Pd/Pa = iFR, like °C = °F

“Pd/Pa seems to offer a universal resting physiological metric with equivalent agreement to iFR. Although not numerically identical, 1 index can be linearly transformed into the other, much like the conversion of units of temperature. Using the binary cutoff of iFR ≤0.89 as a reference standard, Pd/Pa showed excellent agreement according to ROC curve analysis and the best cutoff value of Pd/Pa was ≤0.91.”

Kobayashi Y, et al. JACC Oct 2017.

	Pd/Pa	iFR
Single Cutoff¹	≤0.91	≤0.89
Hybrid Algorithm^2,3	0.88-0.97	0.86-0.93
FDA-Cleared⁴	✔	✔
Inclusion in Appropriate Use Criteria^5,6	✔	✔
SCAI/ACC Reimbursement Recommendation⁷	✔	✔
Equivalent Correlation to FFR^8,9,10,11	✔	✔
Equivalent Correlation to CFR¹²	✔	✔
Results Integrate into All Major Hemodynamic Systems	✔	X
ECG-free Algorithm Widely Available¹³	✔	X
Workhorse Pressure Guidewire Available	✔	X