Adjunctive Diagnostics in the Cath Lab: Will Value-based Economics Tip the Scale?

Why has the uptake of adjunctive diagnostic procedures like FFR, IVUS and OCT been slow? On the other hand, is there really a need for interventionalists to move beyond angiographic guidance?

During a press conference at last fall’s Transcatheter Cardiovascular Therapeutics (TCT.16) meeting in Washington, D.C., moderator Ajay Kirtane, MD, SM, associate professor of medicine at Columbia University Medical Center, asked the assembled panel of experts a personal and pointed question: Would they want imaging performed if they were having a stent implanted? Hands shot up, signaling yes, they would want their own PCI to be guided by adjunctive tests.

That display of unanimity was meant as a vote of confidence in a forum where attendees were learning the results of the first three-way comparison between IVUS (intravascular ultrasound), OCT (optimal coherence tomography) and angiography. The ILUMIEN III: OPTIMIZE PCI trial, published simultaneously in the Lancet (2016;388[10060]:2618-28), showed that OCT was able to detect malapposition and major dissection missed by IVUS. But the study was far from a game-changer since it otherwise failed to produce the kind of results that might convince physicians who rely solely on angiography to make the leap to newer high-resolution modalities.

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Other studies, however, have painted a much clearer picture of the value of advanced imaging techniques and physiological assessment. DEFINE-FLAIR and IFR-SWEDEHEART, for example, recently found that iFR (instantaneous wave-free ratio) provides clinical benefits similar to FFR without the major side effects, including discomfort, chest pain and shortness of breath. The two studies, published in the New England Journal of Medicine in May (376[19]:1824-34 and 376[19]:1813-23) and presented at the American College of Cardiology (ACC) Scientific Session in Washington, D.C., this past March, were the first to assess how using iFR—which, unlike FFR, measures pressure in the coronary artery when the heart is relaxed and a vasodilator is, therefore, not necessary—affects patient outcomes. DEFINE-FLAIR found that patient- and physician-reported symptoms of adverse events occurred in 3 percent of iFR patients compared to nearly 31 percent of FFR patients, while IFR-SWEDEHEART reported that 3 percent of iFR patients experienced discomfort (based on a post-procedure questionnaire) compared to 68 percent of FFR patients.

IVUS also has been on the receiving end of positive data. In 2011, PROSPECT (Providing Regional Observations to Study Predictors of Events in the Coronary Tree) found that vulnerable plaques that are likely culprits for future adverse cardiovascular events can be identified months to years before they occur through a combination of imaging modalities based on IVUS (N Engl J Med 2011;364[3]:226-35). Furthermore, ADAPT-DES (Assessment of Dual Antiplatelet Therapy with Drug-Eluting Stents) showed that IVUS compared to angiography guidance was associated with reduced rates of stent thrombosis, myocardial infarction and major adverse cardiac events within one year of drug-eluting stent implantation (Circulation 2014;129[4]:463-70).

The accumulation of clinical evidence in recent years has only served to heighten the conundrum of why advanced imaging modalities are underused in today’s catheterizations.

Data from the National Cardiovascular Data Registry (NCDR) show that FFR evaluation was used for only 6.1 percent of intermediate coronary lesions and IVUS for 20.3 percent (see figure on page 23) (J Am Coll Cardiol 2012;60[22]:2335-42). Use of OCT is believed to be even lower as angiography continues to reign as the lab workhorse. Kirtane frames the utilization question this way: “Why are interventional cardiologists using angiography alone—basically circa 1995 standard of care—when in 2017 they can be using all the adjunctive tools we have to take better care of the patient?”

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Resistance to change

The answers are diverse and complex, reaching beyond clinical evidence, practice guidelines, even cost and time constraints. They’re often rooted in cultural and generational issues, personalities and preferences. In simple terms, many interventional cardiologists have been taking pictures for years the old way and aren’t interested in change.

“I think angiographers who are over the age of 55 or 60 are somewhat resistant [to adjunctive technologies] vs. those who are younger and more interested in using it,” says Lloyd Klein, MD, professor of medicine at Rush Medical College in Chicago and senior author of the Society for Cardiovascular Angiography and Interventions (SCAI) expert consensus statement on the use of FFR, IVUS and OCT (Catheter Cardiovasc Interv 2014;83[4]:509-18). But Klein feels the decision may also be “philosophical,” irrespective of age. “At what level of visualization of the stenosis are you comfortable saying, ‘I know what the severity is without an adjunct test?’” he asks. Based on his own observations, “most angiographers think that most of the time they can assess the lesion severity without resorting to these extra procedures.”

Beyond physician bias, institutional size can be instrumental in determining which imaging tools are routinely deployed. Ralph Brindis, MD, MPH, clinical professor of medicine at the University of California, San Francisco, and a past president of the ACC, points out that large academic medical centers are typically more receptive to modalities like IVUS, OCT and FFR as part of their training regimens. During his previous travels as a consultant for Stanford University’s Center for Clinical Excellence he noticed “a marked variation in the enthusiasm for these technologies” among other labs, particularly in smaller hospitals and rural areas where resources are more limited.

There’s also the fact that while newer technologies can add value to patient diagnosis and treatment, they also can measurably impact time and cost of any procedure. As labs are well aware, imaging can add between five and 20 minutes to a baseline angiogram, depending on the skills and experience of the operator. And for a host of reasons—including the pressing need for continuous lab throughput and concern for patient comfort and radiation exposure—labs are often loathe to commit to that additional time. As for cost, interventionalists estimate that IVUS and OCT (and to a lesser degree FFR) can add about $700 to the cost of an angiogram just to cover catheters and help defray the capital cost of equipment.

Still, a growing number of clinical studies suggest that when weighed against patient outcomes, the cost of adjunctive diagnostic procedures may be a sound economic investment over the longer term. For example, the FAME 1 (Fractional Flow Reserve versus Angiography for Mulivessel Evaluation) trial found that FFR-guided PCI led to improved clinical outcomes at lower cost (by $2,000 per patient at one year) than angiography-guided PCI (JACC Cardiovasc Interv 2011;[11]:1183-9). And FAME 2 reported that while PCI performed with FFR had higher initial costs than a medical therapy strategy, the difference in cost was cut by more than half over one-year of follow-up. “PCI in the setting of an abnormal FFR appears to provide good value for the added cost,” the study authors observed, “with an ICER [incremental cost-effectiveness ratio] well below the standard willingness to pay threshold of $50,000 per QALY [quality adjusted life year]” (Circulation 2013;128[12]:1335-40).

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What will tip the scale?

In the end, economics could well coax coronary imaging off the dime. “As we move toward alternative payment models, bundled payments and accountable care organizations, the appropriateness of stenting is going to be further enhanced,” Brindis predicts. “And I believe that will further increase the need and the desire for interventional cardiologists and their hospital systems to use cath lab–based imaging.”

That thought is echoed by Mahboob Alam, MD, an interventional cardiologist at Baylor Heart Clinic in Houston, who has studied the role of intracoronary plaque imaging. “If an insurance company, for example, is going to bundle payments for procedures and everyone’s share is tied to outcomes, then there will be more emphasis on fine-tuning your work,” he says. “And that’s when IVUS and OCT will grow in use.” On a personal level, he says he relies on IVUS for between 30 and 40 percent of his PCIs. “If I have any questions or it’s a complex case, I know I have to use it. The fact is, it results in a better decision.”

Sums up Kirtane, cath lab director at New York Presbyterian/Columbia: “I don’t feel [adjunctive imaging] needs to be used in every case because there are some where it probably won’t modify what you decide to do. But as the disease gets more complex and restenosis rates get higher and/or it becomes less clear how to optimize your stent, then imaging can become a very useful adjunct.”