Early Revascularization in NSTEMI Linked to Lower Mortality: AHRQ Analysis

(UPDATED) Patients presenting with non-ST-elevation myocardial infarction treated early with PCI have a lower risk of rehospitalization and death at 30 days compared with patients treated in the subsequent days after hospital admission, a large analysis from the Nationwide Readmissions Database (NRD) shows.

Ron Waksman, MD (MedStar Washington Hospital Center, Washington, DC), the study’s senior author, said the results lend support for the early revascularization of NSTEMI patients, but added the data points to the much larger question of exactly when to revascularize NSTEMI patients after they have been admitted to the hospital. The time has come, said Waksman, for randomized trials to evaluate the potential merits of truly early revascularization, that being within 90 minutes of presenting to the hospital, just like in STEMI patients.

“As a clinician, I have a feeling we miss a lot with non-STEMI patients,” he told TCTMD. “We don’t have strict timing for taking them to the cath lab for revascularization. In STEMI, we have the door-to-balloon time of 90 minutes—it’s been established, it’s in the performance metrics—but with non-STEMI it’s really all over the place. And many patients we take to the lab with non-STEMI are basically STEMIs—it just doesn’t reflect that on the ECG.”

For example, Waksman said it’s not uncommon to take an NSTEMI patient to the cath lab only for the diagnostic angiogram to reveal a total occlusion of the circumflex artery despite the ECG not showing any evidence of STEMI. “It shows some ST changes, flipping of T-waves, but when you do the angiogram the artery is completely occluded,” he said. “I think there’s some inequality with how we treat these patients.”

Overall, 54% of patients with NSTEMI revascularized with PCI were treated within 1 day of presenting to the hospital, which is line with clinical guidelines recommending early revascularization, particularly for stabilized high-risk subgroups. The European Society of Cardiology clinical guidelines currently recommend that high-risk NSTE ACS patients undergo invasive angiography within 24 hours and intermediate-risk patients within 72 hours. The American College of Cardiology/American Heart Association clinical guidelines for NSTE ACS management make similar recommendations.

Door-to-Balloon Times Just Like in STEMI?

The new analysis, published online August 16, 2020, ahead of print in the American Journal of Cardiology, is an attempt to get a better sense of how patients with NSTE ACS are currently treated in the United States, said Waksman. The study included 748,463 hospital admissions for NSTEMI in 2016 recorded in the NRD from the Agency for Healthcare Research and Quality (AHRQ). Of these patients, 50.3% underwent diagnostic angiography, 255,199 of whom were revascularized with PCI (77.6%) or CABG surgery (22.4%).

For the patients treated with PCI, revascularization was performed the day of hospital admission in 32.9% of cases, the next day (day 1) in 31.6% of cases, and on day 2 in 13.0% of cases.

With PCI, there was an increase in the prevalence of comorbidities as revascularization was delayed, but the prevalence of comorbidities didn’t differ in the CABG group based on the timing of surgery. A previous analysis from the ACTION registry also showed that patients with more comorbidities are more likely to be delayed revascularization, say investigators. To TCTMD, Waksman said patients with comorbidities, who likely had higher risk scores, would have likely benefited from early revascularization.

“There’s often the excuse to defer them for further evaluation,” said Waksman.

With respect to outcomes, those who didn’t receive a diagnostic angiogram had the highest rate of hospital readmission at 30 days. The 30-day readmission rate for patients treated with PCI was lowest for patients revascularized on the day of hospital admission (9.0%) and increased each day PCI was delayed. The readmission rates for CABG were lowest when surgery was performed on day 2 (9.6%).

In terms of crude in-hospital mortality, the rate was highest for same-day PCI (2.1%) and lowest (1.5%) if patients were treated on day 1. In-hospital mortality began to increase if PCI was delayed beyond day 3, peaking at 6.6% if patients were treated 10 days after presenting to the hospital. With surgery, the in-hospital mortality rate was highest (3.2%) if they underwent surgery the day of admission and lowest (2.2%) if surgery occurred on day 4.

For NSTEMI patients revascularized with PCI on the same day they presented to the hospital, the adjusted 30-day mortality rate was 3.5%, and this risk of mortality increased with each day’s delay. For example, for those treated with PCI 1 to 6 days after presentation, the 30-day mortality rate was 4.1%, 4.5%, 4.9%, 5.6%, 7.7%, and 9.7%, respectively. With CABG surgery, the 30-day mortality rate was lowest at 2.6% if patients were treated on day 1 and 2.

Sanjit Jolly, MD (McMaster University/Hamilton General Hospital, Canada), who wasn’t involved in the study, said their typical plan of action is to take NSTE ACS patients to the cath lab for diagnostic angiography within 24 to 48 hours. “The higher-risk patients will jump the line and go quicker and will be cathed on weekends,” he told TCTMD. “We don’t typically take NSTEMIs directly to the lab—we don’t treat them like a STEMI—but the days where patients might wait a week in hospital are long gone.”

More than a decade ago, their group, led by Shamir Mehta, MD (McMaster University/Hamilton General Hospital), published the TIMACS study showing that intervening within 24 hours did not reduce the risk of the primary endpoint of death, MI, or stroke at 6 months when compared with a delayed-intervention strategy (≥ 36 hours). However, early intervention did significantly reduce the risk of the primary endpoint and significantly reduced the risk of death, MI, or refractory ischemia at 6 months.

Like Waksman, Jolly said the NSTE ACS patient with an occluded circumflex artery not picked up on ECG would benefit from the early intervention. “The question is, how do you find these patients and treat them accordingly?” he asked. Chest pain typically resolves in NSTE ACS patients administered nitroglycerin and other therapies, but if it doesn’t, and cardiac enzymes continue to rise, Jolly said these patients will then be taken to the cath lab “day or night” given the concerns of an electrically silent occlusion.

While these new data support the early revascularization strategy, Waksman said they are looking for more-detailed information with respect to the timing of revascularization. The researchers are currently working on obtaining funding from the National Institutes of Health to study whether NSTEMI patients benefit from revascularization within 90 minutes, the same door-to-balloon time goal used in STEMI.

In 2018, data from the EARLY trial showed that sending NSTE ACS patients for invasive angiography within 2 hours of presentation reduced the risk of cardiovascular death or recurrent ischemia at 30 days when compared with a delayed strategy, a benefit that was driven primarily by the reduction in ischemia. The VERDICT trial, on the other hand, found no advantages to invasive angiography within 12 hours when compared with sending NSTE ACS patients to the lab 2 or 3 days later, although there was a signal of benefit in a high-risk subgroup.