PLATFORM: More Than 60% of Planned Catheterizations Cancelled When CT-Derived FFR Guides Care

LONDON, England—Fractional flow reserve measured by CT angiography (FFR_CT) has the potential to cut the need for invasive testing of symptomatic, intermediate-risk patients with suspected CAD by more than half, according to results of the PLATFORM study. Presented September 1, 2015, at the European Society of Cardiology Congress and simultaneously published in the European Heart Journal, the study showed that using the strategy first— instead of recommended angiograms—ruled out obstructive disease without raising safety concerns.

The strategy “was safe and improved patient selection for invasive catheterization,” said Pamela S. Douglas, MD, of Duke Clinical Research Institute (Durham, NC).

In PLATFORM, researchers led by Pamela S. Douglas, MD, of the Duke Clinical Research Institute, examined the use of FFR_CT guidance in 584 patients (mean age 60.9 years; 39.6% women) with new-onset chest pain, no prior history of CAD, and an intermediate pretest likelihood of obstructive CAD who were treated at 11 European sites and Duke Clinical Research Institute between September 2013 and November 2014.

The nonrandomized study included 2 cohorts of patients—a planned noninvasive testing group (n = 204) and a planned catheterization group (n = 380). Each cohort was further subdivided into 2 groups and assigned to usual care or FFR_CT. Optimal medical therapy was encouraged in all groups, and local physicians made all subsequent clinical decisions following standard practice.

Low Rate of Obstructive Disease

At 90 days, there were high rates of finding no obstructive disease at invasive catheterization by core lab assessment in both the planned noninvasive and planned invasive groups, which were slightly lower on visual readings vs core lab assessment. Similar results were found across subgroups. Radiation exposure was lower with usual care in the planned noninvasive group, but not in the planned invasive group (table 1).

 

Rates of MACE and vascular complications were too low to assess. There were no differences in revascularization rates among patients allocated to CT angiography/FFR_CT vs usual care in either the planned noninvasive (P = .29) or planned invasive (P = .58) groups.

Invasive procedures were cancelled in 61% of patients after physicians received the CT angiography/FFR_CT results.

Improving on Imaging

In a press conference, Dr. Douglas said numerous large trials have found extremely high rates of no obstructive disease at angiography in this patient population, making it an important quality-care issue to address.

“If there’s a way to find a technique that increases [accuracy of diagnosis] and decreases the rate of unnecessary procedures and is safe and efficient, then I would say that would be something that would be very welcome,” she added.

Although 2 recent trials—PROMISE and SCOT-HEART—support the notion that CT angiography can improve diagnostic assessment by appropriately altering planned investigations and treatment options, Dr. Douglas said FFR_CT  improves upon this by providing combined functional and anatomic data.

Asked about long-term sequelae in those who had cancelled tests, Dr. Douglas said there were no adverse events out to 90 days, and noted that follow-up is planned to continue for 12 months.

“It’s certainly something new for many of us,” commented Patrick W. Serruys, MD, PhD, of Erasmus Medical Center (Rotterdam, the Netherlands), adding that “we have to see how the community is going to adopt [it].”

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Source:
Douglas PS, Pontone G, Hlatky MA, et al. Clinical outcomes of fractional flow reserve by computed tomographic angiography-guided diagnostic strategies vs. usual care in patients with suspected coronary artery disease: the prospective longitudinal trial of FFRct: outcome and resource impacts study. Eur Heart J. 2015;Epub ahead of print.

Disclosures:

• The study was sponsored by HeartFlow.
• Dr. Douglas reports having research contracts with HeartFlow. 

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