BACKGROUND: Fractional flow reserve (FFR) uses pressure-based measurements to assess the severity of a coronary stenosis. Distal pressure (Pd) is often at a different vertical height to that of the proximal aortic pressure (Pa). The difference in pressure between Pd and Pa due to hydrostatic pressure, may impact FFR calculation. METHODS: One hundred computed tomography coronary angiographies were used to measure height differences between the coronary ostia and points in the coronary tree. Mean heights were used to calculate the hydrostatic pressure effect in each artery, using a correction factor of 0.8 mmHg/cm. This was tested in a simulation of intermediate coronary stenosis to give the "corrected FFR" (cFFR) and percentage of values, which crossed a threshold of 0.8. RESULTS: The mean height from coronary ostium to distal left anterior descending (LAD) was +5.26 cm, distal circumflex (Cx) -3.35 cm, distal right coronary artery-posterior left ventricular artery (RCA-PLV) -5.74 cm and distal RCA-posterior descending artery (PDA) +1.83 cm. For LAD, correction resulted in a mean change in FFR of +0.042, -0.027 in the Cx, -0.046 in the PLV and +0.015 in the PDA. Using 200 random FFR values between 0.75 and 0.85, the resulting cFFR crossed the clinical treatment threshold of 0.8 in 43% of LAD, 27% of Cx, 47% of PLV and 15% of PDA cases. CONCLUSIONS: There are significant vertical height differences between the distal artery (Pd) and its point of normalization (Pa). This is likely to have a modest effect on FFR, and correcting for this results in a proportion of values crossing treatment thresholds. Operators should be mindful of this phenomenon when interpreting FFR values.
BACKGROUND: Fractional flow reserve (FFR) uses pressure-based measurements to assess the severity of a coronary stenosis. Distal pressure (Pd) is often at a different vertical height to that of the proximal aortic pressure (Pa). The difference in pressure between Pd and Pa due to hydrostatic pressure, may impact FFR calculation. METHODS: One hundred computed tomography coronary angiographies were used to measure height differences between the coronary ostia and points in the coronary tree. Mean heights were used to calculate the hydrostatic pressure effect in each artery, using a correction factor of 0.8 mmHg/cm. This was tested in a simulation of intermediate coronary stenosis to give the "corrected FFR" (cFFR) and percentage of values, which crossed a threshold of 0.8. RESULTS: The mean height from coronary ostium to distal left anterior descending (LAD) was +5.26 cm, distal circumflex (Cx) -3.35 cm, distal right coronary artery-posterior left ventricular artery (RCA-PLV) -5.74 cm and distal RCA-posterior descending artery (PDA) +1.83 cm. For LAD, correction resulted in a mean change in FFR of +0.042, -0.027 in the Cx, -0.046 in the PLV and +0.015 in the PDA. Using 200 random FFR values between 0.75 and 0.85, the resulting cFFR crossed the clinical treatment threshold of 0.8 in 43% of LAD, 27% of Cx, 47% of PLV and 15% of PDA cases. CONCLUSIONS: There are significant vertical height differences between the distal artery (Pd) and its point of normalization (Pa). This is likely to have a modest effect on FFR, and correcting for this results in a proportion of values crossing treatment thresholds. Operators should be mindful of this phenomenon when interpreting FFR values.
Authors: Frederik M Zimmermann; Angela Ferrara; Nils P Johnson; Lokien X van Nunen; Javier Escaned; Per Albertsson; Raimund Erbel; Victor Legrand; Hyeong-Cheol Gwon; Wouter S Remkes; Pieter R Stella; Pepijn van Schaardenburgh; G Jan Willem Bech; Bernard De Bruyne; Nico H J Pijls Journal: Eur Heart J Date: 2015-09-23 Impact factor: 29.983
Authors: Nobuaki Kobayashi; Akiko Maehara; Sorin J Brener; Philippe Généreux; Bernhard Witzenbichler; Giulio Guagliumi; Jan Z Peruga; Roxana Mehran; Gary S Mintz; Gregg W Stone Journal: Am J Cardiol Date: 2015-09-11 Impact factor: 2.778
Authors: Tobias Härle; Mareike Luz; Sven Meyer; Felix Vahldiek; Pim van der Harst; Randy van Dijk; Daan Ties; Javier Escaned; Justin Davies; Albrecht Elsässer Journal: Clin Res Cardiol Date: 2017-11-02 Impact factor: 5.460
Authors: Panagiotis Xaplanteris; Stephane Fournier; Nico H J Pijls; William F Fearon; Emanuele Barbato; Pim A L Tonino; Thomas Engstrøm; Stefan Kääb; Jan-Henk Dambrink; Gilles Rioufol; Gabor G Toth; Zsolt Piroth; Nils Witt; Ole Fröbert; Petr Kala; Axel Linke; Nicola Jagic; Martin Mates; Kreton Mavromatis; Habib Samady; Anand Irimpen; Keith Oldroyd; Gianluca Campo; Martina Rothenbühler; Peter Jüni; Bernard De Bruyne Journal: N Engl J Med Date: 2018-05-22 Impact factor: 91.245
Authors: Justin E Davies; Zachary I Whinnett; Darrel P Francis; Charlotte H Manisty; Jazmin Aguado-Sierra; Keith Willson; Rodney A Foale; Iqbal S Malik; Alun D Hughes; Kim H Parker; Jamil Mayet Journal: Circulation Date: 2006-04-03 Impact factor: 29.690
Authors: Ricardo Petraco; Javier Escaned; Sayan Sen; Sukhjinder Nijjer; Kaleab N Asrress; Mauro Echavarria-Pinto; Tim Lockie; Muhammed Z Khawaja; Cecilia Cuevas; Nicolas Foin; Christopher Broyd; Rodney A Foale; Nearchos Hadjiloizou; Iqbal S Malik; Ghada W Mikhail; Amarjit Sethi; Raffi Kaprielian; Christopher S Baker; David Lefroy; Michael Bellamy; Mahmud Al-Bustami; Masood A Khan; Alun D Hughes; Darrel P Francis; Jamil Mayet; Carlo Di Mario; Simon Redwood; Justin E Davies Journal: EuroIntervention Date: 2013-05-20 Impact factor: 6.534
Authors: Sukhjinder S Nijjer; Guus A de Waard; Sayan Sen; Tim P van de Hoef; Ricardo Petraco; Mauro Echavarría-Pinto; Martijn A van Lavieren; Martijn Meuwissen; Ibrahim Danad; Paul Knaapen; Javier Escaned; Jan J Piek; Justin E Davies; Niels van Royen Journal: Eur Heart J Date: 2015-11-26 Impact factor: 29.983