Deep embedded clustering generalisability and adaptation for integrating mixed datatypes: two critical care cohorts.

We validated a Deep Embedded Clustering (DEC) model and its adaptation for integrating mixed datatypes (in this study, numerical and categorical variables). Deep Embedded Clustering (DEC) is a promising technique capable of managing extensive sets of variables and non-linear relationships. Nevertheless, DEC cannot adequately handle mixed datatypes. Therefore, we adapted DEC by replacing the autoencoder with an X-shaped variational autoencoder (XVAE) and optimising hyperparameters for cluster stability. We call this model "X-DEC". We compared DEC and X-DEC by reproducing a previous study that used DEC to identify clusters in a population of intensive care patients. We assessed internal validity based on cluster stability on the development dataset. Since generalisability of clustering models has insufficiently been validated on external populations, we assessed external validity by investigating cluster generalisability onto an external validation dataset. We concluded that both DEC and X-DEC resulted in clinically recognisable and generalisable clusters, but X-DEC produced much more stable clusters.

Two-year follow-up of 4 months metformin treatment vs. placebo in ST-elevation myocardial infarction: data from the GIPS-III RCT.

OBJECTIVES: Preclinical and clinical studies suggested cardioprotective effects of metformin treatment. In the GIPS-III trial, 4 months of metformin treatment did not improve left ventricular ejection fraction in patients presenting with ST-elevation myocardial infarction (STEMI). Here, we report the 2-year follow-up results. METHODS: Between January 2011 and May 2013, 379 STEMI patients without diabetes undergoing primary percutaneous coronary intervention were randomized to a 4-month treatment with metformin (500 mg twice daily) (N = 191) or placebo (N = 188) in the University Medical Center Groningen. Two-year follow-up data was collected to determine its effect on predefined secondary endpoints: the incidence of major adverse cardiac events (MACE), its individual components, all-cause mortality, and new-onset diabetes. RESULTS: For all 379 patients all-cause mortality data were available. For seven patients (2%) follow-up data on MACE was limited, ranging from 129 to 577 days. All others completed the 2-year follow-up visit. Incidence of MACE was 11 (5.8%) in metformin and 6 (3.2%) in placebo treated patients [hazard ratio (HR) 1.84, confidence interval (CI) 0.68-4.97, P = 0.22]. Three patients died in the metformin group and one in the placebo treatment group. Individual components of MACE were also comparable between both groups. New-onset diabetes mellitus was 34 (17.8%) in metformin and 32 (17.0%) in placebo treated patients (odds ratio 1.15, CI 0.66-1.98, P = 0.84). After multivariable adjustment the incidence of MACE was comparable between the treatment groups (HR 1.02, CI 0.10-10.78, P = 0.99). CONCLUSIONS: Four months metformin treatment initiated at the time of hospitalization in STEMI patients without diabetes did not exert beneficial long-term effects. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01217307.

Predictors of left ventricular remodeling after ST-elevation myocardial infarction.

Adverse left ventricular (LV) remodeling after acute ST-elevation myocardial infarction (STEMI) is associated with morbidity and mortality. We studied clinical, biochemical and angiographic determinants of LV end diastolic volume index (LVEDVi), end systolic volume index (LVESVi) and mass index (LVMi) as global LV remodeling parameters 4 months after STEMI, as well as end diastolic wall thickness (EDWT) and end systolic wall thickness (ESWT) of the non-infarcted myocardium, as compensatory remote LV remodeling parameters. Data was collected in 271 patients participating in the GIPS-III trial, presenting with a first STEMI. Laboratory measures were collected at baseline, 2 weeks, and 6-8 weeks. Cardiovascular magnetic resonance imaging (CMR) was performed 4 months after STEMI. Linear regression analyses were performed to determine predictors. At baseline, patients were 21% female, median age was 58 years. At 4 months, mean LV ejection fraction (LVEF) was 54 ± 9%, mean infarct size was 9.0 ± 7.9% of LVM. Strongest univariate predictors (all p < 0.001) were peak Troponin T for LVEDVi (R2 = 0.26), peak CK-MB for LVESVi (R2 = 0.41), NT-proBNP at 2 weeks for LVMi (R2 = 0.24), body surface area for EDWT (R2 = 0.32), and weight for ESWT (R2 = 0.29). After multivariable analysis, cardiac biomarkers remained the strongest predictors of LVMi, LVEDVi and LVESVi. NT-proBNP but none of the acute cardiac injury biomarkers were associated with remote LV wall thickness. Our analyses illustrate the value of cardiac specific biochemical biomarkers in predicting global LV remodeling after STEMI. We found no evidence for a hypertrophic response of the non-infarcted myocardium.

In vivo coronary lesion differentiation with computed tomography angiography and intravascular ultrasound as compared to optical coherence tomography.

BACKGROUND: In vitro studies have shown the feasibility of coronary lesion grading with computed tomography angiography (CTA), intravascular ultrasound (IVUS) and optical coherence tomography (OCT) as compared to histology, whereas OCT had the highest discriminatory capacity. OBJECTIVE: We investigated the ability of CTA and IVUS to differentiate between early and advanced coronary lesions in vivo, OCT serving as standard of reference. METHODS: Multimodality imaging was prospectively performed in 30 NSTEMI patients. Plaque characteristics were assessed in 1083 cross-sections of 30 culprit lesions, co-registered among modalities. Absence of plaque, fibrous and fibrocalcific plaque on OCT were defined as early plaque, whereas lipid rich-plaque on OCT was defined as advanced plaque. Odds ratios adjusted for clustering were calculated to assess associations between plaque types on CTA and IVUS with early or advanced plaque. RESULTS: Normal findings on CTA as well as on IVUS were associated with early plaque. Non-calcified, calcified plaques and the napkin ring sign on CTA were associated with advanced plaque. On IVUS, fatty and calcified plaques were associated with advanced plaque. CONCLUSIONS: In vivo coronary plaque characteristics on CTA and IVUS are associated with plaque characteristics on OCT. Of note, normal findings on CTA and IVUS relate to early lesions on OCT. Nevertheless, multiple plaque features on CTA and IVUS are related to advanced plaques on OCT, which may make it difficult to use qualitative plaque assessment in clinical practice.

The contemporary value of peak creatine kinase-MB after ST-segment elevation myocardial infarction above other clinical and angiographic characteristics in predicting infarct size, left ventricular ejection fraction, and mortality.

BACKGROUND: Complex multimarker approaches to predict outcome after ST-elevation myocardial infarction (STEMI) have only considered a single baseline sample, while neglecting easily obtainable peak creatine kinase and creatine kinase-MB (CK-MB) values during hospitalization. METHODS: We studied 476 patients undergoing primary percutaneous coronary intervention for STEMI and cardiac magnetic resonance imaging (CMRI) at 4-6 months after STEMI. We determined the association with cardiac biomarkers (peak CK-MB, peak troponin T, N-terminal pro-brain natriuretic peptide), clinical and angiographic characteristics with infarct size, and LVEF, followed by association with mortality in 1120 STEMI patients. RESULTS: Peak CK-MB was the strongest predictor for infarct size (P<0.001, R 2 =0.60) and LVEF (P<0.001, R 2 =0.40). The additional value of clinical and angiographic characteristics was limited. The optimal peak CK-MB cutpoints, for differentiation among small (<10% of the left ventricle), moderate (≥10%-<30%), and large infarct size (≥30%), were 210 U/L and 380 U/L, respectively. These cutpoints were associated with 90-day mortality; the hazard ratio for moderate infarct was 2.99 (95% confidence interval [CI]: 1.51-5.93, P=0.002) and for large infarct 6.53 (95% CI: 3.63-11.76, P<0.001). CONCLUSIONS: Classical peak CK-MB measured during hospitalization for STEMI was superior to other clinical and angiographic characteristics in predicting CMRI-defined infarct size and LVEF, and should be included and validated in future multimarker studies. Peak CK-MB cutpoints differentiated among infarct size categories and were associated with increased 90-day mortality risk.

The Effect of Metformin on Diastolic Function in Patients Presenting with ST-Elevation Myocardial Infarction.

INTRODUCTION: Diastolic dysfunction is an important predictor of poor outcome after myocardial infarction. Metformin treatment improved diastolic function in animal models and patients with diabetes. Whether metformin improves diastolic function in patients presenting with ST-segment elevation myocardial infarction (STEMI) is unknown. METHODS: The GIPS-III trial randomized STEMI patients, without known diabetes, to metformin or placebo initiated directly after PCI. The previously reported primary endpoint was left ventricular ejection fraction at 4 months, which was unaffected by metformin treatment. This is a predefined substudy to determine an effect of metformin on diastolic function. For this substudy trans-thoracic echocardiography was performed during hospitalization and after 4 months. Diastolic dysfunction was defined as having the combination of a functional alteration (i.e. decreased tissue velocity: mean of septal e' and lateral e') and a structural alteration (i.e. increased left atrial volume index (LAVI)). In addition, left ventricular mass index and transmitral flow velocity (E) to mean e' ratio (E/e') were measured to determine an effect of metformin on individual echocardiographic markers of diastolic function. RESULTS: In 237 (63%) patients included in the GIPS-III trial diastolic function was measured during hospitalization as well as at 4 months. Diastolic dysfunction was present in 11 (9%) of patients on metformin and 11 (9%) patients on placebo treatment (P = 0.98) during hospitalization. After 4 months 22 (19%) of patients with metformin and 18 (15%) patients with placebo (P = 0.47) had diastolic dysfunction. In addition, metformin did not improve any of the individual echocardiographic markers of diastolic function. CONCLUSIONS: In contrast to experimental and observational data, our randomized placebo controlled trial did not suggest a beneficial effect of short-term metformin treatment on diastolic function in STEMI patients.

Chronic ischemic mitral regurgitation and papillary muscle infarction detected by late gadolinium-enhanced cardiac magnetic resonance imaging in patients with ST-segment elevation myocardial infarction.

BACKGROUND: Both papillary muscle infarction (PMI) and chronic ischemic mitral regurgitation (CIMR) are associated with reduced survival after myocardial infarction. The influence of PMI on CIMR and factors influencing both entities are incompletely understood. OBJECTIVES: We sought to determine the influence of PMI on CIMR after primary percutaneous coronary intervention (PCI) for ST-segment elevation myocardial infarction (STEMI) and to define independent predictors of PMI and CIMR. METHODS: Between January 2011 and May 2013, 263 patients (mean age 57.8 ± 11.5 years) underwent late gadolinium-enhanced cardiac magnetic resonance imaging and transthoracic echocardiography 4 months after PCI for STEMI. Infarct size, PMI, and mitral valve and left ventricular geometric and functional parameters were assessed. Univariate and multivariate analyses were performed to identify predictors of PMI and CIMR (≥grade 2+). RESULTS: PMI was present in 61 patients (23 %) and CIMR was present in 86 patients (33 %). In patients with PMI, 52 % had CIMR, and in patients without PMI, 27 % had CIMR (P < 0.001). In multivariate analyses, infarct size [odds ratio (OR) 1.09 (95 % confidence interval 1.04-1.13), P < 0.001], inferior MI [OR 4.64 (1.04-20.62), P = 0.044], and circumflex infarct-related artery [OR 8.21 (3.80-17.74), P < 0.001] were independent predictors of PMI. Age [OR 1.08 (1.04-1.11), P < 0.001], infarct size [OR 1.09 (1.03-1.16), P = 0.003], tethering height [OR 19.30 (3.28-113.61), P = 0.001], and interpapillary muscle distance [OR 3.32 (1.31-8.42), P = 0.011] were independent predictors of CIMR. CONCLUSIONS: The risk of PMI is mainly associated with inferior infarction and infarction in the circumflex coronary artery. Although the prevalence of CIMR is almost doubled in the presence of PMI, PMI is not an independent predictor of CIMR. Tethering height and interpapillary muscle distance are the strongest independent predictors of CIMR.

Right Ventricular Function After Acute Myocardial Infarction Treated With Primary Percutaneous Coronary Intervention (from the Glycometabolic Intervention as Adjunct to Primary Percutaneous Coronary Intervention in ST-Segment Elevation Myocardial Infarction III Trial).

Right ventricular (RV) dysfunction is a powerful risk marker after acute myocardial infarction (MI). Primary percutaneous coronary intervention (PCI) has markedly reduced myocardial damage of the left ventricle, but reliable data on RV damage using cardiac magnetic resonance imaging (MRI) are scarce. In a recent trial of patients with acute MI treated with primary PCI, in which the primary end point was left ventricular (LV) ejection fraction after 4 months measured with MRI, we conducted a prospectively defined substudy in which we examined RV function. RV ejection fraction (RVEF) and RV scar size were measured with MRI at 4 months. Tricuspid annular plane systolic excursion (TAPSE) and RV free wall longitudinal strain (FWLS) were assessed using echocardiography before discharge and at 4 months. We studied 258 patients without diabetes mellitus; their mean age was 58 ± 11 years, 79% men and mean LV ejection fraction was 54 ± 8%. Before discharge, 5.2% of patients had TAPSE <17 mm, 32% had FWLS > -20% and 11% had FWLS > -15%. During 4 months, TAPSE increased from 22.8 ± 3.6 to 25.1 ± 3.9 mm (p <0.001) and FWLS increased from -22.6 ± 5.8 to -25.9 ± 4.7% (p <0.001). After 4 months, mean RVEF on MRI was 64.1 ± 5.2% and RV scar was detected in 5 patients (2%). There was no correlation between LV scar size and RVEF (p = 0.9), TAPSE (p = 0.1), or RV FWLS (p = 0.9). In conclusion, RV dysfunction is reversible in most patients and permanent RV ischemic injury is very uncommon 4 months after acute MI treated with primary PCI.

Effect of Metformin Treatment on Lipoprotein Subfractions in Non-Diabetic Patients with Acute Myocardial Infarction: A Glycometabolic Intervention as Adjunct to Primary Coronary Intervention in ST Elevation Myocardial Infarction (GIPS-III) Trial.

OBJECTIVE: Metformin affects low density lipoprotein (LDL) and high density (HDL) subfractions in the context of impaired glucose tolerance, but its effects in the setting of acute myocardial infarction (MI) are unknown. We determined whether metformin administration affects lipoprotein subfractions 4 months after ST-segment elevation MI (STEMI). Second, we assessed associations of lipoprotein subfractions with left ventricular ejection fraction (LVEF) and infarct size 4 months after STEMI. METHODS: 371 participants without known diabetes participating in the GIPS-III trial, a placebo controlled, double-blind randomized trial studying the effect of metformin (500 mg bid) during 4 months after primary percutaneous coronary intervention for STEMI were included of whom 317 completed follow-up (clinicaltrial.gov Identifier: NCT01217307). Lipoprotein subfractions were measured using nuclear magnetic resonance spectroscopy at presentation, 24 hours and 4 months after STEMI. (Apo)lipoprotein measures were obtained during acute STEMI and 4 months post-STEMI. LVEF and infarct size were measured by cardiac magnetic resonance imaging. RESULTS: Metformin treatment slightly decreased LDL cholesterol levels (adjusted P = 0.01), whereas apoB remained unchanged. Large LDL particles and LDL size were also decreased after metformin treatment (adjusted P<0.001). After adjustment for covariates, increased small HDL particles at 24 hours after STEMI predicted higher LVEF (P = 0.005). In addition, increased medium-sized VLDL particles at the same time point predicted a smaller infarct size (P<0.001). CONCLUSION: LDL cholesterol and large LDL particles were decreased during 4 months treatment with metformin started early after MI. Higher small HDL and medium VLDL particle concentrations are associated with favorable LVEF and infarct size.

Galectin-3 and sST2 in prediction of left ventricular ejection fraction after myocardial infarction.

BACKGROUND: Fibrosis is a pivotal event in infarct repair and progressive remodeling after myocardial infarction (MI). Biomarkers may be used to monitor fibrosis, and therefore we evaluated the predictive value of galectin-3 and sST2 for cardiac remodeling after MI. METHODS: Plasma galectin-3 and sST2 were measured in patients admitted with primary percutaneous coronary intervention (PCI) for acute MI, at baseline and at 4months. Left ventricular ejection fraction (LVEF) and infarct size were measured after 4months with cardiac MRI (CMR). RESULTS: In total, 247 patients had blood samples and CMR data available (mean age 57.7±11.6years; 79.8% male). Increased baseline galectin-3 (≥17.8ng/mL) identified patients with lower LVEF (50.3% (±9.1) vs. non-elevated galectin-3 55.0% (±8.0); P<0.001), and larger infarct size (13.8g. (±12.9) vs. 8.6g. (±8.7); P=0.002) after 4months. Elevated sST2 (≥35.0ng/mL) did not predict decreased LVEF or larger infarct size. Furthermore we showed that at baseline, galectin-3 was an independent predictor for LVEF (ß=-0.18; P=0.005) and infarct size (ß=0.18; P=0.004). We repeated the analyses using median values of galectin-3 (13.4ng/mL) and sST2 (30.3ng/mL) as a cut point, and this validated our results. CONCLUSION: The fibrosis biomarker galectin-3, but not sST2, taken immediately after MI, predicts LVEF and infarct size after 4months. We hypothesize that galectin-3 may play a role in the pathophysiology of cardiac remodeling after acute MI.

The effect of metformin on cardiovascular risk profile in patients without diabetes presenting with acute myocardial infarction: data from the Glycometabolic Intervention as adjunct to Primary Coronary Intervention in ST Elevation Myocardial Infarction (GIPS-III) trial.

OBJECTIVE: In patients with diabetes mellitus, metformin treatment is associated with reduced mortality and attenuation of cardiovascular risk. As a subanalysis of the Glycometabolic Intervention as adjunct to Primary Coronary Intervention in ST Elevation Myocardial Infarction (GIPS-III) study, we evaluated whether metformin treatment in patients with ST-segment elevation myocardial infarction (STEMI) without diabetes improves the cardiovascular risk profile. METHODS: A total of 379 patients, without known diabetes, presenting with STEMI were randomly allocated to receive metformin 500 mg twice daily or placebo for 4 months. RESULTS: After 4 months, the cardiovascular risk profile of patients receiving metformin (n=172) was improved compared with placebo (n=174); glycated hemoglobin (5.83% (95% CI 5.79% to 5.87%) vs 5.89% (95% CI 5.85% to 5.92%); 40.2 mmol/mol (95% CI 39.8 to 40.6) vs 40.9 mmol/mol (40.4 to 41.2), p=0.049); total cholesterol (3.85 mmol/L (95% CI 3.73 to 3.97) vs 4.02 mmol/L (95% CI 3.90 to 4.14), p=0.045); low-density lipoprotein cholesterol (2.10 mmol/L (95% CI 1.99 to 2.20) vs 2.3 mmol/L (95% CI 2.20 to 2.40), p=0.007); body weight (83.8 kg (95% CI 83.0 to 84.7) vs 85.2 kg (95% CI 84.4 to 86.1), p=0.024); body mass index (26.8 kg/m(2) (95% CI 26.5 to 27.0) vs 27.2 kg/m(2) (95% CI 27.0 to 27.5), p=0.014). Levels of fasting glucose, postchallenge glucose, insulin, high-density lipoprotein cholesterol, and blood pressure were similar in both groups. CONCLUSIONS: Among patients with STEMI without diabetes, treatment with metformin for 4 months resulted in a modest improvement of the cardiovascular risk profile compared with placebo. TRIAL REGISTER NUMBER: NCT01217307.

Effect of Metformin on Renal Function After Primary Percutaneous Coronary Intervention in Patients Without Diabetes Presenting with ST-elevation Myocardial Infarction: Data from the GIPS-III Trial.

PURPOSE: The association between metformin use and renal function needs further to be elucidated since data are insufficient whether metformin affects renal function in higher risk populations such as after ST-elevation myocardial infarction (STEMI). METHODS: We studied 379 patients included in the GIPS-III trial in which patients without diabetes or renal dysfunction, who underwent primary percutaneous coronary interventions (PCI) for STEMI, were randomized to metformin 500 mg or placebo twice daily for four months. At baseline and at seven scheduled visits up to four months after PCI, estimated glomerular filtration rate (eGFR) was determined (2582 values). Contrast-induced acute kidney injury (CI-AKI) was defined as an increase in serum creatinine of ≥0.3 mg/dl or 25 % rise within 48 h after PCI. RESULTS: At all visits, the mean eGFR was similar in patients randomized to metformin or placebo. Over the four month period, mixed-effect repeated-measures model analysis showed a least-squares mean ± standard error change in eGFR of -5.9±0.8 ml/min/1.73 m2 in the metformin group and −7.1 ±0.8 ml/min/1.73 m2 in the control group (P=0.27 for overall interaction). The incidence of CI-AKI was 14.8 %; 29 (15.2 %) patients in the metformin group versus 27 (14.4 %) controls (P=0.89). After adjustment for covariates, metformin treatment was not associated with CI-AKI (odds ratio: 0.96, 95%CI 0.52−1.75, P=0.88). CONCLUSION: We conclude that initiation of metformin shortly after primary PCI has no adverse effect on renal function in patients without diabetes or prior renal impairment, further providing evidence of the safety of metformin use after myocardial infarction and subsequent contrast exposure.

Effect of metformin on left ventricular function after acute myocardial infarction in patients without diabetes: the GIPS-III randomized clinical trial.

IMPORTANCE: Metformin treatment is associated with improved outcome after myocardial infarction in patients with diabetes. In animal experimental studies metformin preserves left ventricular function. OBJECTIVE: To evaluate the effect of metformin treatment on preservation of left ventricular function in patients without diabetes presenting with ST-segment elevation myocardial infarction (STEMI). DESIGN, SETTING, AND PARTICIPANTS: Double-blind, placebo-controlled study conducted among 380 patients who underwent primary percutaneous coronary intervention (PCI) for STEMI at the University Medical Center Groningen, The Netherlands, between January 1, 2011, and May 26, 2013. INTERVENTIONS: Metformin hydrochloride (500 mg) (n = 191) or placebo (n = 189) twice daily for 4 months. MAIN OUTCOMES AND MEASURES: The primary efficacy measure was left ventricular ejection fraction (LVEF) after 4 months, assessed by magnetic resonance imaging. A secondary efficacy measure was the N-terminal pro-brain natriuretic peptide (NT-proBNP) concentration after 4 months. The incidence of major adverse cardiac events (MACE; the combined end point of death, reinfarction, or target-lesion revascularization) was recorded until 4 months as a secondary efficacy measure. RESULTS: At 4 months, all patients were alive and none were lost to follow-up. LVEF was 53.1% (95% CI, 51.6%-54.6%) in the metformin group (n = 135), compared with 54.8% (95% CI, 53.5%-56.1%) (P = .10) in the placebo group (n = 136). NT-proBNP concentration was 167 ng/L in the metformin group (interquartile range [IQR], 65-393 ng/L) and 167 ng/L in the placebo group (IQR, 74-383 ng/L) (P = .66). MACE were observed in 6 patients (3.1%) in the metformin group and in 2 patients (1.1%) in the placebo group (P = .16). Creatinine concentration (79 µmol/L [IQR, 70-87 µmol/L] vs 79 µmol/L [IQR, 72-89 µmol/L], P = .61) and glycated hemoglobin (5.9% [IQR, 5.6%-6.1%] vs 5.9% [IQR, 5.7%-6.1%], P = .15) were not significantly different between both groups. No cases of lactic acidosis were observed. CONCLUSIONS AND RELEVANCE: Among patients without diabetes presenting with STEMI and undergoing primary PCI, the use of metformin compared with placebo did not result in improved LVEF after 4 months. The present findings do not support the use of metformin in this setting. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT01217307.

Time of symptom onset and value of myocardial blush and infarct size on prognosis in patients with ST-elevation myocardial infarction.

In patients with ST-segment elevation myocardial infarction (STEMI), the time of onset of ischemia has been associated with myocardial infarction (MI) size. Myocardial blush grade (MBG) reflects myocardial response to ischemia/reperfusion injury, which may differ according to time of the day. The aim of our study was to explore the 24-hour variation in MBG and MI size in relation to outcomes in STEMI patients. A retrospective multicenter analysis of 6970 STEMI patients was performed. Time of onset of STEMI was divided into four 6-hour periods. STEMI patients have a significant 24-hour pattern in onset of symptoms, with peak onset around 09:00 hour. Ischemic time was longest and MI size, estimated by peak creatine kinase concentration, was largest in patients with STEMI onset between 00:00 and 06:00 hours. Both MBG and MI size were independently associated with mortality. Time of onset of STEMI was not independently associated with mortality when corrected for baseline and procedural factors. Interestingly, patients presenting with low MBG between 00:00 and 06:00 hours had a better prognosis compared to other groups. In conclusion, patients with symptom onset between 00:00 and 06:00 hours have longer ischemic time and consequently larger MI size. However, this does not translate into a higher mortality in this group. In addition, patients with failed reperfusion presenting in the early morning hours have better prognosis, suggesting a 24-hour pattern in myocardial protection.

Chronic metformin treatment is associated with reduced myocardial infarct size in diabetic patients with ST-segment elevation myocardial infarction.

PURPOSE: Increased myocardial infarct (MI) size is associated with higher risk of developing left ventricular dysfunction, heart failure and mortality. Experimental studies have suggested that metformin treatment reduces MI size after induced ischaemia but human data is lacking. We aimed to investigate the effect of metformin on MI size in patients presenting with an acute MI. METHODS: All consecutive patients (n = 3,288) presenting to our hospital with ST-segment elevation myocardial infarction (STEMI) undergoing primary PCI between January 2004 and December 2010 were included in this retrospective analysis. Patients with diabetes were divided according to metformin versus non-metformin based pharmacotherapy. MI size was estimated using peak values of serum creatine kinase (CK), myocardial band of CK (CK-MB), and troponin-T. RESULTS: We identified 677 (20.6 %) patients with diabetes, of whom 189 (27.9 %) were treated with metformin. Chronic metformin treatment was associated with lower peak levels of CK (1,101 vs. 1,422 U/L, P = 0.005), CK-MB (152 vs. 182 U/L, P = 0.018) and troponin-T (2.5 vs. 4.0 ng/L, P = 0.021) compared to non-metformin using diabetics. After adjustment for age, sex, TIMI flow post PCI, and previous MI, the use of metformin treatment remained an independent predictor of smaller MI size. Patient with diabetes treated with metformin had even smaller MI size than patients without diabetes. CONCLUSIONS: Chronic metformin treatment is associated with reduced MI size compared to non-metformin based strategies in diabetic patients presenting with STEMI. Metformin might have additional beneficial effects beyond glucose lowering efficacy.

Circulating alpha-klotho levels are not disturbed in patients with type 2 diabetes with and without macrovascular disease in the absence of nephropathy.

BACKGROUND: Diabetes is associated with a high incidence of macrovascular disease (MVD), including peripheral and coronary artery disease. Circulating soluble-Klotho (sKlotho) is produced in the kidney and is a putative anti-aging and vasculoprotective hormone. Reduced Klotho levels may therefore increase cardiovascular risk in diabetes. We investigated if sKlotho levels are decreased in type 2 diabetes and associate with MVD in the absence of diabetic nephropathy, and whether hyperglycemia affects renal Klotho production in vitro and in vivo. METHODS: sKlotho levels were determined with ELISA in diabetic and non-diabetic patients with and without MVD, and healthy control subjects. Human renal tubular epithelial cells (TECs) were isolated and exposed to high glucose levels (15 and 30 mM) in vitro and Klotho levels were measured with qPCR and quantitative immunofluorescence. Klotho mRNA expression was quantified in kidneys obtained from long term (3 and 8 months) diabetic Ins2Akita mice and normoglycemic control mice. RESULTS: No significant differences in sKlotho levels were observed between diabetic patients with and without MVD (527 (433-704) pg/mL, n = 35), non-diabetic MVD patients (517 (349-571) pg/mL, n = 27), and healthy control subjects (435 (346-663) pg/mL, n = 15). High glucose (15 and 30 mM) did not alter Klotho expression in TECs. Long-term hyperglycemia in diabetic Ins2Akita mice (characterized by increased HbA1c levels [12.9 ± 0.3% (3 months) and 11.3 ± 2.0% (8 months)], p < 0.05 vs. non-diabetic mice) did not affect renal Klotho mRNA expression. CONCLUSIONS: These data indicate that sKlotho levels are not affected in type 2 diabetes patients with and without MVD. Furthermore, hyperglycemia per se does not affect renal Klotho production. As type 2 diabetes does not alter sKlotho levels, sKlotho does not seem to play a major role in the pathogenesis of MVD in type 2 diabetes.