Results of a recent web-based survey suggest that most interventional cardiologists rely on visual assessment alone when deciding whether to revascularize intermediate lesions in stable patients. This preference runs contrary to US and European guidelines that recommend using fractional flow reserve (FFR) to assess lesions of uncertain functional significance, note the authors of a report on the survey outcomes, published online October 21, 2014, ahead of print in Circulation: Cardiovascular Interventions.

Overall, the survey findings highlight a “significant disconnect between evidence and the way interventional cardiologists practice,” they say.

Overall, 495 participants provided 4,421 lesion evaluations. Among a total of 3,597 visually estimated percent diameter stenoses, there was an absolute overestimation of 18% compared with the corresponding QCA values, with the most pronounced overestimation in the RCA (22%). Variability in results differed among vessels; the largest standard deviation was seen for the LAD (20%), intermediate for the LCX (15%), and smallest for the RCA (12%; P < .001 for paired comparisons).

Reliance on Visual Assessment Predominates

Most decisions (71%) regarding lesion significance were based solely on visual assessment; those that agreed with FFR (38%) slightly outweighed discordant decisions (34%). When an additional diagnostic tool was requested, FFR was chosen more often than any of the imaging modalities (21% vs 8%).

The higher the operator’s PCI volume, the more likely he or she was to select FFR to evaluate lesions of uncertain significance (P for trend = .041). Growing experience with imaging modalities also inclined operators to select FFR for lesion evaluation following both IVUS (P for trend < .001) and OCT (P for trend = .009), as did increasing experience with FFR (P for trend < .001). However, growing familiarity with IVUS or OCT did not translate into a trend toward more imaging, and increasing FFR experience reduced preference for imaging assessment (P for trend < .001).

Only a narrow majority (53%) of angiogram-based decisions agreed with FFR. Regardless of operator experience, PCI volume, and experience with FFR or imaging, concordance never exceeded 57% of all angiogram-based decisions. Agreement with FFR increased only with growing experience with the functional test (from 49% to 57%; P for trend = .001) or IVUS (from 50% to 55%; P for trend = .012).

On multivariable analysis, no single participant characteristic predicted a decision pattern or concordant decisions.

Among 252 respondents who provided the angiographic cutoff values they use when determining lesion significance, the majority (57.1%) selected 70%, although values ranged from 50% to 90%.

Visual Strategy Leads to Over- and Undertreatment

Overall, the survey “found that despite its known inaccuracy, interventional cardiologists are still very prone to make decisions about an intermediate stenosis purely on the basis of its angiographic appearance in almost three-quarters of all cases, even when noninvasive proof of ischemia is missing, and even when the use of additional invasive diagnostic tools is not restricted by financial limitations,” the authors say.

They note that translated into real life, “these practice habits might lead to unnecessary stenting or inappropriate deferral in about a third of all cases.”

Prior research has suggested several possible explanations for the failure of clinicians to adhere to guidelines, including lack of awareness of or agreement with them or simple inertia, Dr. Wijns and colleagues point out. Interestingly, they add, external factors seem to play only a marginal role.

‘A Huge Wake-up Call’

In a telephone interview with TCTMD, John A. Spertus, MD, MPH, of St. Luke’s Mid America Heart Institute (Kansas City, MO), said although online surveys have limitations, the current findings provide important insight into interventionalists’ thinking.

“The vast majority still rely on the gestalt of looking visually at an angiogram, but [the test’s results] are all over the map,” he observed. “That variability is why a lot of times interventional procedures aren’t as beneficial as they ought to be.”

Dr. Spertus continued, “This should be a huge wake-up call to the interventional community that they need to create a systematic strategy for evaluating intermediate lesions and ensuring consistency of interpretation across doctors [because the current situation] is a major threat to the quality of care.”

He attributed the reluctance of clinicians to adopt FFR to the fact that they often have tremendous confidence in their ability to read angiograms. “It’s the bread and butter of being an interventionalist,” Dr. Spertus commented, adding that the absence of feedback on judgment calls tends to enable this overconfidence. “If you think an angiogram shows an 80% stenosis and you dilate it, for all intents and purposes, you’re absolutely correct. I think that’s a real problem.”

But changing physician practice is very difficult, he observed, as “it requires a major commitment by the leaders of the profession. They have to teach essentially a new skill set to thousands of interventional cardiologists.”

Dr. Spertus predicted growing use of FFR “as we create economic incentives to be more judicious. We need to think about building quality-assessment programs. If doctors were held accountable for their misreads [of angiograms], I think they would quickly change their practice.”

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Source:
Toth GG, Toth B, Johnson NP, et al. Revascularization decisions in patients with stable angina and intermediate lesions: results of the International Survey on Interventional Strategy. Circ Cardiovasc Interv. 2014;Epub ahead of print.

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