OAT Fails to Change Practice: No Decrease in Late PCI for Stable MI Patients

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Despite findings from a widely reported trial 5 years ago that showed no benefit to performing percutaneous coronary intervention (PCI) for total occlusions identified late after myocardial infarction (MI), practice patterns do not appear to have changed, even though the study led to a shift in national guidelines. The new report was published online July 11, 2011, in Archives of Internal Medicine.

In  the Occluded Artery Trial (OAT), 2,166 stable patients with a total occlusion of the infarct-related artery that was identified a minimum of 24 hours post MI were randomized to optimal medical therapy with or without stenting. The main results, published in 2006 (Hochman JS, et al. N Engl J Med. 2006;355:2395-2407), showed that PCI did not reduce the primary composite endpoint of death, reinfarction, or class IV heart failure out to 4 years. As a result, changes were made to the 2007 updates of the ACC/AHA guidelines regarding unstable angina and NSTEMI, STEMI, and PCI.

For the new study, researchers led by OAT’s primary investigator, Judith S. Hochman, MD, of the New York University School of Medicine (New York, NY), examined data from the CathPCI Registry on 28,780 patient visits in 896 hospitals for angiography at least 24 hours after MI. The procedures were performed from January 1, 2005, through December 31, 2008, a time frame that lasted from the year before OAT was published through 1 year after the guidelines were updated.

The vast majority of patients presented with NSTEMI (90.7%), and most had either 1-vessel (43.9%) or 2-vessel disease (49.9%). Overall, just over half of patients with qualifying occlusions (53%) underwent PCI targeting a total occlusion identified after MI, while 25.3% did not undergo PCI and 21.7% had PCI of nonoccluded targets.

No Effect of OAT

The crude rate of PCI for total occlusions was slightly but significantly lower after the publication of OAT (52.8% vs. 54.2% before publication) and declined again after the guideline revisions (51.9%; P < 0.001 for comparison across all 3 groups). However, there was an unexpected peak in the rate of PCI for occlusions in March 2006, 8 months prior to the presentation and publication of the OAT results. This peak substantially accounted for the observed decline in the crude rate of PCI in subsequent time periods.

There was a significant decline in the adjusted rate of PCI for occlusions from the peak in March 2006 to the OAT publication. However, there was no significant further decline after publication of the OAT results or after the guideline revisions (table 1).

Table 1. PCI Trends by Time Frame in Relation to OAT

 

OR (95% CI)

P Value

Before OAT Publication
(Mar 2006-Dec 2006)

0.976 (0.964-0.987)

< 0.001

After OAT Publication
(Dec 2006-Nov 2007)

0.997 (0.988-1.006)

0.54

After Guideline Revisions (Dec 2007-Mar 2009)

1.007 (0.992-1.022)

0.34


There also was no difference in the adjusted monthly trends of total occlusion PCI between the time period after publication of OAT and the time period after the guideline revisions (P = 0.40 for comparison of slopes).

Among hospitals with the highest quartile for reporting diagnostic catheterizations to the registry, there was no difference in the adjusted monthly rate of PCI for occlusions after publication of OAT (OR 1.018; 95% CI 0.995-1.042). However, there was a trend toward decline in the adjusted monthly rate of total occlusion PCI after the guideline revisions (OR 0.963; 95% CI 0.928-1.000).

According to Dr. Hochman and colleagues, the findings “suggest that the evidence provided by OAT and other small studies and the resultant class III guideline recommendations (“should not be performed”) for PCI in clinically stable patients with persistently occluded [infarct-related arteries] more than 24 hours after STEMI or NSTEMI have not, to date, been widely incorporated into clinical practice in a large cross-section of hospitals in the United States.”

Possible Reasons for Resistance to Change

The study authors say the reason for the lack of adherence to the guideline recommendations is likely multifactorial, a sentiment echoed in an accompanying editorial by Mauro Moscucci, MD, of the University of Miami Miller School of Medicine (Miami, FL).

“Physicians’ barriers to the applications of new guidelines include lack of awareness, lack of familiarity, and lack of agreement with the evidence supporting the guidelines,” he writes. “Patients’ related barriers and preferences and environment-related barriers act as additional external forces impairing the application of new guidelines. Finally, it has been suggested that guidelines aimed at the elimination of a behavior might be more difficult to implement than guidelines aimed at the introduction of a new behavior.”

But Dr. Moscucci says clinicians “must heed the call to professional responsibility” by not performing tests and treatments that do not benefit patients, “and for which the net effects will be added costs, waste, and possible harm.”

Sensing a Disconnect

In a telephone interview with TCTMD, Christopher J. White, MD, of the Ochsner Clinic Foundation (New Orleans, LA), and president of the Society for Cardiovascular Angiography and Interventions, said while the new study is a “good addition to the literature,” it raises more questions than it answers.

“OAT looked at stable patients, but the guidelines said asymptomatic patients, so right away there was some disconnect in that respect,” he said. “Now we have this study looking at before, during, and after the guidelines. When you attempt to change practice, it doesn’t happen like a speedboat, it happens more at the rate of an oil tanker. It takes a while to accept and incorporate changes.” If the study were performed today, Dr. White observed, it is quite possible the data would be different.

He added that another problem with any categorical conclusion is that there is some “wiggle room in the argument” for physicians who feel their patients do benefit from PCI beyond the time period specified by OAT. Therefore, the position of the OAT investigators that clinicians are not following guidelines may be more of a “10,000-foot overview” rather than a close-up look at clinical practice.

“It’s not really fair to say, ‘Gee, nobody is paying attention’ when in fact there is more to this that we still need to understand,” he said. “This paper is hypothesis generating and it should encourage further drilling down to answer some of these questions.”

Dr. White added that the OAT investigators acknowledge that their data are limited by the fact that they come solely from hospitals that report to the CathPCI registry.

OAT Does Not Apply

“The other thing about this,” Dr. White said, “is that OAT was about STEMI, whereas the NCDR data are mostly NSTEMI. It’s not clear that the OAT data apply to NSTEMI at all.”

Jeffrey W. Moses, MD, of Weill Cornell Medical College (New York, NY), agreed.

“The cohort that they cite has nothing to do with the original OAT study,” he told TCTMD in a telephone interview. “OAT was mainly untreated STEMI, who had by definition had minimal or no symptoms and either had Q-waves or no ischemia. That’s a very small group. When we looked at how many patients like that we cathed at Columbia in a year, it was 1% of our population. You can’t generalize because OAT does not apply to most patients we see in clinical practice. Use your evidence for the population you are studying. Period.”

Dr. Moses also took issue with the cutpoint of 24 hours after MI used in the registry study since the cutpoint in OAT was 48 hours.

“It’s frustrating, because the implication is that interventionalists need to be educated,” Dr. Moses said. “That’s not the problem.”

 


Sources:
1. Deyell MW, Buller CE, Miller LH, et al. Impact of national clinical guideline recommendations for revascularization of persistently occluded infarct-related arteries on clinical practice in the United States. Arch Intern Med. 2011;Epub ahead of print.

2. Moscucci M. Medical reversal, clinical trials, and the “late” open artery hypothesis in acute myocardial infarction. Arch Intern Med. 2011;Epub ahead of print.

 

  • Drs. Hochman and Moscucci report no relevant conflicts of interest.
  • Dr. White reports receiving research support from Boston Scientific and serving on the advisory boards of Baxter Healthcare, Cellular Therapy, Neovasc, and St. Jude Medical.
  • Dr. Moses reports receiving consulting fees from Boston Scientific and Cordis.

 

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Disclosures
  • The NCDR CathPCI Registry is an initiative of the ACC Foundation and the SCAI. The study was supported by the NCDR and the National Heart, Lung, and Blood Institute.

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