Roughly one third of patients hospitalized for COVID-19 have some degree of myocardial injury and this comes hand in hand with increased mortality compared against patients with no troponin elevation. 

Even mild forms of myocardial injury, such as 0.03 to 0.09 ng/mL troponin elevation, is associated with close to 100% increase in mortality (HR: 1.75; CI 95% 1.37-2.24).

In patients with greater injury (troponins over 0.09 ng/mL) mortality increases over 200% (HR 3.03; CI 95% 2.42-3.80).

This recent observational study soon to be published in JACC included 3069 patients diagnosed with COVID-19, hospitalized in New York.

The aim of this study was to better understand the prevalence of these troponin elevation and its impact on prognosis. 

Read also: Estimating the Risk of Infection for Healthcare Personnel.

Over 90% of patients were measured at least once for troponin-I elevation within 24hrs of admission. 455 of these showed mild elevation (0.03-0.09 ng/mL) and 530 significant elevation (> 0.09 ng/mL). 

Over one third of patients with significant elevation had previously been diagnosed with CAD. Atrial fibrillation and cardiac failure were also prevalent among patients with significant troponin-I elevation. 

The older the patient, the higher the body mass index and disease severity, the higher the mortality rate. After adjusting for covariables, troponin elevation continued to be a clear indicator of worse prognosis. 

Read also: Priorities in the Cath Lab to Escape COVID-19 Tsunami.

One of the limitations to this study was that other than troponin concentration no other tests were carried out, not even a 12-derivation electrocardiogram.      

With this information, we can conclude that troponin elevation is a prognosis marker, though it is hard to speculate about its etiology. 

It could be due to the cytokine storm or because of other acute phase reactants; it might also be the direct impact of the virus as myocarditis, or a non-ischemic myocardial injury due to the demand/offer imbalance, or a common acute coronary syndrome triggered by the inflammatory condition.

Read also: Covid-19 and Unaccounted Collateral Damage.

The COVID-19 pandemic history is being written and we are learning as we go. 

Original Title: Prevalence and impact of myocardial injury in patients hospitalized with COVID-19 infection.

Reference: Lala A et al. J Am Coll Cardiol. 2020; Epub ahead of print. doi: 10.1101/2020.04.20.20072702.

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