Rhabdomyolysis: A Noncardiac Source of Increased Circulating Concentrations of Cardiac Troponin T?

Clinical Interpretation of Serum Troponin in the Era of High-Sensitivity Testing

Cardiac troponin (Tn) plays a central role in the evaluation of patients with angina presenting with acute coronary syndrome. The advent of high-sensitivity assays has improved the analytic sensitivity and precision of serum Tn measurement, but this advancement has come at the cost of poorer specificity. The role of clinical judgment is of heightened importance because, more so than ever, the interpretation of serum Tn elevation hinges on the careful integration of findings from electrocardiographic, echocardiographic, physical exam, interview, and other imaging and laboratory data to formulate a weighted differential diagnosis. A thorough understanding of the epidemiology, mechanisms, and prognostic implications of Tn elevations in each cardiac and non-cardiac etiology allows the clinician to better distinguish between presentations of myocardial ischemia and myocardial injury-an important discernment to make, as the treatment of acute coronary syndrome is vastly different from the workup and management of myocardial injury and should be directed at the underlying cause.

Sex-specific differences in myocardial injury incidence after COVID-19 mRNA-1273 booster vaccination

AIMS

To explore the incidence and potential mechanisms of oligosymptomatic myocardial injury following COVID-19 mRNA booster vaccination.

METHODS AND RESULTS

Hospital employees scheduled to undergo mRNA-1273 booster vaccination were assessed for mRNA-1273 vaccination-associated myocardial injury, defined as acute dynamic increase in high-sensitivity cardiac troponin T (hs-cTnT) concentration above the sex-specific upper limit of normal on day 3 (48-96 h) after vaccination without evidence of an alternative cause. To explore possible mechanisms, antibodies against interleukin-1 receptor antagonist (IL-1RA), the SARS-CoV-2-nucleoprotein (NP) and -spike (S1) proteins and an array of 14 inflammatory cytokines were quantified. Among 777 participants (median age 37 years, 69.5% women), 40 participants (5.1%; 95% confidence interval [CI] 3.7-7.0%) had elevated hs-cTnT concentration on day 3 and mRNA-1273 vaccine-associated myocardial injury was adjudicated in 22 participants (2.8% [95% CI 1.7-4.3%]). Twenty cases occurred in women (3.7% [95% CI 2.3-5.7%]), two in men (0.8% [95% CI 0.1-3.0%]). Hs-cTnT elevations were mild and only temporary. No patient had electrocardiographic changes, and none developed major adverse cardiac events within 30 days (0% [95% CI 0-0.4%]). In the overall booster cohort, hs-cTnT concentrations (day 3; median 5, interquartile range [IQR] 4-6 ng/L) were significantly higher compared to matched controls (n = 777, median 3 [IQR 3-5] ng/L, p < 0.001). Cases had comparable systemic reactogenicity, concentrations of anti-IL-1RA, anti-NP, anti-S1, and markers quantifying systemic inflammation, but lower concentrations of interferon (IFN)-λ1 (IL-29) and granulocyte-macrophage colony-stimulating factor (GM-CSF) versus persons without vaccine-associated myocardial injury.

CONCLUSION

mRNA-1273 vaccine-associated myocardial injury was more common than previously thought, being mild and transient, and more frequent in women versus men. The possible protective role of IFN-λ1 (IL-29) and GM-CSF warrant further studies.

Not All ST Elevation Is STEMI: Brugada Phenocopy Induced by Hyperkalemia

Brugada syndrome (BrS) is a hereditary channelopathy associated with malignant ventricular arrhythmia and sudden death in individuals with a structurally normal heart. It is characterized by an ST-segment elevation in the precordial leads. Brugada phenocopy (BrP) is a term given to conditions that could result in ST morphologies identical to those found in Brugada syndrome (Brugada pattern electrocardiogram (EKG) changes) without the actual channelopathy responsible for Brugada syndrome. BrP is a rare EKG manifestation of hyperkalemia, commonly seen at high serum levels of potassium, and associated with malignant arrhythmia. Here, we present a case with Brugada pattern EKG changes associated with hyperkalemia and metabolic acidosis, which normalized after correcting the electrolyte abnormalities. In this case, we also wanted to highlight that not all ST-segment elevation is due to myocardial infarction (MI). In young patients with no coronary artery disease (CAD) risk factors, other potential ST elevation causes should be considered.

Earlier continuous renal replacement therapy is associated with reduced mortality in rhabdomyolysis patients

Background

Continuous renal replacement therapy (CRRT) is commonly employed for rhabdomyolysis (RM) patients. However, the optimal initiation timing of CRRT and prognostic factors were not well evaluated for patients with RM. We aimed to investigate the efficacy of CRRT timing on mortality and the risk factors for death in RM patients who received CRRT.

Methods

RM patients who received CRRT between 1 May 2010 and 31 May 2021 in our center were retrospectively included. Univariate and multivariate logistic analyses were performed to identify the risk factors for primary outcome (90-day mortality).

Results

A total of 134 patients were included in our study. The 90-day mortality rate was 38.06%. The median time from CRRT initiation to peak CK occurrence was 4.8 h (IQR −16, 14), 67 patients received CRRT before 4.8 h after peak CK occurrence (early CRRT), and 67 patients received CRRT beyond 4.8 h after peak CK occurrence (late CRRT). Multivariate logistic regression analysis showed that the time from CRRT initiation to the peak CK (per 1 h, OR 1.026, 95% CI 1.004–1.049, p = 0.023), late CRRT (OR 3.082, 95% CI 1.072–8.859, p = 0.037), elevated serum cardiac troponin I (cTnI) (per 1 ng/mL, OR 1.218, 95% CI 1.011–1.468, p = 0.038), older age (per 1 year, OR 1.042, 95% CI 1.003–1.081, p = 0.032), and need of mechanical ventilation support (OR 4.632, 95% CI 1.292–16.61, p = 0.019) were independent risk factors for 90-day mortality.

Conclusions

Earlier CRRT initiation before 4.8 h after peak CK occurrence was associated with lower 90-day patient mortality.

Skeletal Muscle Disorders: A Noncardiac Source of Cardiac Troponin T

BACKGROUND

Cardiac troponin (cTn) T and cTnI are considered cardiac specific and equivalent in the diagnosis of acute myocardial infarction. Previous studies suggested rare skeletal myopathies as a noncardiac source of cTnT. We aimed to confirm the reliability/cardiac specificity of cTnT in patients with various skeletal muscle disorders (SMDs).

METHODS

We prospectively enrolled patients presenting with muscular complaints (≥2 weeks) for elective evaluation in 4 hospitals in 2 countries. After a cardiac workup, patients were adjudicated into 3 predefined cardiac disease categories. Concentrations of cTnT/I and resulting cTnT/I mismatches were assessed with high-sensitivity (hs-) cTnT (hs-cTnT-Elecsys) and 3 hs-cTnI assays (hs-cTnI-Architect, hs-cTnI-Access, hs-cTnI-Vista) and compared with those of control subjects without SMD presenting with adjudicated noncardiac chest pain to the emergency department (n=3508; mean age, 55 years; 37% female). In patients with available skeletal muscle biopsies, TNNT/I1-3 mRNA differential gene expression was compared with biopsies obtained in control subjects without SMD.

RESULTS

Among 211 patients (mean age, 57 years; 42% female), 108 (51%) were adjudicated to having no cardiac disease, 44 (21%) to having mild disease, and 59 (28%) to having severe cardiac disease. hs-cTnT/I concentrations significantly increased from patients with no to those with mild and severe cardiac disease for all assays (all P<0.001). hs-cTnT-Elecsys concentrations were significantly higher in patients with SMD versus control subjects (median, 16 ng/L [interquartile range (IQR), 7-32.5 ng/L] versus 5 ng/L [IQR, 3-9 ng/L]; P<0.001), whereas hs-cTnI concentrations were mostly similar (hs-cTnI-Architect, 2.5 ng/L [IQR, 1.2-6.2 ng/L] versus 2.9 ng/L [IQR, 1.8-5.0 ng/L]; hs-cTnI-Access, 3.3 ng/L [IQR, 2.4-6.1 ng/L] versus 2.7 ng/L [IQR, 1.6-5.0 ng/L]; and hs-cTnI-Vista, 7.4 ng/L [IQR, 5.2-13.4 ng/L] versus 7.5 ng/L [IQR, 6-10 ng/L]). hs-cTnT-Elecsys concentrations were above the upper limit of normal in 55% of patients with SMD versus 13% of control subjects (P<0.01). mRNA analyses in skeletal muscle biopsies (n=33), mostly (n=24) from individuals with noninflammatory myopathy and myositis, showed 8-fold upregulation of TNNT2, encoding cTnT (but none for TNNI3, encoding cTnI) versus control subjects (n=16, P_Wald<0.001); the expression correlated with pathological disease activity (R=0.59, P_t-statistic<0.001) and circulating hs-cTnT concentrations (R=0.26, P_t-statistic=0.031).

CONCLUSIONS

In patients with active chronic SMD, elevations in cTnT concentrations are common and not attributable to cardiac disease in the majority. This was not observed for cTnI and may be explained in part by re-expression of cTnT in skeletal muscle.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique identifier: NCT03660969.

[Hypoxic and hypoglycemic brain damage as a result of an adrenal cortex crisis-An important differential diagnosis in cases of unspecific symptoms]

Acute adrenal cortex insufficiency is a rare disease, which is hard to diagnose because of its diffuse symptoms. Symptoms, such as general weakness, nausea or vomiting, fatigue, hyponatremia, hyperkalemia, hypoglycemia and pronounced hypotension up to shock can be crucial in the diagnosis of an adrenal cortex crisis. The underlying disease of adrenal cortex insufficiency is also characterized by not always obvious symptoms, which are differently expressed depending on whether it is the primary or secondary type.After the diagnosis is made it is important to educate the patients, determine the optimal dosage of the substitution and ensure the compliance of the patients to optimize the further process and avoid an adrenal crisis. An adrenal crisis is one of the reasons for a higher mortality of these patients, which is well-described in the current literature. Descriptions of fatal courses and their reasons are rare; however, knowledge of the disease and the importance of rapid intervention is very important, especially for physicians who work in the emergency room or intensive care unit (ICU).This article reports about a female patient with a known secondary adrenal cortex insufficiency who developed the complete picture of an adrenal crisis. Despite rapid diagnosis and initiation of treatment massive brain damage could not be averted due to hypoxia and hypoglycemia. This case report demonstrates the potential symptoms, in particular a massive hypoglycemia and an initial shock refractory to catecholamine. It also shows the severity of that disease and the importance of rapid treatment even though it is difficult to make the diagnosis.

Diagnosis, Investigation and Management of Patients with Acute and Chronic Myocardial Injury

The application of high-sensitivity cardiac troponins in clinical practice has led to an increase in the recognition of elevated concentrations in patients without myocardial ischaemia. The Fourth Universal Definition of Myocardial Infarction encourages clinicians to classify such patients as having an acute or chronic myocardial injury based on the presence or absence of a rise or a fall in cardiac troponin concentrations. Both conditions may be caused by a variety of cardiac and non-cardiac conditions, and evidence suggests that clinical outcomes are worse than patients with myocardial infarction due to atherosclerotic plaque rupture, with as few as one-third of patients alive at 5 years. Major adverse cardiovascular events are comparable between populations, and up to three-fold higher than healthy individuals. Despite this, no evidence-based strategies exist to guide clinicians in the investigation of non-ischaemic myocardial injury. This review explores the aetiology of myocardial injury and proposes a simple framework to guide clinicians in early assessment to identify those who may benefit from further investigation and treatment for those with cardiovascular disease.