Most cardiologists who participated in an international web survey used angiography results to assess intermediate stenoses over requesting fractional flow reserve (FFR) measurements or other techniques, contrary to guidelines. This was the case even when resources were not an obstacle.
European and American guidelines both highly recommend FFR when assessing intermediate stenoses for revascularization. To evaluate the adoption of the recommendations, Gabor G. Toth, MD, of the OLV-Ziekenhuis Cardiovascular Research Center in Aalst, Belgium, and colleagues conducted the International Survey on Interventional Strategy. They published results from the survey online Oct. 21 in Circulation: Cardiovascular Interventions.
The online survey consisted of two parts. First, a questionnaire assessed physician’s own professional experience in interventional cardiology, annual PCI volume, and time spent with quantitative coronary angiography (QCA), FFR, intravascular ultrasound (IVUS) and optical coherence tomography (OCT). Secondly, physicians were asked to review five patient case coronary angiograms with 12 stenoses each and respond on how they evaluated each stenosis.
In each case, FFR and QCA were already known for each stenosis, and those used were ordered randomly without pattern for difficulty.
Using initial angiographic images, physicians were asked to indicate relevant stenosis, define percent diameter stenosis, and determine how significant stenosis was. If they were uncertain based on the given image, they were asked to select the cath lab tool results they needed to aid decision-making: QCA, IVUS, OCT or FFR using best clinical practices in the virtual world.
Physicians had access to the web portal between October 2012 and May 2013.
Only 59 percent of all respondents completed all five cases. They found that 71 percent of decisions were made by visual assessment only. Of those, 53 percent of purely visual decisions were concordant with FFR and 47 percent were not.
Twenty-seven percent of respondents did not request FFR at all through the course of the survey.
FFR was requested most frequently in the remainder of cases, when physicians felt they could not adequately assess stenosis based on angiography (21 percent). QCA, IVUS and OCT combined were requested in 8 percent of cases.
Operators had increased frequency of FFR requests the more their PCI volume increased, even when they had a higher level of experience with imaging tools. Still, Toth et al found that no physician requested FFR in all cases as would have been expected based on the guidelines.
"When using visual estimation, as expected, marked interobserver variability and notable overestimation of visual %DS [percent diameter of stenosis] were found as compared with QCA. Surprisingly, different cutoff values for angiographic significance were applied among participants, further contributing to inconsistencies of angiogram-guided strategies,” Toth et al wrote.
Toth et al noted that angiogram-based decisions were largely discordant (47 percent), falsely significant (30 percent) or falsely nonsignificant (17 percent) in all cases with FFR value. “These results underline the profound diagnostic instability of decisions merely based on visual estimates of stenosis severity, meaning that inadequate treatment might follow in a large proportion of cases.”
They wrote, “When translated in real life, these practice habits might lead to unnecessary stenting or inappropriate deferral in about a third of all cases.”