Shelley Wood

May 28, 2014

PARIS, FRANCE — There are more registry data to suggest that using a pressure wire to measure fractional flow reserve (FFR) will lead to a change in the planned treatment strategy in a large proportion of CAD patients undergoing coronary angiography.

In the POST-IT registry, physicians changed their choice of treatment following FFR in a full 44% of patients, according to Dr Sergio Baptista (Hospital Prof Fernando da Fonseca, Amadora, Portugal), who presented the results last week at EuroPCR 2014 .

The findings echo those of a smaller trial, RIPCORD , presented at last year's meeting, although the number of patients in POST-IT whose course of treatment was altered after FFR is almost twice as high as in the earlier study.

"Nowadays, most operators still believe that they know how a patient should be treated, because they are experienced, but in fact we know that CAD is a pretty good-prognosis disease, and probably most of the lesions we see could be left without treatment," Baptista said. "Using this technique, you can [determine] the lesions you shouldn't treat, and you can avoid implanting a stent that isn't needed, but that's not the approach for most interventionalists at this time."

And in fact, in POST-IT, the overall number of PCI procedures did not decline between the planned strategy and final, post-FFR strategy, but patients and lesions were treated differently from what was initially planned, Baptista said.

Early Results; More to Come

POST-IT is a prospective, national registry with 19 participating centers in Portugal enrolling 918 patients. The longer-term aim of the trial is to assess the overall impact of FFR-guided treatment in reducing major adverse cardiac events in this unselected patient population; those results are due out in late 2014.

For the current analysis, investigators looked only at planned and actual treatment strategy. For the entire cohort, 55.7% of patients were treated according to the initial plans of the physician, based on results from the initial coronary angiogram, prior to FFR.

In the remaining 44.3%, however, the treating physician altered the treatment plan after the FFR results were in:

  • Among 361 for whom a strategy of medical therapy was planned, 23% were instead sent for PCI and 4% were sent for CABG (73% were treated, as planned, with medical therapy).

  • Additional testing in the form of an imaging stress test was planned for 202 patients but scrapped after FFR, with 47% given medical therapy, 40% sent for PCI, and 13% treated with CABG.

  • PCI was planned for 319 patients, 72% of whom were subsequently treated as intended; however, 25% of these patients were instead treated medically and 3% were sent to surgery.

  • In 36 patients, planned CABG was ultimately performed in 56%, but 19% instead underwent PCI and the remaining 25% were treated medically.

Commenting on these results during a EuroPCR press conference, Dr Jean Fajadet (Clinique Pasteur, Toulouse, France) noted that these results can be appreciated in two ways.

"You could say, if you don't use FFR, your judgment will be wrong in 23%, 25%, or 40% of cases, but the reverse is, if you don't use FFR, you are right in the majority cases for selecting patients for medical therapy and for PCI. But for me, the big problem is the patients [planned] for surgery." With FFR, "close to half of the patients will avoid surgery . . . which is important for a patient," he said. "Surgery is an adventure."

Baptista said that in Portugal, as in most of Europe, FFR is not being used routinely. "That's something we must understand [better], because [physicians do not have enough information on most of their patients] when they get to the cath lab," he said. "This is one of the challenges we have for the future—to try to use the technology we have in the right way and fit it to the patient we have in front of us. . . . FFR, in my opinion, should be much more used."

Underused or Overembraced?

That's not the opinion of Dr Armin Zadeh (Johns Hopkins University School of Medicine, Baltimore, MD), who took aim at the whole concept of FFR-guided PCR in a "Controversies in Cardiovascular Medicine" paper in Circulation earlier this month. In it, Zadeh argues that the worldwide acceptance of FFR, among cardiologists, is based on flawed science—namely, the belief that cardiac-event risk is linked to provocable ischemia, rather than the presence and extent of atherosclerotic disease.

"The FAME study has been so enthusiastically embraced by the medical community that its fundamental validity has never been seriously questioned," Zadeh told heartwire . "A careful review of the FAME study reveals that the benefit of FFR is due to fewer PCIs and fewer associated periprocedural events—without evidence that the same effect could not have been provided with omitting PCIs without the aid of FFR."

What's more, he argued, FAME II confirmed the lack of reduced hard events with FFR-guided PCI vs medical therapy, "but yet the FFR paradigm lives on. What it comes down to is that we cannot lose sight of the mechanisms underlying risk from coronary artery disease. . . . We are in need [of] more fundamental discussions on what matters for patient outcome—ie, an ischemia- and/or atherosclerosis-guided approach."

With regards to the POST-IT registry results, Zadeh congratulated Baptista and colleagues "on their efforts to investigate the impact of FFR testing on clinical decision making in clinical practice," adding that it will be interesting to see how the altered decisions based on FFR testing affect patient outcome.

The larger question, he insists, is determining whether there really is any benefit from FFR assessment beyond rerouting certain patients away from a planned PCI and its associated risks.

Some answers may come from the ISCHEMIA trial, where, Baptista noted, FFR is being used to evaluate lesions that are less than 80% stenotic. "We know that ischemia patients have a worse prognosis than other patients," he noted. "We know ischemia matters, but we don't know if that lesion in particular should be treated."

The ISCHEMIA trial, he also observed, is struggling to complete enrollment. "That's probably happening because operators are not including patients, particularly the ones with the most severe ischemia, who are the ones that probably most should be included."

Baptista disclosed receiving institutional research support from St Jude Medical. Zadeh had no disclosures.

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