The use of a fiber-optic pressure wire for physiologic assessment yielded discordance between two measures, diastolic pressure ratio (dPR) and fractional flow reserve (FFR) similar to that with piezo-electric sensors, a new study shows. Mario Sadaba, MD, of Hospital de Galdakao, Spain, reported these findings during a Featured Clinical Science presentation Sunday at Cardiovascular Research Technologies (CRT) 2023 in Washington, D.C. When evidence of ischemia is not available in the setting of intermediate-grade stenosis, European guidelines recommend instantaneous wave-free ratio or FFR to measure hemodynamic relevance. Piezo-electric sensors require electric contact that is more susceptible to moisture, such as saline or blood. It is critical to align the electrical contacts alignment to obtain accurate measurements. By contrast, fiber-optic sensors are not affected by changes in temperature, saline or blood, and they have a simple and reliable connection. READI EPIC-14 was a prospective, observational, multicenter study in patients with intermediate angiographic stenosis (>50%) to whom a functional assessment is performed with a fiber-optic pressure wire. Two consecutive dPR measurements (with cutoff point of 0.89) and FFR (cutoff point of 0.80) were performed in each stenosis. Clinical and anatomical variables related to discordance between FFR and dPR were analyzed. The study enrolled 361 patients from 13 centers with 428 stenoses. At baseline, the patients’ mean age was 65.8 years, 76.9% were male, 63.3% had hypertension, 64% had hypercholesterolemia, and 30.5% had a previous acute coronary syndrome (ACS). Nearly half (45.8%) presented with chest pain and 23.1% with ACS. The mean dPR reading was 0.90 ± 0.08, and the mean FFR value was 0.83 ± 0.08. dPR was positive 31.7% of the time, and FFR was positive 29.4% of the time. Most of the lesions assessed were left main or left anterior descending artery (63%), with the remainder being right coronary artery (20%) and left circumflex (16%). The discordance between dPR and FFR was 72%. Sadaba concluded that FFR and dPR discordance with a fiber optic pressure wire remained similar to previous studies with piezo-electric pressure wire and largely depended on how close the values were to the borderline value. “As myocardial ischemia is not a dichotomic value, when discordance occurs or FFR/dPR value [is] close to the cutoff point, we should consider other factors [such] as symptoms, stress test and coronary anatomy to provide the best treatment to the patient,” Sadaba said. Image Credit: Jason Wermers/CRTonline.org