Pd/Pa identifies residual ischemia after PCI

LAS VEGAS — The ratio of mean coronary pressure to mean aortic pressure was accurate at diagnosing residual ischemia after PCI, according to findings presented at the Society for Cardiovascular Angiography and Interventions Scientific Sessions.

The ratio (Pd/Pa) can be measured with any pressure wire and works similarly to fractional flow reserve, but without the need for adenosine, Abdul Hakeem, MD, FACC, FSCAI, FASE, associate professor of medicine at Robert Wood Johnson Medical School of Rutgers University, said during a press conference.

“No non-hyperemic pressure ratio post-PCI has been validated or formally studied prospectively to guide clinical decision-making,” Hakeem said. “It is not known whether the comparative effectiveness of non-hyperemic pressure ratios compared with FFR is the same after PCI. Everyone has been using them because there is cost benefit and fewer patient side effects” compared with FFR.

Hakeem and colleagues analyzed a reference pre-PCI cohort (1,560 vessels from 1,255 patients), a derivation post-PCI cohort (655 vessels from 574 patients) and a prospective post-PCI validation cohort (255 vessels from 230 patients).

“About a third of patients have residual ischemia after successful PCI,” Hakeem said. “If you react to a suboptimal post-PCI FFR and pursue further intervention, you can improve the hemodynamic outcome of the PCI.”

Hakeem said there was a strong correlation between Pd/Pa and FFR after PCI, and the diagnostic performance of Pd/Pa with a cutoff value of 0.9 after PCI was good (area under the curve, 0.91; sensitivity, 76%; specificity, 92%).

“That means we are 91% certain that if we use a Pd/Pa cutoff value of less than or equal to 0.9, we will be able to correctly identify ischemic vs. nonischemic post-PCI lesions,” he said.

“Pd/Pa is universally available and we have demonstrated that it has better diagnostic performance than [instantaneous wave-free ratio], though this is not a head-to-head comparison.”

Pd/Pa illustrated the same degree of ischemic reduction after PCI as FFR did (FFR, from 0.69 before PCI to 0.84 after; P < .0001; Pd/Pa, from 0.86 before PCI to 0.94 after; P < .0001), Hakeem said.

“In the prospective cohort, about 34% of patients had persistent ischemia after angiographically successful PCI,” he said during the press conference. “The Pd/Pa threshold of less than 0.9 identified virtually all these patients. So Pd/Pa could be used as a replacement for post-PCI FFR.” – by Erik Swain

Reference:

Hakeem A, et al. Featured Clinical Research II. Presented at: Society for Cardiovascular Angiography and Interventions Scientific Sessions; May 19-22, 2019; Las Vegas.

Disclosure: Hakeem reports no relevant financial disclosures.