Feature | November 01, 2013

Study Demonstrates Accuracy of Noninvasive CT-FFR in Evaluating CAD Patients

CT FFR, HeartFlow

HeartFlow's CT-FFR software uses supercomputing algorithms to calculate the flow of blood through a lesion in part by tracking the speed of the CT iodine contrast.

CT FFR, HeartFlow

HeartFlow's CT-FFR software showing a coronary artery tree created from a CT scan showing the FFR for a lesion.

November 1, 2013 — Clinical trial results demonstrated that a noninvasive coronary computed tomography angiography (CTA)-based test accurately assesses coronary artery disease (CAD) with results closely matching those of invasively measured fractional flow reserve (FFR), and may inform potential revascularization treatment options, including angioplasty and coronary artery bypass surgery (CABG), better than current methods. The findings of the HeartFlowNXT trial were presented at the 25th annual Transcatheter Cardiovascular Therapeutics scientific symposium (TCT 2013).
Current guidelines for the management of stable CAD recommend non-invasive ischemia testing such as treadmill testing, single photon emission computed tomography (SPECT), stress echocardiography or cardiac magnetic resonance before invasive coronary angiography (ICA) or coronary revascularization is considered. An invasive test, FFR, is considered the gold standard for lesion-specific coronary revascularization decisions in patients with stable CAD. 
However, the current noninvasive testing options such as treadmill testing, SPECT and stress echocardiography correlate poorly to FFR, and thus selection of patients for invasive angiography and coronary revascularization is often inaccurate.
The HeartFlowNXT trial was a blinded, prospective core lab adjudicated trial that investigated FFR-CT, a new, noninvasive FFR calculation derived from CTA images and using high-performance computing to create a 3-D map of the coronary arteries showing locations of obstructions and FFR-CT values.
The primary study objective was to compare per-patient diagnostic performance of FFR-CT compared to coronary CTA alone for the diagnosis of at least one hemodynamically significant stenosis using direct measurement of FFR (? 0.8) as the reference standard. The trial also measured per-vessel and per-patient diagnostic accuracy, sensitivity and specificity as well as positive and negative predictive values of FFR-CT.
The prospective study enrolled 254 patients scheduled to undergo non-emergent clinically indicated invasive angiography due to suspected CAD. 
The FFR-CT data matched closely with invasively measured FFR. The area under the receiver operating characteristic curve (AUC) for FFR-CT (? 0.8) was 0.82 versus 0.63 for coronary CTA (p < 0.0001) with invasive FFR as the reference standard. Per-patient sensitivity and specificity were 86 percent and 79 percent for FFR-CT versus 94 percent and 34 percent for coronary CTA and 91 percent and 51 percent for invasive coronary angiography (lumen reduction > 50 percent).
“Fractional flow reserve non-invasively calculated from coronary CTA data sets matches closely with invasively measured FFR and allows for identification of patients with hemodynamically significant coronary lesions with good accuracy. When compared to both coronary CTA and ICA, FFR-CT led to a significant reduction in the proportion of false-positive results,” said Bjarne Nørgaard, M.D., Ph.D., Aarhaus University Hospital, Denmark and lead investigator of the study. “The addition of FFR-CT to coronary CTA allows for a comprehensive anatomic and functional assessment of coronary artery disease.”

Limits of the Current Technology

CT-FFR may one day eliminate the need to refer patients for diagnostic catheter angiographies. However, today, users of the HeartFlow technology say it requires sending the CT DICOM dataset to the company in California. It then takes the supercomputing power of the HeartFlow computer system about a day to process the data and render a report. While this may eliminate CT-FFR's use for acute chest pain patients, it offers an option for patients considering elective PCI. Coronary CT experts say computing speed and power doubles every couple years, which will eventually enable CT-FFR to be processed onsite in minutes, instead of days or hours. 

For more information: www.crf.org

Related Content

St. Jude Medical, ADO II AS trial, congenital heart disease, PDA, Amplatzer Duct Occluder II AS
News | Congenital Heart| October 19, 2016
St. Jude Medical Inc. announced the launch of the ADO II AS (AMPLATZER Duct Occluder II Additional Sizes) pediatric...
Lantheus, flurpiridaz F-18, myocardial perfusion imaging, MPI, cardiac stress testing, ASNC 2016
News | Radiopharmaceuticals and Tracers| October 17, 2016
Lantheus Holdings Inc. announced in late September that sub-analysis data from the first Phase 3 study of flurpiridaz F...
Medtronic, FIRE AND ICE trial, Arctic Front, cryoballoon catheter ablation, radiofrequency RF ablation, study results, Asia Pacific Heart Rhythm Society Scientific Sessions
News | Ablation Systems| October 17, 2016
Medtronic plc last week unveiled new health economic analysis data from the FIRE AND ICE trial that favor cryoballoon...
Toshiba CT, picking a CT scanner, choosing a CT scanner, CT 101, what to look for in CT scanners, Aquilion ONE ViSION

The Toshiba Aquilion One Vision system is among the new generation of CT systems on the market that offers several dose lowering technologies and a hardware/software combination to enhance image quality over previous-generation scanners.

Feature | CT Angiography (CTA)| October 14, 2016 | Dave Fornell
As hospitals begin replacing their first-generation 64-slice computed tomography (CT) scanners after a decade of use,
transcarotid artery revascularization, TCAR Surveillance Project, Society for Vascular Surgery Patient Safety Organization, SVS PSO,
News | Stents Carotid| October 13, 2016
A surveillance project to evaluate the safety and effectiveness of transcarotid artery revascularization (TCAR) in...
Shockwave lithoplasty system, VIVA 16, Vascular Interventioanl Advances, VIA Physicians, late-breaking endovascular clinical trial results
News | Cath Lab| October 12, 2016
VIVA (Vascular Interventional Advances) Physicians announced a number of highly anticipated late-breaking clinical...
ZipLine Medical, Zip Surgical Skin Closure, cath lab time savings, PACE study
News | EP Lab| October 10, 2016
October 10, 2016 — ZipLine Medical Inc.
Mercator MedSystems, Bullfrog Micro-Infusion Device, DANCE trial, VIVA 2016, 13-month results
News | Peripheral Arterial Disease (PAD)| October 07, 2016
Mercator MedSystems recently announced that 13-month data from the DANCE trial was presented during a late-breaking...
Keystone Heart, TriGuard Embolic Protection Device, Neuro-TAVR study, brain lesions, American Journal of Cardiology
News | Heart Valve Technology| October 03, 2016
Keystone Heart Ltd. announced data recently published in the American Journal of Cardiology demonstrating new brain...
TCT 2016, TCT.16, main arena, late breaking trials
Feature | Cath Lab| September 28, 2016
September 28, 2016 — The Cardiovascular Research Foundation (CRF) has announced the 11 late-breaking trials and 16 fi
Overlay Init