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ST-segment myocardial infarction (STEMI) in COVID-19 patients had poorer outcomes across the board, despite no delay in treatment times at the hospital, the first data from a North American registry showed.

In-hospital mortality was 32% for confirmed infected patients compared with 12% among suspected but ultimately SARS-CoV-2-negative patients and 6% among propensity-matched historical controls (P<0.001 for both comparisons).

Length of stay averaged 6 days versus 3 in the other groups, and ICU stay averaged 4 days versus 2 in the initially-suspected patients. Infected patients also had numerically higher rates of reinfarction (2% vs 1% in suspected/uninfected patients and 0% in controls, not significant) and in-hospital stroke (3.4% vs 2% vs 0.6%, respectively, P=0.039 for infected patients vs controls).

However, door-to-balloon times didn't differ substantially among the three groups (mean 80 minutes in COVID-19 patients, 78 in suspected but uninfected patients, and 86 in matched controls), Timothy D. Henry, MD, of The Christ Hospital in Cincinnati, reported at the virtual .

"I am amazed by the door-to-balloon time... because in our experience you need more time for protective measures, for personal protection, et cetera," commented Adnan Kastrati, MD, of the Technical University of Munich, Germany, a press conference panel discussant. "This is a great thing that they have achieved."

On the other hand, a separate analysis of the Global ACS Registry showed markedly longer door-to-balloon times in COVID-19 patients: 83.0 versus 37.0 min in historical controls (P<0.001). This was from 144 infected STEMI patients at 85 hospitals around the world from March through August, with controls identified in a U.K. database from a prior year.

There was no difference in door-to-angiography time in the 121 COVID-positive non-ST-segment elevation MI (NSTEMI) cases compared with controls, Anthony Gershlick, MBBS, of the University of Leicester, England, reported at the conference.

He did, however, report likewise high in-hospital mortality -- 22.9% in STEMI and 6.6% in NSTEMI.

Gershlick speculated that the high mortality was likely related to the higher incidence of cardiogenic shock in these patients:

• With STEMI, 20.1% in the COVID-19 patients versus 8.7% in controls (P<0.001)
• With NSTEMI, 5.0% vs 1.4% (P=0.007)

In the North American STEMI cohort, the shock rate was similar at 20% versus 5% in controls.

Henry and Gershlick agreed that late presentation after symptom onset due to fear of going to the hospital in the pandemic was likely a key factor in the high shock rates, and thus the excess mortality.

"Future public information strategies need to be reassuring, proactive, simple, and more effective," Gershlick concluded.

There was a fair amount of controversy initially over whether COVID-19 patients should be given lytics or taken to the cath lab at all, noted TCT press conference moderator Ajay Kirtane, MD, SM, of NewYork-Presbyterian/Columbia University Medical Center in New York City.

Recommendations published in late March recommended sticking with primary PCI when possible. In the North American COVID Myocardial Infarction Registry (NACMI) database, only 6% of the COVID-19 STEMI patients got a thrombolytic, on par with the 3% rate in the propensity-matched controls.

"The guidelines that show that primary PCI is preferable clearly have been successful," Henry said at the press conference. "In fact, it looks to us that in North America, people are enacting those guidelines quite successfully."

Of the 79% in his registry undergoing angiography, 71% went on to primary PCI and 20% received medical therapy for reperfusion.

Henry said he was not surprised at these figures, as it "in general in North America means we have been relatively aggressive with these patients."

"A lot of it has to do with someone who is super sick with COVID from a respiratory standpoint. They may not be coming to the lab, and then there are other patients that have STEMI mimickers and so by doing point-of-care echo or otherwise you might not see wall motion abnormality [and] they might not come to the lab," noted Kirtane. "And then there are people who come to the lab who don't have an identifiable lesion, which has been well described as well."

Further analysis is in the works, since this is only the first look at the database, which was closed last Sunday night, Henry said. For example, "I can tell you briefly that the lowest mortality is in the patients who actually underwent PCI, but of course that's a selective group that we have to be careful about talking about that at this time."

The North American registry had no standardized protocols for treatment. It included 171 confirmed COVID-19 positive patients and 423 people with COVID-19 suspected but later confirmed negative. Patients presented at the 64 participating sites in the U.S. and Canada with ST-segment elevation or new left bundle branch block on ECG.

Inclusion criteria were "very broad," requiring only that patients be at least age 18 and have a clinical correlate of myocardial ischemia, such as chest or abdominal discomfort, dyspnea, cardiac arrest, shock, or mechanical ventilation. There were effectively no exclusion criteria.

A propensity-matched, historical-control group of STEMI-activation patients from the Midwest STEMI Consortium formed the comparator arm.

In this largest reported COVID-STEMI cohort, Henry noted the "striking difference" in ethnic distribution: Caucasians accounted for only 33% of the COVID-positive group but 74% of the confirmed negative group.

"A lot of times people will pooh-pooh observational data, but this is exactly the type of data that we need," Kirtane said. "I think many of us around the world will see these data, and it will echo their own experience."

The goal ultimately is to "develop data-driven treatment plans, guidelines and diagnostic acumen regarding these unique patients," Henry said.

Another reason behind the poor outcomes in COVID-positive STEMI in part because of small intramyocardial and epicardial thrombi often found on autopsy that wouldn't be treated by PCI, noted session co-chair Renu Virmani, MD, of CVPath Institute in Gaithersburg, Maryland.

"We need to get to bottom of what is the underlying cause of that thrombosis," she argued.

Kirtane noted the many antithrombotic trials ongoing that may help improve outcomes.

The NACMI registry was a collaboration between the Society for Cardiovascular Angiography and Interventions, the Canadian Association of Interventional Cardiology, and the American College of Cardiology Interventional Council.

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