December 01, 2006
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OAT: Medical therapy without late PCI worked for those not at highest risk

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CHICAGO — New data from the Occluded Artery Trial show that opening an occluded artery with percutaneous coronary intervention with stenting three to 28 days after a myocardial infarction may not be as beneficial as it is in the first 12 to 24 hours after the event.

Judith Hochman, MD, Harold Snyder Family Professor of Cardiology, clinical chief and director of the Cardiovascular Clinical Research Center at the New York University School of Medicine, presented the results of OAT at the American Heart Association’s Scientific Sessions 2006. The data were also published online in the New England Journal of Medicine.

“This is a very well-done study and the authors are to be commended,” R. David Anderson, MD, director of interventional cardiology at the University of Florida, Gainesville, told Cardiology Today. “It does have the potential to change practice and may be most important for patients initially treated at smaller centers without the ability to perform primary PCI.”

No benefit

The trial enrolled 2,166 patients from 217 sites in 27 countries between 2000 and 2005. Confirmed index MI, total occlusion of the infarct-related artery with absent or poor thrombolysis in MI flow (0 or 1) and a high-risk feature-ejection fraction of less than 50% and/or proximal occlusion was inclusion criteria. Patients needed to meet two of three qualifications for index MI: ischemic symptoms for 30 minutes or more, elevated cardiac markers or electrocardiogram criteria.

Patients at highest-risk were excluded from the study, including those with NYHA class III or IV HF, rest or low threshold angina or significant left main or three-vessel CAD.

Eligible patients were randomized to PCI and optimal medical therapy (n=1,082) or optimal medical therapy alone (n=1,084). Of these patients, 2.5% crossed over to PCI within 30 days, 5.8% after 30 days. Drug-eluting stents were used in 8.1% of patients.

The researchers tested the hypothesis that the strategy of late PCI to open occluded arteries three to 28 days after MI would reduce the first occurrence of the composite death, reinfarction or NYHA class IV HF by 25% compared with optimal therapy alone on an average follow-up of three years. Primary endpoint was composite of death, reinfarction or HF after an average three years of follow-up.

The four-year centrally judicated event rate for the medical therapy group was 15.6% and the rate for the PCI group was17.2% (hazard ratio = 1.16; 95% CI, 0.92-1.45). Covariant-adjusted and as-treated analysis compared successful PCI patients (n=937) with the medical therapy group that did not cross over to PCI within 30 days (n=1,057) and found similar results: HR=1.17; 95% CI, 0.93-1.41 and HR=1.15; 95% CI, 0.91-1.46, respectively.

Primary end-point events as determined by the sites occurred in 170 patients assigned PCI and medical therapy and 142 patients assigned medical therapy alone (HR=1.22; 95% CI, 0.97-1.52). Fatal and nonfatal reinfarction rates were 7% in the PCI group and 5.3% in the medical therapy group (HR=1.36; 95% CI, 0.92-2.0). Rates of nonfatal reinfarction were 6.9% among patients undergoing PCI and 5% in the medical therapy group (HR=1.44; 95% CI, 0.96-2.16). Six reinfarctions were attributed to PCI.

“These results support routine use of aggressive secondary prevention without revascularization as the preferred therapy for OAT-eligible patients,” Hochman said.

Anderson said there are several issues that require further study.

“It would be important to know if there was a benefit in those patients unable to take beta-blockers for whatever reason,” he said. “This might identify a subgroup in whom late mechanical reperfusion is beneficial.

“Overall, it seems that in patients with a late presentation after MI (on average over one week), routine treatment with PCI for an occluded infarct-related artery should not be performed. In patients with preserved LV function after an MI, without spontaneous or inducible ischemia, or refractory arrhythmia, the use of routine angiography could even be questioned.” – by Judith Rusk

OAT trial scorecard

For more information:

  • Hochman J. The Occluded Artery Trial (OAT). Late-breaking clinical trials II. Presented at: American Heart Association Scientific Sessions 2006; Nov. 12-15, 2006; Chicago.
  • Hochman JS, Lamas GA, Buller CE, et al. Coronary intervention for persistent occlusion after myocardial infarction. N Engl J Med. 2006;10.1056/NEJMoa066139.