Author + information
- Received October 11, 2016
- Revision received November 28, 2016
- Accepted December 16, 2016
- Published online April 17, 2017.
- Tobias Härle, MDa,∗ (, )
- Mareike Luz, MDa,
- Sven Meyer, MD, PhDa,
- Kay Kronberg, MDa,
- Britta Nickau, MDb,
- Javier Escaned, MD, PhDc,
- Justin Davies, MD, PhDd and
- Albrecht Elsässer, MDa
- aDepartment of Cardiology, Klinikum Oldenburg, European Medical School Oldenburg-Groningen, Carl von Ossietzky University Oldenburg, Germany
- bDepartment of Diagnostic and Interventional Radiology, Klinikum Oldenburg, European Medical School Oldenburg-Groningen, Carl von Ossietzky University Oldenburg, Germany
- cCardiovascular Institute, Hospital Clinico San Carlos, Madrid, Spain
- dInternational Centre for Circulatory Health, National Heart and Lung Institute, Imperial College London, London, United Kingdom
- ↵∗Address for correspondence:
Dr. Tobias Härle, Klinikum Oldenburg, Department of Cardiology, Rahel-Straus-Strasse 10, 26133 Oldenburg, Germany.
Objectives The authors sought to analyze height differences within the coronary artery tree in patients in a supine position and to quantify the impact of hydrostatic pressure on intracoronary pressure measurements in vitro.
Background Although pressure equalization of the pressure sensor and the systemic pressure at the catheter tip is mandatory in intracoronary pressure measurements, subsequent measurements may be influenced by hydrostatic pressure related to the coronary anatomy in the supine position. Outlining and quantifying this phenomenon is important to interpret routine and pullback pressure measurements within the coronary tree.
Methods Coronary anatomy was analyzed in computed tomography angiographies of 70 patients to calculate height differences between the catheter tip and different coronary segments in the supine position. Using a dynamic pressure simulator, the effect of the expected hydrostatic pressure resulting from such height differences on indices stenosis severity was assessed.
Results In all patients, the left anterior and right posterior descending arteries are the highest points of the coronary tree with a mean height difference of −4.9 ± 1.6 cm and −3.8 ± 1.0 cm; whereas the circumflex artery and right posterolateral branches are the lowest points, with mean height differences of 3.9 ± 0.9 cm and 2.6 ± 1.6 cm compared with the according ostium. In vitro measurements demonstrated a correlation of the absolute pressure differences with height differences (r = 0.993; p < 0.0001) and the slope was 0.77 mm Hg/cm. The Pd/Pa ratio and instantaneous wave-free ratio correlated also with the height difference (fractional flow reserve r = 0.98; p < 0.0001; instantaneous wave-free ratio r = 0.97; p < 0.0001), but both were influenced by the systemic pressure level.
Conclusions Hydrostatic pressure variations resulting from normal coronary anatomy in a supine position influence intracoronary pressure measurements and may affect their interpretation during stenosis severity assessment.
The technical equipment for the dynamic pressure simulator was a loan from Volcano Corporation. Dr. Escaned has served as a consultant and a speaker at educational events for Philips Volcano and Boston Scientific. Dr. Davies is a consultant for Volcano Corporation; and holds licensed patents pertaining to the iFR technology. All other authors have reported that they have no relationships relevant to the contents of this paper to disclose.
- Received October 11, 2016.
- Revision received November 28, 2016.
- Accepted December 16, 2016.
- 2017 American College of Cardiology Foundation