Signature STEMI Sign May Be Less Diagnostic in the COVID-19 Age

April 21, 2020

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The signature electrocardiographic sign indicating ST-segment-elevation myocardial infarction (STEMI) may be a less consistent indicator of actual STEMI at a time when patients with COVID-19 have come to overwhelm many hospital intensive care units.

Many of the 18 such patients identified at six New York City hospitals who showed ST-segment elevation (STE) on their 12-lead electrocardiogram in the city's first month of fighting the pandemic turned out to be free of either obstructive coronary artery disease (CAD) by angiography or of regional wall-motion abnormalities (RWMA) by echocardiography, notes an April 17 letter to the New England Journal of Medicine.

Those 10 patients in the 18-case series were said to have noncoronary myocardial injury, perhaps from myocarditis — a prevalent feature of severe COVID-19 — and the remaining eight patients with obstructive CAD, RWMA, or both were diagnosed with STEMI.

Of the latter patients, 6 six went to the cath lab and five of those underwent percutaneous coronary intervention (PCI), report the authors, led by Sripal Bangalore, MD, MHA, NYU Grossman School of Medicinem New York City.

Speaking with | Medscape Cardiology, Bangalore framed the case-series report as a caution against substituting fibrinolytic therapy for primary PCI in patients with STE while hospitals are unusually burdened by the COVID-19 pandemic and invasive procedures intensify the threat of SARS-CoV-2 exposure to clinicians.

The strategy was recently advanced as an option for highly selected patients in a statement from the American College of Cardiology (ACC) and Society for Cardiovascular Angiography and Interventions (SCAI).

"During the COVID-19 pandemic, one of the main reasons fibrinolytic therapy has been pushed is to reduce the exposure to the cath lab staff," Bangalore observed. "But if you pursue that route, it's problematic because more than half may not have obstructive disease and fibrinolytic therapy may not help. And if you give them fibrinolytics, you're potentially increasing their risk of bleeding complications," he said.

"The take-home from these 18 patients is that it's very difficult to guess who is going to have obstructive disease and who is going to have nonobstructive disease," Bangalore said. "Maybe we should assess these patients with not just an ECG but with a quick echo, then make a decision. Our practice so far has been to take these patients to the cath lab."

The ACC/SCAI statement proposed that "fibrinolysis can be considered an option for the relatively stable STEMI patient with active COVID-19" after careful consideration of possible patient benefit vs the risks of cath-lab personnel exposure to the virus, as | Medscape Cardiology recently reported.

Only six patients in the current series, including five in the STEMI group, are reported to have had chest pain at about the time of STE, observed MichaelJ. Blaha, MD, MPH, Johns Hopkins Hospital, Baltimore, who isn't associated with the publication.

So, he said in an interview, "one of their points is that you have to take ST elevations with a grain of salt in this [COVID-19] era, because there are a lot of people presenting with ST elevations in the absence of chest pain."

That, and the high prevalence of nonobstructive disease in the series, indeed argues against the use of fibrinolytic therapy in such patients, Blaha said.

Normally, when there is STE, "the pretest probability of STEMI is so high, and if you can't make it to the cath lab for some reason, sure, it makes sense to give lytics." However, he said, "COVID-19 is changing the clinical landscape. Now, with a variety of virus-mediated myocardial injury presentations, including myocarditis, the pretest probability of MI is lower."

The current report "confirms that in the COVID era, ST elevations are not diagnostic for MI and must be considered within the totality of clinical evidence, and a conservative approach to going to the cath lab is probably warranted," Blaha told | Medscape Cardiology.

However, with the reduced pretest probability of STE for STEMI, he agreed, "I almost don't see any scenario where I'd be comfortable, based on ECG changes alone, giving lytics at this time."

Bangalore pointed out that all of the 18 patients in the series had elevated levels of the fibrin degradation product D-dimer, a biomarker that reflects ongoing hemostatic activation. Levels were higher in the eight patients who ultimately received a STEMI diagnosis than in the remaining 10 patients.

But COVID-19 patients in general may have elevated D-dimer and "a lot of microthrombi," he said. "So the question is, are those microthrombi also causal for any of the ECG changes we are also seeing?"

Aside from microthrombi, global hypoxia and myocarditis could be other potential causes of STE in COVID-19 patients in the absence of STEMI, Bangalore proposed. "At this point we just generally don't know."

Bangalore reported no conflicts; disclosures for the other authors are available at Blaha has recently disclosed receiving grants from Amgen and serving on advisory boards for Amgen and other pharmaceutical companies.

N Engl J Med. Published online April 17, 2020. Letter

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