Non-cardiac determinants of impaired aerobic capacity in adult congenital heart disease (ACHD)

<bold>Introduction:</bold> Patients with congenital heart disease (CHD) undergo open surgical repair (OSR) to improve survival. Breathlessness is a common symptom in adults with CHD (ACHD). OSR has been previously associated with impaired breathing mechanics and restrictive spirometry (RS). The impact of OSR on exercise capacity is not widely described. The aim of this study is to establish the association between OSR, RS and peak VO2 in ACHD patients. <bold>Methods:</bold> Spirometry and CPET data from 75 ACHD patients were reviewed. OSR type was collected from patients clinic letters. RS was defined as a forced vital capacity (FVC) standardised residual (SR) <-1.64 and abnormal peak VO2 was defined as <80% predicted value. Pearson chi-square explored associations between OSR, RS and peak VO2. <bold>Results:</bold> Patient demographics are shown in Table 1. In total 73% had OSR, 37% RS and 71% an abnormal peak VO2. There was a statistically significant association between OSR and abnormal peak VO2 (χ(1) = 5.62, p = 0.018); RS and abnormal peak VO2 (χ(1) = 10.01, p = 0.001). Only 25% of those who had OSR had RS, with no statistically significant association (χ(1) = 0.63, p = 0.428). <table-wrap><object-id>erj;64/suppl_68/PA1453/TB1</object-id><object-id>T1</object-id><object-id>TB1</object-id><table><colgroup><col></col><col></col></colgroup><tbody><tr><td>Demographics</td><td>N=75</td></tr><tr><td>Sex (m;%)</td><td>63</td></tr><tr><td>Age (years)</td><td>32 (23-48)</td></tr><tr><td>BMI (kg/m²)</td><td>27 (23-32)</td></tr><tr><td>Beta-Blockers (%)</td><td>25</td></tr><tr><td>FVC (SR)</td><td>-1.3 (−2.04 - -0.17)</td></tr><tr><td>Peak VO2 (%pred)</td><td>71 (59-88)</td></tr></tbody></table></table-wrap> ^{<bold>Table 1. Data expressed as medians with 25-75% quartiles and percentages</bold>} <bold>Conclusions:</bold> An abnormal peak VO2 is positively associated with OSR, RS or both and therefore should be considered determinants of reduced aerobic capacity and functional status in ACHD.