‘Transient’ STEMI Patients Can Be Immediately Treated or Safely Deferred to Next Day

PARIS, France—When faced with a STEMI patient who now has a normalized ST segment and is no longer symptomatic, physicians can either opt for immediate PCI or delay treatment without serious repercussions, according to the results of a small study.

Presenting results of the TRANSIENT trial during a hotline session at EuroPCR 2018, Jorrit Lemkes, MD (VU University Medical Center, Amsterdam, the Netherlands), said “transient” STEMI poses a therapeutic challenge, as physicians are uncertain if they should handle patients as a STEMI or NSTEMI case. If handled as a STEMI patient, immediate PCI is recommended, but a delayed approach based on patient risk is the preferred approach in NSTEMI patients.

“Up until now, nobody’s really looked at this question in a randomized fashion,” Lemkes told TCTMD. “These patients start out with an occlusion and reperfusion is established, either with the administration of medication given in the ambulance or spontaneously, and the question then becomes how quickly we need to proceed with angiography and PCI.”

There was no statistical difference in infarct size assessed by MRI at 4 days, the study’s primary endpoint. Given these results, Lemkes said the decision to perform PCI immediately or wait until the next day will likely boil down to hospital and personnel logistics.

“If the patient presents to the cath lab and your team is ready to go, I would just go ahead and do PCI,” said Lemkes. “On the other hand, if there are problems and the cath lab is not available, then you can admit the patient to the [coronary care unit] and treat them like an NSTEMI patient and do the cath the next day or whenever it’s available.”

Mamas A. Mamas, BMBCh (Keele University, Stoke-on-Trent, England), who was not involved in the study, said TRANSIENT is an important trial, as these types of patients are often encountered in clinical care.

This is a debate we have in our cath lab all the time. Mamas Mamas

“This is a debate we have in our cath lab all the time,” said Mamas. “It’s not that uncommon—maybe 10% in my experience—where the patient has very clear ST-segment elevation and comes across where it’s resolved and the patient is asymptomatic. What do you do? For me, what I’ve done in the past, I’ve undertaken the PCI because you’ve called the cath lab staff in and you treat [the patient] in case they reinfarct overnight.”

However, other physicians at his hospital will take the opposite approach, arguing that the patient is asymptomatic and angiography can be safely deferred until the next day. “There is no guidance,” said Mamas. “I think this is an important trial driving how we should treat these patients. Actually, what it shows is that there is no wrong answer.” 

TRANSIENT: Small but Important

The TRANSIENT study included 142 patients with STEMI who had an ECG obtained in the field by emergency medical services and in whom the ST segment had normalized and symptoms had resolved prior to randomization. Investigators randomized patients to immediate coronary angiography and revascularization or an NSTEMI-like approach where angiography and revascularization were delayed.

In the study, the median time to coronary angiography was approximately 18 minutes among those randomized to immediate treatment and 22.7 hours for those randomized to the delayed approach.

Overall, infarct size in both treatment arms was very small, likely because patients in both arms had open coronary vessels at the time of reperfusion, said Lemkes. In addition to no difference in the MRI results, there was no significant difference in cardiac troponin levels at 24 and 72 hours and no difference in clinical outcomes at 30-day follow-up.

Patients deferred for coronary angiography were more likely to undergo CABG, with 11% of these patients treated with surgery compared with none of those sent immediately to the catheterization laboratory (P = 0.01). Comparatively, 90% of those randomized to immediate angiography underwent PCI compared with 75% in the deferred angiography arm (P = 0.03). 

To TCTMD, Lemkes said the difference in coronary revascularization strategies is likely a reflection of how STEMI and NSTEMI patients are treated. For those randomized to immediate angiography, which is how STEMI patients are handled, there is a tendency to treat the culprit vessel alone. For those randomized to delayed angiography, which is a reflection of NSTEMI-like care, physicians can slow down to think about the overall treatment strategy, particularly if there is evidence of multivessel disease.

“In NSTEMI, you have more time, including time to discuss with the surgeon the optimal treatment,” said Lemkes. “For me, if I have a transient STEMI patient with ST-segment normalization and three-vessel disease, if I had done the angiogram, knowing what I know now, I would feel comfortable waiting until the next day to discuss the optimal treatment strategy with the heart team.”   

Speaking during the hotline session, James Nolan, MD (University Hospitals of North Midlands, Stoke-on-Trent, Stafford, England), zeroed in on the different revascularization strategies depending on how patients were initially managed.

“Some of the patients who were deferred were later referred on to surgery rather than angioplasty of the individual vessels,” said Nolan. “It’s speculation, but those people may receive better revascularization than those who receive immediate PCI. Over a large population, played out over some years, it’s perfectly possible that will result in better long-term outcomes.”

For panelist Fernando Alfonso Manterola, MD (Hospital Universitario De La Princesa, Madrid, Spain), however, these data suggest there is no reason to delay PCI. He noted that four patients with transient STEMI in the deferred angiography arm crossed over because they had ST-segment changes warranting immediate PCI.

Lemkes, for his part, also believes there is no reason to delay, but said each hospital can safely make either choice without adversely affecting patient care.