title: Wave speed in human coronary arteries is not influenced by microvascular vasodilation: implications for wave intensity analysis.
abstract: Wave intensity analysis and wave separation are powerful tools for interrogating coronary, myocardial and microvascular physiology. Wave speed is integral to these calculations and is usually estimated by the single-point technique (SPc), a feasible but as yet unvalidated approach in coronary vessels. We aimed to directly measure wave speed in human coronary arteries and assess the impact of adenosine and nitrate administration. In 14 patients, the transit time Δt between two pressure signals was measured in angiographically normal coronary arteries using a microcatheter equipped with two high-fidelity pressure sensors located Δs = 5 cm apart. Simultaneously, intracoronary pressure and flow velocity were measured with a dual-sensor wire to derive SPc. Actual wave speed was calculated as DNc = Δs/Δt. Hemodynamic signals were recorded at baseline and during adenosine-induced hyperemia, before and after nitroglycerin administration. The energy of separated wave intensity components was assessed using SPc and DNc. At baseline, DNc equaled SPc (15.9 ± 1.8 vs. 16.6 ± 1.5 m/s). Adenosine-induced hyperemia lowered SPc by 40 % (p < 0.005), while DNc remained unchanged, leading to marked differences in respective separated wave energies. Nitroglycerin did not affect DNc, whereas SPc transiently fell to 12.0 ± 1.2 m/s (p < 0.02). Human coronary wave speed is reliably estimated by SPc under resting conditions but not during adenosine-induced vasodilation. Since coronary wave speed is unaffected by microvascular dilation, the SPc estimate at rest can serve as surrogate for separating wave intensity signals obtained during hyperemia, thus greatly extending the scope of WIA to study coronary physiology in humans.
authors: Department of Biomedical Engineering and Physics, Academic Medical Center, University of Amsterdam, Meibergdreef 9, P.O. Box 2270, 1105 AZ, Amsterdam, The Netherlands.
authors: M Cristina
authors: MC
authors: Rolandi
authors: Kalpa
authors: K
authors: De Silva
authors: Matthew
authors: M
authors: Lumley
authors: Timothy P E
authors: TP
authors: Lockie
authors: Brian
authors: B
authors: Clapp
authors: Jos A E
authors: JA
authors: Spaan
authors: Divaka
authors: D
authors: Perera
authors: Maria
authors: M
authors: Siebes
mesh_terms: D000241:Adenosine / Q000008:administration & dosage; D000368:Aged; D060050:Angina, Stable / Q000503:physiopathology / Q000628:therapy; D003331:Coronary Vessels / Q000187:drug effects / Q000502:physiology*; D005260:Female; D006439:Hemodynamics / Q000187:drug effects / Q000502:physiology; D006801:Humans; D006940:Hyperemia / Q000139:chemically induced / Q000503:physiopathology; D008297:Male; D008833:Microcirculation / Q000187:drug effects / Q000502:physiology*; D008875:Middle Aged; D008955:Models, Cardiovascular; D005996:Nitroglycerin / Q000008:administration & dosage; D063177:Pulse Wave Analysis / Q000379:methods*; D014655:Vascular Resistance / Q000187:drug effects / Q000502:physiology; D014664:Vasodilation / Q000187:drug effects / Q000502:physiology*; D014665:Vasodilator Agents / Q000008:administration & dosage
chemical_list: D014665:Vasodilator Agents; D005996:Nitroglycerin; D000241:Adenosine