SNOWMASS, COLO. – An early invasive strategy is particularly beneficial in octogenarians with non–ST-segment elevation myocardial infarction, according to a recent study involving close to 1 million NSTEMI patients aged 80 years or older.
The very eldest are an understudied segment of the NSTEMI population, for whom an initial conservative strategy has been the dominant approach in daily practice.
Dr. David R. Holmes, Jr.
"This is an important study. We can see that as you get older and older, by virtue of the fact that you have more and more coronary disease, probably you’re going to be better off with an invasive strategy, all other things being equal," Dr. David R. Holmes Jr. commented in highlighting the study at the Annual Cardiovascular Conference at Snowmass.
The study included 968,542 octogenarians hospitalized with NSTEMI during 2003-2010 and entered into the Nationwide Inpatient Sample. Eighty-three percent were managed via an initial conservative approach, with coronary angiography performed only in the event of hemodynamic or electrical instability, refractory angina despite optimal medical therapy, or a test result indicative of high risk. The other 17% underwent an early invasive approach, with angiography within 48 hours of presentation.
Octogenarians managed via an early invasive strategy were more often younger, obese, smokers, dyslipidemic, hypertensive, white, and male, and more likely to have known vascular disease. In a multivariate analysis adjusted for potential confounders, the early invasive strategy group had a 34% reduction in in-hospital mortality compared with the conservatively managed group. They also had a 37% lower rate of acute ischemic stroke, a 40% reduction in intracranial hemorrhage, a 37% lower risk of gastrointestinal bleeding, and a shorter length of stay by an average of half a day. On the other side of the ledger, they had a 2.1-fold increased rate of cardiogenic shock (Am. J. Med. 2013;126:1076-83).
Does time to cath lab matter?
Another recent study looked at the optimal time frame for taking an NSTEMI patient to the cardiac catheterization laboratory as part of an invasive strategy. This was a meta-analysis of seven randomized controlled trials totaling 5,370 NSTEMI patients, along with four observational studies with more than 77,000 NSTEMI patients. The conclusion: There is as yet no persuasive evidence that the time interval makes a difference in outcomes (Ann. Intern. Med. 2013;158:261-70).
"That’s the data that’s available. It doesn’t matter how quickly you get the patient to the cath lab within that first period of time. You just need to take them, whether it’s in 2 hours, 6 hours, or 18 hours," Dr. Holmes said.
This has important implications as we think about systems of care. If somebody comes into the hospital late on a Friday night, do you have to take them to the cath lab Friday night, or can you wait electively and take them tomorrow or potentially even Monday morning when everybody’s there?" commented Dr. Holmes, professor of medicine at the Mayo Clinic in Rochester, Minn.
GRACE and CRUSADE
The cornerstone of decision making as to whether to opt for an invasive versus a conservative strategy in a given NSTEMI patient involves application of a formal risk score. A plethora of these risk scoring systems are in use today. Which is the best choice for a cardiologist as an aid to decision making? A meta-analysis involving 36 studies with nearly 117,000 NSTEMI patients has concluded that the GRACE (Global Registry of Acute Cardiac Events) risk score (JAMA 2004;291:2727-33) is the best of the pack. It significantly outperformed the TIMI score, which is the other widely used scoring system, as well as others less widely known (Contemp. Clin. Trials 2012:33:507-14).
"GRACE looks like it performs better. We’ll need better ones in the future, of course. But at the present time, select GRACE for risk stratification," advised the cardiologist, adding that a Grace score app is available.
Despite the fact that physicians are diagnosing and treating NSTEMI earlier in its course, in large part because of the widespread use of troponin assays in the emergency department, NSTEMI is still associated with substantial long-term morbidity and mortality, particularly in the elderly. This was underscored in a recent analysis of 19,336 NSTEMI patients aged 65 years or older who underwent early catheterization and were included in the CRUSADE (Can Rapid Risk Stratification of Unstable Angina Patients Suppress Adverse Outcomes with Early Implementation of the ACC/AHA Guidelines) registry.
Twenty-one percent of patients received medical management alone, 60.8% underwent percutaneous coronary intervention, and 18.2% had coronary artery bypass graft surgery. The 5-year unadjusted all-cause mortality rate was 50% in the medically managed group, 33.5% in older patients who underwent PCI, and 24.2% in those who underwent CABG surgery. The unadjusted 5-year rate of a composite of death, readmission for MI, or readmission for stroke was 62.4% with medical management, 44.9% with PCI, and 33% with CABG. The investigators concluded that long-term outcomes in elderly NSTEMI patients appear to be better in this large registry when revascularization is accomplished via CABG than with PCI. This sets the stage for future confirmatory trials (Circ. Cardiovasc. Qual. Outcomes 2013;6:323-32).