Author + information
- Nina van der Hoeven1,
- Guus de Waard1,
- Alicia Quirós2,
- Alfonso de Hoyos2,
- Sukhjinder Nijjer3,
- Tim van de Hoef4,
- Ricardo Petraco5,
- Roel Driessen6,
- Hernan Mejia-Renteria7,
- Martijn Meuwissen8,
- Paul Knaapen9,
- Jan Piek10,
- Justin Davies3,
- Niels van Royen11 and
- Javier Escaned12
- 1VU University Medical Centre, Amsterdam, Netherlands
- 2Hospital Clínico San Carlos and Universidad Complutense de Madrid, Madrid, Spain
- 3Imperial College London, London, United Kingdom
- 4Academic Medical Center - University of Amsterdam, Amsterdam, Netherlands
- 5Hammersmith Hospital, Imperial College Healthcare NHS Trust, London, United Kingdom
- 6Baylor Heart and Vascular Hospital, Dallas, Texas, Amsterdam, Netherlands
- 7Hospital Universitario Clinico San Carlos, Madrid, Spain
- 8Breda Amphia Ziekenhuis, Breda, Netherlands
- 9VU University Medical Center, Amsterdam, Netherlands
- 10Academic Medical Center, University of Amsterdam, Amsterdam, Netherlands
- 11Radboud University, Nijmegen, Netherlands
- 12Hospital Clínico San Carlos, Madrid, Spain
Invasive assessment of the coronary circulation has been largely based on the use of pressure ratios (epicardial-) and resistance (micro-vessels). Simultaneous assessment of epicardial- (CEPI) and microvascular conductance (CMICRO), might provide a more coherent (same units for both compartments) and intuitive (expressing deliverability of blood) approach.
Validation of this new approach was performed in a total of 403 both obstructive and non-obstructive coronary vessels interrogated with intracoronary Doppler and pressure in 261 patients with stable angina pectoris. Hyperaemic mid-late diastolic pressure and flow velocity (PV) relationships were calculated from PV loops using an automated algorithm. The slope of the linear PV relationship was first calculated from both aortic and intracoronary pressures and, subsequently, used to derive separately CEPI , CMICRO and zero-flow pressure (Pfz).
Median CEPI and CMICRO were 4.56 (IQR 2.18 – 8.64) and 1.28 (IQR 0.95-1.73) cm/s/mmHg respectively. Concordance in stenosis severity classification of two validated indices of stenosis severity (FFR and hyperemic stenosis resistance) was used as a robust reference standard to validate CEPI. ROC curves demonstrated an excellent ability of CEPI to characterize significant epicardial stenoses indicating a cutoff of 1.69 (AUC 0.93) with a sensitivity of 93% and a specificity of 82%. Validation of CMICRO (previously reported in endomyocardial biopsies) was not feasible in this population given the lack of a reference standard. Mean Pzf was 29.89±14.16 mmHg.
A comprehensive assessment of the coronary circulation, based on separate calculation of epicardial- and microcirculatory conductance, is feasible and provides a clear, coherent depiction of coronary haemodynamics in ischaemic heart disease. As part of this novel approach, calculation of zero flow pressure (an index of extravascular compression) can also be performed. The findings should foster the development of simple, reliable methods for its calculation in the clinical arena.
IMAGING: FFR and Physiologic Lesion Assessment