Impaired Pulmonary Function is an Additional Potential Mechanism for the Reduction of Functional Capacity in Clinically Stable Fontan Patients

Abstract

Central factors negatively affect the functional capacity of Fontan patients (FP), but "non-cardiac" factors, such as pulmonary function, may contribute to their exercise intolerance. We studied the pulmonary function in asymptomatic FP and its correlations with their functional capacity. Pulmonary function and cardiopulmonary exercise tests were performed in a prospective study of 27 FP and 27 healthy controls (HC). Cardiovascular magnetic resonance was used to evaluate the Fontan circulation. The mean age at tests, the mean age at surgery, and the median follow-up time of FP were 20(±6), 8(±3), and 11(8-17) years, respectively. Dominant ventricle ejection fraction was within normal range. The mean of peak VO expressed in absolute values (L/min), the relative values to body weight (mL/kg/min), and their predicted values were lower in FP compared with HC: 1.69 (±0.56) vs 2.81 (±0.77) L/min; 29.9 (±6.1) vs 41.5 (±9.3) mL/kg/min p < 0.001 and predicted VO Peak [71% (±14) vs 100% (±20) p < 0.001]. The absolute and predicted values of the forced vital capacity (FVC), forced expiratory volume in one second (FEV), inspiratory capacity (IC), total lung capacity (TLC), diffusion capacity of carbon monoxide of the lung (DLCO), maximum inspiratory pressure (MIP), and sniff nasal inspiratory pressure (SNIP) were also significantly lower in the Fontan population compared to HC. An increased risk of restrictive ventilatory pattern was found in patients with postural deviations (OD:10.0, IC:1.02-97.5, p = 0.042). There was a strong correlation between pulmonary function and absolute peak VO [FVC (r = 0.86, p < 0.001); FEV (r = 0.83, p < 0.001); IC (r = 0.84, p < 0.001); TLC (r = 0.79, p < 0.001); and DLCO (r = 0.72, p < 0.001). The strength of the inspiratory muscles in absolute and predicted values was also reduced in FP [-79(±28) vs -109(±44) cmHO (p = 0.004) and 67(±26) vs 89(±36) % (p = 0.016)]. Thus, we concluded that the pulmonary function was impaired in clinically stable Fontan patients and the static and dynamic lung volumes were significantly reduced compared with HC. We also demonstrated a strong correlation between absolute Peak VO with the FVC, FEV, TLC, and DLCO measured by complete pulmonary test.

Analysis of cavopulmonary and cardiac flow characteristics in fontan Patients: Comparison with healthy volunteers

“…Further, reductions in IVC and SVC KE over time may be an indication of pathological pulmonary vascular remodeling and rising pulmonary vascular resistance, which is a complication of the Fontan physiology . The Fontan circulation is uniquely vulnerable to unfavorable lung mechanics and abnormal pulmonary function is highly prevalent in this population . MR quantification of cavopulmonary flow may provide an additional tool to evaluate the complex cardiopulmonary interplay in this distinctive physiology.…”

“…24 The Fontan circulation is uniquely vulnerable to unfavorable lung mechanics and abnormal pulmonary function is highly prevalent in this population. 25,26 MR quantification of cavopulmonary flow may provide an additional tool to evaluate the complex cardiopulmonary interplay in this distinctive physiology.…”

Impaired lung function in children and adolescents with Fontan circulation may improve after endurance training

“…Turquetto et al(103) have also reported restrictive lung physiology, reduced diffusing capacity, and an association between lung function and exercise capacity in these patients. A multi-center study byOpotowsky et al (32) also showed the association between impaired lung function and exercise capacity.…”

“…This could be a result of several surgical procedures that leads to a restrictive lung physiology and non-ventilated lung sections peripherally. Ohuchi et al (36) and Turquetto et al (103) both suggest that the restrictive physiology and air trapping may limit exercise performance in these patients.…”

Physical activity and heart rate monitoring in Fontan patients – Should we recommend activities in higher intensities?

“…Previous studies, investigating exercise capacity showed a relevant impairment with approximately 60% of _ V O 2peak in patients after Fontan palliation compared to age-matched healthy subjects [2][3][4]. Besides cardiac function, including chronotropic incompetence, other causes of this impairment (such as lung function, skeletal muscle, and endothelial dysfunction) remain undefined [5][6][7][8].…”