Type-II myocardial infarction and chronic myocardial injury rates, invasive management, and 4-year mortality among consecutive patients undergoing high-sensitivity troponin T testing in the emergency department

Late Outcomes of Patients With Prehospital ST-Segment Elevation and Appropriate Cardiac Catheterization Laboratory Nonactivation

Background Patients with suspected ST-segment-elevation myocardial infarction (STEMI) and cardiac catheterization laboratory nonactivation (CCL-NA) or cancellation have reportedly similar crude and higher adjusted risks of death compared with those with CCL activation, though reasons for these poor outcomes are not clear. We determined late clinical outcomes among patients with prehospital ECG STEMI criteria who had CCL-NA compared with those who had CCL activation. Methods and Results We identified consecutive prehospital ECG transmissions between June 2, 2010 to October 6, 2016. Diagnoses according to the Fourth Universal Definition of myocardial infarction (MI), particularly rates of myocardial injury, were adjudicated. The primary outcome was all-cause death. Secondary outcomes included cardiovascular death/MI/stroke and noncardiovascular death. To explore competing risks, cause-specific hazard ratios (HRs) were obtained. Among 1033 included ECG transmissions, there were 569 (55%) CCL activations and 464 (45%) CCL-NAs (1.8% were inappropriate CCL-NAs). In the CCL activation group, adjudicated index diagnoses included MI (n=534, 94%, of which 99.6% were STEMI and 0.4% non-STEMI), acute myocardial injury (n=15, 2.6%), and chronic myocardial injury (n=6, 1.1%). In the CCL-NA group, diagnoses included MI (n=173, 37%, of which 61% were non-STEMI and 39% STEMI), chronic myocardial injury (n=107, 23%), and acute myocardial injury (n=47, 10%). At 2 years, the risk of all-cause death was higher in patients who had CCL-NA compared with CCL activation (23% versus 7.9%, adjusted risk ratio, 1.58, 95% CI, 1.24-2.00), primarily because of an excess in noncardiovascular deaths (adjusted HR, 3.56, 95% CI, 2.07-6.13). There was no significant difference in the adjusted risk for cardiovascular death/MI/stroke between the 2 groups (HR, 1.23, 95% CI, 0.87-1.73). Conclusions CCL-NA was not primarily attributable to missed STEMI, but attributable to "masquerading" with high rates of non-STEMI and myocardial injury. These patients had worse late outcomes than patients who had CCL activation, mainly because of higher rates of noncardiovascular deaths.

Diagnostic features, management and prognosis of type 2 myocardial infarction compared to type 1 myocardial infarction: a systematic review and meta-analysis

IMPORTANCE

Distinguishing type 2 (T2MI) from type 1 myocardial infarction (T1MI) in clinical practice can be difficult, and the management and prognosis for T2MI remain uncertain.

OBJECTIVE

To compare precipitating factors, risk factors, investigations, management and outcomes for T2MI and T1MI.

DATA SOURCES

Medline and Embase databases as well as reference list of recent articles were searched January 2009 to December 2020 for term 'type 2 myocardial infarction'.

STUDY SELECTION

Studies were included if they used a universal definition of MI and reported quantitative data on at least one variable of interest.

DATA EXTRACTION AND SYNTHESIS

Data were pooled using random-effect meta-analysis. Risk of bias was assessed using Newcastle-Ottawa quality assessment tool. Preferred Reporting Items for Systematic Reviews and Meta-analyses guidelines were followed. All review stages were conducted by two reviewers.

MAIN OUTCOMES AND MEASURES

Risk factors, presenting symptoms, cardiac investigations such as troponin and angiogram, management and outcomes such as mortality.

RESULTS

40 cohort studies comprising 98 930 patients with T1MI and 13 803 patients with T2MI were included. Compared with T1MI, patients with T2MI were: more likely to have pre-existing chronic kidney disease (OR 1.87; 95% CI 1.53 to 2.28) and chronic heart failure (OR 2.35; 95% CI 1.82 to 3.03), less likely to present with typical cardiac symptoms of chest pain (OR 0.19; 95% CI 0.13 to 0.26) and more likely to present with dyspnoea (OR 2.64; 95% CI 1.86 to 3.74); more likely to demonstrate non-specific ST-T wave changes on ECG (OR 2.62; 95% CI 1.81 to 3.79) and less likely to show ST elevation (OR 0.22; 95% CI 0.17 to 0.28); less likely to undergo coronary angiography (OR 0.09; 95% CI 0.06 to 0.12) and percutaneous coronary intervention (OR 0.06; 95% CI 0.04 to 0.10) or receive cardioprotective medications, such as statins (OR 0.25; 95% CI 0.16 to 0.38) and beta-blockers (OR 0.45; 95% CI 0.33 to 0.63). T2MI had greater risk of all cause 1-year mortality (OR 3.11; 95% CI 1.91 to 5.08), with no differences in short-term mortality (OR 1.34; 95% CI 0.63 to 2.85).

CONCLUSION AND RELEVANCE

This review has identified clinical, management and survival differences between T2MI and T1MI with greater precision and scope than previously reported. Differential use of coronary revascularisation and cardioprotective medications highlight ongoing uncertainty of their utility in T2MI compared with T1MI.

Clinical characteristics and outcome of elderly patients admitted in emergency department with an oxygen mismatch and type 2 myocardial infarction or myocardial injury

BACKGROUND

Aging is a risk factor for type 2 myocardial infarction or myocardial injury, but few data are available on the elderly. We aimed to determine the factors associated with these pathologies and mortality in the elderly population and its age classes.

METHODS

A retrospective cohort of all patients with oxygen mismatch (anemia, hypoxia, tachycardia, hypo/hypertension) for whom a troponin drawn was performed at admission in 2 emergency departments. Medical records were reviewed and classified as having type 2 myocardial infarction, acute or chronic myocardial injury, or no myocardial injury.

RESULTS

Of the 824 patients who presented with oxygen mismatch, 675 (81.9%) were older than 65 years. Age over 85 years was a risk factor for acute non-ischemic myocardial injury (odds ratio, 95% confidence interval 2.23, 1.34-3.73). Non-ischemic myocardial injury was associated with hypoxemia, tachycardia, and acute renal failure in those older than 85 years, but only with acute infection in the 75-84-year-old group. Type 2 myocardial infarction was associated only with acute renal failure in the oldest group and, in the 75-84-year-old group, with acute heart failure and shock. Patients older than 85 years with acute myocardial injury, with or without infarction, had a higher in-hospital mortality, but subsequently, mortality depends more on the comorbidities than on age.

CONCLUSION

Factors associated with type 2 myocardial infarction and acute non-ischemic myocardial injury in elderly admitted with oxygen mismatch vary notably between age classes. They are associated with in-hospital mortality but not with subsequent mortality when other cormorbities are taken into account.