PCI Tools Provide Guidance for the Gray Zone

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Interventional cardiologists are under the gun to ensure that only patients who will benefit from PCI undergo the procedure. But strict adherence to appropriate use criteria could actually harm patients who don't fall within categories used to define the criteria. Tools, such as fractional flow reserve (FFR), intravascular ultrasound (IVUS) and optical coherence tomography (OCT), won't eliminate what cardiologists term the gray zone—those ambiguous cases that fall between appropriate and not—but they may provide evidence to help clinicians use good judgment.

Appropriate use pros & cons

For interventional cardiologists, appropriate use criteria may be a mixed blessing. On one hand, the appropriate use criteria (AUC) spelled out by the American College of Cardiology (ACC) Foundation Criteria Task Force in 2009 (J Am Coll Cardiol 2009;53[6]530-553) showed a good-faith effort by the cardiology community to proactively ensure quality care for patients at a time when overuse of PCI was making nationwide headlines. On the other hand, the guidelines do not represent the spectrum of patients seen in clinical practice, sometimes putting clinicians who handle complex cases at odds with benchmarks that some suggest are imperfect and outdated.

"It is never as simple as to establish these criteria to determine whether a procedure is appropriate or not," says Craig A. Thompson, MD, an interventional cardiologist at Yale University Medical Center in New Haven, Conn. "There is some black and white, but there is a big gray scale where one needs to be permissive. If you are too strict then all of sudden you could be detrimental to patient care."

Some decision-making and assessment tools have gained traction in the past decade that may help interventionists navigate the gray. Cardiologists can apply FFR and IVUS, for instance, to assess lesions and determine whether or not to intervene. If they decide to proceed with PCI, they can use the imaging capabilities of IVUS or OCT to select stent size and ensure the stent is properly implanted. Personal preference and experience seem to be driving the adoption of these technologies, which could improve patient outcomes and contain costs. But need, skill and good clinical judgment must align to achieve maximum value.

"Certainly these technologies are going to have a role in improving quality of care and some may create benchmarks that will be rolled into appropriateness and decision-making," says Thompson. He adds that no one test will definitively categorize a procedure as appropriate but the tools will add value if they are applied judiciously and their results are interpreted correctly. "The more quality information that informs the decision matrix, the better off a physician will be. At a minimum, the standard of care and process of care will be improved with these technologies."

Eliminating inappropriateness

In-stent restenosis with dissection: OCT provides high-resolution tissue characterization. Source: St. Jude Medical

The evidence-based AUC are designed to ensure that the literature is used efficiently to provide quality care. They are intended to assist but not supplant clinical decision-making, the AUC authors wrote, and are not a surrogate for experience and judgment.

In a landmark study on PCI appropriate use, Paul S. Chan, MD, a cardiologist at Saint Luke's Mid America Heart and Vascular Institute in Kansas City, Mo., and colleagues found that 98.6 percent of PCIs for acute MIs were deemed appropriate, while almost 12 percent of procedures performed on non-acute patients were classified as inappropriate. The study applied the appropriate use criteria to 500,154 PCIs submitted to the ACC's National Cardiovascular Data Registry between July 1, 2009, and Sept. 30, 2010 (JAMA 2011;306[1]53-61).

Chan says that the appropriateness rate could be improved but there always will be exceptions. "There are situations where the AUC would deem a procedure as inappropriate or uncertain but, in fact, for a particular patient, it may be very appropriate to perform the intervention," Chan says. Conversely, he envisions scenarios where PCI would be inappropriate although it meets the appropriateness standard.

"Clinical decision-making can't be cookie cutter," he emphasizes. "That is why the inappropriate rates are never expected to be 0 percent, and in many ways, they shouldn't be 0 percent because it then removes the clinician from the loop of clinical judgment."

FFR as a decision-making