Effects of alirocumab on types of myocardial infarction: insights from the ODYSSEY OUTCOMES trial

Neutrophil lymphocyte ratio and heart type fatty acid binding protein as a prognostic marker in Myocardial infarction within 48 h of admission

BACKGROUND

The neutrophil to lymphocyte ratio (NLR) is a measure of systemic inflammation, whereas Heart type fatty acid protein (HFABP) is a cytosolic protein released early after acute coronary syndrome (ACS). The aim of this research study is to determine whether NLR and H-FAB are useful in predicting the prognosis in patients with ST segment elevation myocardial infarction (STEMI) 48 h after admission. This is a prospective observational study conducted on 97 patients who had been admitted to emergency room with ST-elevation myocardial infarction in their ECG in a tertiary care centre of south India. The neutrophil-lymphocyte ratio was measured at the time of admission, 24th hour and 48th hour, and then compared with the outcome. To determine their significance in the MI episode, troponin-I and H-FABP were also measured.

RESULTS

A significant correlation was found in the final outcomes of patients and the NLR at the time of admission and at 48 h (p = 0.01). Additionally, a substantial correlation between NLR and various degrees of LV dysfunction was also observed (p = 0.01). H-FABP was found to be positive in all 97 of the patients examined, whereas Troponin-I was only found to be positive in 56.7%.

CONCLUSION

The study's findings, indicated strong correlations between NLR and LVEF, indicated that NLR might serve as an early predictor of cardiac events which could be either poor prognosis or higher mortality. This research found that H-FABP may serve as an early MI diagnostic marker.

Research trends in lipid-lowering therapies for coronary heart disease combined with hyperlipidemia: a bibliometric study and visual analysis

Background

Cardiovascular disease (CVD) poses a significant global health and economic challenge, with atherosclerosis being a primary cause. Over the past 40 years, substantial research has been conducted into the prevention and reversal of atherosclerosis, resulting in the development of lipid-lowering agents such as statins and fibrates. Despite the extensive literature and formulation of numerous therapeutic guidelines in this domain, a comprehensive bibliometric analysis of the current research landscape and trends has not been performed. This study aimed to elucidate the evolution and milestones of research into lipid-lowering treatments for coronary heart disease (CHD) in conjunction with hyperlipidemia through bibliometric analysis, offering insights into future directions for treatment strategies.

Methods

This study examined publications from 1986 to 2023 retrieved from the Web of Science database (Core Collection). Utilizing tools such as VOSviewer, Pajek, and CiteSpace, we analyzed publication and citation numbers, H-indexes, contributions by countries and institutions, authorship, journal sources, and keyword usage to uncover research trajectories and areas of focus.

Results

Our analysis of 587 publications revealed a recent surge in research output, particularly post-2003. The American Journal of Cardiology published the highest number of studies, with 40 articles, whereas Circulation received the highest number of citations (6,266). Key contributors included the United States, Japan, and China, with the United States leading in citation numbers and the H-index. Harvard University and Leiden University emerged as pivotal institutions, and Professors J. Wouter Jukema and Robert P. Giugliano were identified as leading experts. Keyword analysis disclosed five thematic clusters, indicating a shift in research towards new drug combinations and strategies, signaling future research directions.

Conclusion

The last 4 decades have seen a notable rise in publications on lipid-lowering therapies for CHD and hyperlipidemia, with the United States retaining world-leading status. The increase in international collaboration aids the shift towards research into innovative lipid-lowering agents and therapeutic approaches. PCSK9 inhibitors and innovative combination therapies, including antisense oligonucleotides and angiopoietin-like protein 3 inhibitors, provide avenues for future research, intending to maximize the safety and efficacy of treatment approaches.

Alirocumab effect on preventing periprocedural ischaemic events in coronary heart disease patients undergoing coronary stenting (APPEASE trial): study protocol of a multicentre, open-label, randomised controlled trial

INTRODUCTION

Percutaneous coronary intervention (PCI)-related myocardial infarction (type 4a MI) and major periprocedural myocardial injury have been demonstrated leading to poor prognosis of patients with coronary heart disease (CHD) undergoing elective PCI and still remain high occurrence even after the therapy of dual antiplatelet agents and statins. Proprotein convertase subtilisin/kexin type 9 inhibitor alirocumab has been shown to be effectively in reducing the risk of acute MI (AMI). However, the effect of alirocumab on preventing PCI-related MI or major periprocedural myocardial injury in patients with CHD undergoing elective PCI remains uncertain.

METHODS AND ANALYSIS

Alirocumab effect on Preventing Periprocedural ischaemic Events in coronary heart diseAse patients undergoing coronary StEnting trial is a multicentre, open-label, randomised controlled trial aiming to determine whether alirocumab could reduce the incidence of type 4a MI or major periprocedural myocardial injury in patients with CHD undergoing elective PCI. In total, 422 non-AMI CHD patients planned to undergo elective PCI will be randomly assigned to receive standard pharmacotherapy of CHD (control group) or additional use of subcutaneous alirocumab 75 mg 1 day before procedure (alirocumab group). The primary outcome is type 4a MI or major periprocedural myocardial injury defined as high-sensitivity cardiac troponin elevating above 5×99 th percentile upper reference limit in 48 hours after PCI. Patients will continue receiving standard pharmacotherapy or additional biweekly subcutaneous alirocumab 75 mg for 3 months according to the initial randomisation group. We will follow up for 3 months and record all the major adverse cardiovascular events (MACEs). Incidence of PCI-related MI or major periprocedural myocardial injury, and MACE in 3 months after PCI will be compared between control group and alirocumab group.

ETHICS AND DISSEMINATION

Ethics approval has been obtained from the Medical Ethics Committee of the Third Affiliated Hospital of Sun Yat-sen University with approval number: (2022)02-140-01. The results of this study will be reported through peer-reviewed journals and conference presentations.

TRIAL REGISTRATION NUMBER

ChiCTR2200063191.

Management and outcome trends in type 2 myocardial infarction: an investigation from the SWEDEHEART registry

Despite poor prognosis, patients with type 2 myocardial infarction (MI) tend to be underdiagnosed and undertreated compared to those with type 1 MI. Whether this discrepancy has improved over time is uncertain. We conducted a registry-based cohort study investigating type 2 MI patients managed at Swedish coronary care units (n = 14,833) during 2010-2022. Multivariable-adjusted changes (first three vs last three calendar years of the observation period) were assessed regarding diagnostic examinations (echocardiography, coronary assessment), provision of cardioprotective medications (betablockers, renin-angiotensin-aldosterone-system inhibitors, statins) and 1-year all-cause mortality. Compared to type 1 MI patients (n = 184,329), those with type 2 MI less often had diagnostic examinations and cardioprotective medications. Increases in the use of echocardiography (OR 1.08 [95% confidence interval 1.06-1.09]) and coronary assessment (OR 1.06 [95% confidence interval 1.04-1.08]) were smaller compared to type 1 MI (p_interaction < 0.001). The provision of medications did not increase in type 2 MI. All-cause mortality rate in type 2 MI was 25.4% without temporal change (OR 1.03 [95% confidence interval 0.98-1.07]). Taken together, the provision of medications and all-cause mortality did ot improve in type 2 MI despite modest increases in diagnostic procedures. This emphasizes the need of defining optimal care pathways in these patients.

Interaction of Cardiovascular Nonmodifiable Risk Factors, Comorbidities and Comedications With Ischemia/Reperfusion Injury and Cardioprotection by Pharmacological Treatments and Ischemic Conditioning

Preconditioning, postconditioning, and remote conditioning of the myocardium enhance the ability of the heart to withstand a prolonged ischemia/reperfusion insult and the potential to provide novel therapeutic paradigms for cardioprotection. While many signaling pathways leading to endogenous cardioprotection have been elucidated in experimental studies over the past 30 years, no cardioprotective drug is on the market yet for that indication. One likely major reason for this failure to translate cardioprotection into patient benefit is the lack of rigorous and systematic preclinical evaluation of promising cardioprotective therapies prior to their clinical evaluation, since ischemic heart disease in humans is a complex disorder caused by or associated with cardiovascular risk factors and comorbidities. These risk factors and comorbidities induce fundamental alterations in cellular signaling cascades that affect the development of ischemia/reperfusion injury and responses to cardioprotective interventions. Moreover, some of the medications used to treat these comorbidities may impact on cardioprotection by again modifying cellular signaling pathways. The aim of this article is to review the recent evidence that cardiovascular risk factors as well as comorbidities and their medications may modify the response to cardioprotective interventions. We emphasize the critical need for taking into account the presence of cardiovascular risk factors as well as comorbidities and their concomitant medications when designing preclinical studies for the identification and validation of cardioprotective drug targets and clinical studies. This will hopefully maximize the success rate of developing rational approaches to effective cardioprotective therapies for the majority of patients with multiple comorbidities. SIGNIFICANCE STATEMENT: Ischemic heart disease is a major cause of mortality; however, there are still no cardioprotective drugs on the market. Most studies on cardioprotection have been undertaken in animal models of ischemia/reperfusion in the absence of comorbidities; however, ischemic heart disease develops with other systemic disorders (e.g., hypertension, hyperlipidemia, diabetes, atherosclerosis). Here we focus on the preclinical and clinical evidence showing how these comorbidities and their routine medications affect ischemia/reperfusion injury and interfere with cardioprotective strategies.

In-hospital initiation of PCSK9 inhibitor and short-term lipid control in patients with acute myocardial infarction

Background

Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitors have been shown to improve cardiovascular outcomes when added to conventional statin therapy. This study aims to investigate the efficacy and safety of in-hospital initiation of PCSK9 inhibitors among patients with acute myocardial infarction (AMI) based on real-world experience.

Methods and results

Data were collected from the Biobank of the First Affiliated Hospital of Xi’an Jiaotong University between January 2016 and December 2020. A total of 7556 AMI patients were screened for eligibility. Propensity Score Match (PSM) was employed, and covariates were age, sex, admission blood pressure and lipid profiles.

Eligible participants were (1) propensity-matched 1:2:2 of statin plus evolocumab (dual therapy) vs. statin vs. statin plus ezetimibe. Ninety-five statin plus evolocumab users achieved significantly decreased low density lipoprotein (LDL) levels (0.92 ± 0.62 mmol/L in the 1st month and 1.17 ± 0.73 in the 3rd month) and a promising attainment rate of LDL (79.5% in the 1st month and 80.0% in the 3rd month) compared to the other two groups. (2) Propensity-matched 1:2:2 of statin plus ezetimibe evolocumab (triple therapy) vs. statin vs. statin plus ezetimibe. Similarly, 75 triple medication users achieved significantly decreased LDL levels and a promising attainment rate of LDL compared to the other two groups. In-hospital mortality and readmission rates within 3 months were then analyzed, and a decreased readmission rate was observed with PCSK9i therapy.

Conclusions

Based on the present single-center real-world PSM-adjusted study, PCSK9i has been effective in short-term lipid control among AMI patients. The long-term effectiveness for reducing major cardiovascular events among AMI patients based on real-world experience remains to be explored.

Trial registration

The study was registered at ClinicalTrials.gov, ClinicalTrials.gov ID: NCT05184530

Graphical Abstract

Supplementary Information

The online version contains supplementary material available at 10.1186/s12944-022-01724-9.

Impact of early PCSK9 inhibitor treatment on heart after percutaneous coronary intervention in patients with STEMI: Design and rationale of the PERFECT II trial

Background and aims

Primary percutaneous coronary intervention (PPCI) is the most effective treatment strategy for ST-segment elevation myocardial infarction (STEMI). Nevertheless, dysregulated inflammation induced by myocardial reperfusion injury may increase the final infarct size and induce maladaptive myocardial remodeling. Proprotein convertase subtilisin/kexin 9 (PCSK9) inhibitor, as a novel and potent lipid-lowering drug, plays an important role in inflammation. The aim of this study is to investigate whether the early application of PCSK9 inhibitor can increase the myocardial salvage index (MSI) and improve ventricular remodeling in patients with STEMI.

Design

The PERFECT II trial is a prospective, open-label, multicenter, randomized controlled study involving 160 patients with STEMI who are scheduled to undergo PPCI. The eligible patients will be divided into PCSK9 inhibitor group and control group via the interactive web response system, at a 1:1 ratio. In the PCSK9 inhibitor group, the PCSK9 inhibitor alirocumab at a dose of 75 mg will be subcutaneously injected immediately after PPCI and administered every 2 weeks thereafter for 3 months based on conventional treatment. In the control group, conventional treatment will be administered. The primary endpoint is MSI, as measured by cardiac magnetic resonance imaging (CMR) at 1 week after PPCI. The secondary endpoints are the peak time of creatine kinase (CK)-MB and troponin I (TnI)/TnT after PPCI; the postoperative fall time of the ST segment on electrocardiography (ECG); the rate of plasma low-density lipoprotein cholesterol (LDL-C) compliance (&lt; 1.4 mmol/L and a reduction of &gt;50% from baseline) at 1, 3, and 6 months after PPCI; infarct size and ejection fraction (EF) measured by CMR at 6 months after PPCI; the occurrence of major adverse cardiovascular event (MACE: a composite of cardiovascular death, non-fatal myocardial infarction, stent thrombosis, repeat revascularization, stroke, and heart failure needed to be hospitalized).

Conclusions

This is the first multicenter study to investigate the effect of early application of the PCSK9 inhibitor alirocumab on MSI in patients with STEMI undergoing PPCI. The findings will provide an opportunity to explore novel ideas and methods for the treatment of acute myocardial infarction.

Trial registration

ClinicalTrials.gov, identifier: NCT05292404.

PCSK9 Modulates Macrophage Polarization-Mediated Ventricular Remodeling after Myocardial Infarction

Background and Aims

An increasing number of high-risk patients with coronary heart disease (similar to acute myocardial infarction (AMI)) are using PCSK9 inhibitors. However, whether PCSK9 affects myocardial repair and the molecular mechanism of PCSK9 modulation of immune inflammation after AMI are not known. The present research investigated the role of PCSK9 in the immunomodulation of macrophages after AMI and provided evidence for the clinical application of PCSK9 inhibitors after AMI to improve cardiac repair.

Methods and Results

Wild-type C57BL6/J (WT) and PCSK9^−/− mouse hearts were subjected to left anterior descending (LAD) coronary artery occlusion to establish an AMI model. Correlation analysis showed that higher PCSK9 expression indicated worse cardiac function after AMI, and PCSK9 knockout reduced infarct size, improved cardiac function, and attenuated inflammatory cell infiltration compared to WT mice. Notably, the curative effects of PCSK9 inhibition were abolished after the systemic depletion of macrophages using clodronate liposomes. PCSK9 showed a regulatory effect on macrophage polarization in vivo and in vitro. Our studies also revealed that activation of the TLR4/MyD88/NF-κB axis was a possible mechanism of PCSK9 regulation of macrophage polarization.

Conclusion

Our data suggested that PCSK9 modulated macrophage polarization-mediated ventricular remodeling after myocardial infarction.

Association of genetic polymorphisms of PCSK9 with type 2 diabetes in Uygur Chinese population

Background

PCSK9 gene expression is associated with biological processes such as lipid metabolism, glucose metabolism, and inflammation. In the present study, our primary objective was to assess the association between the single-nucleotide polymorphisms in the PCSK9 gene and type 2 diabetes in Uygur subjects, in Xinjiang, China.

Methods

We designed a case–control study including 662 patients diagnosed with T2DM and 1220 control subjects. Four single-nucleotide polymorphisms (rs11583680, rs2483205, rs2495477 and rs562556) of PCSK9 gene were genotyped using the improved multiplex ligation detection reaction technique.

Results

For rs2483205, the distribution of genotypes, dominant model (CC vs CT + TT), overdominant model (CC + TT vs CT) showed significant differences between T2DM patients and the controls (P = 0.011 and P = 0.041 respectively). For rs2495477, the distribution of genotypes, the dominant model (AA vs GA + GG) showed significant differences between T2DM patients and the controls (P = 0.024). Logistic regression analysis suggested after adjustment of other confounders, the differences remained significant between the two groups [for rs2483205 CC vs CT + TT: odds ratio (OR) = 1.321, 95% confidence interval (CI) 1.078–1.617, P = 0.007; CC + TT vs CT: OR = 1.255, 95% CI 1.021–1.542, P = 0.03; for rs2495477 AA vs GA + GG: OR = 1.297, 95% CI 1.060–1.588, P = 0.012].

Conclusion

The present study indicated that CT + TT genotype and CT genotype of rs2483205, as well as GA + GG genotype of rs2495477 in PCSK9 gene were associated with an increased risk of type 2 diabetes in the Uygur population in Xinjiang.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12872-022-02710-w.

Acute coronary syndromes

Although substantial progress has been made in the diagnosis and treatment of acute coronary syndromes, cardiovascular disease remains the leading cause of death globally, with nearly half of these deaths due to ischaemic heart disease. The broadening availability of high-sensitivity troponin assays has allowed for rapid rule-out algorithms in patients with suspected non-ST-segment elevated myocardial infarction (NSTEMI). Dual antiplatelet therapy is recommended for 12 months following an acute coronary syndrome in most patients, and additional secondary prevention measures including intensive lipid-lowering therapy (LDL-C <1·4 mmol/L), neurohormonal agents, and lifestyle modification, are crucial. The scientific evidence for diagnosis and management of acute coronary syndromes continues to evolve rapidly, including adapting to the COVID-19 pandemic, which has impacted all aspects of care. This Seminar provides a clinically relevant overview of the pathobiology, diagnosis, and management of acute coronary syndromes, and describes key scientific advances.

Characteristics and Outcomes of Type 2 Myocardial Infarction

Question

What are the characteristics and outcomes of type 2 myocardial infarction (T2MI) compared with type 1 myocardial infarction (T1MI) in patients presenting to the emergency department (ED) with acute chest discomfort?

Findings

In this cohort study 6253 patients, 251 patients (4.0%) and 1027 patients (16.4%) were diagnosed with T2MI and T1MI, respectively, and had comparable all-cause and cardiovascular mortality at 2 years. Tachyarrhythmia and hypertension were responsible for more than two-thirds of patients with T2MI and had lower mortality compared with patients with hypotension, hypoxemia, or anemia.

Meaning

Improved understanding of the specifics of patients with T2MI should help improve management strategies.

Importance

In contrast to type 1 myocardial infarction (T1MI) caused by atherothrombosis, characteristics and outcomes of type 2 myocardial infarction (T2MI) caused by supply-demand mismatch are incompletely understood.

Objective

To explore the characteristics and outcomes of patients with T2MI compared with those with T1MI.

Design, Setting, and Participants

In a prospective, international, multicenter cohort study including 12 emergency departments (EDs) in 5 European countries, unselected patients presenting with acute chest discomfort were enrolled from April 2006 to April 2018. Follow-up was done by telephone or in written form 3, 12, and 24 months after hospital discharge. Data were analyzed from April 2006 to April 2020.

Interventions

The final diagnoses of T2MI and T1MI were centrally adjudicated according to the Fourth Universal Definition of Myocardial Infarction by 2 independent cardiologists, including the pathophysiological trigger of T2MI.

Main Outcomes and Measures

Patient characteristics and outcomes, including 2-year all-cause and cardiovascular mortality and future T2MI and T1MI events.

Results

Of 6253 included patients, 2078 (33.2%) were women, and the median (IQR) age was 61 (48-74) years. Among 6253 patients with acute chest discomfort, the final adjudicated diagnosis was T2MI in 251 patients (4.0%), with tachyarrhythmia and hypertension responsible for two-thirds of cases, and T1MI in 1027 patients (16.4%). All-cause and cardiovascular mortality were comparable at 2 years (T2MI: adjusted hazard ratio, 1.0; 95% CI, 0.7-1.5; T1MI: adjusted hazard ratio, 0.7; 95% CI, 0.4-1.1). Patients with tachyarrhythmia or hypertension as their underlying trigger of T2MI had a lower mortality compared with patients with hypotension, hypoxemia, or anemia. Future T2MI was more likely among patients with index T2MI compared with patients with index T1MI (hazard ratio, 3.2; 95% CI, 1.4-7.5). Similarly, future T1MI was more likely to occur among patients with index T1MI (hazard ratio, 3.0; 95% CI, 1.2-7.4).

Conclusions and Relevance

Among patients with T2MI, tachyarrhythmia and hypertension were responsible for more than two-thirds of T2MI cases. While T2MI and T1MI had comparable all-cause and cardiovascular mortality at 2 years, patients with tachyarrhythmia or hypertension as their underlying trigger of T2MI had a lower mortality compared with patients with hypotension, hypoxemia, or anemia. Future T2MI occurred 3-fold more frequently among patients with T2MI vs T1MI as the index event. Improved understanding of the specifics of patients with T2MI should help improve management strategies.

New horizons in Type 2 myocardial infarction: pathogenesis, assessment and management of an emerging geriatric disease

Type 2 myocardial infarction (MI) is characterised by a functional imbalance between myocardial oxygen supply and demand in the absence of a thrombotic process, leading to myocardial necrosis. This type of MI was relatively unknown among clinicians until the third universal definition of MI was published in 2017, differentiating Type 2 from Type 1 MI, which follows an acute atherothrombotic event. The pathogenesis, diagnostic and therapeutic aspects of Type 2 MI are described in the present review. Type 2 MI is a condition that is strongly linked to age because of vascular ageing concerning both epicardic vessels and microcirculation, age-related atherosclerosis and stress maladaptation. This condition predominantly affects multimorbid individuals with a history of cardiovascular disease. However, the conditions that lead to the functional imbalance between oxygen supply and demand are frequently extra-cardiac (e.g. pneumonia or anaemia). The great heterogeneity of the underlying etiological factors requires a comprehensive approach that is tailored to each case. In the absence of evidence for the benefit of invasive reperfusion strategies, the treatment of Type 2 MI remains to date essentially based on the restoration of the balance between oxygen supply and demand. For older co-morbid patients with Type 2 MI, geriatricians and cardiologists need to work together to optimise etiological investigations, treatment and prevention of predisposing conditions and precipitating factors.

Type 2 MI and Myocardial Injury in the Era of High-sensitivity Troponin

Troponin has been the cornerstone of the definition of MI since its introduction to clinical practice. High-sensitivity troponin has allowed clinicians to detect degrees of myocardial damage at orders of magnitude smaller than previously and is challenging the definitions of MI, with implications for patient management and prognosis. Detection and diagnosis are no doubt enhanced by the greater sensitivity afforded by these markers, but perhaps at the expense of specificity and clarity. This review focuses on the definitions, pathophysiology, prognosis, prevention and management of type 2 MI and myocardial injury. The five types of MI were first defined in 2007 and were recently updated in 2018 in the fourth universal definition of MI. The authors explore how this pathophysiological classification is used in clinical practice, and discuss some of the unanswered questions in this era of availability of high-sensitivity troponin.

Risk factors for type 1 and type 2 myocardial infarction

AIMS

Whilst the risk factors for type 1 myocardial infarction due to atherosclerotic plaque rupture and thrombosis are established, our understanding of the factors that predispose to type 2 myocardial infarction during acute illness is still emerging. Our aim was to evaluate and compare the risk factors for type 1 and type 2 myocardial infarction.

METHODS AND RESULTS

We conducted a secondary analysis of a multi-centre randomized trial population of 48 282 consecutive patients attending hospital with suspected acute coronary syndrome. The diagnosis of myocardial infarction during the index presentation and all subsequent reattendances was adjudicated according to the Universal Definition of Myocardial Infarction. Cox regression was used to identify predictors of future type 1 and type 2 myocardial infarction during a 1-year follow-up period. Within 1 year, 1331 patients had a subsequent myocardial infarction, with 924 and 407 adjudicated as type 1 and type 2 myocardial infarction, respectively. Risk factors for type 1 and type 2 myocardial infarction were similar, with age, hyperlipidaemia, diabetes, abnormal renal function, and known coronary disease predictors for both (P < 0.05 for all). Whilst women accounted for a greater proportion of patients with type 2 as compared to type 1 myocardial infarction, after adjustment for other risk factors, sex was not a predictor of type 2 myocardial events [adjusted hazard ratio (aHR) 0.82, 95% confidence interval (CI) 0.66-1.01]. The strongest predictor of type 2 myocardial infarction was a prior history of type 2 events (aHR 6.18, 95% CI 4.70-8.12).

CONCLUSIONS

Risk factors for coronary disease that are associated with type 1 myocardial infarction are also important predictors of type 2 events during acute illness. Treatment of these risk factors may reduce future risk of both type 1 and type 2 myocardial infarction.

Alirocumab after acute coronary syndrome in patients with a history of heart failure

AIMS 

Patients with heart failure (HF) have not been shown to benefit from statins. In a post hoc analysis, we evaluated outcomes in ODYSSEY OUTCOMES in patients with vs. without a history of HF randomized to the proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor alirocumab or placebo.

METHODS AND RESULTS 

Among 18 924 patients with recent acute coronary syndrome (ACS) receiving intensive or maximum-tolerated statin treatment, the primary outcome of major adverse cardiovascular events (MACE) was compared in patients with or without a history of HF. The pre-specified secondary outcome of hospitalization for HF was also analysed. Overall, 2815 (14.9%) patients had a history of HF. Alirocumab reduced low-density lipoprotein cholesterol and lipoprotein(a) similarly in patients with or without HF. Overall, alirocumab reduced MACE compared with placebo [hazard ratio (HR): 0.85; 95% confidence interval (CI): 0.78-0.93; P = 0.0001]. This effect was observed among patients without a history of HF (HR: 0.78; 95% CI: 0.70-0.86; P < 0.0001), but not in those with a history of HF (HR: 1.17; 95% CI: 0.97-1.40; P = 0.10) (Pinteraction = 0.0001). Alirocumab did not reduce hospitalization for HF, overall or in patients with or without prior HF.

CONCLUSION

Alirocumab reduced MACE in patients without a history of HF but not in patients with a history of HF. Alirocumab did not reduce hospitalizations for HF in either group. Patients with a history of HF are a high-risk group that does not appear to benefit from PCSK9 inhibition after ACS.

KEY QUESTION

Patients with heart failure (HF) have not been shown to benefit from statins. In a post hoc analysis of the ODYSSEY OUTCOMES trial in patients with recent acute coronary syndrome (ACS), we evaluated major adverse cardiovascular events (MACE) in patients with or without a history of HF assigned to treatment with the proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor alirocumab or placebo.

KEY FINDING

Alirocumab reduced low-density lipoprotein cholesterol similarly in patients with or without HF. However, alirocumab reduced MACE among patients without a history of HF, but not in those with a history of HF.

TAKE HOME MESSAGE

The current hypothesis-generating analysis does not provide a basis to recommend PCSK9 inhibitors to patients with recent ACS and a history of HF. A prospective placebo-controlled evaluation of PCSK9 inhibition in this setting is warranted.

Statin Therapy and Intensity: Prognosis in Patients with Myocardial Injury

BACKGROUND

No guideline-directed pharmacological therapy has been established for patients with myocardial injury without type 1 myocardial infarction. We investigated the impact of statin treatment in patients with myocardial injury.

METHODS

Patients with myocardial injury (nonischemic acute and chronic myocardial injury), type 2 myocardial infarction, and type 1 myocardial infarction with at least 1 emergency department visit for chest pain from 2011 to 2014 were included. Dispensed prescriptions of all types of statins with dosage within 180 days from the index visit were collected. In total, 2054 patients were divided into 3 groups: 1) acute myocardial injury (type 2 myocardial infarction, acute nonischemic myocardial injury), 2) chronic myocardial injury, and 3) type 1 myocardial infarction. We estimated the adjusted hazard ratio with 95% confidence interval for death with low- (reference), moderate-, and high-intensity statin therapy.

RESULTS

The mean follow-up was 4.2 ± 1.8 years. Only 13% of patients with acute and chronic myocardial injury and 30% with type 1 myocardial infarction were treated with high-intensity statins. Adjusted mortality rates were higher in patients with acute and chronic myocardial injury than in those with type 1 myocardial infarction across all statin intensity categories. In patients with type 1 myocardial infarction, the adjusted mortality risk was 20% (hazard ratio, 0.80; 95% confidence interval, 0.36-1.77) lower in patients with high-intensity therapy. Point estimates in the adjusted models indicated similar associations between statin intensity and mortality risk in patients with acute and chronic myocardial injury.

CONCLUSION

Patients with myocardial injury may benefit from high-intensity statin treatment, but the associations were not statistically significant when adjusting for confounders.

Association of Contemporary Statin Pretreatment Intensity and LDL-C Levels on the Incidence of STEMI Presentation

Constituting hypolipidemic and pleiotropic effects, statins stabilize coronary artery plaque and may prevent STEMI events. This study investigated the association between contemporary statin pretreatment intensity, low-density lipoprotein cholesterol (LDL-C) levels, and the type of acute coronary syndrome (ACS) presentation: STEMI vs. NSTE-ACS. Data were drawn from the ACS Israeli Survey (ACSIS), a biennial prospective national survey that took place in 2008–2018. The rate of STEMI vs. NSTE-ACS was calculated by statin use, including statin intensity (high-intensity statin therapy (HIST) and low-intensity statin therapy (LIST) prior to the index ACS event. Among 5103 patients, 2839 (56%) were statin-naive, 1389 (27%) used LIST and 875 (17%) used HIST. Statin pretreated patients were older and had a higher rates of co-morbidities, cardiovascular disease history and pretreatment with evidence-based medications. STEMI vs. NSTE-ACS was lower among HIST vs. LIST vs. statin-naive patients (31.0%, 37.8%, and 54.0%, respectively, p for trend < 0.001). Multivariate analysis revealed that HIST was independently associated with lower STEMI presentation (OR_adj 0.70; 95% CI 0.57–0.86), while LIST (OR_adj 0.92; 95% CI 0.77–1.10) and LDL-C < 70 mg/dL (OR_adj 0.96; 95% CI 0.82–1.14) were not. In conclusion, among patients admitted with ACS, pretreatment with HIST was independently associated with a lower probability of STEMI presentation, while LIST and LDL-C < 70 mg/dL were not.

Reduction in Acute Limb Ischemia with Rivaroxaban versus Placebo in Peripheral Artery Disease after Lower Extremity Revascularization: Insights from VOYAGER PAD

Background: Patients with peripheral artery disease (PAD) are at heightened risk of acute limb ischemia (ALI), a thrombotic event associated with amputation, disability, and mortality. Prior lower extremity revascularization (LER) is associated with increased ALI risk in chronic PAD. However, the pattern of risk, clinical correlates, and outcomes after ALI early after LER are not well-studied, and effective therapies to reduce ALI post-LER are lacking. Methods: VOYAGER PAD (NCT02504216) randomized patients with PAD undergoing LER to rivaroxaban 2.5 mg twice daily or placebo on a background of low-dose aspirin. The primary outcome was a composite of ALI, major amputation of vascular cause, myocardial infarction, ischemic stroke, or cardiovascular death. ALI was prospectively ascertained and adjudicated by a blinded committee. The cumulative incidence of ALI was calculated using Kaplan Meier estimates, and Cox proportional-hazards models were used to generate hazard ratios and associated confidence intervals. Analyses were performed as intention-to-treat. Results: Among 6,564 patients followed for a median of 2.3 years, 382 (5.8%) had a total of 508 ALI events. In placebo patients, the 3-year cumulative incidence of ALI was 7.8%. After multivariable modeling, prior LER, baseline ABI <0.50, surgical LER, and longer target lesion length were associated with increased risk of ALI. Incident ALI was associated with subsequent all-cause mortality (HR 2.59, 95% CI 1.98-3.39) and major amputation (HR 24.87, 95% CI 18.68-33.12). Rivaroxaban reduced ALI relative to placebo by 33% (absolute risk reduction 2.6% at 3 years, HR 0.67, 95% CI 0.55-0.82, P=0.0001), with benefit starting early (HR 0.45, 95% CI 0.24-0.85, P=0.0068 at 30 days). Benefit was present for severe ALI (associated with death, amputation, or prolonged hospitalization and ICU stay, HR 0.58, 95% CI 0.40-0.83, P=0.003) and regardless of LER type (surgical vs endovascular revascularization, p-interaction=0.42) or clopidogrel use (p-interaction=0.59). Conclusions: After LER for symptomatic PAD, ALI is frequent, particularly early after LER, and is associated with poor prognosis. Low-dose rivaroxaban plus aspirin reduces ALI after LER, including ALI events associated with the most severe outcomes. The benefit of rivaroxaban for ALI appears early, continues over time, and is consistent regardless of revascularization approach or clopidogrel use.

Renal Ischemia/Reperfusion Early Induces Myostatin and PCSK9 Expression in Rat Kidneys and HK-2 Cells

During visceral interventions, the transient clampage of supraceliac aorta causes ischemia/reperfusion (I/R) in kidneys, sometime resulting in acute renal failure; preclinical studies identified redox imbalance as the main driver of I/R injury. However, in humans, the metabolic/inflammatory responses seem to prevail on oxidative stress. We investigated myostatin (Mstn) and proprotein convertase subtilisin/kexin type 9 (PCSK9), proatherogenic mediators, during renal I/R. Compared to sham-operated animals, the kidneys of rats who had experienced ischemia (30 min) had higher Mstn and PCSK9 expression after 4 h of reperfusion. After 24 h, they displayed tubular necrosis, increased nitrotyrosine positivity, and nuclear peroxisome proliferator-activated receptor gamma coactivator-1alpha relocation, markers of oxidative stress and mitochondria imbalance. Mstn immunopositivity was increased in tubuli, while PCSK9 immunosignal was depleted; systemically, PCSK9 was higher in plasma from I/R rats. In HK-2 cells, both ischemia and reperfusion enhanced reactive oxygen species production and mitochondrial dysfunction. H₂O₂ upregulated Mstn and PCSK9 mRNA after 1 and 3.5 h, respectively. Accordingly, ischemia early induced Mstn and PCSK9 mRNA; during reperfusion Mstn was augmented and PCSK9 decreased. Mstn treatment early increased PCSK9 expression (within 8 h), to diminish over time; finally, Mstn silencing restrained ischemia-induced PCSK9. Our study demonstrates that renal I/R enhances Mstn and PCSK9 expression and that Mstn induces PCSK9, suggesting them as therapeutic targets for vascular protection during visceral surgery.

Acute Myocardial Infarction Cohorts Defined by International Classification of Diseases, Tenth Revision Versus Diagnosis-Related Groups: Analysis of Diagnostic Agreement and Quality Measures in an Integrated Health System

BACKGROUND

Among Medicare value-based payment programs for acute myocardial infarction (AMI), the Hospital Readmissions Reduction Program uses International Classification of Diseases, Tenth Revision (ICD-10) codes to identify the program denominator, while the Bundled Payments for Care Improvement Advanced program uses diagnosis-related groups (DRGs). The extent to which these programs target similar patients, whether they target the intended population (type 1 myocardial infarction), and whether outcomes are comparable between cohorts is not known.

METHODS

In a retrospective study of 2176 patients hospitalized in an integrated health system, a cohort of patients assigned a principal ICD-10 diagnosis of AMI and a cohort of patients assigned an AMI DRG were compared according to patient-level agreement and outcomes such as mortality and readmission.

RESULTS

One thousand nine hundred thirty-five patients were included in the ICD-10 cohort compared with 662 patients in the DRG cohort. Only 421 patients were included in both AMI cohorts (19.3% agreement). DRG cohort patients were older (70 versus 65 years, P<0.001), more often female (48% versus 30%, P<0.001), and had higher rates of heart failure (52% versus 33%, P<0.001) and kidney disease (42% versus 25%, P<0.001). Comparing outcomes, the DRG cohort had significantly higher unadjusted rates of 30-day mortality (6.6% versus 2.5%, P<0.001), 1-year mortality (21% versus 8%, P<0.001), and 90-day readmission (26% versus 19%, P=0.006) than the ICD-10 cohort. Two observations help explain these differences: 61% of ICD-10 cohort patients were assigned procedural DRGs for revascularization instead of an AMI DRG, and type 1 myocardial infarction patients made up a smaller proportion of the DRG cohort (34%) than the ICD-10 cohort (78%).

CONCLUSIONS

The method used to identify denominators for value-based payment programs has important implications for the patient characteristics and outcomes of the populations. As national and local quality initiatives mature, an emphasis on ICD-10 codes to define AMI cohorts would better represent type 1 myocardial infarction patients.

Treatment With Cardiovascular Medications: Prognosis in Patients With Myocardial Injury

Background There is no clinical guidance on treatment in patients with non-ischemic myocardial injury and type 2 myocardial infarction (T2MI). Methods and Results In a cohort of 22 589 patients in the emergency department at Karolinska University Hospital in Sweden during 2011 to 2014 we identified 3853 patients who were categorized into either type 1 myocardial infarction, T2MI, non-ischemic acute and chronic myocardial injury. Data from all dispensed prescriptions within 180 days of the visit to the emergency department were obtained concerning β-blockers, angiotensin-converting enzyme inhibitors/angiotensin II receptor blockers, statins, and platelet inhibitors. We estimated adjusted hazard ratios (HR) with 95% CI for all-cause mortality in relationship to the number of medications (categorized into 0-1 [referent], 2-3 and 4 medications) in the groups of myocardial injury. In patients with T2MI, treatment with 2 to 3 and 4 medications was associated with a 50% and 56% lower mortality, respectively (adjusted HR [95% CI], 0.50 [0.25-1.01], and 0.43 [0.19-0.96]), while corresponding associations in patients with acute myocardial injury were 24% and 29%, respectively (adjusted HR [95% CI], 0.76 [0.59-0.99] and 0.71 [0.5-1.02]), and in patients with chronic myocardial injury 27% and 37%, respectively (adjusted HR [95% CI], 0.73 [0.58-0.92] and 0.63 [0.46-0.87]). Conclusions Patients with T2MI and non-ischemic acute or chronic myocardial injury are infrequently prescribed common cardiovascular medications compared with patients with type 1 myocardial infarction. However, treatment with guideline recommended drugs in patients with T2MI and acute or chronic myocardial injury is associated with a lower risk of death after adjustment for confounders.

PCSK9: Associated with cardiac diseases and their risk factors?

PCSK9 plays a critical role in cholesterol metabolism via the PCSK9-LDLR axis. Liver-derived, circulating PCSK9 has become a novel drug target in lipid-lowering therapy. Accumulative evidence supports the possible association between PCSK9 and cardiac diseases and their risk factors. PCSK9 exerts various effects in the heart independently of LDL-cholesterol regulation. Acute myocardial infarction (AMI) induces local and systemic inflammation and reactive oxygen species generation, resulting in increased PCSK9 expression in hepatocytes and cardiomyocytes. PCSK9 upregulation promotes excessive autophagy and apoptosis in cardiomyocytes, thereby contributing to cardiac insufficiency. PCSK9 might also participate in the pathophysiology of heart failure by regulating fatty acid metabolism and cardiomyocyte contractility. It also promotes platelet activation and coagulation in patients with atrial fibrillation. PCSK9 is an independent predictor of aortic valve calcification and accelerates calcific aortic valve disease by regulating lipoprotein(a) catabolism. Accordingly, the use of PCSK9 inhibitors significantly reduced infarct sizes and arrhythmia and improves cardiac contractile function in a rat model of AMI. Circulating PCSK9 levels are positively correlated with age, diabetes mellitus, obesity, and hypertension. Here, we reviewed recent clinical and experimental studies exploring the association between PCSK9, cardiac diseases, and their related risk factors and aiming to identify possible underlying mechanisms.

Cardiovascular Mortality After Type 1 and Type 2 Myocardial Infarction in Young Adults

BACKGROUND

Type 2 myocardial infarction (MI) and myocardial injury are associated with increased short-term mortality. However, data regarding long-term mortality are lacking.

OBJECTIVES

This study compared long-term mortality among young adults with type 1 MI, type 2 MI, or myocardial injury.

METHODS

Adults age 50 years or younger who presented with troponin >99th percentile or the International Classification of Diseases code for MI over a 17-year period were identified. All cases were adjudicated as type 1 MI, type 2 MI, or myocardial injury based on the Fourth Universal Definition of MI. Cox proportional hazards models were constructed for survival free from all-cause and cardiovascular death.

RESULTS

The cohort consisted of 3,829 patients (median age 44 years; 30% women); 55% had type 1 MI, 32% had type 2 MI, and 13% had myocardial injury. Over a median follow-up of 10.2 years, mortality was highest for myocardial injury (45.6%), followed by type 2 MI (34.2%) and type 1 MI (12%) (p < 0.001). In an adjusted model, type 2 MI was associated with higher all-cause (hazard ratio: 1.8; 95% confidence interval: 1.2 to 2.7; p = 0.004) and cardiovascular mortality (hazard ratio: 2.7; 95% confidence interval: 1.4 to 5.1; p = 0.003) compared with type 1 MI. Those with type 2 MI or myocardial injury were younger and had fewer cardiovascular risk factors but had more noncardiovascular comorbidities. They were significantly less likely to be prescribed cardiovascular medications at discharge.

CONCLUSIONS

Young patients who experience a type 2 MI have higher long-term all-cause and cardiovascular mortality than those who experience type 1 MI, with nearly one-half of patients with myocardial injury and more than one-third of patients with type 2 MI dying within 10 years. These findings emphasize the need to provide more aggressive secondary prevention for patients who experience type 2 MI and myocardial injury.

PCSK9 Inhibition: Insights From Clinical Trials and Future Prospects

In 2003, clinical observations led to the discovery of the involvement of proprotein convertase subtilisin/kexin type 9 (PCSK9) in lipid metabolism. Functional studies demonstrated that PCSK9 binds to the low-density lipoprotein (LDL) receptor directing it to its lysosomal degradation. Therefore, carriers of gain-of-function mutations in PCSK9 exhibit decreased expression of LDL receptors on the hepatocyte surface and have higher LDL cholesterol (LDL-C) levels. On the contrary, loss-of-function mutations in PCSK9 are associated with low LDL-C concentrations and significantly reduced lifetime risk of cardiovascular disease. These insights motivated the search for strategies to pharmacologically inhibit PCSK9. In an exemplary rapid development, fully human monoclonal antibodies against PCSK9 were developed and found to effectively reduce LDL-C. Administered subcutaneously every 2–4 weeks, the PCSK9 antibodies evolocumab and alirocumab reduce LDL-C by up to 60% in a broad range of populations either as monotherapy or in addition to statins. Two large cardiovascular outcome trials involving a total of ∼46,000 cardiovascular high-risk patients on guideline-recommended lipid-lowering therapy showed that treatment with evolocumab and alirocumab led to a relative reduction of cardiovascular risk by 15% after 2.2 and 2.8 years of treatment, respectively. These findings expanded the armamentarium of pharmacological approaches to address residual cardiovascular risk associated with LDL-C. Furthermore, the unprecedented low LDL-C concentrations achieved (e.g., 30 mg/dL in the FOURIER study) suggest that the relationship between LDL-C and cardiovascular risk is without a lower threshold, and without associated adverse events during the timeframe of the studies. The side effect profile of PCSK9 antibodies is favorable with few patients exhibiting injection-site reactions. Currently, the access to PCSK9 antibodies is limited by high treatment costs. The development of novel approaches to inhibit PCSK9 such as the use of small interfering RNA to inhibit PCSK9 synthesis seems promising and may soon become available.

PCSK9 in Myocardial Infarction and Cardioprotection: Importance of Lipid Metabolism and Inflammation

Extensive evidence from epidemiologic, genetic, and clinical intervention studies has indisputably shown that elevated low-density lipoprotein cholesterol (LDL-C) concentrations play a central role in the pathophysiology of atherosclerotic cardiovascular disease. Apart from LDL-C, also triglycerides independently modulate cardiovascular risk. Reduction of proprotein convertase subtilisin/kexin type 9 (PCSK9) has emerged as a therapeutic target for reducing plasma LDL-C, but it is also associated with a reduction in triglyceride levels potentially through modulation of the expression of free fatty acid transporters. Preclinical data indicate that PCSK9 is up-regulated in the ischaemic heart and decreasing PCSK9 expression impacts on infarct size, post infarct inflammation and remodeling as well as cardiac dysfunction following ischaemia/reperfusion. Clinical data support that notion in that PCSK9 inhibition is associated with reductions in the incidence of myocardial infarction, stroke, and coronary revascularization and an improvement of endothelial function in subjects with increased cardiovascular risk. The aim of the current review is to summarize the current knowledge on the importance of free fatty acid metabolism on myocardial ischaemia/reperfusion injury and to provide an update on recent evidence on the role of hyperlipidemia and PCSK9 in myocardial infarction and cardioprotection.

PCSK9 inhibitor effectively attenuates cardiometabolic impairment in obese-insulin resistant rats

Long-term high-fat diet consumption causes obese-insulin resistance and cardiac mitochondrial dysfunction, leading to impaired left ventricular (LV) function. Atorvastatin effectively improved lipid profiles in obese patients. However, inadequate reduction in low density lipoprotein cholesterol (LDL-C) level was found. Proprotein convertase subtilisin/kexin type 9 (PCSK9) inhibitor effectively reduced LDL-C levels. We hypothesized that this PCSK9 inhibitor has a greater efficacy in attenuating cardiometabolic impairments than atorvastatin in obese-insulin resistant rats. Female rats were fed with either a high fat or normal diet for 12 weeks. High fat diet fed rats (HFD) were then divided into 3 groups and were given vehicle, atorvastatin (40 mg/kg/day; s.c.), or PCSK9 inhibitor (4 mg/kg/day; s.c.) for additional 3 weeks. The metabolic parameters, cardiac and mitochondrial function and [Ca²⁺]_i transients were determined. HFD rats developed obese-insulin resistance as indicated by increased plasma insulin and HOMA index. Although high-fat diet fed rats treated with vehicle (HFV) rats had markedly impaired LV function as indicated by reduced %LVFS, impaired cardiac mitochondrial function, and [Ca²⁺]_i transient regulation, these impairments were attenuated in high-fat diet fed rats treated with atorvastatin (HFA) and high-fat diet fed rats treated with PCSK9 inhibitor (HFP) rats. However, these improvements were greater in HFP rats than HFA rats. Our findings indicated that the PCSK9 inhibitor exerted greater cardioprotection than atorvastatin through improved mitochondrial function in obese-insulin resistant rats.

Platelet lipidome: Dismantling the "Trojan horse" in the bloodstream

The platelet-lipid chapter in the story of atherothrombosis is an old one, recapitulated and revised in many contexts. For decades several stimulating facets have been added to it, both unraveling and increasing the perplexity of platelet-lipid interplay and its pathophysiological consequences. The recent paradigm shift in our perspective has evolved with lipidomic analysis of the intraplatelet compartment and platelet releasate. These investigations have disclosed that platelets are in constant interaction with circulatory lipids, often reflected in their lipid repertoire. In addition, they offer a shielded intracellular space for oxidative lipid metabolism generating "toxic" metabolites that escape degradation by plasma lipases and antioxidant defense, circulate undetected by conventional plasma lipid profile, and deposited at atherosclerotic lesions or thrombus. Lipidomics divulges this silent invader in platelet vehicles, thereby providing potential biomarkers of pathologic manifestations and therapeutic targets to be exploited, which is surmised in this review.

Incidence, Trends, and Outcomes of Type 2 Myocardial Infarction in a Community Cohort

BACKGROUND

Type 2 myocardial infarction (T2MI) occurs because of an acute imbalance in myocardial oxygen supply and demand in the absence of atherothrombosis. Despite being frequently encountered in clinical practice, the population-based incidence and trends remain unknown, and the long-term outcomes are incompletely characterized.

METHODS

We prospectively recruited residents of Olmsted County, Minnesota, who experienced an event associated with a cardiac troponin T >99th percentile of a normal reference population (≥0.01 ng/mL) between January 1, 2003, and December 31, 2012. Events were retrospectively classified into type 1 myocardial infarction (T1MI, atherothombotic event), T2MI, or myocardial injury (troponin rise not meeting criteria for myocardial infarction [MI]) using the universal definition. Outcomes were long-term all-cause and cardiovascular mortality and recurrent MI. T2MI was further subclassified by the inciting event for supply/demand mismatch.

RESULTS

A total of 5460 patients had at least one cardiac troponin T ≥0.01 ng/mL; 1365 of these patients were classified as index T1MI (age, 68.5±14.8 years; 63% male) and 1054 were classified as T2MI (age, 73.7±15.8 years; 46% male). The annual incidence of T1MI decreased markedly from 202 to 84 per 100 000 persons between 2003 and 2012 (P<0.001), whereas the incidence of T2MI declined from 130 to 78 per 100 000 persons (P=0.02). In comparison with patients with T1MI, patients with T2MI had higher long-term all-cause mortality after adjustment for age and sex, driven by early and noncardiovascular death. Rates of cardiovascular death were similar after either type of MI (hazard ratio, 0.8 [95% CI, 0.7-1.0], P=0.11). Subclassification of T2MI by cause demonstrated a more favorable prognosis when the principal provoking mechanism was arrhythmia, in comparison with postoperative status, hypotension, anemia, and hypoxia. After index T2MI, the most common MI during follow-up was a recurrent T2MI, whereas the occurrence of a new T1MI was relatively rare (estimated rates at 5 years, 9.7% and 1.7%).

CONCLUSIONS

There has been an evolution in the type of MI occurring in the community over a decade, with the incidence of T2MI now being similar to T1MI. Mortality after T2MI is higher and driven by early and noncardiovascular death. The provoking mechanism of supply/demand mismatch affects long-term survival. These findings underscore the healthcare burden of T2MI and provide benchmarks for clinical trial design.

Clinicopathological complexity in the application of the universal definition of myocardial infarction

A universal definition of myocardial infarction (UDMI) has been established, periodically updated, and refined over the past twenty years. The primary purpose of the UDMI is to bring uniformity and accuracy to clinical diagnosis. Herein, a review and analysis of the UDMI is presented with emphasis on clinicopathological correlation. Determination of the presence of myocardial injury is based on the detection of abnormal serum cardiac biomarkers, particularly cardiac troponin (cTn), and in the current fourth iteration of the UDMI, high sensitivity (hs)-cTn. Differentiation of myocardial infarction from other causes of myocardial injury requires the documentation of clinical evidence of myocardial ischemia. In this review, difficulties in applying the UDMI in actual practice are discussed, based on the experience and perspective of those of us who face these problems as part of our own practice of pathology. The complexity in application of the UDMI is highlighted by the presentation of five illustrative cases involving the differential diagnosis of myocardial injury and myocardial infarction due to atherothrombotic and nonatherothrombotic coronary artery disease. The cases include myocardial infarction due to severe coronary atherosclerosis, supply-demand mismatch, coronary artery dissection associated with an eosinophilic coronary periarteritis, and coronary thromboembolism, and a case with a differential diagnosis of myocarditis and myocardial infarction. These cases illustrate how pathological findings can contribute to more accurate application of the UDMI and how, when critically applied, the UDMI can be used to better characterize myocardial infarcts in clinical practice.

PCSK9 inhibition and inflammation: A narrative review

Atherosclerotic cardiovascular disease (ASCVD) remains a leading cause of morbidity and mortality despite excellent pharmacological and revascularization approaches. Low-density lipoproteins (LDL) are undoubtedly the most significant biochemical variables associated with atheroma, however, compelling data identify inflammation as critical for the maintenance of the atherosclerotic process, underlying some of the most feared vascular complications. Although its causal role is questionable, high-sensitivity C-reactive protein (hs-CRP) represents a major biomarker of inflammation and associated risk in CVD. While statin-associated reduced risk may be related to the lowering of both LDL-C and hs-CRP, PCSK9 inhibitors leading to dramatic LDL-C reductions do no alter hs-CRP levels. On the other hand, hs-CRP levels identify groups of patients with a high risk of CV disease achieving better ASCVD prevention in response to PCSK9 inhibition. In the FOURIER study, even in patients with extremely low levels of LDL-C, there was a stepwise risk increment according to the values of hs-CRP: +9% (<1 mg/L), +10.8% (1-3 mg/L) and +13.1% (>3 mg/L). Likewise, in the SPIRE-1 and -2 studies, bococizumab patients with hs-CRP> 3 mg/L had a 60% greater risk of future CV events. Most of the patients enrolled in the PCSK9 trials were on maximally tolerated statin therapy at baseline, and an elevated hs-CRP may reflect residual inflammatory risk after standard LDL-C lowering therapy. Moreover, data on changes in inflammation markers in carriers of PCSK9 loss-of-function mutations are scanty and not conclusive, thus, evidence from the effects of anti-inflammatory molecules on PCSK9 levels might help unravel this hitherto complex tangle.

Should myocardial infarction type 2 be regarded as two separate entities?

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