The impact of the 2007 ESC-ACC-AHA-WHF Universal definition on the incidence and classification of acute myocardial infarction: a retrospective cohort study

Evidence-based medicine and the cardiac troponin 99th percentile for the diagnosis of acute myocardial infarction

The 99th percentile of cardiac troponin assays for determining the presence of acute myocardial infarction (AMI) was set when assay analytical performance was much less precise than currently and was chosen, in part, to reduce the frequency of 'false-positive' results. A result greater than 99th percentile criterion has been a requirement of each version of the universal definition of MI. It also became used as a dichotomous decision-making threshold in diagnostic strategies for investigating AMI in acute care settings. There are numerous difficulties in deriving the 99th percentile which undermine its reliability as a standalone test threshold. It is important for patient safety that all users are aware of the challenges and pitfalls of using the 99th percentile for decision-making. We present a focused review of the 99th percentile, highlighting some difficulties with its use as a decision threshold as well as possible adjunctive strategies and alternative approaches.

Type 2 myocardial infarction: challenges in diagnosis and treatment

The Fourth Universal Definition of Myocardial Infarction recommends a classification based on aetiology, in recognition that the underlying pathophysiology of myocardial infarction influences the approach to investigation and treatment. Type 1 myocardial infarction occurs due to atherosclerotic plaque rupture with thrombosis, whereas type 2 myocardial infarction occurs due to an imbalance in myocardial oxygen supply or unmet need in myocardial oxygen demand, without atherothrombosis, usually in the context of another acute illness. In this state-of-the-art review, the diagnosis, investigation, and treatment of patients with type 2 myocardial infarction are considered, with general advice for clinical practice and a consideration of future research directions.

Copeptin for the differentiation of type 1 versus type 2 myocardial infarction or myocardial injury

BACKGROUND

The rapid and reliable differentiation of myocardial infarction (MI) due to atherothrombosis (T1MI) from MI due to supply-demand mismatch (T2MI) or acute myocardial injury is of major clinical relevance due to very different treatments, but still a major unmet clinical need. This study aimed to investigate whether copeptin, a stress hormone produced in the hypothalamus, helps to differentiate between T1MI versus T2MI or injury.

METHODS

In a retrospective analysis, 1271 unselected consecutive patients presenting with symptoms suggestive of MI to the emergency department were evaluated. Patients diagnosed with ST-elevation MI were excluded. All patients with elevated cardiac troponin I (cTnI) concentration possibly indicating MI were classified into T1MI, T2MI, or acute myocardial injury using detailed clinical assessment and coronary imaging. Copeptin plasma concentration was measured in a blinded fashion. A multicenter diagnostic study with central adjudication of the final diagnosis served as external validation cohort (n = 1390).

RESULTS

Among 1161 patients, 154 patients had increased cTnI concentration. Of these, 78 patients (51%) were classified as T1MI and 76 (49%) as T2MI or myocardial injury. Patients with T2MI or myocardial injury had significantly higher copeptin plasma concentration between patients versus T1MI (21,4 pmol/l versus 8,1 pmol/l, p = 0,001). A multivariable regression analysis revealed that higher concentrations of copeptin and C-reactive protein, higher heart rate at presentation and lower frequency of smoking remained significantly associated with T2MI and myocardial injury. Findings were largely confirmed in the external validation cohort.

CONCLUSION

In patients without ST-segment elevation, copeptin concentration was higher in T2MI and myocardial Injury versus T1MI and may help in their differential diagnosis.

Type 2 Myocardial Infarction and Long-Term Mortality Risk Factors: A Retrospective Cohort Study

INTRODUCTION

In-hospital risk factors for type 1 myocardial infarction (MI) have been extensively investigated, but risk factors for type 2 MI are still emerging. Moreover, type 2 MI remains an underdiagnosed and under-researched condition. Our aim was to assess survival rates after type 2 MI and to analyze the risk factors for patient prognosis after hospitalization.

METHODS

We conducted a retrospective database analysis of patients with MI diagnosis who were treated in Vilnius University Hospital Santaros Klinikos. A total of 6495 patients with the diagnosis of MI were screened. The primary study endpoint was long-term all-cause mortality. The predictive value of laboratory tests was estimated including blood hemoglobin, D dimer, creatinine, brain natriuretic peptide (BNP), C-reactive protein (CRP), and troponin levels.

RESULTS

Out of all the patients diagnosed with MI there were 129 cases of type 2 MI (1.98%). Death rate almost doubled from 19.4% at 6 months to 36.4% after 2 years of follow-up. Higher age and impaired kidney function were risk factors for death both during hospitalization and after 2 years of follow-up. Lower hemoglobin (116.6 vs. 98.9 g/L), higher creatinine (90 vs. 161.9 μmol/L), higher CRP (31.4 vs. 63.3 mg/l), BNP (707.9 vs. 2999.3 ng/L), and lower left ventricle ejection fraction were all predictors of worse survival after 2 years of follow-up. Preventive medication during hospitalization can decrease the mortality risk: angiotensin-converting enzyme inhibitor (ACEi) (HR 0.485, 95% CI 0.286-0.820) and statins (HR 0.549, 95% CI 0.335-0.900). No significant influence was found for beta blockers (HR 0.662, 95% CI 0.371-1.181) or aspirin (HR 0.901, 95% CI 0.527-1.539).

CONCLUSIONS

There is significant underdiagnosis of type 2 MI (1.98% out of all MIs). If the patient is prescribed a preventive medication like ACEi or statins, the mortality risk is lower. Increased awareness of elevation of laboratory results could help to improve the treatment of these patients and identify the most vulnerable groups.

Long-term clinical outcomes of type 1 vs. type 2 myocardial infarction in patients who underwent angiography: data from the Korea acute myocardial infarction-national institute of health registry

BACKGROUND

In the cause of increase the clinical research observational evidence on type 2 myocardial infraction (T2MI), the study compared the characteristics of T2MI and T1MI with respect to major adverse cardiac events (MACE) and mortality as long-term outcomes from a large, nationwide, prospective Korean cohort registry.

METHODS

From 13,105 consecutively enrolled individuals in the Korea Acute Myocardial Infarction-National Institute of Health (KAMIR-NIH) registry between October 2011 and December 2015, 11,053 acute myocardial infarction (AMI) patients were divided into the T1MI (n=10,545) and T2MI (n=508) groups. All patients completed ≥3 years of follow-up.

RESULTS

The Kaplan-Meier curve analysis and Cox proportional hazard regression models showed that the cumulative rate of MACE was similar between the 2 groups (11.4% vs. 13.4%, log-rank P=0.185) at 3 years. However, the T2MI group showed higher rates of all-cause death [12.6% vs. 9.4%, log-rank P=0.019; hazard ratio (HR), 1.42; 95% CI: 1.08-1.85; P=0.012] and non-cardiac death (3.5% vs. 5.3%, log-rank P=0.043; HR, 1.55; 95% CI: 1.01-2.37; P=0.043) than the T1MI group. Male sex (HR 1.540; 95% CI: 1.218-1.947, P<0.001), old age (≥65 years; HR, 3.546; 95% CI: 2.645-4.753, P<0.001), low hemoglobin level (<12 g/dL; HR, 2.335; 95% CI: 1.841-2.961, P<0.001), high heart rate (>100 beats/min; HR, 1.852; 95% CI: 1.436-2.388, P<0.001), low glomerular filtration rate (GFR) (<60 mL/min/1.73 m2; HR, 2.373; 95% CI: 1.874-3.005, P<0.001), high body mass index (>25 kg/m2; HR, 0.644; 95% CI: 0.514-0.805, P<0.001), and low left ventricular ejection fraction (LVEF) (<40%; HR, 1.487; 95% CI: 1.095-2.020, P=0.011) were the independent predictors for 3-year non-cardiac mortality.

CONCLUSIONS

Although the 2 groups did not differ in MACE, the total mortality rate was higher in T2MI than in T1MI, especially non-cardiac mortality. The independent predictors for non-cardiac mortality were male sex, old age, anemia, low GFR, tachycardia, obesity, and low LVEF.

Sex-Based Differences in Prevalence and Outcomes of Common Acute Conditions Associated With Type 2 Myocardial Infarction

Little is known about the association between acute prevalent conditions in patients with type 2 Myocardial Infarction (T2MI) and clinical outcomes, particularly between genders. Using the Nationwide Inpatient Sample (2017), we examined outcomes of T2MI in patients stratified by prevalent associated conditions (renal failure, decompensated heart failure, infection, acute respiratory failure, cardiac arrhythmias, bleeding) and gender. Multivariable logistic regression was performed to assess the odds ratios (OR) of in-hospital all-cause mortality in each of the study groups. A total of 38,715 T2MI patients were included in the analysis, of which 47.9% (n = 18,540) were females. Renal failure was the most common prevalent condition in both genders (males: 60%; females: 52.6%). Acute respiratory failure was associated with the greatest odds of mortality (OR 5.46, 95% confidence interval (CI) 5.02 to 5.94) when compared with other conditions: renal failure (OR 2.20 95% CI 2.01 to 2.40), infections (OR 2.96 95% CI 2.72 to 3.21), major bleeding (OR 1.71 95% CI 1.52 to 1.93), arrhythmias (OR 1.30 95% CI 1.19 to 1.43) and decompensated heart failure (OR 0.71, 95% CI 0.65 to 0.77). However, there was no difference in mortality between genders for all acute conditions except renal failure (females OR: 1.02, 95% CI 1.02 to 1.02, p = 0.011). In conclusion, in-hospital mortality after T2MI differs according to the underlying acute condition, with acute respiratory failure being associated with the highest rate of mortality. No significant differences in mortality were observed between genders amongst all prevalent acute conditions, with the exception of renal failure which was marginally higher in females.

Concordance and Prognostic Relevance of Angiographic and Clinical Definitions of Myocardial Infarction Type

BACKGROUND

Atherothrombosis is the principal mechanism of type 1 (T1) myocardial infarction (MI), while type 2 (T2) MI is typically diagnosed in the presence of triggers (anemia, arrhythmia, etc.). We aimed to evaluate the proportions of T1 vs. T2 MI based on angiographic and clinical definitions, their concordance and prognosis.

METHODS

Consecutive MI patients [n = 712, 61% male; age 64.6 ± 12.3 years] undergoing coronary angiography were classified according to the presence of atherothrombosis and identifiable triggers. Association of angiographic and clinical MI type criteria with adverse outcomes (Time follow-up was 1.5 years) was evaluated. Predictive ability of GRACE risk score for all-cause mortality was then assessed.

RESULTS

Atherothrombosis and clinical triggers were identified in 397 (55.6%) and 324 (45.5%) subjects, respectively. Only 247 (34.7%) patients had "true" T1MI (atherothrombosis+ / triggers-); 174 (24.4%) were diagnosed with "true" T2MI (atherothrombosis- / triggers+), while 291 (40.9%) had discordant clinical and angiographic characteristics. All-cause mortality in T2MI (20.1%) patients was higher than in T1MI (9.3%), P = 0.002. Presence of triggers [odds ratio (OR) 2.4, 95% CI 1.5-3.6, P < 0.0001] but not atherothrombosis [OR 0.8, 95% confidence interval (CI) 0.5-1.3, P = 0.26] was associated with worse prognosis. GRACE score is a better predictor of death in T1MI vs. T2MI: area under curve 0.893 (95% CI 0.830-0.956) vs 0.748 (95% CI 0.652-0.843), P = 0.013.

CONCLUSION

Angiographic and clinical definitions of MI type are discordant in a substantial proportion of patients. Clinical triggers are associated with all-cause mortality. Predictive performance of GRACE score is worse in T2MI patients.

Brief Report: Differences in Types of Myocardial Infarctions Among People Aging With HIV

BACKGROUND

Type 1 myocardial infarctions (T1MIs) result from atherosclerotic plaque instability, rupture, and/or erosion. Type 2 MIs (T2MIs) are secondary to causes such as sepsis and cocaine-induced vasospasm resulting in an oxygen demand-supply mismatch and are associated with higher mortality than T1MIs. T2MIs account for a higher proportion of MIs among people living with HIV (PLWH) compared with the general population. We compared MI rates by type among aging PLWH. We hypothesized that increases in MI rates with older age would differ by MI types, and T2MIs would be more common than T1MIs in younger individuals.

METHODS

Potential MIs from 6 sites were centrally adjudicated using physician notes, electrocardiograms, procedure results, and laboratory results. Reviewers categorized MIs by type and identified causes of T2MIs. We calculated T1MI and T2MI incidence rates. Incidence rate ratios were calculated for T2MI vs. T1MI rates per decade of age.

RESULTS

We included 462 T1MIs (52%) and 413 T2MIs (48%). T1MI rates increased with older age, although T1MIs occurred in all age decades including young adults. T2MI rates were significantly higher than T1MI rates for PLWH younger than 40 years. T1MI rates were similar or higher than T2MI rates among those older than 40 years (significantly higher for those aged 50-59 and 60-69 years).

CONCLUSIONS

Rates of T2MIs were higher than T1MIs until age 40 years among PLWH, differing from the general population, but rates of both were high among older PLWH. Given prognostic differences between MI types, these results highlight the importance of differentiating MI types among PLWH.

Patient Characteristics and Clinical Outcomes of Type 1 Versus Type 2 Myocardial Infarction

BACKGROUND

Type 2 myocardial infarction (MI) patients may have different characteristics and outcomes when compared with type 1 MI.

OBJECTIVES

The purpose of this study was to compare patients with type 1 MI to those with type 2 MI in the United States.

METHODS

Using the Nationwide Readmissions Database, MI patients were categorized over the 3 months following the introduction of an International Classification of Diseases-10th Revision code specific for type 2 MI. Baseline characteristics and inpatient and post-discharge outcomes among both cohorts were compared.

RESULTS

There were 216,657 patients with type 1 MI, 37,765 patients with type 2 MI, and 1,525 patients with both type 1 and 2 MI. Patients with type 2 MI were older (71 years vs. 69 years; p < 0.001), were more likely to be women (47.3% vs. 40%; p < 0.001), and had higher prevalence of heart failure (27.9% vs. 10.9%; p < 0.001), kidney disease (35.7% vs. 25.7%; p < 0.001), and atrial fibrillation (31% vs. 21%; p < 0.001). Rates of coronary angiography (10.9% vs. 57.3%; p < 0.001), percutaneous coronary intervention (1.7% vs. 38.5%; p < 0.001), and coronary artery bypass grafting (0.4% vs. 7.8%; p < 0.001) were lower among type 2 MI patients. Patients with type 2 MI had lower risk of in-hospital mortality (adjusted odds ratio: 0.57 [95% confidence interval: 0.54 to 0.60]) and 30-day MI readmission (adjusted odds ratio: 0.46 [95% confidence interval: 0.35 to 0.59]). There was no difference in risk of 30-day all-cause or heart failure readmission.

CONCLUSIONS

Patients with type 2 MI have a unique cardiovascular phenotype when compared with type 1 MI, and are managed in a heterogenous manner. Validated management strategies for type 2 MI are needed.

Type 2 Myocardial Infarction: CURRENT CONCEPTS AND OUR EXPERIENCE WITH CARDIAC REHABILITATION

BACKGROUND

Type 2 myocardial infarction (T2MI) is commonly encountered in clinical practice, yet little is known about this challenging condition. Outpatient cardiac rehabilitation (CR) is an integral component in the care of patients with MI. However, specific recommendations for CR, information on the feasibility of participation, and outcome measures for patients with T2MI are lacking.

CLINICAL CONSIDERATIONS

The frequency of T2MI is markedly variable and depends on the studied population, disease definition, adjudication process, cardiac troponin assays, and cutoff values used to make the diagnosis of T2MI. Clinically, it is difficult to distinguish T2MI from type 1 MI or myocardial injury. Type 2 myocardial infarction occurs due to myocardial oxygen supply-demand mismatch without acute atherothrombotic plaque disruption and is associated with adverse short- and long-term prognoses. Currently, there are substantial gaps in knowledge regarding T2MI and there are no clear guidelines for the optimal management of these patients.

SUMMARY

In this article, we present important current concepts surrounding T2MI including the definition, pathophysiology, epidemiology, diagnosis, prognosis, and management. We also discuss referral patterns to CR and participation rates and provide our experience with a case series of 17 patients. Very few patients with T2MI are referred to and participate in CR. Our small case series indicated that patients with T2MI respond favorably to CR and that exercise training following standard guidelines appears safe and is well tolerated.

Type II Myocardial Infarction: Predisposing Factors, Precipitating Elements, and Outcomes

Introduction Myocardial infarction (MI) is a subset of the spectrum of the disease known as acute coronary syndrome (ACS), which comprises three distinct entities including unstable angina (UA) and MI with or without ST-segment elevation. However, many clinicians are unaware that MI itself is classified into five types, the most common being type I, followed by type II. Type II MI occurs due to coronary insufficiency not related to acute plaque change in the coronary vasculature. Data available on type II MI is still limited, particularly in the South Asian setting, despite documented poorer outcomes for the same compared to other types. Therefore, we conducted this study as an attempt to outline the predisposing factors, precipitating elements, and possible outcomes of type II MI. Materials and methods This prospective study was conducted at a tertiary care hospital in Kochi, Kerala for 12 months. A total of 59 patients of ages 10-99 years, with a final diagnosis of MI based on the levels of cardiac biomarkers and electrocardiography (ECG), no previous history of coronary angiography, thrombolysis, percutaneous coronary intervention (PCI), and non-ischemic conditions producing elevations in cardiac biomarkers were included in this study. Demographic features, cardiac biomarker levels, comorbidities, precipitating factors, foci of sepsis, and outcomes of type II MI were noted. The mean was calculated for age and cardiac biomarkers. The frequency and percentages were calculated for gender, comorbidities, precipitating factors, foci of sepsis, and the outcomes of type II MI. Results The mean age of the patients was 69.66 years; 38 (64.4%) patients were males and 21 (35.59%) were females. Mean elevation of creatine kinase myocardial band (CK-MB) was 47.457 IU/L and highly sensitive troponin I (Hs-Trop I) was 8.712 ng/mL. Diabetes mellitus [44 (74.57%)] and hypertension [41 (69.49%)] were the most common underlying patient comorbidities followed by dyslipidemia [38 (64.4%)]. Most of the patients had more than two comorbidities at a time; 33 (55.93%) patients had sepsis, 31 (52.4%) patients had anemia, 29 (49.1%) patients had electrolyte imbalance, 19 (32.2%) patients had respiratory failure, 16 (27.11%) patients had arrhythmia (tachyarrhythmia/bradyarrhythmia), and two (3.3%) patients had postoperative (non-cardiothoracic) stress. Sepsis was originating from the lower respiratory tract in 14 (42.42%) patients, blood in 11 (33.33%) patients, urinary tract in eight (24.24%) patients, and abdomen in six (18.18%) patients. Thirty-four (57.62%) patients had heart failure, 13 (22.03%) had arrhythmias, and 19 (32.20%) patients died. Conclusions Type II MI has a high mortality rate, mostly due to heart failure and arrhythmia. Patients with diabetes mellitus and hypertension are at increased risk of type II MI. Sepsis is the most common precipitating factor, primarily originating from the lower respiratory tract, followed by anemia and dyselectrolytemia. Treatment of precipitating factors is the primary way to manage type II MI.

[The Frequency of Type 2 Myocardial Infarction in the Structure of Hospital Mortality According to 7-Years Data of a State University Clinic]

 Aim      To evaluate the proportion of type 2 myocardial infarction (MI) in the structure of mortality at a multidisciplinary hospital; to describe major causes for MI development, and characteristics of patients with a verified diagnosis of type 2 MI by data of postmortem examination.Material and methods  1574 protocols of the autopsies performed at the Central Pathology Department of the I.I. Mechnikov North-West State Medical University from 01.01.10 through 31.12.16 were studied retrospectively by the continuous sampling method. A group with verified diagnosis of type 2 MI was isolated from the total sample of autopsies. Major causes for and the proportion of type 2 MI among the causes of death were studied. Also, major demographic parameters, hospitalization profile, and condition of coronary arteries (CA) were compared in patients with fatal type 2 MI and those who died from atherothrombotic type 1 MI.Results Analysis of 1574 fatal cases among patients of the multidisciplinary hospital showed that in 360 cases (22.87 %), the cause of death was MI, including 137 cases of fatal type 2 MI. Proportions of men and women among the patients with postmortem verification of type 2 MI were comparable. Analysis of the age structure showed the highest incidence of type 2 MI in elderly (48.2 %) and senile (34.3 %) age. Mean age of patients with type 2 MI was 71.7 years (68.2 years for men and 75.3 years for women), which was comparable with the age range of patients with fatal type 1 MI. In both groups, men with fatal MI were significantly younger than women. Analysis of causes for type 2 MI demonstrated that the most frequent ones were tachysystolic arrhythmias (59.12 %) and severe hypoxia of different origin (35.04 %). Analysis of the type of CA lesions showed that significant lesions were significantly more frequently absent in type 2 MI (32.85 %) while in type 1 MI, the proportion of patients with unchanged CA was 1.84 %. In the group of patients with fatal type 1 MI, 67.29 % had multivascular lesions, and one in two patients had an occlusive lesion. In the group with type 2 MI, multivascular lesions were half as frequent (31.38 %), and only 4.38 % of patients had a complete occlusion of a coronary vessel. Comparison of death rate in different departments of the multidisciplinary hospital showed that only 29.2 % of patients with type 2 MI originally were managed at a specialized cardiological department; 45.3 % of patients were admitted to an internal medicine department for different conditions often not related with ischemic heart disease. Furthermore, 25.5 % of patients with subsequently developed type 2 MI originally even received scheduled or emergency medical care for a leading surgical condition.Conclusion      Cardiovascular diseases predominate among causes of mortality in a multidisciplinary hospital. This study showed that almost one in four patients dies from MI, and type 2 MI accounts for more than one third of fatal MIs. Among major causes for type 2 MI, tachysystolic arrhythmias (59.12 %) and pronounced hypoxia associated with anemia and severe respiratory failure (35.04 %) should be noted. Gender and age characteristics of patients with type 2 MI were comparable with those of patients with fatal type 1 MI. Furthermore, surgical patients accounted for 25.5 % of fatal cases of type 2 MI.

Association Between Chronic Hepatitis C Virus Infection and Myocardial Infarction Among People Living With HIV in the United States

Hepatitis C virus (HCV) infection is common among people living with human immunodeficiency virus (PLWH). Extrahepatic manifestations of HCV, including myocardial infarction (MI), are a topic of active research. MI is classified into types, predominantly atheroembolic type 1 MI (T1MI) and supply-demand mismatch type 2 MI (T2MI). We examined the association between HCV and MI among patients in the Centers for AIDS Research (CFAR) Network of Integrated Clinical Systems, a US multicenter clinical cohort of PLWH. MIs were centrally adjudicated and categorized by type using the Third Universal Definition of Myocardial Infarction. We estimated the association between chronic HCV (RNA+) and time to MI while adjusting for demographic characteristics, cardiovascular risk factors, clinical characteristics, and history of injecting drug use. Among 23,407 PLWH aged ≥18 years, there were 336 T1MIs and 330 T2MIs during a median of 4.7 years of follow-up between 1998 and 2016. HCV was associated with a 46% greater risk of T2MI (adjusted hazard ratio (aHR) = 1.46, 95% confidence interval (CI): 1.09, 1.97) but not T1MI (aHR = 0.87, 95% CI: 0.58, 1.29). In an exploratory cause-specific analysis of T2MI, HCV was associated with a 2-fold greater risk of T2MI attributed to sepsis (aHR = 2.01, 95% CI: 1.25, 3.24). Extrahepatic manifestations of HCV in this high-risk population are an important area for continued research.

Association Between Bilirubin, Atazanavir, and Cardiovascular Disease Events Among People Living With HIV Across the United States

OBJECTIVE

Bilirubin is an antioxidant that may suppress lipid oxidation. Elevated bilirubin is associated with decreased cardiovascular events in HIV-uninfected populations. We examined these associations in people living with HIV (PLWH).

METHODS

Potential myocardial infarctions (MIs) and strokes were centrally adjudicated. We examined MI types: type 1 MI (T1MI) from atherosclerotic plaque instability and type 2 MI (T2MI) in the setting of oxygen demand/supply mismatch such as sepsis. We used multivariable Cox regression analyses to determine associations between total bilirubin levels and outcomes adjusting for traditional and HIV-specific risk factors. To minimize confounding by hepatobiliary disease, we conducted analyses limited to bilirubin values <2.1 mg/dL; among those with fibrosis-4 values <3.25; and among everyone. We repeated analyses stratified by hepatitis C status and time-updated atazanavir use.

RESULTS

Among 25,816 PLWH, there were 392 T1MI and 356 T2MI during follow-up. Adjusted hazard ratios for the association of higher bilirubin levels with T1MI were not significant. Higher bilirubin levels were associated with T2MI. By contrast, among PLWH on atazanavir, higher bilirubin levels were associated with fewer T2MI (hazard ratio 0.56:0.33-1.00). Higher bilirubin levels among those on atazanavir were associated with fewer T1MI combined with ischemic stroke.

LIMITATIONS

Analyses were conducted with total rather than unconjugated bilirubin.

CONCLUSIONS

Among PLWH, higher bilirubin levels were associated with T2MI among some subgroups. However, among those on atazanavir, there was a protective association between bilirubin and T2MI. These findings demonstrate different associations between outcomes and elevated bilirubin due to diverse causes and the importance of distinguishing MI types.

Type 2 Myocardial Infarction: JACC Review Topic of the Week

Acute myocardial infarction (MI) can occur from increased myocardial oxygen demand and/or reduced supply in the absence of acute atherothrombotic plaque disruption; a condition called type 2 myocardial infarction (T2MI). As with any MI subtype, there must be clinical evidence of myocardial ischemia to make the diagnosis. This condition is increasingly diagnosed due to the increasing sensitivity of cardiac troponin assays and is associated with adverse short-term and long-term prognoses. Limited data exist defining optimal management strategies because T2MI is a heterogeneous entity with varying etiologies and triggers. Thus, these patients require individualized care. A major barrier is the absence of a uniform definition that can be operationalized with high reproducibility. This document provides a synthesis of the data about T2MI to assist clinicians' understanding of its pathobiology, when to deploy the diagnosis, and its associated treatments. It also clarifies prognosis, identifies gaps in knowledge, and provides recommendations for moving forward.

Type 2 myocardial infarction in general medical wards: Clinical features, treatment, and prognosis in comparison with type 1 myocardial infarction

Type 2 myocardial infarction (MI) is defined as myocardial necrosis due to imbalance between myocardial oxygen supply and demand. The objective of this study was to assess the features, treatments, and outcomes of patients with type 2 MI in comparison with patients with type 1 MI hospitalized in general medical wards. A retrospective review was performed on patients admitted to general medicine wards diagnosed with MI in Sheba Medical Center between January 1, 2016 and December 31, 2016. Comparative analysis between patients with type 1 and type 2 MI was performed. The study included 349 patients with type 1 MI and 206 patients with type 2 MI. The main provoking factors for type 2 MI were sepsis (38.1%), anemia (29.1%), and hypoxia (23.8%). Patients with type 2 MI were older (79.1 ± 11.9 vs 75.2 ± 11.7, P < .001) and had a lower rate of prior MI (23.3% vs 38.1%, P < .001) and percutaneous coronary intervention (PCI) (34% vs 48.7%, P = .023) compared with patients with type 1 MI. Patients with type 2 MI were significantly less prescribed antiplatelet therapy (79.1% vs 96%, P < .001) and statins (60.7% vs 80.2%, P < .001), and were less referred to coronary angiography (10.7% vs 54.4%, P < .001). Type 2 MI was associated with a significantly higher 1-year mortality rate compared with type 1 MI (38.8% vs 26.6%, P = .004), but after accounting for age and sex differences, this association lacked statistical significance. In conclusion, type 2 MI patients were older and had similar comorbidities compared with those with type 1 MI. These patients were less prescribed medical therapy and coronary intervention, and had a higher 1-year mortality rate. Establishing a clear therapeutic approach for type 2 MI is required.

Assessment and Treatment of Patients With Type 2 Myocardial Infarction and Acute Nonischemic Myocardial Injury

Although coronary thrombus overlying a disrupted atherosclerotic plaque has long been considered the hallmark and the primary therapeutic target for acute myocardial infarction (MI), multiple other mechanisms are now known to cause or contribute to MI. It is further recognized that an MI is just one of many types of acute myocardial injury. The Fourth Universal Definition of Myocardial Infarction provides a taxonomy for acute myocardial injury, including 5 subtypes of MI and nonischemic myocardial injury. The diagnosis of MI is reserved for patients with myocardial ischemia as the cause of myocardial injury, whether attributable to acute atherothrombosis (type 1 MI) or supply/demand mismatch without acute atherothrombosis (type 2 MI). Myocardial injury in the absence of ischemia is categorized as acute or chronic nonischemic myocardial injury. However, optimal evaluation and treatment strategies for these etiologically distinct diagnoses have yet to be defined. Herein, we review the epidemiology, risk factor associations, and diagnostic tools that may assist in differentiating between nonischemic myocardial injury, type 1 MI, and type 2 MI. We identify limitations, review new research, and propose a framework for the diagnostic and therapeutic approach for patients who have suspected MI or other causes of myocardial injury.

A systematic review on the triggers and clinical features of type 2 myocardial infarction

Little is known about the correlation between triggering factors, clinical characteristics, diagnosis, and prognosis of patients with type 2 myocardial infarction (T2MI). The triggers and features of T2MI are linked to its diagnosis and prognosis. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines were followed. A structured search of three databases (PubMed, Embase, and Medline) was undertaken to identify peer-reviewed articles related to the triggers and clinical features of T2MI published between January 2012 and August 2018. Seven retrospective cohort studies and seven prospective cohort studies involving 3867 patients with T2MI were included. All selected studies were rated as being of high or acceptable quality. Nine studies revealed that the leading trigger of T2MI was arrhythmia, especially tachyarrhythmia. Six studies revealed that the proportion of single-trigger T2MIs was higher than that of multiple triggers and two studies showed that two-trigger cases formed the majority of multiple trigger cases. All included studies found that a greater prevalence of T2MI in the older population. Thirteen studies revealed that the patients with T2MI often had a previous relevant medical history. The leading trigger of T2MI is arrhythmia, especially tachyarrhythmia, and the majority of cases arise from a single trigger. Two-trigger is the most common form of multiple-trigger T2MI, which often occurs in older patients with cardiovascular risk factors or comorbidities. Non-cardiovascular causes may be the triggering factors and are strongly associated with the diagnosis, treatment, and prognosis of T2MI.

Wake Forest University long-term follow-up of type 2 myocardial infarction: The Wake-Up T2MI Registry

Background

The Wake‐Up T2MI Registry is a retrospective cohort study investigating patients with type 2 myocardial infarction (T2MI), acute myocardial injury, and chronic myocardial injury. We aim to explore risk stratification strategies and investigate clinical characteristics, management, and short‐ and long‐term outcomes in this high‐risk, understudied population.

Methods

From 1 January 2009 to 31 December 2010, 2846 patients were identified with T2MI or myocardial injury defined as elevated cardiac troponin I with at least one value above the 99th percentile upper reference limit and coefficient of variation of 10% (>40 ng/L) and meeting our inclusion criteria. Data of at least two serial troponin values will be collected from the electronic health records to differentiate between acute and chronic myocardial injury. The Fourth Universal Definition will be used to classify patients as having (a) T2MI, (b) acute myocardial injury, or (c) chronic myocardial injury during the index hospitalization. Long‐term mortality data will be collected through data linkage with the National Death Index and North Carolina State Vital Statistics.

Results

We have collected data for a total of 2205 patients as of November 2018. The mean age of the population was 65.6 ± 16.9 years, 48% were men, and 64% were white. Common comorbidities included hypertension (71%), hyperlipidemia (35%), and diabetes mellitus (30%). At presentation, 40% were on aspirin, 38% on β‐blockers, and 30% on statins.

Conclusion

Improved characterization and profiling of this cohort may further efforts to identify evidence‐based strategies to improve cardiovascular outcomes among patients with T2MI and myocardial injury.

True 99th centile of high sensitivity cardiac troponin for hospital patients: prospective, observational cohort study

OBJECTIVE

To determine the distribution, and specifically the true 99th centile, of high sensitivity cardiac troponin I (hs-cTnI) for a whole hospital population by applying the hs-cTnI assay currently used routinely at a large teaching hospital.

DESIGN

Prospective, observational cohort study.

SETTING

University Hospital Southampton NHS Foundation Trust, Southampton, United Kingdom, between 29 June 2017 and 24 August 2017.

PARTICIPANTS

20 000 consecutive inpatients and outpatients undergoing blood tests for any clinical reason. Hs-cTnI concentrations were measured in all study participants and nested for analysis except when the supervising doctor had requested hs-cTnI for clinical reasons.

MAIN OUTCOME MEASURES

Distribution of hs-cTnI concentrations of all study participants and specifically the 99th centile.

RESULTS

The 99th centile of hs-cTnI for the whole population was 296 ng/L compared with the manufacturer's quoted level of 40 ng/L (currently used clinically as the upper limit of normal; ULN). Hs-cTnI concentrations were greater than 40 ng/L in one in 20 (5.4%, n=1080) of the total population. After excluding participants diagnosed as having acute myocardial infarction (n=122) and those in whom hs-cTnI was requested for clinical reasons (n=1707), the 99th centile was 189 ng/L for the remainder (n=18 171). The 99th centile was 563 ng/L for inpatients (n=4759) and 65 ng/L for outpatients (n=9280). Patients from the emergency department (n=3706) had a 99th centile of 215 ng/L, with 6.07% (n=225) greater than the recommended ULN. 39.02% (n=48) of all patients from the critical care units (n=123) and 14.16% (n=67) of all medical inpatients had an hs-cTnI concentration greater than the recommended ULN.

CONCLUSIONS

Of 20 000 consecutive patients undergoing a blood test for any clinical reason at our hospital, one in 20 had an hs-cTnI greater than the recommended ULN. These data highlight the need for clinical staff to interpret hs-cTnI concentrations carefully, particularly when applying the recommended ULN to diagnose acute myocardial infarction, in order to avoid misdiagnosis in the absence of an appropriate clinical presentation.

TRIAL REGISTRATION

Clinicaltrials.gov NCT03047785.

Risk Estimation in Type 2 Myocardial Infarction and Myocardial Injury: The TARRACO Risk Score

BACKGROUND

Despite adverse prognoses of type 2 myocardial infarction and myocardial injury, an effective, practical risk stratification method remains an unmet clinical need. We sought to develop an efficient clinical bedside tool for estimating the risk of major adverse cardiovascular events at 180 days for this patient population.

METHODS

The derivation cohort included patients with type 2 myocardial infarction or myocardial injury admitted to a tertiary hospital between 2012 and 2013 (n = 611). The primary outcome was a major adverse cardiovascular event (death or readmission for heart failure or myocardial infarction). The score included clinical variables significantly associated with the outcome. External validation was conducted using the UTROPIA cohort (n = 401).

RESULTS

The TARRACO Score included cardiac troponin (cTn) concentrations and 5 independent clinical predictors of adverse cardiovascular events: age, hypertension, absence of chest pain, dyspnea, and anemia. The score exhibited good discriminative accuracy (area under the curve = 0.74; 95% CI, 0.70-0.79). Patients were classified into low-risk (score 0-6) and high-risk (score ≥7) categories. Major adverse cardiovascular events rates were 5 times more likely in high-risk patients compared with those at low risk (78.9 vs 15.4 events/100 patient-years, respectively; logrank P < .001). The external validation showed equivalent prognostic capacity (area under the curve=0.71, 0.65-0.78).

CONCLUSION

A novel risk score based on bedside clinical variables and cTn concentrations allows risk stratification for death and cardiac-related rehospitalizations in patients with type 2 myocardial infarctions and myocardial injury. This score identifies patients at the highest risk of adverse events, a subset of patients who may benefit from close observation, medical intensification, or both.

Differentiation of Type 1 and Type 2 Myocardial Infarctions Among HIV-Infected Patients Requires Adjudication Due to Overlap in Risk Factors

The Universal Myocardial infarction (MI) definition divides MIs into different types. Type 1 MIs (T1MI) result spontaneously from atherosclerotic plaque instability. Type 2 MIs (T2MI) are due to secondary causes of myocardial oxygen demand/supply mismatch such as occurs with sepsis. T2MI are much more common among those with HIV than in the general population. T1MI and T2MI have different mechanisms, risk factors, and potential treatments suggesting that they should be distinguished to achieve a better scientific understanding of MIs in HIV. We sought to determine whether MI type could be accurately predicted by patient characteristics without adjudication in HIV-infected individuals. We developed a statistical model to predict T2MI versus T1MI using adjudicated events from six sites utilizing demographic characteristics, traditional cardiovascular, and HIV-related risk factors. Validation was assessed in a seventh site via mean calibration, and discrimination level was assessed by the area under the curve (AUC). Of 812 MIs, 388 were T2MI. HIV-related factors including hepatitis C infection were predictive of T2MI, whereas traditional cardiovascular risk factors including total cholesterol predicted T1MI. The score predicted 69 T2MI in the validation sample resulting in poor calibration, given that 90 T2MIs were observed. The development sample AUC was 0.75 versus 0.65 in the validation sample, suggesting relatively poor discrimination. The level of discrimination to predict MI type based on patient characteristics is insufficient for individual level prediction. Adjudication is required to distinguish MI types, which is necessary to advance understanding of this important outcome among HIV populations.

Treatment and outcomes of type 2 myocardial infarction and myocardial injury compared with type 1 myocardial infarction

BACKGROUND

Type 2 myocardial infarction (MI) is defined by a rise and fall of cardiac biomarkers and evidence of ischemia without unstable coronary artery disease (CAD) because of a mismatch in myocardial oxygen supply and demand. Myocardial injury is similar but does not fulfill the clinical criteria for MI. There is uncertainty in terms of the clinical characteristics, management, and outcomes of type 2 MI and myocardial injury in comparison with type 1 MI.

PATIENTS AND METHODS

Patients admitted to a Veterans Affairs tertiary care hospital with a rise and fall in cardiac troponin were identified. MI and injury subtypes, presentation, management, and outcomes were determined.

RESULTS

Type 1 MI, type 2 MI, and myocardial injury occurred in 137, 146, and 175 patients, respectively. Patients with type 2 MI were older (P=0.02), had lower peak cardiac troponin (P<0.001), and were less likely to receive aspirin and statin at discharge (P<0.001) than type 1 MI survivors. All-cause mortality (median follow-up: 1.8 years) was not different between patient groups (type 1 MI mortality: 29.9%, type 2 MI: 30.8%, myocardial injury: 29.7%; log rank P=0.94). A significant proportion of deaths were attributed to cardiovascular causes in all subgroups (type 1 MI: 34.1%, type 2 MI: 17.8%, myocardial injury: 30.8%).

CONCLUSION

Patients with type 2 MI and myocardial injury were less likely to receive medical therapy for CAD than those with type 1 MI. No differences in all-cause mortality among MI subtypes were observed. Additional studies to determine optimal medical therapy and risk stratification strategies for these high-risk populations are warranted.

Different Causes of Death in Patients with Myocardial Infarction Type 1, Type 2, and Myocardial Injury

BACKGROUND

Data outlining the mortality and the causes of death in patients with type 1 myocardial infarction, type 2 myocardial infarction, and those with myocardial injury are limited.

METHODS

During a 1-year period from January 2010 to January 2011, all hospitalized patients who had cardiac troponin I measured on clinical indication were prospectively studied. Patients with at least one cardiac troponin I value >30 ng/L underwent case ascertainment and individual evaluation by an experienced adjudication committee. Patients were classified as having type 1 myocardial infarction, type 2 myocardial infarction, or myocardial injury according to the criteria of the universal definition of myocardial infarction. Follow-up was ensured until December 31, 2014. Data on mortality and causes of death were obtained from the Danish Civil Registration System and the Danish Register of Causes of Death.

RESULTS

Overall, 3762 consecutive patients were followed for a mean of 3.2 years (interquartile range 1.3-3.6 years). All-cause mortality differed significantly among categories: Type 1 myocardial infarction 31.7%, type 2 myocardial infarction 62.2%, myocardial injury 58.7%, and 22.2% in patients with nonelevated troponin values (log-rank test; P < .0001). In patients with type 1 myocardial infarction, 61.3% died from cardiovascular causes, vs 42.6% in patients with type 2 myocardial infarction (P = .015) and 41.2% in those with myocardial injury (P < .0001). The overall mortality and the causes of death did not differ substantially between patients with type 2 myocardial infarction and those with myocardial injury.

CONCLUSIONS

Patients with type 2 myocardial infarction and myocardial injury exhibit a significantly higher long-term mortality compared with patients with type 1 myocardial infarction . However, most patients with type 1 myocardial infarction die from cardiovascular causes in contrast to patients with type 2 myocardial infarction and myocardial injury, in whom noncardiovascular causes of death predominate.

Long-Term Outcomes in Patients With Type 2 Myocardial Infarction and Myocardial Injury

BACKGROUND

Type 2 myocardial infarction and myocardial injury are common in clinical practice, but long-term consequences are uncertain. We aimed to define long-term outcomes and explore risk stratification in patients with type 2 myocardial infarction and myocardial injury.

METHODS

We identified consecutive patients (n=2122) with elevated cardiac troponin I concentrations (≥0.05 µg/L) at a tertiary cardiac center. All diagnoses were adjudicated as per the universal definition of myocardial infarction. The primary outcome was all-cause death. Secondary outcomes included major adverse cardiovascular events (eg, nonfatal myocardial infarction or cardiovascular death) and noncardiovascular death. To explore competing risks, cause-specific hazard ratios were obtained using Cox regression models.

RESULTS

The adjudicated index diagnosis was type 1 or 2 myocardial infarction or myocardial injury in 1171 (55.2%), 429 (20.2%), and 522 (24.6%) patients, respectively. At 5 years, all-cause death rates were higher in those with type 2 myocardial infarction (62.5%) or myocardial injury (72.4%) compared with type 1 myocardial infarction (36.7%). The majority of excess deaths in those with type 2 myocardial infarction or myocardial injury were because of noncardiovascular causes (hazard ratio, 2.32; 95% confidence interval, 1.92-2.81 versus type 1 myocardial infarction). Despite this finding, the observed crude major adverse cardiovascular event rates were similar between groups (30.6% versus 32.6%), with differences apparent after adjustment for covariates (hazard ratio, 0.82; 95% confidence interval, 0.69-0.96). Coronary heart disease was an independent predictor of major adverse cardiovascular events in those with type 2 myocardial infarction or myocardial injury (hazard ratio, 1.71; 95% confidence interval, 1.31-2.24).

CONCLUSIONS

Despite an excess in noncardiovascular death, patients with type 2 myocardial infarction or myocardial injury have a similar crude rate of major adverse cardiovascular events as those with type 1 myocardial infarction. Identifying underlying coronary heart disease in this vulnerable population may help target therapies that could modify future risk.

High sensitivity troponins in contemporary cardiology practice: are we turning a corner?

INTRODUCTION

Troponin is considered to be the gold standard biomarker for ruling out MI. There has been a drive to improve the diagnostic speed, and as such the high sensitivity cardiac troponin (hs-cTn) assays have been introduced into clinical practice and are now part of international guidelines. Their novel value in clinical practice more generally is becoming apparent. Areas covered: In this review we will evaluate the evidence for the use of hs-cTn assays in clinical practice, the issues with the assay and how the hs-cTn can be utilized in the future as a biomarker of cardiovascular risk. Expert commentary: The use of the hs-cTn assays as a 'rule out' test for MI is compelling, as a 'rule in' there are significant issues relating the specificity of the assay for MI. The future of the assay may lie in population screening and risk modeling.

Patient selection for high sensitivity cardiac troponin testing and diagnosis of myocardial infarction: prospective cohort study

Objective To evaluate how selection of patients for high sensitivity cardiac troponin testing affects the diagnosis of myocardial infarction across different healthcare settings.Design Prospective study of three independent consecutive patient populations presenting to emergency departments.Setting Secondary and tertiary care hospitals in the United Kingdom and United States.Participants High sensitivity cardiac troponin I concentrations were measured in 8500 consecutive patients presenting to emergency departments: unselected patients in the UK (n=1054) and two selected populations of patients in whom troponin testing was requested by the attending clinician in the UK (n=5815) and the US (n=1631). The final diagnosis of type 1 or type 2 myocardial infarction or myocardial injury was independently adjudicated.Main outcome measures Positive predictive value of an elevated cardiac troponin concentration for a diagnosis of type 1 myocardial infarction.Results Cardiac troponin concentrations were elevated in 13.7% (144/1054) of unselected patients, with a prevalence of 1.6% (17/1054) for type 1 myocardial infarction and a positive predictive value of 11.8% (95% confidence interval 7.0% to 18.2%). In selected patients, in whom troponin testing was guided by the attending clinician, the prevalence and positive predictive value were 14.5% (843/5815) and 59.7% (57.0% to 62.2%) in the UK and 4.2% (68/1631) and 16.4% (13.0% to 20.3%) in the US. Across both selected patient populations, the positive predictive value was highest in patients with chest pain, with ischaemia on the electrocardiogram, and with a history of ischaemic heart disease.Conclusions When high sensitivity cardiac troponin testing is performed widely or without previous clinical assessment, elevated troponin concentrations are common and predominantly reflect myocardial injury rather than myocardial infarction. These observations highlight how selection of patients for cardiac troponin testing varies across healthcare settings and markedly influences the positive predictive value for a diagnosis of myocardial infarction.

Type 2 versus type 1 myocardial infarction: a comparison of clinical characteristics and outcomes with a meta-analysis of observational studies

BACKGROUND

Type 2 myocardial infarction (MI) is an imbalance between myocardial oxygen demand and supply, leading to myocardial ischemia. It is not due to plaque rupture, and is usually caused by a condition other than coronary artery disease (CAD). However, limited data are available comparing the prevalence of traditional coronary risk factors and mortality between type 1 and type 2 MI. We hypothesize that type 2 MI carries a higher mortality than type 1.

METHODS

We searched the databases of PubMed, EMBASE, CENTRAL, and MEDLINE for studies comparing type 1 MI with type 2 MI. The baseline variables were compared in each cohort. Summary risk ratios and 95% confidence intervals were calculated using the random effects model to compare mortality between the two groups.

RESULTS

The included studies yielded 25,872 patients of whom 2,683 (10%) had type 2 MI. Compared to the type 1 cohort, the type 2 cohort had significantly higher inpatient (15% vs. 4.7%, P<0.00001), 30-day (17.6% vs. 5.3%, P<0.00001) and 1-yr mortality (27% vs. 13%, P<0.00001), as well as higher 30-day major adverse cardiovascular events (20% vs. 9%, P<0.0001). Operative stress (20%) was the most common trigger of type 2 MI, followed by sepsis (19%), arrhythmia (18.63%), heart failure (15%), and anemia (12%).

CONCLUSIONS

Type 2 MI is a common entity and is more common in females, older age groups, and in patients with multiple comorbidities: it also tends to result in higher mortality.

Circulating Prolidase Activity in Patients with Myocardial Infarction

Background

Collagen is a major determinant of atherosclerotic plaque stability. Thus, identification of differences in enzymes that regulate collagen integrity could be useful for predicting susceptibility to atherothrombosis or for diagnosing plaque rupture. In this study, we sought to determine whether prolidase, the rate-limiting enzyme of collagen turnover, differs in human subjects with acute myocardial infarction (MI) versus those with stable coronary artery disease (CAD).

Methods

We measured serum prolidase activity in 15 patients with stable CAD and 49 patients with acute MI, of which a subset had clearly defined thrombotic MI (n = 22) or non-thrombotic MI (n = 12). Prolidase activity was compared across study time points (at cardiac catheterization, T0; 6 h after presentation, T6; and at a quiescent follow-up, Tf/u) in acute MI and stable CAD subjects. We performed subgroup analyses to evaluate prolidase activity in subjects presenting with acute thrombotic versus non-thrombotic MI.

Results

Although prolidase activity was lower at T0 and T6 versus the quiescent phase in acute MI and stable CAD subjects (p < 0.0001), it was not significantly different between acute MI and stable CAD subjects at any time point (T0, T6, and Tf/u) or between thrombotic and non-thrombotic MI groups. Preliminary data from stratified analyses of a small number of diabetic subjects (n = 8) suggested lower prolidase activity in diabetic acute MI subjects compared with non-diabetic acute MI subjects (p = 0.02).

Conclusion

Circulating prolidase is not significantly different between patients with acute MI and stable CAD or between patients with thrombotic and non-thrombotic MI. Further studies are required to determine if diabetes significantly affects prolidase activity and how this might relate to the risk of MI.

[Left-heart catheterization followed by other invasive procedures: Regional comparisons reveal peculiar differences]

BACKGROUND AND AIMS

Diagnostic left heart catheterization (LHC) is recommended if the therapeutic consequences of a bypass operation or percutaneous coronary intervention (PCI) are being considered. The present study examines regional differences in healthcare provision and therapeutic consequences of LHC, differentiated by counties and hospitals of the German federal state of Saxony-Anhalt. In addition, it looks at which patient-related factors influence the proportion of follow-up interventions. The relation between the rates of LHC, interventions and hospital discharge due to myocardial infarction is examined.

METHODS

The data of 9,791 individuals having statutory health insurance coverage by the AOK Saxony-Anhalt with 10,906 anonymized inpatient cases of LHCs in 2011 were followed until 12/31/2012, and it was examined whether they subsequently received a coronary bypass or PCI. The data was used to compare both the counties of Saxony-Anhalt (according to residence, adjusted for age and sex) and their hospitals. Regression analysis was run to identify determinants of receiving a LHC without consequences.

RESULTS

Overall, 54.2 % of the patients with LHC had no invasive follow-up intervention. Regression analysis showed an approximately linear relationship for the counties: the number of LHCs provided correlates with the number of LHCs requiring no PCI or bypass within a period of at least 12 months. Regional LHC rates are not correlated with hospitalizations due to acute myocardial infarction. No bypass or PCI in the follow-up period was reported for 37 to 85 % of the cases, depending on the hospital providing the LHC. Women and younger patients have a higher risk to undergo LHC without therapeutic impact.

DISCUSSION

The analysis indicates that there are specific regions in Saxony-Anhalt and diagnoses where the indications for LHC should be more conservative. However, more detailed analyses are needed to verify the identified potentials for improving healthcare provision.

Incidence, Frequency, and Clinical Characteristics of Type 3 Myocardial Infarction in Clinical Practice

OBJECTIVES

Cardiac death in a patient with symptoms and electrocardiographic changes indicative of myocardial ischemia but without available measurements of cardiac biomarkers is designated a type 3 myocardial infarction. We wanted to investigate the incidence, the frequency, and the characteristics of patients diagnosed as type 3 myocardial infarction.

METHODS

The occurrence of deaths in a well-defined geographic region was retrieved from the Danish Civil Registration System during a 1-year period from 2010 to 2011. Complementary data concerning causes of deaths were obtained from the Danish Register of Causes of Death, and ambulance and hospital patient files. Adjudication of the diagnosis was done by 2 local experts and one external senior cardiologist.

RESULTS

A total of 2766 of the 246,723 adult residents in the region had died. A type 3 myocardial infarction was diagnosed in 18 individuals, corresponding to an annual incidence of 7.3/100,000 person-years. During the same 1-year period, 488 patients had other types of myocardial infarction implying a 3.6% frequency of type 3 myocardial infarction (18 of 506) among all myocardial infarctions.

CONCLUSION

Type 3 myocardial infarction is a rare observation in clinical practice with an annual incidence below 10/100,000 person-years and a frequency of 3%-4% among all types of myocardial infarction. If autopsy data are included, the number of type 3 myocardial infarctions will increase.

Type 2 myocardial infarction due to supply-demand mismatch

The best-accepted definition of myocardial infarction (MI) is provided by statements from the Universal Definition of MI Global Task force. This article, now in its third iteration, defines MI as myocardial cell death due to prolonged myocardial ischemia. It further delineates an increasingly incident subclassification of MI known as type 2 MI (T2MI). T2MI identifies instances of myocardial necrosis in which an imbalance between myocardial oxygen supply and/or demand occurs for reasons other than atherosclerotic plaque disruption. While associated with considerable risk (comparable to that of type 1 MI, which has well-defined management strategies), the spectrum of potential etiologies for T2MI makes development of precise diagnostic criteria and therapeutic implications of the diagnosis challenging.

Types of Myocardial Infarction Among Human Immunodeficiency Virus-Infected Individuals in the United States

Importance

The Second Universal Definition of Myocardial Infarction (MI) divides MIs into different types. Type 1 MIs result spontaneously from instability of atherosclerotic plaque, whereas type 2 MIs occur in the setting of a mismatch between oxygen demand and supply, as with severe hypotension. Type 2 MIs are uncommon in the general population, but their frequency in human immunodeficiency virus (HIV)-infected individuals is unknown.

Objectives

To characterize MIs, including type; identify causes of type 2 MIs; and compare demographic and clinical characteristics among HIV-infected individuals with type 1 vs type 2 MIs.

Design, Setting, and Participants

This longitudinal study identified potential MIs among patients with HIV receiving clinical care at 6 US sites from January 1, 1996, to March 1, 2014, using diagnoses and cardiac biomarkers recorded in the centralized data repository. Sites assembled deidentified packets, including physician notes and electrocardiograms, procedures, and clinical laboratory tests. Two physician experts adjudicated each event, categorizing each definite or probable MI as type 1 or type 2 and identifying the causes of type 2 MI.

Main Outcomes and Measures

The number and proportion of type 1 vs type 2 MIs, demographic and clinical characteristics among those with type 1 vs type 2 MIs, and the causes of type 2 MIs.

Results

Among 571 patients (median age, 49 years [interquartile range, 43-55 years]; 430 men and 141 women) with definite or probable MIs, 288 MIs (50.4%) were type 2 and 283 (49.6%) were type 1. In analyses of type 1 MIs, 79 patients who underwent cardiac interventions, such as coronary artery bypass graft surgery, were also included, totaling 362 patients. Sepsis or bacteremia (100 [34.7%]) and recent use of cocaine or other illicit drugs (39 [13.5%]) were the most common causes of type 2 MIs. A higher proportion of patients with type 2 MIs were younger than 40 years (47 of 288 [16.3%] vs 32 of 362 [8.8%]) and had lower current CD4 cell counts (median, 230 vs 383 cells/µL), lipid levels (mean [SD] total cholesterol level, 167 [63] vs 190 [54] mg/dL, and mean (SD) Framingham risk scores (8% [7%] vs 10% [8%]) than those with type 1 MIs or who underwent cardiac interventions.

Conclusions and Relevance

Approximately half of all MIs among HIV-infected individuals were type 2 MIs caused by heterogeneous clinical conditions, including sepsis or bacteremia and recent use of cocaine or other illicit drugs. Demographic characteristics and cardiovascular risk factors among those with type 1 and type 2 MIs differed, suggesting the need to specifically consider type among HIV-infected individuals to further understand MI outcomes and to guide prevention and treatment.

Myocardial Infarction Type 2 and Myocardial Injury

BACKGROUND

The development and implementation of sensitive and high-sensitivity cardiac troponin assays has not only expedited the early ruling in and ruling out of acute myocardial infarction, but has also contributed to the identification of patients at risk for myocardial injury with necrosis, as confirmed by the presence of cardiac troponin concentrations above the 99th percentile. Myocardial injury with necrosis may occur either in the presence of overt ischemia from myocardial infarction, or in the absence of overt ischemia from myocardial injury accompanying other conditions. Myocardial infarction type 2 (T2MI) has been a focus of attention; conceptually T2MI occurs in a clinical setting with overt myocardial ischemia where a condition other than an acute atherothrombotic event is the major contributor to a significant imbalance between myocardial oxygen supply and/or demand. Much debate has surrounded T2MI and its interrelationship with myocardial injury.

CONTENT

We provide a detailed overview of the current concepts and challenges regarding the definition, diagnosis, management, and outcomes of T2MI, as well as the interrelationship to myocardial injury, and emphasize several critical clinical concepts for both clinicians and researchers moving forward.

SUMMARY

T2MI and myocardial injury are frequently encountered in clinical practice and are associated with poor outcomes in both the short term and long term. Diagnostic strategies to facilitate the clinical distinction between ischemic myocardial injury with or without an acute atheroma-thrombotic event vs non–ischemic-mediated myocardial injury conditions are urgently needed, as well as evidence-based therapies tailored toward improving outcomes for patients with T2MI.

Assessment and classification of patients with myocardial injury and infarction in clinical practice

Myocardial injury is common in patients without acute coronary syndrome, and international guidelines recommend patients with myocardial infarction are classified by aetiology. The universal definition differentiates patients with myocardial infarction due to plaque rupture (type 1) from those due to myocardial oxygen supply-demand imbalance (type 2) secondary to other acute illnesses. Patients with myocardial necrosis, but no symptoms or signs of myocardial ischaemia, are classified as acute or chronic myocardial injury. This classification has not been widely adopted in practice, because the diagnostic criteria for type 2 myocardial infarction encompass a wide range of presentations, and the implications of the diagnosis are uncertain. However, both myocardial injury and type 2 myocardial infarction are common, occurring in more than one-third of all hospitalised patients. These patients have poor short-term and long-term outcomes with two-thirds dead in 5 years. The classification of patients with myocardial infarction continues to evolve, and future guidelines are likely to recognise the importance of identifying coronary artery disease in type 2 myocardial infarction. Clinicians should consider whether coronary artery disease has contributed to myocardial injury, as selected patients are likely to benefit from further investigation and in these patients targeted secondary prevention has the potential to improve outcomes.

Circulating levels of plasminogen and oxidized phospholipids bound to plasminogen distinguish between atherothrombotic and non-atherothrombotic myocardial infarction

Oxidized phospholipids (OxPL) are abundant in atherosclerotic plaques. They are also bound to circulating plasminogen after myocardial infarction (MI), and their binding to plasminogen may accentuate fibrinolysis. We sought to assess whether circulating levels of plasminogen and OxPL bound to plasminogen (OxPL-PLG) increase following acute MI and whether this increase differs between atherothrombotic (Type 1) and non-atherothrombotic (Type 2) MI. We measured circulating levels of plasminogen and OxPL-PLG at 0, 6, 24, 48 h, and >3 months (stable state) following acute MI and following an angiogram for stable coronary artery disease (CAD). Forty-nine subjects met the criteria for acute MI, of whom 34 had clearly defined atherothrombotic (n = 22) or non-atherothrombotic (n = 12) MI; 15 patients met the criteria for stable CAD. Mean baseline levels of plasminogen and OxPL-PLG were lower in the acute MI group than in the stable CAD group (9.75 vs 20.2, p < 0.0001 for plasminogen and 165.5 vs 275.1, p = 0.0002 for OxPL-PLG) and did not change over time or between time points, including the 3-month follow-up. Mean baseline levels of plasminogen and OxPL-PLG were also lower in atherothrombotic (Type 1) than in non-atherothrombotic (Type 2) MI subjects (8.65 vs 12.1, p < 0.03 for plasminogen and 164.5 vs 245.7, p = 0.02 for OxPL-PLG), and this relationship did not change over time or between time points. Plasminogen and OxPL-PLG were lower in patients presenting with an acute MI than in those with stable CAD and also in those with atherothrombotic MI (Type 1) vs. those with non-atherothrombotic MI (Type 2). These findings persisted at a median follow-up of 3 months post-MI. The association of plasminogen and OxPL-PLG with acute MI, particularly atherothrombotic MI (Type 1), could reflect a reduced fibrinolytic capacity, associated with an increased risk of atherothrombotic events differentiating stable CAD from unstable CAD and atherothrombotic MI (Type 1) from non-atherothrombotic MI (Type 2). Additional study with a larger sample size is warranted.

Impact on Long-Term Mortality of Presence of Obstructive Coronary Artery Disease and Classification of Myocardial Infarction

BACKGROUND

In contrast to the associated-with-thromboembolic-event type 1 myocardial infarction, type 2 myocardial infarction is caused by acute imbalance between oxygen supply and demand of myocardium. Type 2 myocardial infarction may be present in patients with or without obstructive coronary artery disease, but knowledge about patient characteristics, treatments, and outcome in relation to coronary artery status is lacking. We aimed to compare background characteristics, triggering mechanisms, treatment, and long-term prognosis in a large real-life cohort of patients with type 1 and type 2 myocardial infarction with and without obstructive coronary artery disease.

METHODS

All 41,817 consecutive patients with type 1 and type 2 myocardial infarction registered in the Swedish myocardial infarction registry (SWEDEHEART) who underwent coronary angiography between January 1, 2011 and December 31, 2013, with the last follow-up on December 31, 2014, were studied.

RESULTS

In 92.8% of 40,501 patients classified as type 1 and in 52.5% of patients classified as type 2 myocardial infarction, presence of an obstructive coronary artery disease could be shown. Within the patients with obstructive coronary artery disease, those with type 2 myocardial infarction were older, and had more comorbidities and smaller necrosis as compared with type 1 myocardial infarction. In contrast, there was almost no difference in risk profile and extent of myocardial infarction between type 1 and type 2 myocardial infarction patients with nonobstructive coronary artery stenosis. The crude long-term mortality was higher in type 2 as compared with type 1 myocardial infarction with obstructive coronary artery disease (hazard ratio [HR] 1.72; 95% confidence interval [CI], 1.45-2.03), but was lower after adjustment (HR 0.76; 95% CI, 0.61-0.94). In myocardial infarction patients with nonobstructive coronary artery stenosis, the mortality risk was similar regardless of the clinical myocardial infarction type (crude HR 1.14; 95% CI, 0.84-1.55; adjusted HR 0.82; 95% CI, 0.52-1.29).

CONCLUSIONS

The substantial differences in risk factors, treatment, and outcome in patients with type 1 and type 2 myocardial infarction with obstructive coronary artery disease supports the relevance of the division between type 1 and type 2 in this population. On the contrary, in patients with nonobstructive coronary artery stenosis, irrespective of the clinical type, a similar risk profile, extent of necrosis, and long-term prognosis were observed, indicating that distinction between type 1 and type 2 myocardial infarction in these patients seems to be inappropriate.

Comparison between type-2 and type-1 myocardial infarction: clinical features, treatment strategies and outcomes

Objective

To assess the differences in incidence, clinical features, current treatment strategies and outcome in patients with type-2 vs. type-1 acute myocardial infarction (AMI).

Methods

We included 824 consecutive patients with a diagnosis of type-1 or type-2 AMI. During index hospitalization, clinical features and treatment strategies were collected in detail. At 1-year follow-up, mortality, stroke, non-fatal myocardial infarction and major bleeding were recorded.

Results

Type-1 AMI was present in 707 (86%) of the cases while 117 (14%) were classified as type-2. Patients with type-2 AMI were more frequently female and had higher co-morbidities such as diabetes, previous non-ST segment elevation acute coronary syndromes, impaired renal function, anaemia, atrial fibrillation and malignancy. However, preserved left ventricular ejection fraction and normal coronary arteries were more frequently seen, an invasive treatment was less common, and anti-platelet medications, statins and beta-blockers were less prescribed in patients with type-2 AMI. At 1-year follow-up, type-2 AMI was associated with a higher crude mortality risk (HR: 1.75, 95% CI: 1.14–2.68; P = 0.001), but this association did not remain significant after multivariable adjustment (P = 0.785). Furthermore, we did not find type-2 AMI to be associated with other clinical outcomes.

Conclusions

In this real-life population, compared with type-1, type-2 AMI were predominantly women and had more co-morbidities. Invasive treatment strategies and cardioprotective medications were less used in type-2, while the 1-year clinical outcomes were similar.

Type 2 myocardial infarction: the chimaera of cardiology?

The term type 2 myocardial infarction first appeared as part of the universal definition of myocardial infarction. It was introduced to cover a group of patients who had elevation of cardiac troponin but did not meet the traditional criteria for acute myocardial infarction although they were considered to have an underlying ischaemic aetiology for the myocardial damage observed. Since first inception, the term type 2 myocardial infarction has always been vague. Although attempts have been made to produce a systematic definition of what constitutes a type 2 myocardial infarction, it has been more often characterised by what it is not rather than what it is. Clinical studies that have used type 2 myocardial infarction as a diagnostic criterion have produced disparate incidence figures. The range of associated clinical conditions differs from study to study. Additionally, there are no agreed or evidence-based treatment strategies for type 2 myocardial infarction. The authors believe that the term type 2 myocardial infarction is confusing and not evidence-based. They consider that there is good reason to stop using this term and consider instead the concept of secondary myocardial injury that relates to the underlying pathophysiology of the primary clinical condition.

Diagnosis and management of type II myocardial infarction: increased demand for a limited supply of evidence

Type 2 myocardial infarction (type 2 MI) is defined as myocardial necrosis that results from an imbalance of myocardial oxygen supply and demand. Although type 2 MI is highly prevalent and strongly associated with mortality, the pathophysiology remains poorly understood. Discrepancies in definitions, frequency of screening, diagnostic approaches, and methods of adjudication lead to confusion and misclassification. To date, there is no consensus on the diagnostic criteria for type 2 MI. No guidelines exist for the optimal management of this condition, and further investigation is urgently needed. This review explores the existing evidence on the pathophysiology, diagnosis, prognosis, and management of type 2 MI.

Universal Definition of Myocardial Infarction: Clinical Insights

Aims: The universal definition of myocardial infarction (MI) classifies acute ischaemia into different classes according to lesion mechanism. Our aim was to perform a detailed comparison between these different types of MI in terms of baseline characteristics, management and prognosis. Methods and Results: An observational retrospective single-centre cohort study was performed, including 1,000 consecutive patients admitted for type 1 (76.4%) or type 2 MI (23.6%). Type 2 MI patients were older, had a higher prevalence of comorbidities and worse medical status at admission. In-hospital mortality did not differ significantly between the MI groups (8.8 vs. 9.7%, p = 0.602). However, mortality during follow-up was almost 3 times higher in type 2 MIs (HR 2.75, p < 0.001). Type 2 MI was an independent all-cause mortality risk marker, adding discriminatory power to the GRACE model. Finally, important differences in traditional risk score performances (GRACE, CRUSADE) were found between both MI types. Conclusions: Several important baseline differences were found between these MI types. Regarding prognosis, long-term survival is significantly compromised in type 2 MIs, potentially translating patients' higher medical complexity and frailty. Distinction between type 1 and type 2 MI seems to have important implications in clinical practice and likely also in the results of clinical trials.