A novel approach for stratifying patients into one of two phenotypes for coronary artery disease (CAD) helped differentiate those who would benefit from percutaneous coronary intervention (PCI) from those who wouldn’t, researchers in Belgium reported in a subanalysis of a single-center, randomized clinical trial.
“What this study adds is that we are actually creating a refined definition of the appropriateness criteria for PCI,” lead study author Carlos Collet, MD, PhD, of the Cardiovascular Center at OLV Hospital in Aalst, Belgium, said in an interview. “We have been too long implanting stents in diffuse disease that actually have no benefit for the patient.”
The study found that patients with diffuse CAD were almost twice as likely to have residual angina 3 months after PCI than patients with focal CAD, with respective rates of 51.9% vs. 27.5% after PCI (P = .02).
The researchers analyzed 103 patients from the TARGET-FFR (Trial of Angiography vs. pressure-Ratio-Guided Enhancement Techniques–Fractional Flow Reserve) conducted at the Golden Jubilee National Hospital in Glasgow. Study patients completed the 7-item Seattle Angina Questionnaire at baseline and at 3 months after PCI, which provided the researchers information on outcomes.
The study,in JACC: Cardiovascular Interventions, used median pullback pressure gradient (PPG) to define focal and diffuse CAD. The operators used the PressureWire X Guidewire (Abbott Vascular) to measure fractional flow reserve (FFR).
The procedure involved administering a 200-mcg bolus of intracoronary nitrate and then positioning the pressure wire sensor at the tip of the guide catheter equalized with aortic pressure. The pressure wire was then advanced to the position sensor in the distal third of the vessel. After hyperemia was induced, coronary flow reserve was assessed using bolus thermodilution. Manual FFR pullback maneuvers were done at a constant speed for 20-30 seconds. The PPG index was calculated post hoc from the manual FFR pullback recordings obtained pre-PCI.
In this study, patients with low PPG needed longer (48 mm vs. 37 mm; P = .015) and more (1.5 vs. 1.0; P = .036) stents during PCI, Dr. Collet and colleagues reported. They concluded that patients with low PPG can be treated with medical therapy.
“The beauty of the PPG is that everything happens before you implant the stent,” Dr. Collet said. “We’re starting to understand that we cannot treat diffuse disease with a focal disease therapy.”
The challenge with differentiating diffuse from focal CAD has been that it relies on visual assessment. “It’s subject to operator variability, and that’s the reason why there are no trials with focal or diffuse disease specifically because, until now, we didn’t have any metric that quantified the diffuseness or the focality of the disease,” Dr. Collet said.
The PPG itself isn’t novel, Dr. Collet said. “The novelty is that for first time we can quantify in a reproducible way the information from the pullback,” he added.
“What this study tells us is that once you have a patient with diffuse coronary artery disease, don’t try PCI because it will not help half of them,” Patrick W. Serruys, MD, PhD, a cardiologist at the National University of Ireland, Galway, and author of the, said in an interview.
He noted that one limitation of the study was that Dr. Collet and colleagues used mechanical PPG to measure the pressure gradient. “We use now a surrogate, which is angiography,” Dr. Serruys said. “It’s not exactly the same as a measurement of pressure with the pressure wire, but we know from many, many studies that it’s quite a good surrogate.” Future research should focus on use of angiography without the pressure wire to evaluate the pressure gradient.
The ongoing PPG Global registry will aim to further validate findings from the subanalysis, Dr. Collet said, and the PPG Primetime study will evaluate deferring PCI in patients with low PPG.
Dr. Collet disclosed relationships with Biosensor, Coroventis Research, Medis Medical Imaging, Pie Medical Imaging, CathWorks, Boston Scientific, Siemens, HeartFlow, OpSens, Abbott Vascular and Philips Volcano. Dr. Serruys disclosed relationships with Sinomedical Sciences Technology, Sahajanand Medical Technological, Philips Volcano, Xeltis and HeartFlow.