SAN FRANCISCO—Would interventional cardiologists be more amenable to incorporating tools for assessing coronary stenosis before performing PCI or CABG if they could ditch the use of vasodilator drugs? Results from the ADVISE II registry trial presented Oct. 30 at the Transcatheter Cardiovascular Therapeutics (TCT) conference in San Francisco may nudge them in that direction.
FAME (Fractional Flow Reserve vs. Angiography in Multivessel Evaluation) established the value of fractional flow reserve (FFR) as a tool for assessing ischemia-causing lesions in coronary vessels. But FFR requires administration of vasodilator drugs such as adenosine, which has drawbacks. Some patients don’t tolerate adenosine well, for instance, and some physicians find the FFR process cumbersome, time consuming and an add-on cost.
In an effort to overcome barriers that hamper the adoption of assessment strategies, researchers have developed several options, including instantaneous wave-free ratio (iFR). “iFr constitutes a recently introduced index. It is a pressure-derived index like FFR,” Javier Escaned, MD, PhD, of Hospital Clinico San Carlos in Madrid, Spain, explained at a press conference. “The difference is that with iFR you do not require adenosine to make an estimate of stenosis.”
ADVISE II (Adenosine Vasodilator Independent Stenosis Evaluations) is a double-blind multicenter registry study that prospectively assessed iFR’s ability to characterize the severity of coronary stenosis determined with FFR. Researchers, led by Escaned, looked at iFR as a dichotomous index and as a hybrid iFR/FFR approach.
They enrolled 797 patients with 690 stenoses. Thirty-one percent of stenoses were associated with the FFR zone (between 0.86 and 0.93) and 69 percent in the iFR zone (cutoffs of 0.85 and less and 0.94 and more).
Of those in the iFR zone, 91.6 were properly classified for hemodynamic severity, which was the primary endpoint. The hybrid approach correctly classified 94.2 percent of coronary stenoses.
“Applying this particular approach, you will reduce drastically the need for adenosine,” he said. Using the hybrid approach would allow 69.1 percent of stenoses and 65.1 percent of the patients to be assessed without adenosine, the results showed.
Discussant James B. Hermiller Jr., MD, of St. Vincent Heart Center of Indiana in Carmel, Ind., said that giving adenosine in the catheterization laboratory is not overly time-consuming but he saw the advantages to iFR. “It will avoid giving adenosine, particularly if it is congruent with the course of the patient,” he said. “If you are uncertain, you might not trust this. But otherwise, the ability to not give adenosine in 65 percent of patients will improve flow through the lab, reduce cost and so I think it is something that will be employed.”
In an exclusive interview, Escaned said that iFR is not meant to supplant FFR. “By no means are we trying to propose that FFR should be substituted by iFR.” Rather, iFR is designed to simplify the process to increase adoption and benefit patients.
ADVISE II was funded by Volcano Corporation.