TY - JOUR

T1 - New insights into the aspects of pulmonary diffusing capacity in Fontan patients

AU - Idorn, Lars

AU - Hanel, Birgitte

AU - Jensen, Annette S

AU - Juul, Klaus

AU - Reimers, Jesper I

AU - Nielsen, Kim G

AU - Søndergaard, Lars

PY - 2014/4

Y1 - 2014/4

N2 - BACKGROUND: Patients with a functionally univentricular heart, palliated a.m. Fontan, consequently have non-pulsatile pulmonary blood flow and are known to have a reduced pulmonary diffusing capacity. However, the cause of this reduction remains unclear. We aimed to assess the possible determinants in the aetiology of a reduced diffusing capacity and also to assess whether it could be increased. Furthermore, we aimed to search for predictors of a reduced diffusing capacity.MATERIAL AND METHODS: A total of 87 Fontan patients (mean age 16.3 ± 7.6 years) performed advanced pulmonary function tests and maximal cycle ergometer tests. A total of 10 Fontan patients and nine matched controls performed a supine pulmonary function test after a supine rest.RESULTS: In the sitting pulmonary function test, the mean z-scores were: diffusing capacity, 2.38 ± 1.20; pulmonary capillary blood volume, 2.04 ± 0.80; and alveolar capillary membrane diffusing capacity, 0.14 ± 0.84. In the supine compared with the sitting pulmonary function test, the diffusing capacity increased by 51.7 ± 11.9% in the Fontan group and by 23.3 ± 17.7% in the control group (p < 0.001); moreover, the pulmonary capillary blood volume increased by 48.3 ± 17.4% in the Fontan group and by 20.2 ± 13.9% in the control group (p = 0.001). In a multiple linear regression analysis including the explanatory variables of surgical data and exercise data at rest and peak exercise, the resting cardiac index was an independent predictor of the diffusing capacity (regression coefficient: 0.18, p < 0.001).CONCLUSIONS: The pulmonary diffusing capacity was reduced in Fontan patients because of a reduced pulmonary capillary blood volume, whereas the alveolar capillary membrane diffusing capacity was preserved. The diffusing capacity was highly increasable in Fontan patients compared with controls, and the resting cardiac index was an independent predictor of the diffusing capacity.

AB - BACKGROUND: Patients with a functionally univentricular heart, palliated a.m. Fontan, consequently have non-pulsatile pulmonary blood flow and are known to have a reduced pulmonary diffusing capacity. However, the cause of this reduction remains unclear. We aimed to assess the possible determinants in the aetiology of a reduced diffusing capacity and also to assess whether it could be increased. Furthermore, we aimed to search for predictors of a reduced diffusing capacity.MATERIAL AND METHODS: A total of 87 Fontan patients (mean age 16.3 ± 7.6 years) performed advanced pulmonary function tests and maximal cycle ergometer tests. A total of 10 Fontan patients and nine matched controls performed a supine pulmonary function test after a supine rest.RESULTS: In the sitting pulmonary function test, the mean z-scores were: diffusing capacity, 2.38 ± 1.20; pulmonary capillary blood volume, 2.04 ± 0.80; and alveolar capillary membrane diffusing capacity, 0.14 ± 0.84. In the supine compared with the sitting pulmonary function test, the diffusing capacity increased by 51.7 ± 11.9% in the Fontan group and by 23.3 ± 17.7% in the control group (p < 0.001); moreover, the pulmonary capillary blood volume increased by 48.3 ± 17.4% in the Fontan group and by 20.2 ± 13.9% in the control group (p = 0.001). In a multiple linear regression analysis including the explanatory variables of surgical data and exercise data at rest and peak exercise, the resting cardiac index was an independent predictor of the diffusing capacity (regression coefficient: 0.18, p < 0.001).CONCLUSIONS: The pulmonary diffusing capacity was reduced in Fontan patients because of a reduced pulmonary capillary blood volume, whereas the alveolar capillary membrane diffusing capacity was preserved. The diffusing capacity was highly increasable in Fontan patients compared with controls, and the resting cardiac index was an independent predictor of the diffusing capacity.

KW - Adolescent

KW - Adult

KW - Case-Control Studies

KW - Child

KW - Exercise Test

KW - Female

KW - Fontan Procedure

KW - Heart Defects, Congenital

KW - Humans

KW - Linear Models

KW - Male

KW - Posture

KW - Pulmonary Diffusing Capacity

KW - Respiratory Function Tests

KW - Supine Position

KW - Young Adult

U2 - 10.1017/S1047951113000358

DO - 10.1017/S1047951113000358

M3 - Journal article

C2 - 23552344

VL - 24

SP - 311

EP - 320

JO - Cardiology in the Young

JF - Cardiology in the Young

SN - 1047-9511

IS - 2

ER -