title: Effect of Inhaled Nitric Oxide on Blood Flow Dynamics in Patients After the Fontan Procedure Using Cardiovascular Magnetic Resonance Flow Measurements.
abstract: Invasive hemodynamic studies have shown that nitric oxide (NO), a selective pulmonary vasodilator, can lower pulmonary vascular resistance in Fontan patients. Because oximetry-derived flow quantification may be unreliable, we sought to detect changes in blood flow within the Fontan circulation after inhalation of NO using cardiovascular magnetic resonance (CMR). Thirty-three patients (mean age 12.8 ± 7.0 years) after the Fontan procedure underwent CMR as part of their routine clinical assessment. Standard two-dimensional blood flow measurements were performed in the Fontan tunnel, superior vena cava (SVC) and ascending aorta (AAO) before and after inhalation of 40 ppm NO for 8-10 min. Systemic-to-pulmonary collateral (SPC) flow was calculated as AAO - (SVC + tunnel). Heart rate (82 ± 18 to 81 ± 18 bpm; p = 0.31) and transcutaneous oxygen saturations (93 ± 4 to 94 ± 3 %; p = 0.13) did not change under NO inhalation. AAO flow (3.23 ± 0.72 to 3.12 ± 0.79 l/min/m(2); p = 0.08) decreased, tunnel flow (1.58 ± 0.40 to 1.65 ± 0.46 l/min/m(2); p = 0.032) increased, and SVC flow (1.01 ± 0.39 to 1.02 ± 0.40 l/min/m(2); p = 0.50) remained unchanged resulting in higher total caval flow (Qs) (2.59 ± 0.58 to 2.67 ± 0.68 l/min/m(2); p = 0.038). SPC flow decreased significantly from 0.64 ± 0.52 to 0.45 ± 0.51 l/min/m(2) (p = 0.002) and resulted in a significant decrement of the Qp/Qs ratio (1.23 ± 0.23 to 1.15 ± 0.23; p = 0.001). Inhalation of NO in Fontan patients results in significant changes in pulmonary and systemic blood flow. The reduction in SPC flow is accompanied by a net increase in effective systemic blood flow suggesting beneficial effects of pulmonary vasodilators on cardiac output, tissue perfusion and exercise capacity.
authors.affiliation: Pediatric Heart Center, Justus-Liebig-University of Giessen, Feulgenstr. 12, 35392, Giessen, Germany. heiner.latus@googlemail.com.
authors.forename: Heiner
authors.initials: H
authors.lastname: Latus
authors.affiliation: Pediatric Heart Center, Justus-Liebig-University of Giessen, Feulgenstr. 12, 35392, Giessen, Germany.
authors.forename: Bettina
authors.initials: B
authors.lastname: Gerstner
authors.affiliation: Pediatric Heart Center, Justus-Liebig-University of Giessen, Feulgenstr. 12, 35392, Giessen, Germany.
authors.forename: Gunter
authors.initials: G
authors.lastname: Kerst
authors.affiliation: Pediatric Heart Center, Justus-Liebig-University of Giessen, Feulgenstr. 12, 35392, Giessen, Germany.
authors.forename: Axel
authors.initials: A
authors.lastname: Moysich
authors.affiliation: Pediatric Heart Center, Justus-Liebig-University of Giessen, Feulgenstr. 12, 35392, Giessen, Germany.
authors.forename: Kerstin
authors.initials: K
authors.lastname: Gummel
authors.affiliation: Pediatric Heart Center, Justus-Liebig-University of Giessen, Feulgenstr. 12, 35392, Giessen, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Apitz
authors.affiliation: Pediatric Heart Center, Justus-Liebig-University of Giessen, Feulgenstr. 12, 35392, Giessen, Germany.
authors.forename: Juergen
authors.initials: J
authors.lastname: Bauer
authors.affiliation: Pediatric Heart Center, Justus-Liebig-University of Giessen, Feulgenstr. 12, 35392, Giessen, Germany.
authors.forename: Dietmar
authors.initials: D
authors.lastname: Schranz
mesh_terms: D000280:Administration, Inhalation; D000293:Adolescent; D000328:Adult; D001011:Aorta / Q000000981:diagnostic imaging; D001783:Blood Flow Velocity / Q000187:drug effects*; D002648:Child; D005260:Female; D018729:Fontan Procedure; D006330:Heart Defects, Congenital / Q000601:surgery*; D006339:Heart Rate / Q000187:drug effects; D006352:Heart Ventricles / Q000503:physiopathology; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine; D008297:Male; D009569:Nitric Oxide / Q000627:therapeutic use*; D011651:Pulmonary Artery / Q000000981:diagnostic imaging; D011652:Pulmonary Circulation / Q000187:drug effects*; D012039:Regional Blood Flow / Q000187:drug effects; D014683:Vena Cava, Superior / Q000000981:diagnostic imaging; D055815:Young Adult
chemical_list: D009569:Nitric Oxide
keywords: Cardiac magnetic resonance imaging; Flow measurement; Fontan procedure; Nitric oxide