Acute Response in the Noninfarcted Myocardium Predicts Long-Term Major Adverse Cardiac Events After STEMI

Determinants and Prognostic Value of Early Gadolinium Enhancement-Derived Myocardial Salvage Index in STEMI

BACKGROUND

T2-weighted imaging is commonly used to measure myocardial salvage in reperfused myocardial infarction but is hindered by poor reproducibility and indistinct boundaries. Early gadolinium enhancement (EGE) emerges as an alternative for measuring the area at risk. This study aims to evaluate the determinants of the myocardial salvage index (MSI) derived from EGE and its prognostic implications.

METHODS

We analyzed acute cardiac magnetic resonance scans of 453 reperfused patients with ST-segment-elevation myocardial infarction (mean age, 60±12 years; 389 men) from April 2017 to July 2023 at a single center retrospectively. EGE was collected at 3 minutes after contrast agent injection, where hyperintense areas (signal intensities > mean+2SD of remote myocardium) were considered as the area at risk, plus the hypointense core within. MSI was calculated as the ratio of salvageable myocardium to the area at risk. Major adverse cardiovascular events included cardiovascular death, hospitalization for heart failure, reinfarction, and unplanned revascularization for the target vessel.

RESULTS

During a median follow-up of 3.2 years (interquartile range, 1.6-4.7 years), at least one major adverse cardiac event occurred in 91 participants (20.1%). The median MSI was 35.0% (interquartile range, 22.9-59.5%), with smaller MSI observed in patients with larger infarcts (P<0.001). Linear regression identified prepercutaneous coronary intervention Thrombolysis in Myocardial Infarction flow (β=3.35, P<0.001) and microvascular obstruction (β=-11.92, P<0.001) as independent determinants of MSI. Multivariable Cox regression showed that every 10% increase in MSI was associated with a 32% reduction in major adverse cardiac event risk (hazard ratio, 0.68 [95% CI, 0.53-0.86]; P=0.001). A graded response was observed between MSI and cardiovascular death and reinfarction. MSI greater than the median was associated with nontarget vessel-related reinfarctions but not target vessel-related ones (nontarget, P=0.027; target vessel, P=0.36). Good reproducibility was reported with EGE-measured area at risk (intraobserver, intraclass correlation coefficient [ICC]=0.95; interobserver, ICC=0.89).

CONCLUSIONS

EGE-derived MSI was associated with prepercutaneous coronary intervention Thrombolysis in Myocardial Infarction flow and microvascular injuries. It was an independent predictor of major adverse cardiac events. Our results highlight the prognostic potential of EGE imaging in acute myocardial infarction.

Prognostic Value of Systemic Inflammation Response Index and N-Terminal Pro-B-Type Natriuretic Peptide in Patients with Myocardial Infarction with Nonobstructive Coronary Arteries- A Retrospective Study

Background

The Systemic Inflammation Response Index (SIRI) and N-terminal Pro-B-type natriuretic peptide (NT-proBNP) have been proposed as reliable predictors of poor prognosis in cardiovascular disease and all-cause mortality, However, their validity has not been extensively evaluated in patients with myocardial infarction with nonobstructive coronary arteries (MINOCA).

Patients and Methods

259 patients diagnosed with MINOCA were enrolled in this study from January 2015 to December 2022, and serum levels of SIRI and NT-proBNP were detected. The primary endpoints were major adverse cardiovascular events (MACE). According to the occurrence of MACE during the follow-up period, patients were grouped into MACE and Non-MACE groups, and divided by the median values for SIRI and NT-proBNP into groups: low SIRI, high SIRI, low NT-proBNP, and high NT-proBNP.

Results

A statistically significant difference in the levels of SIRI and NT-proBNP was observed between the MACE group and the non-MACE group. Kaplan-Meier survival curve analysis revealed that patients with high SIRI and high NT-proBNP had a significantly higher risk of MACE (log-rank P < 0.001). Furthermore, even after adjusting for covariates, the high SIRI and high NT-proBNP were associated with an increased risk of MACE (P<0.001, HR: 3.188, 95% CI 1.940-5.241; P<0.001, HR: 2.245, 95% CI 1.432-3.519). Additionally, the combined prognosis prediction of SIRI and NT-proBNP was superior to a single prediction, and adding SIRI and NT-proBNP to the traditional risk factor model improved the model's predictive value.

Conclusion

High levels of SIRI and NT-proBNP exhibit a significant correlation with an increased risk of MACE, thereby suggesting that SIRI can be used as a reliable inflammatory indicator for predicting the risk in MINOCA patients, with significantly improved prognostic value when combined with NT-proBNP.

Emerging opportunities to target inflammation: myocardial infarction and type 2 diabetes

After myocardial infarction (MI), patients with type 2 diabetes have an increased rate of adverse outcomes, compared to patients without. Diabetes confers a 1.5-2-fold increase in early mortality and, importantly, this discrepancy has been consistent over recent decades, despite advances in treatment and overall survival. Certain assumptions have emerged to explain this increased risk, such as differences in infarct size or coronary artery disease severity. Here, we re-evaluate that evidence and show how contemporary analyses using state-of-the-art characterization tools suggest that the received wisdom tells an incomplete story. Simultaneously, epidemiological and mechanistic biological data suggest additional factors relating to processes of diabetes-related inflammation might play a prominent role. Inflammatory processes after MI mediate injury and repair and are thus a potential therapeutic target. Recent studies have shown how diabetes affects immune cell numbers and drives changes in the bone marrow, leading to pro-inflammatory gene expression and functional suppression of healing and repair. Here, we review and re-evaluate the evidence around adverse prognosis in patients with diabetes after MI, with emphasis on how targeting processes of inflammation presents unexplored, yet valuable opportunities to improve cardiovascular outcomes in this vulnerable patient group.

Cardiovascular Magnetic Resonance Before Invasive Coronary Angiography in Suspected Non-ST-Segment Elevation Myocardial Infarction

BACKGROUND

In suspected non-ST-segment elevation myocardial infarction (NSTEMI), this presumed diagnosis may not hold true in all cases, particularly in patients with nonobstructive coronary arteries (NOCA). Additionally, in multivessel coronary artery disease, the presumed infarct-related artery may be incorrect.

OBJECTIVES

This study sought to assess the diagnostic utility of cardiac magnetic resonance (CMR) before invasive coronary angiogram (ICA) in suspected NSTEMI.

METHODS

A total of 100 consecutive stable patients with suspected acute NSTEMI (70% male, age 62 ± 11 years) prospectively underwent CMR pre-ICA to assess cardiac function (cine), edema (T2-weighted imaging, T1 mapping), and necrosis/scar (late gadolinium enhancement). CMR images were interpreted blinded to ICA findings. The clinical care and ICA teams were blinded to CMR findings until post-ICA.

RESULTS

Early CMR (median 33 hours postadmission and 4 hours pre-ICA) confirmed only 52% (52 of 100) of patients had subendocardial infarction, 15% transmural infarction, 18% nonischemic pathologies (myocarditis, takotsubo, and other forms of cardiomyopathies), and 11% normal CMR; 4% were nondiagnostic. Subanalyses according to ICA findings showed that, in patients with obstructive coronary artery disease (73 of 100), CMR confirmed only 84% (61 of 73) had MI, 10% (7 of 73) nonischemic pathologies, and 5% (4 of 73) normal. In patients with NOCA (27 of 100), CMR found MI in only 22% (6 of 27 true MI with NOCA), and reclassified the presumed diagnosis of NSTEMI in 67% (18 of 27: 11 nonischemic pathologies, 7 normal). In patients with CMR-MI and obstructive coronary artery disease (61 of 100), CMR identified a different infarct-related artery in 11% (7 of 61).

CONCLUSIONS

In patients presenting with suspected NSTEMI, a CMR-first strategy identified MI in 67%, nonischemic pathologies in 18%, and normal findings in 11%. Accordingly, CMR has the potential to affect at least 50% of all patients by reclassifying their diagnosis or altering their potential management.

Management of Myocardial Infarction: Emerging Paradigms for the Future

Despite significant advancements in managing acute ST-segment elevation myocardial infarctions, the prevalence of heart failure has not decreased. Emerging paradigms with a focus on reducing infarct size show promising evidence in the improvement of the incidence of heart failure after experiencing acute coronary syndromes. Limiting infarct size has been the focus of multiple clinical trials over the past decades and has led to left ventricular (LV) unloading as a potential mechanism. Contemporary use of microaxial flow devices for LV unloading has suggested improvement in mortality in acute myocardial infarction complicated by cardiogenic shock. This review focuses on clinical data demonstrating evidence of infarct size reduction and highlights ongoing clinical trials that provide a new therapeutic approach to the management of acute myocardial infarction.

Acute Response of the Noninfarcted Myocardium and Surrounding Tissue Assessed by T2 Mapping After STEMI

BACKGROUND

ST-segment elevation myocardial infarction (STEMI) is associated with a systemic and local inflammatory response with edema. However, their role at the tissue level is poorly characterized.

OBJECTIVES

This study aims to characterize T2 values of the noninfarcted myocardium (NIM) and surrounding tissue and to investigate prognostic relevance of higher NIM T2 values after STEMI.

METHODS

A total of 171 consecutive patients with STEMI without prior cardiovascular events who underwent cardiac magnetic resonance after primary percutaneous coronary intervention were analyzed in terms of standard infarct characteristics. Edema of the NIM, liver, spleen, and pectoralis muscle was assessed based on T2 mapping. Follow-up was available for 130 patients. The primary endpoint was major adverse cardiac events (MACE), defined as cardiovascular death, myocardial infarction, unplanned coronary revascularization or rehospitalization for heart failure. The median time from primary percutaneous coronary intervention to cardiac magnetic resonance was 3 days (IQR: 2-5 days).

RESULTS

Higher (above the median value of 45 ms) T2 values in the NIM area were associated with larger infarct size, microvascular obstruction, and left ventricular dysfunction and did not correlate with C-reactive protein, white blood cells, or T2 values of the pectoralis muscle, liver, and spleen. At a median follow-up of 17 months, patients with higher (>45 ms) NIM T2 values had increased risk of MACE (P < 0.001) compared with subjects with NIM T2 values ≤45 ms, mainly caused by a higher rate of myocardial reinfarction (26.3% vs 1.4%; P < 0.001). At multivariable analysis, higher NIM T2 values independently predicted MACE (HR: 2.824 [95% CI: 1.254-6.361]; P = 0.012).

CONCLUSIONS

Higher NIM T2 values after STEMI are independently associated with worse cardiovascular outcomes, mainly because of higher risk of myocardial infarction.

Effects of canagliflozin on myocardial microvascular density, oxidative stress, and proteomic profile☆

Introduction

Sodium-glucose cotransporter-2 inhibitors (SGLT2i) are cardioprotective, and canagliflozin (CANA), an SGLT2i, has been shown to improve perfusion, AMPK signaling, and oxidative stress in chronically ischemic myocardium. The aim of this study is to determine the effects of CANA in nonischemic myocardium on coronary collateralization, oxidative stress, and other molecular pathways determined by proteomic profiling.

Methods

Yorkshire swine underwent placement of an ameroid constrictor to the left circumflex artery. Two weeks later, pigs received no drug (CON, n = 8) or 300 mg CANA daily (n = 8). Treatment continued for five weeks, followed by tissue harvest of nonischemic myocardium.

Results

CANA was associated with decreased capillary density (p = 0.05) compared to CON, without changes in arteriolar density. Reduced capillary density did not correlate with reduced perfusion. Oxidative stress was reduced with CANA (22 % decrease). In the CANA group, there was a trend towards increased p-eNOS and eNOS, without a change in p-eNOS/eNOS ratio, p-Akt, Akt, and p-Akt/Akt ratio. There was no change in p-ERK1/2, but a decrease in total ERK1/2 and increase in p-ERK1/2/ERK1/2 ratio. There were no changes in expression of p-AMPK, AMPK, with a trend towards increased ratio of p-AMPK/AMPK. Proteomics analysis identified 2819 common proteins, of which 120 were upregulated and 425 were downregulated with CANA. Pathway analysis demonstrated wide regulation of metabolic proteins.

Conclusions

The effects of CANA on myocardial perfusion and AMPK signaling in chronically ischemic myocardium are not found in nonischemic territory, despite attenuation of oxidative stress. Metabolic proteins are widely regulated in nonischemic myocardium with CANA.

Role of Cardiovascular Imaging in Risk Assessment: Recent Advances, Gaps in Evidence, and Future Directions

Optimal risk assessment for primary prevention remains highly challenging. Recent registries have highlighted major discrepancies between guidelines and daily practice. Although guidelines have improved over time and provide updated risk scores, they still fail to identify a significant proportion of at-risk individuals, who then miss out on effective prevention measures until their initial ischemic events. Cardiovascular imaging is progressively assuming an increasingly pivotal role, playing a crucial part in enhancing the meticulous categorization of individuals according to their risk profiles, thus enabling the customization of precise therapeutic strategies for patients with increased cardiovascular risks. For the most part, the current approach to patients with atherosclerotic cardiovascular disease (ASCVD) is homogeneous. However, data from registries (e.g., REACH, CORONOR) and randomized clinical trials (e.g., COMPASS, FOURIER, and ODYSSEY outcomes) highlight heterogeneity in the risks of recurrent ischemic events, which are especially higher in patients with poly-vascular disease and/or multivessel coronary disease. This indicates the need for a more individualized strategy and further research to improve definitions of individual residual risk, with a view of intensifying treatments in the subgroups with very high residual risk. In this narrative review, we discuss advances in cardiovascular imaging, its current place in the guidelines, the gaps in evidence, and perspectives for primary and secondary prevention to improve risk assessment and therapeutic strategies using cardiovascular imaging.

Chronic troponin elevation assessed by myocardial T1 mapping in patients with stable coronary artery disease

BACKGROUND

Cardiac troponin detected with sensitive assays can be chronically elevated, in the absence of unstable coronary syndromes. In patients with chronic coronary artery disease, clinically silent ischemic episodes may cause chronic troponin release. T1 mapping is a cardiovascular magnetic resonance technique useful in quantitative cardiac tissue characterization. We selected patients with anatomically and functionally normal hearts to investigate associations between chronic troponin release and myocardial tissue characteristics assessed by T1 mapping.

METHODS

We investigated the relationship between cardiac troponin I concentrations and cardiovascular magnetic resonance T1 mapping parameters in patients with stable coronary artery disease enrolled in MASS V study before elective revascularization. Participants had no previous myocardial infarction, negative late gadolinium enhancement, normal left ventricular function, chamber dimensions and wall thickness.

RESULTS

A total of 56 patients were analyzed in troponin tertiles: nativeT1 and extracellular volume (ECV) values (expressed as means ± standard deviations) increased across tertiles: nativeT1 (1006 ± 27 ms vs 1016 ± 27 ms vs 1034 ± 37 ms, ptrend = 0.006) and ECV (22 ± 3% vs 23 ± 1.9% vs 25 ± 3%, ptrend = 0.007). Cardiac troponin I concentrations correlated with native T1(R = 0.33, P = .012) and ECV (R = 0.3, P = .025), and were independently associated with nativeT1 (P = .049) and ventricular mass index (P = .041) in multivariable analysis.

CONCLUSION

In patients with chronic coronary artery disease and structurally normal hearts, troponin I concentrations correlated with T1 mapping parameters, suggesting that diffuse edema or fibrosis scattered in normal myocardium might be associated with chronic troponin release.

Prognostic Value of Systemic Immune-Inflammation Index and NT-proBNP in Patients with Acute ST-Elevation Myocardial Infarction

Objective

Our aim was to assess systemic immune-inflammation index (SII) and NT-proBNP value either in singly or in combination to predict acute ST-elevation myocardial infarction (STEMI) patient prognosis.

Methods

Analyzed retrospectively the clinical features and laboratory data of STEMI confirmed patients in our hospital from January to December 2020. The levels of SII and NT-proBNP were detected. The Kaplan-Meier approach and Spearman's rank correlation coefficient were used to construct the overall major adverse cardiac event (MACE) curve. Multivariate Cox regression analysis was applied to detect MACE predictors. In addition, the Delong test and receiver operating characteristic (ROC) curve analyzed each factor performance on its own and composite multivariate index to predict MACEs.

Results

The MACE group showed statistically significant differences in SII, NT- proBNP in comparison to the non-MACE group (P=0.003, P <0.001). Based on Kaplan-Meier analysis, SII and NT-proBNP showed positive correlation with MACE (log-rank P < 0.001). SII and NT-proBNP were independent predicting factors for long-term MACEs in multivariate Cox regression analysis (P <0.001, HR: 2.952, 95% CI 1.565-5.566; P <0.001, HR: 2.112, 95% CI 1.662-2.683). SII and NT-proBNP exhibited a positive correlation (R = 0.187, P < 0.001) in correlation analysis. According to the ROC statistical analysis, the combination exhibited 78.0% sensitivity and 88.0% specificity in the prediction of MACE. According to the results of the AUC and Delong test, the combined SII and NT-proBNP performed better as a prognostic index than each of the individual factor indexes separately (Z = 2.622, P = 0.009; Z = 3.173, P < 0.001).

Conclusion

SII and NT-proBNP were independent indicators of clinical prognosis in acute STEMI patients, and they correlated positively. These factors could be combined to improve clinical prognosis.