title: Pulse transmission coefficient: a novel nonhyperemic parameter for assessing the physiological significance of coronary artery stenoses.
abstract: OBJECTIVE
  We sought to test the hypothesis that the pulse transmission coefficient (PTC) can serve as a nonhyperemic physiologic marker for the severity of coronary artery stenosis in humans.
  
  
  BACKGROUND
  Coronary lesions may impair the transmission of pressure waves across a stenosis, potentially acting as a low-pass filter. The PTC is a novel nonhyperemic parameter that calculates the transmission of high-frequency components of the pressure signal through a stenosis. Thus, it may reflect the severity of the coronary artery stenosis. This study was designed to examine the correlation between PTC and fractional flow reserve (FFR) in patients with coronary artery disease.
  
  
  METHODS
  Pressure signals were obtained by pressure guidewire in 56 lesions (49 patients) in the nonhyperemic state and were analyzed with a new algorithm that identifies the high-frequency components in the pressure signal. The PTC was calculated as the ratio between the distal and proximal high-frequency components of the pressure waveform across the lesion. The FFR measurements were assessed with intracoronary adenosine.
  
  
  RESULTS
  There was a significant correlation between PTC and FFR (r = 0.81, p < 0.001). By using a receiver operating characteristic analysis, we identified a PTC < 0.60 (sensitivity 100%, specificity 98%) to be the optimal cutoff value for predicting an FFR < 0.75.
  
  
  CONCLUSIONS
  Pulse transmission coefficient is a novel nonhyperemic parameter for the physiologic assessment of coronary artery stenoses. It correlates significantly with FFR and may predict an FFR < 0.75 with high accuracy. Pulse transmission coefficient may be useful as an adjunct measurement to FFR, especially in patients with microcirculatory disease and impaired maximal hyperemia.
authors.affiliation: Center for Coronary Physiology and Imaging, Cardiovascular Division, Mayo Clinic Foundation, Rochester, Minnesota 55902, USA.
authors.forename: David
authors.initials: D
authors.lastname: Brosh
authors.forename: Stuart T
authors.initials: ST
authors.lastname: Higano
authors.forename: Marvin J
authors.initials: MJ
authors.lastname: Slepian
authors.forename: Hylton I
authors.initials: HI
authors.lastname: Miller
authors.forename: Morton J
authors.initials: MJ
authors.lastname: Kern
authors.forename: Ryan J
authors.initials: RJ
authors.lastname: Lennon
authors.forename: David R
authors.initials: DR
authors.lastname: Holmes
authors.forename: Amir
authors.initials: A
authors.lastname: Lerman
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001783:Blood Flow Velocity / Q000502:physiology; D017023:Coronary Angiography; D023921:Coronary Stenosis / Q000000981:diagnostic imaging / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D011674:Pulse; D012372:ROC Curve; D012720:Severity of Illness Index; D013223:Statistics as Topic