TY - JOUR

T1 - Flow during exercise in the total cavopulmonary connection measured by magnetic resonance velocity mapping

AU - Pedersen, E M

AU - Stenbøg, E V

AU - Fründ, T

AU - Houlind, K

AU - Kromann, O

AU - Sørensen, K E

AU - Emmertsen, K

AU - Hjortdal, V E

PY - 2002/6

Y1 - 2002/6

N2 - OBJECTIVE: To measure caval and pulmonary flows at rest and immediately after exercise in patients with total cavopulmonary connection (TCPC).DESIGN: An observational study using the patients as their own controls.SETTING: Using a combination of magnetic resonance (MR) phase contrast techniques and an MR compatible bicycle ergometer, blood flow was measured in the superior vena cava, the tunnel from the inferior vena cava, and in the left and right pulmonary arteries during rest and on exercise (0.5 W/kg and 1.0 W/kg).PATIENTS: Eleven patients aged 11.4 (4.6) years (mean (SD)) were studied 6.3 (3.8) years after TCPC operation.MAIN OUTCOME MEASURES: Volume flow measured in all four branches of the TCPC connection during rest and exercise.RESULTS: Systemic venous return (inferior vena cava plus superior vena cava) increased from 2.5 (0.1) l/min/m2 (mean (SEM)) to 4.4 (0.4) l/min/m2 (p < 0.05) during exercise, with even distribution to the two pulmonary arteries. At rest, inferior vena caval flow was higher than superior vena caval flow, at 1.4 (0.1) v 1.1 (0.1) l/min/m2 (p < 0.05). During exercise, inferior vena caval flow doubled (to 3.0 (0.3) l/min/m2) while superior vena caval flow only increased slightly (to 1.4 (0.1) l/min/m2) (p < 0.05). The increased blood flow mainly reflected an increase in heart rate. The inferior vena caval to superior vena caval flow ratio was 1.4 (0.1) at rest and increased to 1.8 (0.1) (p < 0.05) at 0.5 W/kg, and to 2.2 (0.2) at 1.0 W/kg (p < 0.05).CONCLUSIONS: Quantitative flow measurements can be performed immediately after exercise using MR techniques. Supine leg exercise resulted in a more than twofold increase in inferior vena caval flow. This was equally distributed to the two lungs, indicating that pulmonary resistance rather than geometry decides flow distribution in the TCPC circulation.

AB - OBJECTIVE: To measure caval and pulmonary flows at rest and immediately after exercise in patients with total cavopulmonary connection (TCPC).DESIGN: An observational study using the patients as their own controls.SETTING: Using a combination of magnetic resonance (MR) phase contrast techniques and an MR compatible bicycle ergometer, blood flow was measured in the superior vena cava, the tunnel from the inferior vena cava, and in the left and right pulmonary arteries during rest and on exercise (0.5 W/kg and 1.0 W/kg).PATIENTS: Eleven patients aged 11.4 (4.6) years (mean (SD)) were studied 6.3 (3.8) years after TCPC operation.MAIN OUTCOME MEASURES: Volume flow measured in all four branches of the TCPC connection during rest and exercise.RESULTS: Systemic venous return (inferior vena cava plus superior vena cava) increased from 2.5 (0.1) l/min/m2 (mean (SEM)) to 4.4 (0.4) l/min/m2 (p < 0.05) during exercise, with even distribution to the two pulmonary arteries. At rest, inferior vena caval flow was higher than superior vena caval flow, at 1.4 (0.1) v 1.1 (0.1) l/min/m2 (p < 0.05). During exercise, inferior vena caval flow doubled (to 3.0 (0.3) l/min/m2) while superior vena caval flow only increased slightly (to 1.4 (0.1) l/min/m2) (p < 0.05). The increased blood flow mainly reflected an increase in heart rate. The inferior vena caval to superior vena caval flow ratio was 1.4 (0.1) at rest and increased to 1.8 (0.1) (p < 0.05) at 0.5 W/kg, and to 2.2 (0.2) at 1.0 W/kg (p < 0.05).CONCLUSIONS: Quantitative flow measurements can be performed immediately after exercise using MR techniques. Supine leg exercise resulted in a more than twofold increase in inferior vena caval flow. This was equally distributed to the two lungs, indicating that pulmonary resistance rather than geometry decides flow distribution in the TCPC circulation.

KW - Blood Flow Velocity

KW - Child

KW - Exercise/physiology

KW - Female

KW - Fontan Procedure/methods

KW - Heart Defects, Congenital/physiopathology

KW - Heart Rate/physiology

KW - Humans

KW - Magnetic Resonance Angiography/methods

KW - Male

KW - Postoperative Care

KW - Pulmonary Artery/physiology

KW - Pulmonary Circulation/physiology

KW - Stroke Volume/physiology

KW - Vena Cava, Inferior/physiology

KW - Vena Cava, Superior/physiology

U2 - 10.1136/heart.87.6.554

DO - 10.1136/heart.87.6.554

M3 - Journal article

C2 - 12010939

VL - 87

SP - 554

EP - 558

JO - Heart

JF - Heart

SN - 1355-6037

IS - 6

ER -