Patients with Fontan circulation and a restrictive spirometric pattern had lower overall exercise capacity (11.5 vs 13.6 METs, p=0.044) and VO2 peak (25.7 vs 30.7 ml/min/kg, p=0.048).
Observational (n=66)
No
Does a restrictive spirometric pattern at rest impair ventilatory response and exercise capacity in patients with Fontan circulation?
In patients with Fontan circulation, a restrictive spirometric pattern is common and significantly impairs aerobic and overall exercise capacity due to an inability to adequately increase tidal volume during exercise.
Absolute Event Rate: 11.5% vs 13.6%
p-value: p=0.044
Abstract Background In patients with Fontan circulation, pulmonary blood flow is maintained by passive venous return; hence, ventilatory movements and skeletal muscles are essential for augmenting pulmonary perfusion during exercise. However, restrictive ventilatory patterns and impaired pulmonary function are frequently observed, contributing to exercise intolerance. Purpose To compare ventilatory response during exercise in patients undergoing Fontan procedure with or without restrictive spirometric pattern at rest. Methods This observational, single-centre study included patients with Fontan circulation referred for spirometry and maximal cardiopulmonary exercise testing. Results 66 patients were included (mean age 25.5±11.6 years, 63.6% males, BMI 20.9±3.8 kg/m2). 65.2% had left and 34.8% had right systemic ventricle (mean ejection fraction 58.2±8.7%, mean fractional area change 40.4±6.9%). 37.9% of patients had normal and 62.1% had a restrictive spirometry (forced vital capacity 80% of predicted). No significant differences were observed between patients with normal and restrictive spirometry in terms of age and BMI, as well as peripheral oxygen saturation (SpO2) at rest (97% vs 96%, respectively) and at peak exercise (92% vs 90%), VE/VCO2 slope (34.9 vs 35.4), peak heart rate as % of predicted (84.6% vs 81.0%), and O2 pulse ad % of predicted (92% vs 76%). Patients with restrictive spirometry had lower overall exercise capacity (11.5 vs 13.6 METs, p=0.044), VO2 peak (25.7 vs 30.7 ml/min/kg, p=0.048; 64% vs 75% of predicted, p=0.034), and peak ventilation (63 vs 80 l/min, p=0.040). Significant differences emerged for tidal volume (Vt) at both at first and second ventilatory thresholds (VT), in particular: 1.1 vs 1.3 l at VT1 (p=0.042), and 1.4 vs 1.7 l at VT2 (p=0.013), but not for VO2 (ml/min/kg), ventilation and breathing frequency. Additionally, at VT1, patients with restrictive spirometry had lower breathing reserve (63 vs 70%, p=0.002) and higher VO2 as % of their VO2peak (65% vs 61%, p=0.043). Conclusion A certain degree of ventilatory inefficiency was common in our population, accounting for higher ventilatory demands during exercise. Nonetheless, almost 2 out of 3 patients had a restrictive spirometry, resulting in a ventilatory limitation due to an inability to adequately increase Vt during exercise, with a significant impact on aerobic and overall exercise capacity. These findings underline the importance of comprehensive cardiopulmonary assessment in order to identify the specific source of functional limitation, as well as targeted rehabilitation and physical exercise strategies to optimize functional outcomes in this population.VO2 and exercise ventilatory responseFor image description, please refer to the figure legend and surrounding text.
Scettri et al. (Mon,) conducted a observational in Fontan circulation (n=66). Restrictive spirometric pattern vs. Normal spirometric pattern was evaluated on Overall exercise capacity (METs) (p=0.044). Patients with Fontan circulation and a restrictive spirometric pattern had lower overall exercise capacity (11.5 vs 13.6 METs, p=0.044) and VO2 peak (25.7 vs 30.7 ml/min/kg, p=0.048).