'"Late" percutaneous coronary intervention for total coronary occlusions more than 24 hours after MI is still commonplace, even though clinical practice guidelines recommend against it, according to an analysis of the CathPCI registry published online July 11 in Archives of Internal Medicine.
This finding, from an analysis of national trends in PCI use before and after these guidelines were changed in 2007, has two implications: First, it shows that "many stable patients with recent MI and persistent infarct artery occlusion continue to undergo a costly and ineffective procedure."
In addition, it shows that "a large public, scientific, and human patient investment in the generation of robust clinical evidence has yet to broadly influence U.S. practice," said Dr. Marc W. Deyell of the division of cardiology, University of British Columbia, Vancouver, and his associates.
The investigators analyzed data from the National Cardiovascular Data Registry and its CathPCI Registry, the largest clinical catheterization database in the country, to assess whether publication of the Occluded Artery Trial (OAT) in 2006 and the resulting change in clinical practice guidelines in 2007 succeeded in decreasing the inappropriate use of PCI. The randomized, controlled OAT, funded by the National Heart, Lung, and Blood Institute, concluded that PCI of totally occluded infarct-related arteries more than 24 hours after MI failed to reduce rates of mortality, reinfarction, and heart failure, and that its "small" beneficial effect on angina and quality of life was not durable.
The strength of the evidence in OAT compelled the American College of Cardiology/American Heart Association to update three sets of guidelines: those on unstable angina and non–ST-segment elevation MI, on ST-segment elevation MI, and on PCI.
The analysis by Dr. Deyell and his colleagues covered PCI performed in 896 U.S. hospitals in 11,083 patients before publication of the OAT findings, 7,838 patients after that publication but before the guidelines were revised, and 9,859 patients after the guidelines were revised.
There were no differences in rates of late PCI across these three intervals, they said (Arch. Intern. Med. 2011 July 11 [doi:10.1001/archinternmed.2011.315]).
Rates of late PCI also did not decline in any of the subgroups of patients studied, regardless of the presence of heart failure symptoms at presentation, the type of insurance, the geographical region, the type of hospital, or whether patients had experienced STEMI or non-STEMI.
"PCI for total occlusions identified after MI among patients similar to those enrolled in the OAT continues to be performed in a considerable proportion of patients," the researchers said.
The reasons why the updated guidelines have not been incorporated into practice are unclear.
"Cardiologists and interventionalists have been quick to incorporate the results of positive clinical device trials and related guideline recommendations in the past, and to respond to trials reporting clinically significant safety concerns." However, OAT was a "negative" trial and "did not demonstrate excessive harm from PCI, apart from a trend toward increased reinfarction."
"Physicians may be less likely to alter their practice based on negative results, especially when there are important competing factors," they noted.
This study was supported by the American College of Cardiology Foundation’s National Cardiovascular Data Registry and the National Heart, Lung, and Blood Institute. No financial conflicts of interest were reported.