TY - JOUR

T1 - Caval blood flow during supine exercise in normal and Fontan patients

AU - Hjortdal, Vibeke E

AU - Christensen, Thomas D

AU - Larsen, Signe H

AU - Emmertsen, Kristian

AU - Pedersen, Erik M

PY - 2008/2

Y1 - 2008/2

N2 - BACKGROUND: Extracardiac total cavo-pulmonary connection (TCPC) bypasses the right atrium and has in theory better hemodynamics than intraatrial TCPC repair. Both are thought to have inferior hemodynamics compared with a normal circulation. Direct comparison of flow rates at rest and during exercise with magnetic resonance imaging technique have not been performed.METHODS: The study comprised 20 children. Six children (median age, 9.3 years; interquartile range, 2.2) had undergone extracardiac TCPC. Eight children (median age, 8.9 years; interquartile range, 5.0) had an intraatrial TCPC, and 6 children (median age, 10.3 years; interquartile range, 2.6) were healthy control subjects. Blood flows in the aorta, inferior vena cava, and superior vena cava were measured at rest and during two levels of submaximal supine bicycle exercise (0.5 W/kg and 1.0 W/kg) using a magnetic resonance imaging scanner mounted with a bicycle.RESULTS: Heart rate, respiratory rate, inspiratory fraction, and blood flow rates in the aorta and inferior vena cava increased equally in all three groups. If patients were grouped together, flow rates were significantly lower, and the inspiratory flow fraction in the inferior vena cava was significantly higher, than in control subjects. Retrograde flows were observed in all three groups at rest but tapered off with exercise.CONCLUSIONS: At submaximal levels of lower limb exercise, patients with extracardiac as well as intraatrial TCPC showed a similar increase in respiration, heart rate, and aortic and caval flow rates as healthy control subjects. This is in accordance with the observation that many patients with TCPC perform well during daily life activities.

AB - BACKGROUND: Extracardiac total cavo-pulmonary connection (TCPC) bypasses the right atrium and has in theory better hemodynamics than intraatrial TCPC repair. Both are thought to have inferior hemodynamics compared with a normal circulation. Direct comparison of flow rates at rest and during exercise with magnetic resonance imaging technique have not been performed.METHODS: The study comprised 20 children. Six children (median age, 9.3 years; interquartile range, 2.2) had undergone extracardiac TCPC. Eight children (median age, 8.9 years; interquartile range, 5.0) had an intraatrial TCPC, and 6 children (median age, 10.3 years; interquartile range, 2.6) were healthy control subjects. Blood flows in the aorta, inferior vena cava, and superior vena cava were measured at rest and during two levels of submaximal supine bicycle exercise (0.5 W/kg and 1.0 W/kg) using a magnetic resonance imaging scanner mounted with a bicycle.RESULTS: Heart rate, respiratory rate, inspiratory fraction, and blood flow rates in the aorta and inferior vena cava increased equally in all three groups. If patients were grouped together, flow rates were significantly lower, and the inspiratory flow fraction in the inferior vena cava was significantly higher, than in control subjects. Retrograde flows were observed in all three groups at rest but tapered off with exercise.CONCLUSIONS: At submaximal levels of lower limb exercise, patients with extracardiac as well as intraatrial TCPC showed a similar increase in respiration, heart rate, and aortic and caval flow rates as healthy control subjects. This is in accordance with the observation that many patients with TCPC perform well during daily life activities.

KW - Blood Flow Velocity

KW - Case-Control Studies

KW - Child

KW - Child, Preschool

KW - Exercise/physiology

KW - Female

KW - Follow-Up Studies

KW - Fontan Procedure/methods

KW - Heart Bypass, Right/methods

KW - Heart Defects, Congenital/diagnosis

KW - Heart Rate

KW - Hemodynamics/physiology

KW - Humans

KW - Male

KW - Probability

KW - Pulmonary Artery/physiology

KW - Respiration

KW - Risk Assessment

KW - Statistics, Nonparametric

KW - Supine Position

KW - Treatment Outcome

U2 - 10.1016/j.athoracsur.2007.08.062

DO - 10.1016/j.athoracsur.2007.08.062

M3 - Journal article

C2 - 18222273

VL - 85

SP - 599

EP - 603

JO - The Annals of Thoracic Surgery

JF - The Annals of Thoracic Surgery

SN - 0003-4975

IS - 2

ER -