Association between hyperglycemia at admission and microvascular obstruction in patients with ST-segment elevation myocardial infarction

Coronary No-Reflow after Primary Percutaneous Coronary Intervention-Current Knowledge on Pathophysiology, Diagnosis, Clinical Impact and Therapy

Coronary no-reflow (CNR) is a frequent phenomenon that develops in patients with ST-segment elevation myocardial infarction (STEMI) following reperfusion therapy. CNR is highly dynamic, develops gradually (over hours) and persists for days to weeks after reperfusion. Microvascular obstruction (MVO) developing as a consequence of myocardial ischemia, distal embolization and reperfusion-related injury is the main pathophysiological mechanism of CNR. The frequency of CNR or MVO after primary PCI differs widely depending on the sensitivity of the tools used for diagnosis and timing of examination. Coronary angiography is readily available and most convenient to diagnose CNR but it is highly conservative and underestimates the true frequency of CNR. Cardiac magnetic resonance (CMR) imaging is the most sensitive method to diagnose MVO and CNR that provides information on the presence, localization and extent of MVO. CMR imaging detects intramyocardial hemorrhage and accurately estimates the infarct size. MVO and CNR markedly negate the benefits of reperfusion therapy and contribute to poor clinical outcomes including adverse remodeling of left ventricle, worsening or new congestive heart failure and reduced survival. Despite extensive research and the use of therapies that target almost all known pathophysiological mechanisms of CNR, no therapy has been found that prevents or reverses CNR and provides consistent clinical benefit in patients with STEMI undergoing reperfusion. Currently, the prevention or alleviation of MVO and CNR remain unmet goals in the therapy of STEMI that continue to be under intense research.

Nomograms referenced by cardiac magnetic resonance in the prediction of cardiac injuries in patients with ST-elevation myocardial infarction

BACKGROUND

Evaluation of cardiac injuries is essential in patients with ST-elevation myocardial infarction (STEMI). Cardiac magnetic resonance (CMR) has become the gold standard for quantifying cardiac injuries; however, its routine application is limited. A nomogram is a useful tool for prognostic prediction based on the comprehensive utilization of clinical data. We presumed that the nomogram models established using CMR as a reference could precisely predict cardiac injuries.

METHODS

This analysis included 584 patients with acute STEMI from a CMR registry study for STEMI (NCT03768453). The patients were divided into training (n = 408) and testing (n = 176) datasets. The least absolute shrinkage and selection operator method and multivariate logistic regression were used to construct nomograms for predicting left ventricular ejection fraction (LVEF) ≤40%, infarction size (IS) ≥ 20% on the LV mass, and microvascular dysfunction.

RESULTS

The nomogram for predicting LVEF≤40%, IS≥20%, and microvascular dysfunction comprised 14, 10, and 15 predictors, respectively. With the nomograms, the individual risk probability of developing specific outcomes could be calculated, and the weight of each risk factor was demonstrated. The C-index of the nomograms in the training dataset were 0.901, 0.831, and 0.814, respectively, and were comparable in the testing set, showing good nomogram discrimination and calibration. The decision curve analysis demonstrated good clinical effectiveness. Online calculators were also constructed.

CONCLUSIONS

With the CMR results as the reference standard, the established nomograms demonstrated good effectiveness in predicting cardiac injuries after STEMI and could provide physicians with a new option for individual risk stratification.

A historical literature review of coronary microvascular obstruction and intra-myocardial hemorrhage as functional/structural phenomena

The analysis of experimental data demonstrates that platelets and neutrophils are involved in the no-reflow phenomenon, also known as microvascular obstruction (MVO). However, studies performed in the isolated perfused hearts subjected to ischemia/reperfusion (I/R) do not suggest the involvement of microembolization and microthrombi in this phenomenon. The intracoronary administration of alteplase has been found to have no effect on the occurrence of MVO in patients with acute myocardial infarction. Consequently, the major events preceding the appearance of MVO in coronary arteries are independent of microthrombi, platelets, and neutrophils. Endothelial cells appear to be the target where ischemia can disrupt the endothelium-dependent vasodilation of coronary arteries. However, reperfusion triggers more pronounced damage, possibly mediated by pyroptosis. MVO and intra-myocardial hemorrhage contribute to the adverse post-infarction myocardial remodeling. Therefore, pharmacological agents used to treat MVO should prevent endothelial injury and induce relaxation of smooth muscles. Ischemic conditioning protocols have been shown to prevent MVO, with L-type Ca ²⁺ channel blockers appearing the most effective in treating MVO.

Hyperglycemia and intramyocardial hemorrhage in patients with ST-segment elevation myocardial infarction

BACKGROUND

Hyperglycemia at admission and intramyocardial hemorrhage (IMH) are associated with poor prognosis in patients with ST-segment elevation myocardial infarction (STEMI). Little is known about the relationship between glucose levels at admission and IMH. The association between matrix metalloproteinase-9 (MMP-9), which plays an important role in the development of IMH, and hyperglycemia is also unknown. This study aimed to investigate the relationship between hyperglycemia at admission and IMH in patients with STEMI.

METHODS

We enrolled 174 patients with first STEMI who underwent primary percutaneous coronary intervention (PCI) and cardiovascular magnetic resonance (CMR) imaging. T2-weighted imaging and late gadolinium enhancement (LGE)-CMR were performed to detect IMH and microvascular obstruction (MVO), respectively. Two patient groups were created: IMH group and non-IMH group. MMP-9 levels were measured in the culprit coronary arteries of 13 patients.

RESULTS

Glucose level at admission and the value of glycosylated hemoglobin were higher in the IMH group than in the non-IMH group [IMH group vs. non-IMH group; 208.5 (157.8-300.5) mg/dL vs. 157.0 (128.8-204.3) mg/dL, p < 0.001, and 6.2 (5.7-7.5) % vs. 5.8 (5.4-6.6) %, p = 0.030, respectively]. A multivariable logistic regression analysis revealed that only admission glucose level was an independent predictor of IMH (OR: 1.012; 95 % CI: 1.005-1.020, p = 0.001). The MMP-9 levels in patients with IMH were higher than those in patients without IMH [256.0 (161.0-396.0) ng/mL vs. 73.5 (49.5-131.0) ng/mL, p = 0.040]. There was a moderate positive correlation between glucose levels at admission and MMP-9 levels (r = 0.600, p = 0.030).

CONCLUSIONS

Hyperglycemia at admission is associated with the occurrence of IMH in patients with STEMI.

Predictors of Microvascular Reperfusion After Myocardial Infarction

Purpose of Review

In acute ST-segment elevation myocardial infarction (STEMI), successful restoration of blood flow in the infarct-related coronary artery may not secure effective myocardial reperfusion. The mortality and morbidity associated with acute MI remain significant. Microvascular obstruction (MVO) represents failed microvascular reperfusion. MVO is under-recognized, independently associated with adverse cardiac prognosis and represents an unmet therapeutic need.

Recent Findings

Multiple factors including clinical presentation, patient characteristics, biochemical markers, and imaging parameters are associated with MVO after MI.

Summary

Impaired microvascular reperfusion is common following percutaneous coronary intervention (PCI). New knowledge about disease mechanisms underpins precision medicine with individualized risk assessment, investigation, and stratified therapy. To date, there are no evidence-based therapies to prevent or treat MVO post-MI. Identifying novel therapy for MVO is the next frontier.

Effect of Diabetes Mellitus and Left Ventricular Perfusion on Frequency of Development of Heart Failure and/or All-cause Mortality Late After Acute Myocardial Infarction

Type 2 diabetes mellitus (DM) has a detrimental impact on cardiovascular outcomes, with implications for prognosis following ST elevation myocardial infarction (STEMI).The aim was to evaluate the impact of DM and myocardial perfusion on the long-term risk of heart failure (HF) and/or all-cause mortality following primary percutaneous coronary intervention (pPCI) for STEMI. A total of 406 STEMI patients (104 with DM) treated with pPCI were enrolled in this observational study. Myocardial perfusion was reassessed with the Quantitative Myocardial Blush Evaluator. Follow-up data on HF (ICD10 [International Statistical Classification of Diseases] codes I50.0 - I50.9) and all-cause mortality were obtained from the National Health Fund. During a 6-year follow-up, 36 (35%) patients with DM died compared with 45 (15%) patients without DM (p <0.001). Also, 24 (23%) patients with DM developed HF compared with 51 (17%) patients without DM (p = 0.20). Patients with DM and HF had the highest mortality rate (75%), and those with DM and a QuBE score below the median value (9.0 arb. units) had significantly higher risk of HF (hazard ratio [HR] =1.96, 95% CI 1.18 to 3.27, p = 0.0099) and the composite of HF and/or all-cause mortality (HR = 1.89, 95% CI 1.33 to 2.69, p = 0.0004). In conclusion DM (type 2) and diminished myocardial perfusion increase the risk of HF and/or all-cause mortality during a 6-year follow-up after pPCI for STEMI.

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.

Pre-Procedural Hyperglycemia Increases the Risk of Contrast-Induced Nephropathy in Patients Undergoing Coronary Angiography: A Systematic Review and Meta-Analysis

BACKGROUND

Contrast-induced nephropathy (CIN) frequently occurs following coronary angiography (CAG) and is associated with worse outcomes, including both short and long-term mortality. Previous studies reported an association between procedural hyperglycemia (PH) and CIN, with or without diabetes mellitus (DM). We performed a systematic review and meta-analysis to explore the association of PH and CIN in patients undergoing CAG.

METHODS

We searched the databases of MEDLINE and EMBASE from inception to January 2020. Included studies investigated CIN incidence in patients undergoing CAG. Data from each study were combined using the random-effects model.

RESULTS

A total of eight studies were included in this meta-analysis. We found that PH was associated with an increased risk of CIN following CAG (pooled OR = 1.71, 95%CI:1.35-2.16, where PH was defined as ≥140 mg/dl; and pooled OR = 2.07, 95%CI:1.80-2.37, where PH was defined as ≥200 mg/dl). In subgroup analysis of non-diabetic patients and STEMI patients undergoing primary percutaneous coronary intervention, we found that PH was associated with an increased risk of CIN in both subgroups, where PH was defined as ≥140 mg/dl and ≥200mg/dl (p-value < 0.05).

CONCLUSIONS

Our meta-analysis demonstrated that PH significantly increases the risk of CIN following CAG, in both diabetic and non-diabetic populations. Further studies are needed to evaluate whether strict blood glucose control can reduce the incidence of CIN in this population.

Pathophysiology and diagnosis of coronary microvascular dysfunction in ST-elevation myocardial infarction

Early mechanical reperfusion of the epicardial coronary artery by primary percutaneous coronary intervention (PCI) is the guideline-recommended treatment for ST-elevation myocardial infarction (STEMI). Successful restoration of epicardial coronary blood flow can be achieved in over 95% of PCI procedures. However, despite angiographically complete epicardial coronary artery patency, in about half of the patients perfusion to the distal coronary microvasculature is not fully restored, which is associated with increased morbidity and mortality. The exact pathophysiological mechanism of post-ischaemic coronary microvascular dysfunction (CMD) is still debated. Therefore, the current review discusses invasive and non-invasive techniques for the diagnosis and quantification of CMD in STEMI in the clinical setting as well as results from experimental in vitro and in vivo models focusing on ischaemic-, reperfusion-, and inflammatory damage to the coronary microvascular endothelial cells. Finally, we discuss future opportunities to prevent or treat CMD in STEMI patients.

Prognostic value of HbA1c for in-hospital and short-term mortality in patients with acute coronary syndrome: a systematic review and meta-analysis

Background

HbA1c, the most commonly used indicator of chronic glucose metabolism, is closely associated with cardiovascular disease. However, the relationship between HbA1c and the mortality of acute coronary syndrome (ACS) patients has not been elucidated yet. Here, we aim to conduct a systematic review assessing the effect of HbA1c on in-hospital and short-term mortality in ACS patients.

Methods

Relevant studies reported before July 2019 were retrieved from databases including PubMed, Embase, and Central. Pooled relative risks (RRs) and the corresponding 95% confidence interval (CI) were calculated to evaluate the predictive value of HbA1c for the in-hospital mortality and short-term mortality.

Results

Data from 25 studies involving 304,253 ACS patients was included in systematic review. The pooled RR of in-hospital mortality was 1.246 (95% CI 1.113–1.396, p: 0.000, I² = 48.6%, n = 14) after sensitivity analysis in studies reporting HbA1c as categorial valuable. The pooled RR was 1.042 (95% CI 0.904–1.202, p: 0.57, I² = 82.7%, n = 4) in random-effects model for studies reporting it as continuous valuable. Subgroup analysis by diabetic status showed that elevated HbA1c is associated increased short-term mortality in ACS patients without diabetes mellitus (DM) history and without DM (RR: 2.31, 95% CI (1.81–2.94), p = 0.000, I² = 0.0%, n = 5; RR: 2.56, 95% CI 1.38–4.74, p = 0.003, I² = 0.0%, n = 2, respectively), which was not the case for patients with DM and patients from studies incorporating DM and non-DM individuals (RR: 1.16, 95% CI 0.79–1.69, p = 0.451, I² = 31.9%, n = 3; RR: 1.10, 95% CI 0.51–2.38), p = 0.809, I² = 47.4%, n = 4, respectively).

Conclusions

Higher HbA1c is a potential indicator for in-hospital death in ACS patients as well as a predictor for short-term mortality in ACS patients without known DM and without DM.

Association of Hyperglycemia and Final TIMI Flow with One-Year Mortality of Patients with Acute ST-Segment Elevation Myocardial Infarction Undergoing Primary PCI

The association of hyperglycemia at admission and final thrombolysis in myocardial infarction (TIMI) flow with 1-year mortality of patient with acute ST-segment elevation myocardial infarction (STEMI) undergoing primary percutaneous coronary intervention (PCI) has not much been explored. We evaluated the association of hyperglycemia and final TIMI flow with 1-year mortality in patients with acute STEMI who underwent primary PCI. We retrospectively analyzed 856 patients with STEMI who underwent primary PCI in a tertiary care academic center between January 2014 and July 2016. Based on the receiver operating characteristics curve, the cutoff used for hyperglycemia in this study was greater than or equal to 169 mg/dL. Cox proportional hazard model was used to determine the association of hyperglycemia and TIMI flow with 1-year mortality. Compared with patients with lower blood glucose level (<169 mg/dL; n  = 549), a greater proportion of patients who presented with hyperglycemia (≥169 mg/dL; n  = 307) had final TIMI flow 0 to 1 (3.3 vs. 0.5%; adjusted odds ratio = 5.58, 95% confidence interval [CI] 1.30-23.9, p  = 0.02). Hyperglycemia was associated with an increased risk for 1-year mortality (adjusted hazard ratio [HR]= 2.0, 95% CI: 1.13-3.53, p  = 0.017). Multivariable Cox regression showed that the interaction of hyperglycemia and final TIMI flow 0 to 1 was associated with an elevated risk for 1-year mortality (adjusted HR= 9.4, 95% CI: 2.34-37.81, p  = 0.002). A higher proportion of patients with acute STEMI who presented with hyperglycemia had final TIMI flow 0 to 1 after primary PCI. The interaction of hyperglycemia and final TIMI flow 0 to 1 was associated with an increased risk for 1-year mortality. This study suggests that aggressive control of hyperglycemia prior to primary PCI may facilitate better angiographic and clinical outcomes after primary PCI. Clinical Trial Registration  Clinicaltrials.gov Identifier number: NCT02319473.

Effect of stress hyperglycaemia on monocyte chemoattractant protein-1 levels and the short-term prognosis of patients with acute ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention

The present study prospectively investigated the effect of blood glucose level at admission on monocyte chemoattractant protein-1 levels at different time points before and after primary percutaneous coronary intervention, and the postoperative 1-year prognosis of patients with acute ST-segment elevation myocardial infarction. The 146 patients with acute ST-segment elevation myocardial infarction undergoing primary percutaneous coronary intervention were divided into three groups: Group 1, non-diabetic, non-hyperglycemic group; group 2, stress hyperglycemia group; and group 3, diabetic group. Serum monocyte chemoattractant protein-1 levels before and after percutaneous coronary intervention (PCI), and the incidence of major adverse cardiovascular events 1-year post PCI were observed. The increase in monocyte chemoattractant protein-1 levels 24 h after percutaneous coronary intervention, compared with those before percutaneous coronary intervention, was significantly correlated with the blood glucose level at admission. Furthermore, the 1-year postoperative major adverse cardiovascular events rates were significantly higher in groups 2 and 3 compared with group 1. Logistic regression analysis demonstrated that a high blood glucose level at admission, diabetes, and high preoperative monocyte chemoattractant protein-1 levels were risk factors for major adverse cardiovascular events 1-year post-percutaneous coronary intervention. Stress hyperglycemia and diabetes may contribute to high monocyte chemoattractant protein-1 levels and prolonged inflammation. These symptoms are associated with poor prognosis of acute ST-segment elevation myocardial infarction in patients undergoing primary percutaneous coronary intervention.

Evaluation of myocardial fibrosis in diabetes with cardiac magnetic resonance T1-mapping: Correlation with the high-level hemoglobin A1c

AIM

The aim of the study was to assess the extracellular volume fraction (ECV) in type 2 diabetes mellitus (T2DM) patients with different level of hemoglobin A1c (HbA1c) by cardiac magnetic resonance (CMR), and the ability of HbA1c to predict myocardial fibrosis.

METHODS

In total, 80 T2DM patients and 20 age- and sex-matched controls were prospective enrolled and underwent CMR to obtain ECV value and LV function parameters. We divided all patients into a group of HbA1c < 7.0% and a group of HbA1c ≥ 7.0%.

RESULTS

In the higher HbA1c group the ECV value (all p < 0.001) was higher than both lower HbA1c group (36.23% vs. 32.19%, p < 0.001) and controls (36.23% vs. 29.73%, p < 0.001). HbA1c was positively associated (β = 0.36, p = 0.004) with ECV, and it was also an independent predictor of myocardial fibrosis (OR = 2.00, P = 0.014). The ROC analysis showed that 7.1% was the optimal cutoff value of HbA1c that predicted the risk of myocardial fibrosis with high diagnostic accuracy (area under the curve = 0.78).

CONCLUSION

T1 mapping provided myocardial fibrosis information in T2DM patients. HbA1c is positively correlated with myocardial fibrosis and can be an independently predictor of myocardial fibrosis, which may be helpful for the clinical decision-making of blood glucose control.

Impact of acute diabetes decompensation on outcomes of diabetic patients admitted with ST-elevation myocardial infarction

BACKGROUND

Acute hyperglycemia is associated with worse outcomes in diabetic patients admitted with ST-elevation myocardial infarction (STEMI). However, the impact of full-scale decompensated diabetes on STEMI outcomes has not been investigated.

METHODS

We utilized the national inpatient sample (2003-2014) to identify adult diabetic patients admitted with STEMI. We defined decompensated diabetes as the presence of diabetic ketoacidosis (DKA) or hyperglycemic hyperosmolar state (HHS). We compared in-hospital morbidity and mortality and cost between patients with and without diabetes decompensation before and after propensity-score matching.

RESULTS

A total of 73,722 diabetic patients admitted with STEMI were included in the study. Of those, 1131 (1.5%) suffered DKA or HSS during the hospitalization. After propensity-score matching, DKA/HHS remained associated with a significant 32% increase in in-hospital mortality (25.6% vs. 19.4%, p = 0.001). The DKA/HHS group also had higher incidences of acute kidney injury (39.4% vs. 18.9%, p < 0.001), sepsis (7.3% vs. 4.9%, p = 0.022), blood transfusion (11.3% vs. 8.2%) and a non-significant trend towards higher incidence of stroke (3.8% vs. 2.4%, p = 0.087). Also, DKA/HHS diagnosis was associated with lower rates of referral to coronary angiography (51.5% vs. 55.5%, p = 0.023), coronary stenting (26.1% vs. 34.8%, p < 0.001), or bypass grafting (6.2% vs. 8.7%, p = 0.033). Referral for invasive angiography was associated with lower odds of death during the hospitalization (adjusted OR 0.66, 95%CI 0.44-0.98, p = 0.039).

CONCLUSIONS

Decompensated diabetes complicates ~ 1.5% of STEMI admissions in diabetic patients. It is associated with lower rates of referral for angiography and revascularization, and a negative differential impact on in-hospital morbidity and mortality and cost.

Proximal culprit lesion and coronary artery occlusion independently predict the risk of microvascular obstruction in acute myocardial infarction

Microvascular obstruction (MO) and coronary flow have been independently described to have a high prognostic impact after acute myocardial infarction (AMI). Their interdependence has not been precisely elucidated, so far. Aim of this study was to investigate the impact of coronary flow on the occurrence of MO in patients with AMI. 336 patients with revascularized AMI were examined by cardiac magnetic resonance imaging. Patients were categorised into two groups based on the presence of MO. Procedural characteristics and marker of infarct size were analyzed. MO was present in 110 (33 %) and absent in 226 (67 %) patients. Both groups differed significantly regarding pre- and post-interventional thrombolysis in myocardial infarction (TIMI) flow. After multivariable regression analysis pre-interventional TIMI-flow 0, proximal culprit lesion, post-interventional TIMI-flow <III and creatine-kinase-myocardial band (CK-MB) remained strong independent predictors for MO. Odds ratios for pre-interventional TIMI-flow 0 were 2.31 (95 % CI 1.04-5.11, P = 0.034); for proximal culprit lesion 11.94 (95 % CI 5.70-25.01, P < 0.001); for post-interventional TIMI-flow III 0.28 (95 % CI 0.10-0.74, P = 0.010) and for CK-MB 1.50 (95 % CI 1.24-1.82, P < 0.001). Pre-interventional proximal coronary artery occlusion (TIMI 0) and insufficient post-interventional coronary reperfusion (TIMI-flow  <III) have a high impact on the occurrence of MO in AMI.

Association between epicardial adipose tissue volume and myocardial salvage in patients with a first ST-segment elevation myocardial infarction: An epicardial adipose tissue paradox

BACKGROUND

Epicardial adipose tissue (EAT), defined as the adipose tissue between the visceral pericardium and the outer margin of the myocardium, is associated with coronary artery disease in the general population. However, the clinical implications of EAT in patients with ST-segment elevation myocardial infarction (STEMI) remain unclear.

METHODS

A total of 142 patients with a first STEMI, who received reperfusion therapy within 12h from symptom onset, were enrolled. All patients underwent cardiac magnetic resonance imaging to evaluate infarct core (Core), area at risk (AAR), and EAT volume. Myocardial salvage index (MSI) was defined as AAR minus Core divided by AAR. Patients in the lower tertile of EAT volume were classified as the low EAT group (group L) and the other two-thirds as the high EAT group (group H).

RESULTS

The mean MSI was lower in group L than in group H (0.43±0.13 vs 0.49±0.13, p=0.01), and the mean extent of Core was higher in group L than in group H (25±10% vs 19±10%, p<0.01). Multivariate linear regression analysis including coronary risk factors and previously reported predictors of infarct size demonstrated that EAT volume was an independent predictor of MSI (β coefficient=0.002 per 1mL, p=0.002).

CONCLUSIONS

A lower EAT volume is associated with less myocardial salvage and larger infarct size in patients with a first STEMI.