NACMI: Clear Benefit With PCI in STEMI COVID-19 Patients

Patrice Wendling

October 15, 2020

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

Patients with COVID-19 who present with ST-segment elevation MI represent a unique, high-risk population with greater risks for in-hospital death and stroke, according to initial results from the North American COVID-19 ST-Segment Elevation Myocardial Infarction Registry (NACMI).

Although COVID-19 confirmed patients were less likely to undergo angiography than patients under investigation (PUI) for COVID-19 or historical STEMI activation controls, 71% underwent primary percutaneous coronary intervention (PCI).

"Primary PCI is preferable and feasible in COVID-19 positive patients, with door-to-balloon times similar to PUI or COVID-negative patients, and that supports the updated COVID-specific STEMI guidelines," study co-chair Timothy D. Henry, MD, said in a late-breaking clinical science session at TCT Connect, the virtual meeting of Transcatheter Cardiovascular Therapeutics (TCT) 2020.

The multisociety COVID-specific guidelines were initially issued in April, endorsing PCI as the standard of care and allowing for consideration of fibrinolysis-based therapy at non-PCI capable hospitals.

Five previous publications in a total of 174 COVID-19 patients with ST-elevation have shown there are more frequent in-hospital STEMI presentations, more cases without a clear culprit lesion, more thrombotic lesions and microthrombi, and higher mortality, ranging from 12% to 72%. Still, there has been considerable controversy over exactly what to do when COVID-19 patients with ST elevation reach the cath lab, he said.

NACMI represents the largest experience with ST-elevation patients and is a unique collaboration between the Society for Cardiovascular Angiography and Interventions (SCAI), Canadian Association of Interventional Cardiology (CAIC), American College of Cardiology, and Midwest STEMI Consortium, noted Henry, who is medical director of the Lindner Center for Research and Education at The Christ Hospital, Cincinnati, Ohio.

The registry enrolled any COVID-19 positive patient or person under investigation older than 18 years with ST-segment elevation or new-onset left bundle branch block on electrocardiogram with a clinical correlate of myocardial ischemia such as chest pain, dyspnea, cardiac arrest, shock, or mechanical ventilation. There were no exclusion criteria.

Data from 171 patients with confirmed COVID-19 and 423 PUI from 64 sites were then propensity-matched to a control population from the Midwest STEMI Consortium, a prospective, multicenter registry of consecutive STEMI patients.

The three groups were similar in sex and age but there was a striking difference in race, with 27% of African American and 24% of Hispanic patients COVID-confirmed compared with 11% and 6% in the PUI group and 4% and 1% in the control group. Likewise, there was a significant increase in diabetes (44% vs 33% vs 20%), which has been reported previously with influenza.

COVID-19 positive patients, as compared with PUI and controls, were significantly more likely to present with cardiogenic shock before PCI (20% vs 14% vs 5%), but not cardiac arrest (12% vs 17% vs 11%), and to have lower left ventricular ejection fractions (45% vs 45% vs 50%).

They also presented with more atypical symptoms than PUI patients, particularly infiltrates on chest X-ray (49% vs 17%) and dyspnea (58% vs 38%). Data were not available for these outcomes among historic controls.

Importantly, 21% of the COVID-19 patients did not undergo angiography, compared with 5% of PUI patients and 0% of controls (P < .001), "which is much higher than we would expect or have suspected," Henry said. Thrombolytic use was very uncommon in those undergoing angiography, likely as a result of the guidelines.

Very surprisingly, there were no differences in door-to-balloon times between the COVID-positive, PUI, and control groups despite the ongoing pandemic (80 min vs 78 min vs 86 min).

But there was clear worsening in in-hospital mortality in COVID-19 positive patients (32% vs 12% and 6%; P < .001), as well as in-hospital stroke (3.4% vs 2% vs 0.6%) that reached statistical significance only when compared with historical controls (P = .039). Total length of stay was twice as long in COVID-confirmed patients than for both PUI and controls (6 days vs 3 days; P < .001).

Following the formal presentation, invited discussant Philippe Gabriel Steg, MD, Imperial College London, United Kingdom, said the researchers have provided a great service in reporting the data so quickly but noted that an ongoing French registry of events before, during, and after the first COVID-19 wave has not seen an increased death rate.

"Can you tease out whether the increased death rate is related to cardiovascular deaths or to COVID-related pneumonias, shocks, [acute respiratory distress syndromes] ARDSs, and so on and so forth. Because our impression — and that's what we've published in Lancet Public Health —  is that the cardiovascular morality rate doesn't seem that affected by COVID."

Henry replied that these are early data but "I will tell you that patients who did get PCI had a mortality rate that was only around 12% or 13% and the patients who did not undergo angiography or were treated with medical therapy had higher mortality. Now, of course, that's selected and we need to do a much better matching and look at that, but that's our goal and we will have that information," he said.

During a press briefing on the study, discussant Renu Virmani, MD, president and founder of CVPath Institute, noted that in their analysis of 40 autopsy cases from Bergamot, Italy, small intra-myocardial microthrombi were seen in nine patients, whereas epicardial microthrombi were seen in only three or four.

"Some of the cases are being taken as being related to coronary disease but may be more thrombotic than anything else," she said. "I think there's a combination and that's why the outcomes are so poor. You didn't show us TIMI flow but that's something to think about: Was TIMI flow different in the patients who died because you have very high mortality? I think we need to get to the bottom of what is the underlying cause of that thrombosis."

Marco Valgimigli, MD, PhD, University Hospital Bern, Switzerland, questioned during the formal presentation why 21% of patients with STEMI did not undergo angiography and whether the researchers could confirm that patients with STEMI, in whom no culprit was identified, had a rise in cardiac troponin and were really true MI or had only an ECG change leading to suspected primary PCI.

"All of the patients had ST elevation and all the patients have elevated troponin, so the answer to that is, I think, yes," Henry said. With regard to those undergoing angiography, more complete information will be forthcoming but "anecdotally, it appears that some of these patients were too sick to go and some of those patients were already intubated or on [extracorporeal membrane oxygenation] ECMO."

Henry noted that additional analyses will be performed but that enrollment for this analysis was just closed last Sunday night. During his presentation, he also made a pitch for additional sites to join NACMI, and said they are targeting high-COVID prevalence sites in particular and will likely add sites in Mexico and South America.

Future topics of interest include ethnic and regional/country differences; time-to-treatment including chest pain onset-to-arrival; transfer, in-hospital, and no-culprit patients; changes over time during the pandemic; and eventually 1-year outcomes, Henry said.

Press briefing moderator Ajay Kirtane, MD, director of the cardiac catheterization labs at NewYork-Presbyterian/Columbia University Irving, New York City, remarked that "a lot of times people will pooh-pooh observational data, but this is exactly the type of data that we need to try to be able to gather information about what our practices are, how they fit. And I think many of us around the world will see these data and it will echo their own experience."

The study was funded by the Society for Cardiovascular Angiography and Interventions and the Canadian Association of Interventional Cardiology. Henry has disclosed no relevant financial relationships.

Transcatheter Cardiovascular Therapeutics (TCT) Connect. Presented
October 14, 2020.

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