Troponin, Echo a Prognostic Power Combo in COVID-19

October 27, 2020

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

The prevalence of troponin-defined myocardial injury exceeded 60% among selected patients hospitalized with COVID-19 at seven urban centers who underwent transthoracic echocardiography (TTE) for suspected cardiac involvement.  

In-hospital mortality was about five times higher for those with vs without troponin elevations and was increased sixfold in patients positive for both troponins and "major" TTE abnormalities.

Adjusted for major COVID-19 complications like acute respiratory distress, circulatory shock, or acute kidney injury (AKI), the addition of major TTE signs to elevated troponins more than tripled the risk of in-hospital mortality. But the risk didn't climb for those with raised troponins and no TTE abnormalities.

Although troponin assays are increasingly routine in patients hospitalized with COVID-19, there should probably be a low threshold for adding echocardiography — a full TTE study or using a point-of-care system — for those with other signs of cardiac involvement, say researchers based on their study published October 26 in the Journal of the American College of Cardiology.

The 305 predominantly male patients in this study had undergone TTE for assessment of symptoms such as chest pain or shortness of breath, troponin or ECG evidence of acute coronary syndromes (ACS), or suspected cardiogenic pulmonary embolism or stroke.

A full 62.3% of the cohort showed myocardial injury by positive troponins as defined by criteria in place at the respective institutions and measured during the hospitalization before or after TTE.

That rate in this select group is probably three to four times the prevalence of myocardial injury in the broad population of hospitalized COVID-19 patients, lead author Gennaro Giustino, MD, Icahn School of Medicine at Mount Sinai, New York City, told | Medscape Cardiology.

"Troponins should be done in every hospitalized COVID-19 patient, because it gives you information on end-organ damage and the severity of the illness that has been shown to be very prognostic." The assays should be routinely accompanied by echocardiography "in appropriate clinical scenarios," he contends, especially on suspicion of cardiac involvement clinically or by biomarkers, electrocardiography, or other noninvasive test.

The different centers, spread across New York City and Milan, Italy, varied in how frequently they performed TTE in COVID-19 patients, as well in their troponin-based criteria for myocardial damage. For example, the Italian centers used high-sensitivity tests that have been available in Europe for years; but "the older assays" predominated at the New York hospitals. The different assay types performed similarly at identifying ACS in this cohort, Giustino said.

Mechanism and Phenotypes

Whereas elevated troponins indicate myocardial damage, echocardiography, "by showing specific phenotypes of abnormalities, gives you diagnostic clues as to what could be the mechanism of the myocardial injury." And that, he explained, "can guide your management."

The documented major echo abnormalities included right-sided or left-sided ventricular dysfunction in 26.3% and 23.7% of patients, respectively; left-ventricular global dysfunction in 18.4%; grade II or III diastolic dysfunction in 13.2%, and pericardial effusion in 7.2% of patients, the group reported.

More consistent echo use in COVID-19 could potentially sharpen selection of patients for more invasive testing, especially coronary angiography, by, for example, showing regional wall-motion abnormalities along with troponin elevation or potentially ischemic ECG findings, Giustino said.

Of the current cohort, 11 patients, or 3.6%, were sent to the cath lab; angiography disclosed ACS in eight of the 11 and normal coronary arteries in three.

Giustino speculates that some of the apparently "missing cases" of ACS and especially ST-segment-elevation myocardial infarction (STEMI) during the COVID-19 pandemic may have been there all along among patients hospitalized with SARS-CoV-2 infection. Potentially, he proposed, their acute events might have been identified and documented with more consistent use of echocardiography.

"Very Practical Evidence"

Despite its limitations, such as selection bias and the small number of patients, "this study provides very practical evidence to improve current clinical practice during this and possibly other such pandemics," contends an accompanying editorial.

"The current recommendations of the American College of Cardiology endorse the measurement of (cardiac troponin) levels when a diagnosis of acute myocardial infarction is being considered in patients with SARS-CoV-2 infection," observe the authors, led by Carl J. Lavie, MD, Ochsner Clinical School–The University of Queensland School of Medicine, New Orleans, Louisiana.

"This indication seems somehow inadequate according to the information collected by Giustino et al, whereby there is now evidence that troponin-positive COVID-19 patients may benefit from routine TTE, which would allow practitioners to garner useful prognostic information and to establish specific therapeutic options in patients with cardiac injury."

Cardiac troponins, they continue, "play an important role in evaluating disease severity and/or mortality in SARS-CoV-2 infection. Hence, we endorse routine serial measurement of these biomarkers in patients hospitalized for COVID-19 with TTE, at least handheld or full, for most of those with high values."

Major echocardiographic abnormalities were identified in 63.2% of patients with positive troponins, compared to 21.7% of those with negative troponins, for an adjusted odds ratio (OR) of 6.17 (95% CI, 3.62 - 10.51, P < .0001).

Hospital mortality was 18.7% overall. Unadjusted, it was 26.8% for patients with positive troponins and 5.2% for those who were troponin-negative (P < .0001); 21% for those troponin-positive but without TTE abnormalities; and 31.2% for patients positive for both troponins and TTE abnormalities.

Adjusted for major COVID-19 complications, the in-hospital mortality risk for patients with positive troponins plus major abnormalities by TTE went up almost 4 times, (OR, 3.87; 95% CI, 1.27 - 11.80, P = .02), comparable to the adjusted mortality risk associated with circulatory shock in these patients.

Point-of-care echocardiography is an acceptable substitute for this use of full TTE in the COVID-19 era, as it dramatically reduces the potential for viral transmission and it is nearly as effective in showing most major abnormalities, Giustino noted.

In this context, "I think a well performed point-of-care is as helpful as a full transthoracic."

Giustino discloses receiving consulting fees from Bristol-Myers Squibb/Pfizer. Disclosures for the other authors are in the report. Lavie and the other editorialists report that they have no relevant disclosures.

Journal of the American College of Cardiology. Published October 26, 2020. Abstract, Editorial

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