The early strategy did, however, reduce the risk of refractory ischemia compared with delayed management, which the trial, called Timing of Intervention in Patients with Acute Coronary Syndromes (TIMACS), defined as occurring after at least 36 hours.

Importantly, early management in TIMACS also significantly cut the risk of death or CV events among patients who were judged to be at high risk based on their GRACE scores, which stratify risk status as low, intermediate, or high [2].

Among the study's messages, according to its investigators and observers at the meeting, are that high-risk patients should definitely get early invasive management, while low- to moderate-risk patients can go either way, depending on the circumstances. As a practical matter, it suggests, low- to moderate-risk patients who present on the weekend don't actually need to go to the catheterization laboratory on the weekend, but it would be safe to do so. TIMACS showed no significant difference between the early and late strategies in rate of major bleeding.

"Most patients with acute coronary syndromes can be managed safely with either an early or a delayed invasive strategy," Dr Shamir R Mehta (McMaster University, Hamilton, ON) said when presenting the TIMACS study. "However, in a subset of patients at highest risk, early intervention appears to be superior, and these patients should be considered for early heart catheterization. In all other patients with acute coronary syndromes, the decision regarding the timing depends on other factors, such as cath-lab availability, the healthcare system environment, convenience, and economic considerations."

Comments from observers at the meeting highlighted the different ways TIMACS can be interpreted. In a panel discussion after Mehta's presentation, Dr Elliott Antman (Brigham and Women's Hospital, Boston, MA) observed that while early invasive management "certainly seems the way to go" in high-risk patients, there is less certainty regarding the low- to intermediate-risk group.

"From the patient's perspective," he said, "it would seem that it's not necessary to rush quickly to the cath lab. From a healthcare-delivery perspective, it might seem that to prevent the downstream episodes of recurrent ischemia and possible rehospitalization, it might be worthwhile to actually move ahead, since there's no harm with the early invasive strategy."

Because the two strategies were similar with respect to the primary end point, according to Dr Deepak Bhatt (Brigham and Women's Hospital, Boston, MA), the assigned discussant for Mehta's presentation, "hospitals that cath within the first few days can continue to do so, and if there's recurrent ischemia, then they can cath right away. This is still consistent with evidence-based medicine."

He added, "There's a strong suggestion, however, that earlier is better, especially if patients are at high risk. In addition, the shorter length of stay and presumably lower cost would steer me toward taking patients to the catheterization lab earlier rather than later. Finally, from the patient's perspective, it's better to go to cath earlier. There's nothing to lose, there's potential to gain. So if it were me, take me early."

Asked by the panel to provide a "Canadian perspective," Mehta said, "There's certainly no harm to going early" if there is an available cath lab and other resources are in place. And, he observed, it might reduce the patient's length of stay.

"On the other hand, if you get called on a Saturday night and the cath lab is closed, and you have an otherwise low- to intermediate-risk NSTEMI patient," Mehta observed, "it really doesn't make sense to open the cath lab and bring the whole team in to do a case. That patient can likely wait until Monday morning, when more resources and staff are available."

Speaking with heartwire, Dr David Faxon (Brigham and Women's Hospital, Boston, MA), who comoderated the session containing the TIMACS report and was on the trial's steering committee, provided something of a US perspective, focusing on the early-strategy benefit in the higher-risk patient group.

"I think this is going to make the biggest change in practice of any trial presented at this meeting, because I think it can be implemented tomorrow," he said. "There's a very strong feeling in this country that ACS should be treated rapidly."

Unless a center aims to invasively manage all non-ST-elevation ACS patients early, Faxon observed, proper risk stratification is the key to achieving it in the high-risk group. The guidelines say to risk-stratify all ACS patients, he noted, adding that in practice it may not always be done.

TIMACS randomized more than 3000 patients with unstable angina or NSTEMI who were "suitable" for revascularization to early (angiography as soon as possible within 24 hours, followed by PCI or CABG) or delayed (any time after 36 hours, followed by PCI or CABG) invasive management. The median times to angiography were 14 hours and 50 hours, respectively.

Rates of the primary composite end point (death, new MI, or stroke within six months) in the two groups were similar, at 9.7% and 11.7%, respectively. The rates of major bleeding during the index hospitalization were 3.1% and 3.5%, respectively.

To heartwire, Bhatt agreed there may be some movement toward earlier management in the US. "As we've moved to early mobilization of the cath lab for ST-segment-elevation MI, I think the same thing will happen, to an extent, in high-risk non-ST-segment MI and unstable angina."

But, he observed, risk stratification doesn't have to depend on the scoring system used in TIMACS. "Even though the trial studied GRACE risk scores, and that's the totally evidence-based one to use, I'd say it's generalizable. You can use a TIMI risk score, the CRUSADE risk score, probably you can even use the 'clinical-gestalt, gut-feeling' risk score."

Bhatt said he thinks TIMACS was underpowered, "but I think they're the best data we'll have, so we'll have to figure out how we can actually improve patient care with what we've learned from this data set. There are practical things we can do. Does it mean jiggering and reconfiguring the healthcare system a little bit? I think the honest answer to that, although it may be painful in some circumstances, is yes."