and ejection fraction from baseline to 20 months were not different, although diabetic patients demonstrated greater increase in LAVi (4.4 ± 7.7 vs 2.2 ± 6.7 mL/m(2), P = .01).

CONCLUSIONS

After high-risk MI, diabetic patients were at higher risk of death or HF and demonstrated greater baseline LV mass index, relative wall thickness, and LAVi as well as greater left atrial enlargement at 20-month follow-up. These findings suggest greater baseline concentric remodeling and long-term elevation in LV diastolic pressure post-MI among diabetic patients, which may partially mediate this risk.

Left ventricular systolic and diastolic function, remodelling, and clinical outcomes among patients with diabetes following myocardial infarction and the influence of direct renin inhibition with aliskiren

AIMS

We assessed the relationship between diabetes and cardiac structure and function following myocardial infarction (MI) and whether diabetes influences the effect of direct renin inhibition on change in left ventricular (LV) size.

METHODS AND RESULTS

The ASPIRE trial enrolled 820 patients 2-8 weeks after MI with ejection fraction ≤ 45% and randomized them to the direct renin inhibitor aliskiren (n= 423) or placebo (n = 397) added to standard medical therapy. Echocardiography was performed at baseline and after 36 weeks in 672 patients with evaluable paired studies. Compared with non-diabetic patients, diabetic patients (n = 214) were at higher risk for a composite of cardiovascular (CV) death, heart failure hospitalization, recurrent MI, stroke, or aborted sudden death (14 vs. 7%; adjusted hazard ratio 1.63, 95% confidence interval 1.01-2.64, P= 0.045), despite similar left ventricular ejection fraction (37.9 ± 5.3 vs. 37.6 ± 5.2%, P= 0.48) and end-systolic volume (ESV) (84 ± 25 vs. 82 ± 28 mL, P= 0.46). Diabetic patients demonstrated greater concentric remodelling (relative wall thickness 0.38 ± 0.07 vs. 0.36 ± 0.07, P= 0.0002) and evidence of higher LV filling pressure (E/E' 11.1 ± 5.3 vs. 9.1 ± 4.3, P= 0.0011). At 36 weeks, diabetic patients experienced similar per cent reduction in ESV overall (-4.9 ± 17.9 vs. -5.5 ± 16.9, P= 0.67) but tended to experience greater reduction in ESV than non-diabetic patients when treated with aliskiren (interaction P = 0.08).

CONCLUSIONS

Compared with non-diabetic patients, diabetic patients are at increased risk of CV events post-MI despite no greater LV enlargement or reduction in systolic function. Diabetic patients demonstrate greater concentric remodelling and evidence of higher LV filling pressure, suggesting diastolic dysfunction as a potential mechanism for the higher risk observed among these patients.

Long-term prognostic importance of diabetes after a myocardial infarction depends on left ventricular systolic function

OBJECTIVE

This study was performed to understand how left ventricular function modulates the prognostic importance of diabetes after myocardial infarction (MI).

RESEARCH DESIGN AND METHODS

Consecutively hospitalized MI patients screened for three clinical trials were followed for a median of 7 years. Multivariable Cox regression models were used to assess the risk of mortality associated with diabetes, and the importance of diabetes was examined independently within defined left ventricular ejection fraction (LVEF) subgroups.

RESULTS

A total of 16,912 patients were included; 1,819 (11%) had diabetes. Diabetes and 15% unit depression in LVEF were of similar prognostic importance: hazard ratios (HRs) were 1.45 (95% CI 1.37-1.54) and 1.41 (1.37-1.45) for diabetes and LVEF depression, respectively. LVEF modified the outcomes associated with diabetes, with HRs being 1.29 (1.19-1.40) and 1.61 (1.49-1.74) in patients with LVEF <40% and LVEF ≥ 40%, respectively (P = 0.03).

CONCLUSIONS

Patients within the higher LVEF categories have a greater mortality risk attributable to diabetes than patients within the lower LVEF categories.