Comparative Analysis of Respiratory and Functional Outcomes in Children Post-Fontan Procedure Versus Healthy Peers.

Studies have shown that respiratory muscle training enhances functional capacity and pulmonary function in Fontan patients. However, diaphragm muscle characteristics in Fontan children have not been fully elucidated. The aim of this study was to compare respiratory function, maximal and submaximal functional capacities, and quality of life, as well as to assess diaphragm mobility and thickness, between Fontan patients aged 8 to 12 years and healthy individuals. This cross-sectional study included 45 children-27 Fontan patients, Fontan Group (FG) and 18 healthy control Group (CG) subjects. Different examinations were performed: spirometry was used to analyze pulmonary volume and capacity; manovacuometry was used to determine respiratory muscle strength; chest ultrasound was used to determine diaphragm muscle characteristics; cardiopulmonary exercise and the six-minute walk test (6MWT) were used to determine functional capacity; the AUQEI questionnaire was used to determine quality of life. Descriptive analysis and intergroup comparisons were performed for all the data. Compared with the CG, the FG exhibited impaired pulmonary function and reduced functional capacity. Significant differences in median values were noted for forced expiratory volume in one second (FEV1): 2.39 L/min, p = 0.002; forced vital capacity (FVC): 1.73 vs. 3.06 L/min, p = 0.002; maximal inspiratory pressure: - 73 vs. - 117 cmH2O, p = 0.007; absolute peak VO2: 1.09 vs. 1.51 L/min, p < 0.001; relative peak VO2: 31.9 vs. 42.5 mL/kg/min, p = 0.003; and 6MWT distance: 420 vs. 586 m, p < 0.001. Diaphragmatic thickness, mobility and quality of life were similar between the groups. Despite the reduced functional capacity, impaired pulmonary volume and capacity, and respiratory muscle weakness of the FG compared to those of the CG, the diaphragm characteristics and quality of life were similar between the groups.

Efeitos de Longo Prazo do Implante Valvar Pulmonar e Evolução da Prótese em Pacientes com Tetralogia de Fallot Corrigida / Long-Term Effects of Pulmonary Valve Implantation and Prosthesis Evolution in Patients with Repaired Tetralogy of Fallot

Resumo Fundamento A regurgitação valvar pulmonar é uma importante complicação de longo prazo em pacientes com tetralogia de Fallot (TF). Objetivo O presente estudo tem como objetivo investigar os efeitos do implante valvar pulmonar (IVP) na anatomia e função do ventrículo direito (VD) e na evolução em longo prazo da prótese implantada em posição pulmonar. Métodos Uma análise de coorte retrospectiva e unicêntrica foi realizada em 56 pacientes consecutivos com TF submetidos a IVP. O estudo incluiu pacientes de ambos os gêneros, com idade ≥ 12 anos e compreendeu avaliação de dados clínicos e cirúrgicos, ressonância magnética cardiovascular pré e pós-operatória e dados ecocardiográficos obtidos mais de 1 ano após IVP. Resultados Após o IVP, houve uma diminuição significativa do volume sistólico final do VD indexado pela área de superfície corpórea (ASC), de 89 mL/ASC para 69 mL/ASC (p < 0,001) e do volume diastólico final indexado do VD, de 157 mL/ASC para 116 mL/ASC (p < 0,001). Além disso, houve aumento da fração de ejeção corrigida do VD [ FEVDc = fluxo pulmonar ajustado (fluxo pulmonar anterógrado − fluxo regurgitante) / volume diastólico final do VD ] de 23% para 35% (p < 0,001) e da fração de ejeção do ventrículo esquerdo de 58% para 60% (p = 0,008). No entanto, foi observado um aumento progressivo no gradiente de pico da válvula pulmonar ao longo do tempo, com 25% dos pacientes apresentando um gradiente superior a 60 mmHg. Próteses menores (tamanhos 19 a 23) foram associadas a um risco 4,3 vezes maior de gradiente > 60 mmHg em comparação com próteses maiores (tamanhos 25 a 27; p = 0,029; intervalo de confiança: 1,18 a 17,8). Conclusão Conforme esperado, o IVP demonstrou melhorias nos volumes e na função do VD. O acompanhamento e a vigilância a longo prazo são cruciais para avaliar a durabilidade da prótese e detectar potenciais complicações. O dimensionamento adequado das próteses é essencial para melhorar a longevidade da prótese.

Abstract Background Pulmonary valve regurgitation is a significant long-term complication in patients with tetralogy of Fallot (TOF). Objective This study aims to investigate the effects of pulmonary valve implantation (PVI) on the anatomy and function of the right ventricle (RV) and the long-term evolution of the implanted prosthesis in the pulmonary position. Methods A single-center retrospective cohort analysis was performed in 56 consecutive patients with TOF who underwent PVI. The study included patients of both sexes, aged ≥ 12 years, and involved assessing clinical and surgical data, pre- and post-operative cardiovascular magnetic resonance imaging, and echocardiogram data more than 1 year after PVI. Results After PVI, there was a significant decrease in RV end-systolic volume indexed by body surface area (BSA), from 89 mL/BSA to 69 mL/BSA (p < 0.001) and indexed RV end-diastolic volume, from 157 mL/BSA to 116 mL/BSA (p < 0.001). Moreover, there was an increase in corrected RV ejection fraction [ RVEFC = net pulmonary flow (pulmonary forward flow − regurgitant flow) / R V end-diastolic volume] from 23% to 35% (p < 0.001) and left ventricular ejection fraction from 58% to 60% (p = 0.008). However, a progressive increase in the peak pulmonary valve gradient was observed over time, with 25% of patients experiencing a gradient exceeding 60 mmHg. Smaller prostheses (sizes 19 to 23) were associated with a 4.3-fold higher risk of a gradient > 60 mmHg compared to larger prostheses (sizes 25 to 27; p = 0.029; confidence interval: 1.18 to 17.8). Conclusion As expected, PVI demonstrated improvements in RV volumes and function. Long-term follow-up and surveillance are crucial for assessing the durability of the prosthesis and detecting potential complications. Proper sizing of prostheses is essential for improved prosthesis longevity.

Blunted peripheral blood supply and underdeveloped skeletal muscle in Fontan patients: The impact on functional capacity.

BACKGROUND: Changes in circulatory physiology are common in Fontan patients due to suboptimal cardiac output, which may reduce the peripheral blood flow and impair the skeletal muscle. The objective of this study was to investigate the forearm blood flow (FBF), cross-sectional area (CSA) of the thigh and functional capacity in asymptomatic clinically stable patients undergoing Fontan surgery. METHODS: Thirty Fontan patients and 27 healthy subjects underwent venous occlusion plethysmography, magnetic resonance imaging of the thigh musculature and maximal cardiopulmonary exercise testing. Muscle sympathetic nerve activity (MSNA), norepinephrine measures, cardiovascular magnetic resonance, handgrip strength and 6-minute walk test were also performed. RESULTS: Fontan patients have blunted FBF (1.59 ±â€¯0.33 vs 2.17 ±â€¯0.52 mL/min/100 mL p < 0.001) and forearm vascular conductance (FVC) (1.69 ±â€¯0.04 vs 2.34 ±â€¯0.62 units p < 0.001), reduced CSA of the thigh (81.2 ±â€¯18.6 vs 116.3 ±â€¯26.4 cm2p < 0.001), lower peak VO2 (29.3 ±â€¯6 vs 41.5 ±â€¯9 mL/kg/min p < 0.001), walked distance (607 ±â€¯60 vs 701 ±â€¯58 m p < 0.001) and handgrip strength (21 ±â€¯9 vs 30 ±â€¯8 kgf p < 0.001). The MSNA (30 ±â€¯4 vs 22 ±â€¯3 bursts/min p < 0.001) and norepinephrine concentration [265 (236-344) vs 222 (147-262) pg/mL p = 0.006] were also higher in Fontan patients. Multivariate linear regression showed FVC (ß = 0.653; CI = 0.102-1.205; p = 0.022) and stroke volume (ß = 0.018; CI = 0.007-0.029; p = 0.002) to be independently associated with reduced CSA of the thigh adjusted for body mass index. The CSA of the thigh adjusted for body mass index (ß = 5.283; CI = 2.254-8.312; p = 0.001) was independently associated with reduced peak VO2. CONCLUSION: Patients with Fontan operation have underdeveloped skeletal muscle with reduced strength that is associated with suboptimal peripheral blood supply and diminished exercise capacity.