CT-Derived FFR Alters Angiography-Based Management Plans for Stable Angina
PARIS, France—The addition of CT-based FFR screening to angiography alone for measuring the functional significance of coronary lesions causes interventional cardiologists to change management plans for one-third of patients who present with chest pain, according to results of the FFRCT RIPCORD study presented May 19, 2015, at EuroPCR.
“If this novel proof-of-concept result can be confirmed in large-scale trials, this suggests that noninvasive FFRCT can be used as a clinically relevant tool that mimics the well-described ability of invasive FFR to refine management decisions for patients with chest pain that are made based upon [invasive coronary angiography] alone,” said presenter Nick Curzen, PhD, of University Hospital Southampton (Southampton, England).
For the original RIPCORD study, the use of invasive FFR changed the management plans for one-quarter of stable angina patients with suspected CAD. After FFR data became available, 12.5% of patients originally slated for medical management after diagnostic angiography were referred to revascularization and 28.1% were switched from revascularization to medical management.
In the current analysis, 3 interventional cardiologists were tasked with reviewing 200 consecutive cases of stable angina from patients enrolled in the NXT study of FFRCT. By consensus, they decided upon the degree of coronary stenosis and then assigned patients to 1 of 4 groups:
- Optimal medical therapy (OMT)
- PCI and OMT
- CABG and OMT
- More information required (meaning invasive FFR needed)
Then FFRCT data were made available and the physicians were asked to again identify significant vessels and maintain or update their management plans.
FFRCT Highlights ‘Mismatch’
Overall, management plans were altered in 36% of cases (table 1). Importantly, 18% of the vessels originally specified for PCI changed after FFRCT.
Specifically, 26.3% and 11.8% of patients originally in the more information and OMT groups, respectively, required revascularization. Furthermore, 29.8% of patients initially slated for PCI ended up in the OMT group after FFRCT evaluation.
Dr. Curzen said these results are consistent with the findings of invasive FFR in the original RIPCORD study, and that there is a substantial “mismatch” between CT-angiography assessment and the FFRCT-derived estimate of ischemia.
With further study, FFRCT could become the “default method for assessment of coronary anatomy and physiology in angina patients.”
Effect on Current Practice
In response to a question about how reliably FFRCT will be able to be performed at hospitals right now, Dr. Curzen said it is possible to integrate into current practice, “but I would like to see more data before I started using it clinically.
“What this study highlights is more the enormous potential for a test that could for a large group of patients be used as a primary screening tool because it provides not just the anatomy but an assessment of ischemia,” he continued. “The beauty of this if it’s further validated is that you could use it as a triage so a lot of people who end up in the cath lab wouldn’t.” Additionally, he noted, operators would know more precise information about those who do end up in the cath lab, minimizing time waste.
Panelist Chaim Lotan, MD, of the Heart Center at Hadassah Medical Center (Jerusalem, Israel), pointed out that most angina patients are not usually sent for CT, but are streamlined straight to angiogram. “CT is another procedure, [more] money, and we don’t want to give more radiation,” he said.
But, Dr. Curzen countered, “If you were a patient, would you want to go for an angiogram if you could have [a noninvasive test]?... In the real world, it’s often not desperately clear whether someone’s got classical angina or not,” and this test can help sift them out.
In an email with TCTMD, Jeffrey M. Schussler MD, of Cardiology Consultants of Texas (Dallas, TX), said, “It would be ideal if we had a safe, noninvasive test which evaluated for both the presence and severity of coronary disease in patients. This would reduce unnecessary invasive testing, and allow us to focus on performing PCI in those who would gain the most benefit.”
This study, he continued, “shows some promise in combining anatomic with functional noninvasive assessment of coronary stenoses. Larger studies are necessary, but this technique may be able to guide appropriate treatment plans for interventional vs medical strategies.”
Curzen N. The FFRCT RIPCORD study: does the routine availability of computed tomography (CT)-derived fractional flow reserve influence management strategy of patients with stable chest pain compared to CT angiography alone? Presented at: EuroPCR; May 19, 2015; Paris, France.
- FFRCT RIPCORD was funded by HeartFlow.
- Dr. Curzen reports receiving honoraria from HeartFlow, St. Jude Medical, and Volcano and institutional grant support from Boston Scientific, Haemonetics, HeartFlow, and Medtronic.