Delayed Care for NSTEMI Linked to Higher Mortality Over 3 Years

Prehospital delays to treatment can increase the mortality rate of NSTEMI patients up to 3 years later, according to new Korean data.

While much emphasis has been placed on patient education aiming to reduce time to STEMI care in recent years, especially with the added hurdles placed by the COVID-19 pandemic, NSTEMI poses a trickier challenge as the presenting symptoms are not always as obvious.

“A plausible explanation is that patients with NSTEMI may tolerate symptoms and choose to remain at home, leading to late arrival at the hospital,” write Jung-Joon Cha, MD (Korea University College of Medicine, Seoul, Republic of Korea), and colleagues.

Amid the focus on reducing prehospital delays for STEMI, timing for NSTEMI hasn’t been addressed “with the same scientific intensity,” Umesh Khot, MD (Cleveland Clinic, OH), told TCTMD. “The other thing, from a patient standpoint, is that NSTEMI has, if you will, a little more of a complex and variable presentation, so I think it may be sometimes a little bit harder for patients to realize what's happening in the moment.”

B. Hadley Wilson, MD (Sanger Heart & Vascular Institute/Atrium Health, Charlotte, NC), vice present-elect of the American College of Cardiology (ACC), also told TCTMD he was happy to see a study look solely at an NSTEMI population. “It's good to bring them back into the spotlight, because as we can see from their results here, they have significant mortality and morbidity, particularly when there's delay to treatment,” he said.

Studies have shown that an early invasive strategy for NSTEMI leads to lower mortality, particularly in high-risk patients, but most of the data address door-to-balloon time, not the time from symptom onset. In STEMI, however, a systematic emphasis on reducing time from symptom onset has improved outcomes.

Delays Increase Mortality

For the study, published in the February 1, 2022, issue of the Journal of the American College of Cardiology, Cha and colleagues looked at 6,544 patients with NSTEMI (mean age 64.8 years; 71% male) from the Korea Acute Myocardial Infarction Registry–National Institutes of Health between November 2011 and December 2015. Just over one-quarter of patients (27.9%) waited at least 24 hours before arriving at the hospital from the time of symptom onset with a median symptom-to-door (StD) time in this group of 72.0 hours. The median StD time in the group who waited less than 24 hours was only 3.9 hours.

Over a median 1,098-day follow-up period, those with StD times of at least 24 hours had higher rates of 3-year all-cause mortality (17.0% vs 10.5%; adjusted HR 1.35; 95% CI 1.17-1.56) as well as the composite of all-cause mortality, recurrent MI, and hospitalization for heart failure (23.3% vs 15.7%; adjusted HR 1.24; 95% CI 1.10-1.40) than those without delays. Individual rates of recurrent MI (5.3% vs 3.7%; adjusted HR 1.31; 95% CI 1.02-1.69) and cardiac death (10.8% vs 6.4%; adjusted HR 1.37; 95% CI 1.14-1.65) were also higher in those who waited longer than a day, but there were no differences in hospitalization for heart failure or any revascularization.

All-cause mortality results were unchanged in subgroup analyses by age, sex, atypical chest pain, dyspnea, Q-wave in electrocardiogram, use of emergency medical services (EMS), hypertension, diabetes, chronic kidney disease, LV dysfunction, TIMI flow, and GRACE score.

Additionally, older age, female sex, no EMS use, diabetes, and nonspecific symptoms like atypical chest pain or dyspnea were independent predictors of prehospital delays on multivariate analysis.

Most striking about these results for Khot was “how much of an impact this had 3 years out in terms of the impact on mortality,” he said. “Most of the time [with] studies looking at things around MI care, we're looking at impacts in the hospital, the first 30 days, maybe a few months.”

Combatting ‘Patient Reticence’

In an accompanying editorial, José A. Barrabés, MD, PhD (Universitat Autònoma de Barcelona, Spain), and colleagues suggest several reasons for why admission delays may contribute to differences in outcomes.

“First, late presenters might have had more frequent recurrent ischemic episodes—which are associated with a worse prognosis—before admission than the remaining patients,” they say. Also, some of the patients who presented late “might originally have had a STEMI, but they no longer had ST-segment elevation on admission,” the editorialists suggest.

But, most importantly, Barrabés and colleagues write that StD times in this study are longer than has been seen in other NSTEMI registries, rendering the findings not as generalizable. Moreover, they say, there may have been “other comorbidities, supply-demand imbalances, socioeconomic variables, distance to the hospitals, or other barriers to receive rapid medical attention” that the researchers did not include which could explain the study findings better.

Still, “this study underscores the importance of seeking urgent medical attention (preferably by contacting the emergency medical services) in the presence of any symptoms suggestive of myocardial ischemia and confirms some variables related to long symptom-to-door times,” the editorialists conclude.

Wilson agreed. The COVID-19 pandemic has increased “patient reticence” about coming into the hospital for any reason—and hence mortality for both STEMI and NSTEMI have increased over the past 2 years—but this study shows that “even before the pandemic, these were patients that were underrecognized, undertreated, [and] maybe somewhat inattentive to their care because of more focus on STEMIs than NSTEMIs,” he said.

In particular, the findings underscore the importance of increasing awareness to with the goal of bettering care in the female and elderly populations, Wilson added.

For the diabetic population as well, Khot said he would eventually like to see “some type of technology that patients could maybe use at home that would help direct them” in when to go to the hospital. “They have to make that first phone call or medical contact to get things started,” he said, adding that many might hesitate without guidance.

As for future research, Khot said he would like to see similar analyses of NSTEMI registries in other parts of the world, commenting that no such comprehensive database of all NSTEMI patients exists in the United States that would be comparable to the one used in the Korean study. “There are some countries that have more universal access to ambulance care, for example, and things like that,” he said. “So, I think I'd encourage other groups that might have access to similar data in other countries to try to validate these findings.”

Wilson would also like studies to examine whether door-to-balloon time is “as important in the NSTEMI group as much as it is in the STEMI group,” he said.

“The biggest message is that this study supports the importance of taking care of patients in a timely fashion, even in the midst of the pandemic,” Khot said. “We just want to continue to really support the importance of that as we move forward into whatever the pandemic has in store for us.”