Among patients who underwent a PCI, the increased risk of death was similar at one year among those who had a procedural myocardial infarction (pMI) and those who had a spontaneous myocardial infarction (spMI) when their troponin level was >35x the upper reference level (URL), according to results of a new study published in JACC. In contrast, when the troponin increase was <35x URL, only spMI was significantly associated with an increased mortality risk.

The single center registry study conducted at Mount Sinai Hospital in New York included consecutive patients with chronic coronary syndrome (CCS) who had a PCI with a drug-eluting stent between 2012 and 2020 to investigate the impact of pMI and spMI across different levels of troponin elevation.

Of the 10,707 patients included in the analysis, 8,515 presented with CCS and 913 of them had a pMI, while 2,192 presented with an spMI. The mean age of the overall cohort was about 65 and a third were women.

Results showed that troponin peaks >1-5x, >5-35x and >35x URL occurred in 53%, 41% and 6% of patients with pMI and in 24%, 38% and 37% of patients with spMI, respectively.

All-cause mortality at one year, the primary endpoint, was significantly higher among patients who had a troponin peak >35x URL and suffered a pMI or spMI (adjusted hazard rate [HR], 4.40 and 7.57, respectively), compared with those who did not have an MI. The mortality rate in the pMI group was 7.7%, and it was 8.5% in the spMI group and 1.4% among those who did not have an MI. In addition, among patients who had an spMI, mortality was higher when the troponin peak was >1-5x and >5-35x URL.

Alessandro Spirito, MD; Roxana Mehran, MD, FACC; et al., write the study results are "the first to demonstrate that pMI has an impact on mortality similar to that of spMI when troponin elevation exceeds a certain threshold." Moreover, they write that the results "confirm that prognostically relevant pMIs are relatively rare after PCI, occurring in only 0.6% of patients with CCS undergoing PCI."

In an accompanying editorial comment, Michael G. Nanna, MD, MHS, FACC, and Sridhar Mangalesh, MBBS, write that the "powerful prognostic value of a single biomarker at a set cutoff has undeniable practical potential for easy implementation into the busy periprocedural clinical workflow." Looking to the future, they add, "A harmonized definition of pMI from leading professional societies, perhaps centered at a 35x URL troponin elevation as suggested in the present investigation, is a pressing necessity moving forward."